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  • Astaxanthin accumulation difference between non-motile cells and akinetes of Haematococcus pluvialis was affected by pyruvate metabolism
    Bioresour. Bioprocess. (IF 0) Pub Date : 2020-01-24
    Lei Fang, Jingkui Zhang, Zhongnan Fei, Minxi Wan

    Abstract Background Haematococcus pluvialis is the best source of natural astaxanthin, known as the king of antioxidants. H. pluvialis have four cell forms: spore, motile cell, non-motile cell and akinete. Spores and motile cells are susceptible to photoinhibition and would die under photoinduction conditions. Photoinduction using non-motile cells as seeds could result in a higher astaxanthin production than that using akinetes. However, the mechanism of this phenomenon has not been clarified. Results Transcriptome was sequenced and annotated to illustrate the mechanism of this phenomenon. All differentially expressed genes involved in astaxanthin biosynthesis were up-regulated. Particularly, chyb gene was up-regulated by 16-fold, improving the conversion of β-carotene into astaxanthin. Pyruvate was the precursor of carotenoids biosynthesis. Pyruvate kinase gene expression level was increased by 2.0-fold at the early stage of akinetes formation. More changes of gene transcription occurred at the early stage of akinetes formation, 52.7% and 51.9% of total DEGs in control group and treatment group, respectively. Conclusions Genes transcription network was constructed and the synthesis mechanism of astaxanthin was clarified. The results are expected to further guide the in-depth optimization of the astaxanthin production process in H. pluvialis by improving pyruvate metabolism.

  • A sustainable process for biodiesel production using Zn/Mg oxidic species as active, selective and reusable heterogeneous catalysts
    Bioresour. Bioprocess. (IF 0) Pub Date : 2020-01-08
    Marisa B. Navas, José F. Ruggera, Ileana D. Lick, Mónica L. Casella

    Abstract This paper describes the preparation and characterization of MgO and ZnO-based catalysts, pure and mixed in different proportions, supported on γ-Al2O3. Their catalytic performance was studied in the transesterification of soybean oil and castor oil with methanol and butanol, attempting to produce biodiesel. XRD (X-ray diffraction), SEM–EDS (scanning electron microscopy–energy dispersive X-ray spectroscopy), CO2-adsorption and N2-adsorption allowed characterizing the prepared catalysts. The characterization results were in all cases consistent with mesoporous solids with high specific surface area. All the catalysts exhibited good results, especially in the transesterification of castor oil using butanol. For this reaction, the reuse was tested, maintaining high FABE (fatty acid butyl esters) yields after four cycles. This good performance can be attributed to the basic properties of the Mg species, and simultaneously, to the amphoteric properties of ZnO, which allow both triglycerides and free fatty acids to be converted into esters. Using these catalysts, it is possible to obtain second-generation biodiesel, employing castor oil, a raw material that does not compete with the food industry. In addition, butanol can be produced from renewable biomass.

  • Preparation of injectable hydrogel with near-infrared light response and photo-controlled drug release
    Bioresour. Bioprocess. (IF 0) Pub Date : 2020-01-03
    Jianbo Zhao, Xingxing Liang, Hui Cao, Tianwei Tan


  • Selection and screening strategies in directed evolution to improve protein stability
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-12-27
    Chang Ren, Xin Wen, Jun Mencius, Shu Quan

    Protein stability is not only fundamental for experimental, industrial, and therapeutic applications, but is also the baseline for evolving novel protein functions. For decades, stability engineering armed with directed evolution has continued its rapid development and inevitably poses challenges. Generally, in directed evolution, establishing a reliable link between a genotype and any interpretable phenotype is more challenging than diversifying genetic libraries. Consequently, we set forth in a small picture to emphasize the screening or selection techniques in protein stability-directed evolution to secure the link. For a more systematic review, two main branches of these techniques, namely cellular or cell-free display and stability biosensors, are expounded with informative examples.

  • Chlorophyll as key indicator to evaluate astaxanthin accumulation ability of Haematococcus pluvialis
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-12-19
    Lei Fang, Jingkui Zhang, Zhongnan Fei, Minxi Wan

    Natural astaxanthin is mainly derived from Haematococcus pluvialis. In the photoinduction phase, astaxanthin accumulation ability can be significantly affected by the characteristics of H. pluvialis cells in the proliferation phase. Based on sequential heterotrophy–dilution–photoinduction (SHDP) technology, the authors’ previous study showed that high astaxanthin accumulation ability is accompanied by high chlorophyll content of H. pluvialis heterotrophic cell; whereas the mechanism of this result remained largely obscure. Therefore, transcriptome analysis was conducted to explain this mechanism.

  • The effect of methane and odd-chain fatty acids on 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) synthesis by a Methylosinus -dominated mixed culture
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-12-17
    Pawarisa Luangthongkam, Peter James Strong, Syarifah Nuraqmar Syed Mahamud, Paul Evans, Paul Jensen, Gene Tyson, Bronwyn Laycock, Paul Andrew Lant, Steven Pratt


  • 更新日期:2019-12-18
  • 更新日期:2019-11-30
  • Bioleaching of heavy metals from printed circuit board (PCB) by Streptomyces albidoflavus TN10 isolated from insect nest
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-11-30
    Dhanalashmi Kaliyaraj, Menaka Rajendran, Vignesh Angamuthu, Annam Renita Antony, Manigundan Kaari, Shanmugasundaram Thangavel, Gopikrishnan Venugopal, Jerrine Joseph, Radhakrishnan Manikkam

    E-waste management is extremely difficult to exercise owing to its complexity and hazardous nature. Printed circuit boards (PCBs) are the core components of electrical and electronic equipment, which generally consist of polymers, ceramics, and heavy metals.

  • Response surface optimization of biodiesel yield from pre-treated waste oil of rendered pork from a food processing industry
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-11-30
    Arjun C. Gumahin, Jounnever M. Galamiton, Meljane J. Allerite, Rohoney S. Valmorida, Jay-R L. Laranang, Val Irvin F. Mabayo, Renato O. Arazo, Alexander L. Ido


  • Enzyme-catalyzed C–F bond formation and cleavage
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-11-22
    Wei Tong, Qun Huang, Min Li, Jian-bo Wang

    Organofluorines are widely used in a variety of applications, ranging from pharmaceuticals to pesticides and advanced materials. The widespread use of organofluorines also leads to its accumulation in the environment, and two major questions arise: how to synthesize and how to degrade this type of compound effectively? In contrast to a considerable number of easy-access chemical methods, milder and more effective enzymatic methods remain to be developed. In this review, we present recent progress on enzyme-catalyzed C–F bond formation and cleavage, focused on describing C–F bond formation enabled by fluorinase and C–F bond cleavage catalyzed by oxidase, reductase, deaminase, and dehalogenase.

  • Preparation and characterization of cellulose nanocrystal extracted from Calotropis procera biomass
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-11-22
    Kaili Song, Xiaoji Zhu, Weiming Zhu, Xiaoyan Li


  • Thermo-Catalytic Reforming of spent coffee grounds
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-11-21
    Mohamed Elmously, Nils Jäger, Andreas Apfelbacher, Robert Daschner, Andreas Hornung


  • 更新日期:2019-11-28
  • Preparation and purification of novel phosphatidyl prodrug and performance modulation of phosphatidyl nanoprodrug
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-11-01
    Rui Niu, PeiLei Zhang, Feng-Qing Wang, Min Liu, QingHai Liu, Ning Jia, ShengLi Yang, XinYi Tao, DongZhi Wei

    A novel phosphatidyl nanoprodrug system can be selectively released parent drugs in cancer cells, triggered by the local overexpression of phospholipase D (PLD). This system significantly reduces the intrinsic disadvantages of conventional chemotherapeutic drugs. However, the separation and purification processes of phosphatidyl prodrug, the precursor of phosphatidyl nanoprodrug, have not been established, and the preparation of nanocrystals with good stability and tumor-targeting capability is still challenging.

  • Production of biodiesel by enzymatic transesterification of non-edible Salvadora persica (Pilu) oil and crude coconut oil in a solvent-free system
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-10-23
    Azeem Abdul Aziz Budhwani, Ayesha Maqbool, Tanveer Hussain, Muhammad Noman Syed

    It is becoming imperative to develop renewable fuels such as biodiesel which are sustainable and environmentally friendly. Exploiting non-edible oils is more necessary to reduce dependency of edible oils for biodiesel production. The current study investigated biodiesel production from non-edible Salvadora persica seed oil (SPSO) and crude coconut oil (CCO) by Burkholderia cepacia lipase acting as a biocatalyst in a solvent-free system. The biodiesel yield produced from these feedstocks was compared and the effect of ethanol (acyl acceptor) vs. SPSO and CCO in various ratios on biodiesel production was determined.

  • A detailed overview of xylanases: an emerging biomolecule for current and future prospective
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-10-18
    Nisha Bhardwaj, Bikash Kumar, Pradeep Verma

    Xylan is the second most abundant naturally occurring renewable polysaccharide available on earth. It is a complex heteropolysaccharide consisting of different monosaccharides such as l-arabinose, d-galactose, d-mannoses and organic acids such as acetic acid, ferulic acid, glucuronic acid interwoven together with help of glycosidic and ester bonds. The breakdown of xylan is restricted due to its heterogeneous nature and it can be overcome by xylanases which are capable of cleaving the heterogeneous β-1,4-glycoside linkage. Xylanases are abundantly present in nature (e.g., molluscs, insects and microorganisms) and several microorganisms such as bacteria, fungi, yeast, and algae are used extensively for its production. Microbial xylanases show varying substrate specificities and biochemical properties which makes it suitable for various applications in industrial and biotechnological sectors. The suitability of xylanases for its application in food and feed, paper and pulp, textile, pharmaceuticals, and lignocellulosic biorefinery has led to an increase in demand of xylanases globally. The present review gives an insight of using microbial xylanases as an “Emerging Green Tool” along with its current status and future prospective.

  • 更新日期:2019-11-28
  • Solid-state fermentation as an efficient strategy for the biotransformation of lentils: enhancing their antioxidant and antidiabetic potentials
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-10-04
    Ana Elisa Alves Magro, Laura Carvalho Silva, Gabriela Boscariol Rasera, Ruann Janser Soares de Castro

    Fermentation is a classic industrial process that can be applied as an efficient strategy to increase the release of bioactive compounds with antioxidant and antidiabetic activities.

  • Recent progress in directed evolution of stereoselective monoamine oxidases
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-09-23
    Jiaqi Duan, Beibei Li, Youcai Qin, Yijie Dong, Jie Ren, Guangyue Li

    Monoamine oxidases (MAOs) use molecular dioxygen as oxidant to catalyze the oxidation of amines to imines. This type of enzyme can be employed for the synthesis of primary, secondary, and tertiary amines by an appropriate deracemization protocol. Consequently, MAOs are an attractive class of enzymes in biocatalysis. However, they also have limitations in enzyme-catalyzed processes due to the often-observed narrow substrate scope, low activity, or poor/wrong stereoselectivity. Therefore, directed evolution was introduced to eliminate these obstacles, which is the subject of this review. The main focus is on recent efforts concerning the directed evolution of four MAOs: monoamine oxidase (MAO-N), cyclohexylamine oxidase (CHAO), D-amino acid oxidase (pkDAO), and 6-hydroxy-D-nicotine oxidase (6-HDNO).

  • Enhancing the thermostability and activity of uronate dehydrogenase from Agrobacterium tumefaciens LBA4404 by semi-rational engineering
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-09-23
    Hui-Hui Su, Fei Peng, Pei Xu, Xiao-Ling Wu, Min-Hua Zong, Ji-Guo Yang, Wen-Yong Lou

    Glucaric acid, one of the aldaric acids, has been declared a “top value-added chemical from biomass”, and is especially important in the food and pharmaceutical industries. Biocatalytic production of glucaric acid from glucuronic acid is more environmentally friendly, efficient and economical than chemical synthesis. Uronate dehydrogenases (UDHs) are the key enzymes for the preparation of glucaric acid in this way, but the poor thermostability and low activity of UDH limit its industrial application. Therefore, improving the thermostability and activity of UDH, for example by semi-rational design, is a major research goal.

  • 更新日期:2019-11-28
  • Cell-culture growth conditions resulting in the oxidation of a recombinant antigen-binding fragment
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-09-17
    Khandaker Siddiquee, Cheng Zhao, Michelle A. Stemler, Bill Zeck, Jeffrey R. Fishpaugh, Steven P. Allen


  • 更新日期:2019-11-28
  • Optimized sampling protocol for mass spectrometry-based metabolomics in Streptomyces
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-09-10
    Xiaoyun Liu, Tong Wang, Xiaojuan Sun, Zejian Wang, Xiwei Tian, Yingping Zhuang, Ju Chu


  • Enhanced lincomycin A production by calcium gluconate feeding in fermentation of Streptomyces lincolnensis
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-08-22
    Zhihui Zhuang, Liwen Zhang, Cancan Yang, Deyu Zhu, Quangui Mao, Qiyao Wang, Shuhong Gao


  • 更新日期:2019-11-28
  • 更新日期:2019-11-28
  • Reversible photocontrol of oxidase activity by inserting a photosensitive domain into the oxidase
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-08-07
    Tongjing Sun, Baoqi Zhang, Jinping Lin, Yuhong Ren

    Photocontrol of protein activity has become a helpful strategy for regulating biological pathways. Herein, a method for the precise and reversible photocontrol of oxidase activity was developed by using the conformational change of the AsLOV2 domain.

  • Start-up of a nutrient removal system using Scenedesmus vacuolatus and Chlorella vulgaris biofilms
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-07-31
    Jairo Hernán Moreno Osorio, Gabriele Pinto, Antoninio Pollio, Luigi Frunzo, Piet Nicolaas Luc Lens, Giovanni Esposito


  • Accelerated directed evolution of dye-decolorizing peroxidase using a bacterial extracellular protein secretion system (BENNY).
    Bioresour. Bioprocess. (IF 0) Pub Date : 2019-06-25
    Abdulrahman H A Alessa,Kang Lan Tee,David Gonzalez-Perez,Hossam E M Omar Ali,Caroline A Evans,Alex Trevaskis,Jian-He Xu,Tuck Seng Wong

    Background Dye-decolorizing peroxidases (DyPs) are haem-containing peroxidases that show great promises in industrial biocatalysis and lignocellulosic degradation. Through the use of Escherichia coli osmotically-inducible protein Y (OsmY) as a bacterial extracellular protein secretion system (BENNY), we successfully developed a streamlined directed evolution workflow to accelerate the protein engineering of DyP4 from Pleurotus ostreatus strain PC15. Result After 3 rounds of random mutagenesis with error-prone polymerase chain reaction (epPCR) and 1 round of saturation mutagenesis, we obtained 4D4 variant (I56V, K109R, N227S and N312S) that displays multiple desirable phenotypes, including higher protein yield and secretion, higher specific activity (2.7-fold improvement in k cat/K m) and higher H2O2 tolerance (sevenfold improvement based on IC50). Conclusion To our best knowledge, this is the first report of applying OsmY to simplify the directed evolution workflow and to direct the extracellular secretion of a haem protein such as DyP4.

  • Recent updates on different methods of pretreatment of lignocellulosic feedstocks: a review.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-02-07
    Adepu Kiran Kumar,Shaishav Sharma

    Lignocellulosic feedstock materials are the most abundant renewable bioresource material available on earth. It is primarily composed of cellulose, hemicellulose, and lignin, which are strongly associated with each other. Pretreatment processes are mainly involved in effective separation of these complex interlinked fractions and increase the accessibility of each individual component, thereby becoming an essential step in a broad range of applications particularly for biomass valorization. However, a major hurdle is the removal of sturdy and rugged lignin component which is highly resistant to solubilization and is also a major inhibitor for hydrolysis of cellulose and hemicellulose. Moreover, other factors such as lignin content, crystalline, and rigid nature of cellulose, production of post-pretreatment inhibitory products and size of feed stock particle limit the digestibility of lignocellulosic biomass. This has led to extensive research in the development of various pretreatment processes. The major pretreatment methods include physical, chemical, and biological approaches. The selection of pretreatment process depends exclusively on the application. As compared to the conventional single pretreatment process, integrated processes combining two or more pretreatment techniques is beneficial in reducing the number of process operational steps besides minimizing the production of undesirable inhibitors. However, an extensive research is still required for the development of new and more efficient pretreatment processes for lignocellulosic feedstocks yielding promising results.

  • Enzymatic characterization of a recombinant carbonyl reductase from Acetobacter sp. CCTCC M209061.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-09-16
    Ping Wei,Yu-Han Cui,Min-Hua Zong,Pei Xu,Jian Zhou,Wen-Yong Lou

    BACKGROUND Acetobacter sp. CCTCC M209061 could catalyze carbonyl compounds to chiral alcohols following anti-Prelog rule with excellent enantioselectivity. Therefore, the enzymatic characterization of carbonyl reductase (CR) from Acetobacter sp. CCTCC M209061 needs to be investigated. RESULTS A CR from Acetobacter sp. CCTCC M209061 (AcCR) was cloned and expressed in E. coli. AcCR was purified and characterized, finding that AcCR as a dual coenzyme-dependent short-chain dehydrogenase/reductase (SDR) was more preferred to NADH for biocatalytic reactions. The AcCR was activated and stable when the temperature was under 35 °C and the pH range was from 6.0 to 8.0 for the reduction of 4'-chloroacetophenone with NADH as coenzyme, and the optimal temperature and pH were 45 °C and 8.5, respectively, for the oxidation reaction of isopropanol with NAD+. The enzyme showed moderate thermostability with half-lives of 25.75 h at 35 °C and 13.93 h at 45 °C, respectively. Moreover, the AcCR has broad substrate specificity to a range of ketones and ketoesters, and could catalyze to produce chiral alcohol with e.e. >99% for the majority of tested substrates following the anti-Prelog rule. CONCLUSIONS The recombinant AcCR exhibited excellent enantioselectivity, broad substrate spectrum, and highly stereoselective anti-Prelog reduction of prochiral ketones. These results suggest that AcCR is a powerful catalyst for the production of anti-Prelog alcohols.Graphical abstractThe biocatalytic reactions conducted with the recombinant AcCR.

  • Germ soak water as nutrient source to improve fermentation of corn grits from modified corn dry grind process.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-09-12
    Ankita Juneja,Deepak Kumar,Vijay Singh

    Corn fractionation in modified dry grind processes results in low fermentation efficiency of corn grits because of nutrient deficiency. This study investigated the use of nutrient-rich water from germ soaking to improve grits fermentation in the conventional dry grind and granular starch hydrolysis (GSH) processes. Comparison of germ soak water with the use of protease and external B-vitamin addition in improving grits fermentation was conducted. Use of water from optimum soaking conditions (12 h at 30 °C) resulted in complete fermentation with 29 and 8% higher final ethanol yields compared to that of control in conventional and GSH process, respectively. Fermentation rate (4-24 h) of corn grits with germ soak water (0.492 v/v-h) was more than double than that of control (0.208 v/v-h) in case of conventional dry grind process. The soaking process also increased the oil concentration in the germ by about 36%, which would enhance its economic value.

  • Enhancing transglutaminase production of Streptomyces mobaraensis by iterative mutagenesis breeding with atmospheric and room-temperature plasma (ARTP).
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-08-29
    Ying Jiang,Yue-Peng Shang,Hao Li,Chao Zhang,Jiang Pan,Yun-Peng Bai,Chun-Xiu Li,Jian-He Xu

    OBJECTIVES To improve the fermentation production of transglutaminase (TGase) from Streptomyces mobaraensis for applications in the food industry, the atmospheric and room-temperature plasma (ARTP) mutagenesis was applied to breed S. mobaraensis mutants with increased TGase production. RESULTS After eight rounds of iterative ARTP mutagenesis, four genetically stable mutants, Sm5-V1, Sm6-V13, Sm2-V10, and Sm7-V12, were identified, which showed increased TGase production by 27, 24, 24, and 19%, respectively. The best mutant Sm5-V1 exhibited a maximum TGase activity of 5.85 U/mL during flask fermentation. Compared to the wild-type strain, the transcription levels of the zymogen TGase genes in the mutants increased significantly as indicated by quantitative real-time PCR, while the gene nucleotide sequences of the mutants did not change at all. It was shown that the overexpression of TGase zymogen gene in the mutants contributes to the increase in TGase production. CONCLUSIONS ARTP is a potentially efficient tool for microbial mutation breeding to bring some significant changes required for the industrial applications.

  • Photocontrolled reversible self-assembly of dodecamer nitrilase.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-08-22
    Qiao Yu,Yong Wang,Shengyun Zhao,Yuhong Ren

    BACKGROUND Naturally photoswitchable proteins act as a powerful tool for the spatial and temporal control of biological processes by inducing the formation of a photodimerizer. In this study, a method for the precise and reversible inducible self-assembly of dodecamer nitrilase in vivo (in Escherichia coli) and in vitro (in a cell-free solution) was developed by means of the photoswitch-improved light-inducible dimer (iLID) system which could induce protein-protein dimerization. RESULTS Nitrilase was fused with the photoswitch protein AsLOV2-SsrA to achieve the photocontrolled self-assembly of dodecamer nitrilase. The fusion protein self-assembled into a supramolecular assembly when illuminated at 470 nm. Scanning electron microscopy showed that the assembly formed a circular sheet structure. Self-assembly was also induced by light in E. coli. Dynamic light scattering and turbidity assay experiments showed that the assemblies formed within a few seconds under 470-nm light and completely disassembled within 5 min in the dark. Assembly and disassembly could be maintained for at least five cycles. Both in vitro and in vivo, the assemblies retained 90% of the initial activity of nitrilase and could be reused at least four times in vitro with 90% activity. CONCLUSIONS An efficient method was developed for the photocontrolled assembly and disassembly of dodecamer nitrilase and for scaffold-free reversible self-assembly of multiple oligomeric enzymes in vivo and in vitro, providing new ideas and methods for immobilization of enzyme without carrier.

  • Application of methanol and sweet potato vine hydrolysate as enhancers of citric acid production by Aspergillus niger.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-08-15
    Daobing Yu,Yanke Shi,Qun Wang,Xin Zhang,Yuhua Zhao

    BACKGROUND Agricultural waste is as an alternative low-cost carbon source or beneficial additives which catch most people's eyes. In addition, methanol and sweet potato vine hydrolysate (SVH) have been reported as the efficient enhancers of fermentation according to some reports. The objective of the present study was to confirm SVH as an efficient additive in CA production and explore the synergistic effects of methanol and SVH in fermentation reactions. RESULTS The optimal fermentation conditions resulted in a maximum citric acid concentration of 3.729 g/L. The final citric acid concentration under the optimized conditions was increased by 3.6-fold over the original conditions, 0.49-fold over the optimized conditions without methanol, and 1.8-fold over the optimized conditions in the absence of SVH. Kinetic analysis showed that Qp, Yp/s, and Yx/s in the optimized systems were significantly improved compared with those obtained in the absence of methanol or SVH. Further, scanning electron microscopy (SEM) revealed that methanol stress promoted the formation of conidiophores, while SVH could neutralize the effect and prolong Aspergillus niger vegetative growth. Cell viability analysis also showed that SVH might eliminate the harmful effects of methanol and enhance cell membrane integrity. CONCLUSIONS SVH was a superior additive for organic acid fermentation, and the combination of methanol and SVH displayed a significant synergistic effect. The research provides a preliminary theoretical basis for SVH practical application in the fermentation industry.

  • Recent progress on deep eutectic solvents in biocatalysis.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-08-11
    Pei Xu,Gao-Wei Zheng,Min-Hua Zong,Ning Li,Wen-Yong Lou

    Deep eutectic solvents (DESs) are eutectic mixtures of salts and hydrogen bond donors with melting points low enough to be used as solvents. DESs have proved to be a good alternative to traditional organic solvents and ionic liquids (ILs) in many biocatalytic processes. Apart from the benign characteristics similar to those of ILs (e.g., low volatility, low inflammability and low melting point), DESs have their unique merits of easy preparation and low cost owing to their renewable and available raw materials. To better apply such solvents in green and sustainable chemistry, this review firstly describes some basic properties, mainly the toxicity and biodegradability of DESs. Secondly, it presents several valuable applications of DES as solvent/co-solvent in biocatalytic reactions, such as lipase-catalyzed transesterification and ester hydrolysis reactions. The roles, serving as extractive reagent for an enzymatic product and pretreatment solvent of enzymatic biomass hydrolysis, are also discussed. Further understanding how DESs affect biocatalytic reaction will facilitate the design of novel solvents and contribute to the discovery of new reactions in these solvents.

  • Microbial transformation of artemisinin by Aspergillus terreus.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-08-05
    Hongchang Yu,Baowu Zhu,Yulian Zhan

    BACKGROUND Artemisinin (1) and its derivatives are now being widely used as antimalarial drugs, and they also exhibited good antitumor activities. So there has been much interest in the structural modification of artemisinin and its derivatives because of their effective bioactivities. The microbial transformation is a promising route to obtain artemisinin derivatives. The present study focuses on the microbial transformation of artemisinin by Aspergillus terreus. RESULTS During 6 days at 28 °C and 180 rpm, Aspergillus terreus transformed artemisinin to two products. They were identified as 1-deoxyartemisinin (2) and 4α-hydroxy-1-deoxyartemisinin (3) on the basis of their spectroscopic data. CONCLUSIONS The microbial transformation of artemisinin by Aspergillus terreus was investigated, and two products (1-deoxyartemisinin and 4α-hydroxy-1-deoxyartemisinin) were obtained. This study is the first to report on the microbial transformation of artemisinin by Aspergillus terreus.

  • Mycoremediation potential of Pleurotus species for heavy metals: a review.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-29
    Meena Kapahi,Sarita Sachdeva

    Mycoremediation is one of the biotechniques that recruits fungi to remove toxic pollutants from environment in an efficient and economical manner. Mushrooms, macro-fungi, are among the nature's most important mycoremediators. Pleurotus species (also called oyster mushrooms) are considered to be the most popular and widely cultivated varieties worldwide and this might be attributed to their low production cost and higher yields. Apart from their nutritive and therapeutic properties, Pleurotus species have high biosorption potential due to their extensive biomass, i.e. mycelial production. The genus has been reported to accumulate high levels of heavy metals. The current state-of-the art review mainly summarises previous investigations carried out by researchers on different roles and mechanisms played by Pleurotus species on heavy metals mycoremediation.

  • Study on community structure of microbial consortium for the degradation of viscose fiber wastewater.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-28
    Chao-Qun Ding,Kun-Rong Li,Yun-Xia Duan,Shi-Ru Jia,He-Xin Lv,He Bai,Cheng Zhong

    BACKGROUND Enrichment culture was applied to obtain microbial consortium from activated sludge samples collected from biodegradation system, a chemical fiber plant in Hebei Province, China. Bacterial composition and community dynamic variation were assessed employing denaturing gradient gel electrophoresis fingerprinting technology based on amplified 16S rRNA genes in the entire process of enrichment culture for viscose fiber wastewater. RESULTS Four bacteria named as VF01, VF02, VF03, and VF04 were isolated from the microbial consortium adopting the spray-plate method. The DNA bands of these four bacteria were corresponded to the predominant DNA bands in the electrophoresis pattern. VF01, VF02, VF03, and VF04 were phylogenetically closed to Bacillus licheniformis, Bacillus subtilis, Paracoccus tibetensis, and Pseudomonas sp. by sequence analysis, respectively. The degradation effects for CODCr of single isolated strain, mixed strains, and microbial consortium (VF) originally screened from viscose fiber wastewater were determined. The degradation ability was as follows: microbial consortium (VF) > mixed strains > single isolated strain. Microbial consortium (VF) showed the optimum degradation rate of CODCr of 87% on 14th day. Degradation of pollutants sped up by bio-augmentation of four strains. The molecular weight distribution of organic matter showed that viscose fiber wastewater contained a certain amount of large molecular organic matter, which could be decomposed into smaller molecular substances by microbial consortium (VF). CONCLUSIONS The microbial consortium (VF) obtained from enrichment culture exhibited great potential for CODCr degradation. The screened strains had bio-augmentation functions and the addition of a mixture of four bacteria could speed up the degradation rate of pollutants.

  • Comparative evaluation of wastewater-treatment microbial fuel cells in terms of organics removal, waste-sludge production, and electricity generation.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-25
    Yusuke Asai,Morio Miyahara,Atsushi Kouzuma,Kazuya Watanabe

    Microbial fuel cells (MFCs) are devices that exploit living microbes for electricity generation coupled to organics degradation. MFCs are expected to be applied to energy-saving wastewater treatment (WWT) as alternatives to activated-sludge reactors (ASRs). Although extensive laboratory studies have been performed to develop technologies for WWT-MFCs, limited information is available for comparative evaluation of MFCs and ASRs in terms of organics removal and waste-sludge production. In the present study, laboratory WWT experiments were performed using cassette-electrode MFCs and ASRs that were continuously supplied either with artificial domestic wastewater (ADW) containing starch and peptone or with artificial industrial wastewater (AIW) containing methanol as the major organic matter. We found that these two types of WWT reactors achieved similar organics-removal efficiencies, namely, over 93% based on chemical oxygen demands for the ADW treatment and over 97% for the AIW treatment. Sludge was routinely removed from these reactors and quantified, showing that amounts of waste sludge produced in MFCs were approximately one-third or less compared to those in ASRs. During WWT, MFCs continuously generated electricity with Coulombic efficiencies of 20% or more. In reference to ASRs, MFCs are demonstrated to be attractive WWT facilities in terms of stable organics removal and low waste-sludge production. Along with the unnecessity of electric power for aeration and the generation of power during WWT, the results obtained in the present study suggest that MFCs enable substantial energy saving during WWT.

  • Biochemical properties of a new thermo- and solvent-stable xylanase recovered using three phase partitioning from the extract of Bacillus oceanisediminis strain SJ3.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-25
    Nawel Boucherba,Mohammed Gagaoua,Amel Bouanane-Darenfed,Cilia Bouiche,Khelifa Bouacem,Mohamed Yacine Kerbous,Yacine Maafa,Said Benallaoua

    The present study investigates the production and partial biochemical characterization of an extracellular thermostable xylanase from the Bacillus oceanisediminis strain SJ3 newly recovered from Algerian soil using three phase partitioning (TPP). The maximum xylanase activity recorded after 2 days of incubation at 37 °C was 20.24 U/ml in the presence of oat spelt xylan. The results indicated that the enzyme recovered in the middle phase of TPP system using the optimum parameters were determined as 50% ammonium sulfate saturation with 1.0:1.5 ratio of crude extract: t-butanol at pH and temperature of 8.0 and 10 °C, respectively. The xylanase was recovered with 3.48 purification fold and 107% activity recovery. The enzyme was optimally active at pH 7.0 and was stable over a broad pH range of 5.0-10. The optimum temperature for xylanase activity was 55 °C and the half-life time at this temperature was of 6 h. At this time point the enzyme retained 50% of its activity after incubation for 2 h at 95 °C. The crude enzyme resist to sodium dodecyl sulfate and β-mercaptoethanol, while all the tested ions do not affect the activity of the enzyme. The recovered enzyme is, at least, stable in tested organic solvents except in propanol where a reduction of 46.5% was observed. Further, the stability of the xylanase was higher in hydrophobic solvents where a maximum stability was observed with cyclohexane. These properties make this enzyme to be highly thermostable and may be suggested as a potential candidate for application in some industrial processes. To the best of our knowledge, this is the first report of xylanase activity and recoverey using three phase partitioning from B. oceanisediminis.

  • Microbial degradation of petrochemical waste-polycyclic aromatic hydrocarbons.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-21
    M H Fulekar

    BACKGROUND Petrochemical industry is one of the fastest growing industries. This industry has immense importance in the growth of economy and manufacture of large varieties of chemicals. The petrochemical industry is a hazardous group of industry generating hazardous waste containing organic and inorganic compounds. In spite of the present treatment process, the hazardous waste compounds are found untreated to the acceptable level and found discharged at soil-water environment resulting into the persistent organic-inorganic pollutant into the environment. The bioremediation will be the innovative techniques to remove the persistent pollutants in the environment. RESULT Petrochemical contaminated site was found to be a rich source of microbial consortium degrading polycyclic aromatic hydrocarbons. Indigenous microbial consortiums were identified and used for bioremediation of polycyclic aromatic hydrocarbons (naphthalene and anthracene) at the concentrations of 250, 500, and 750 ppm. The potential microorganism was also identified for naphthalene and anthracene, and their bioremediation was studied at varying concentrations. The bioremediation with consortium was found to be comparatively more effective than the potential microorganism used for bioremediation of each compound. Pseudomonas aeruginosa a potential organism was identified by 16S rRNA and further studied for the gene responsible for the PAH compounds. CONCLUSION Indigenous microorganism as a consortium has been found effective and efficient source for remediation of organic compound-Polycyclic aromatic hydrocarbon and this will also be applicable to remediate the toxic compounds to clean up the environment.

  • Lobster processing by-products as valuable bioresource of marine functional ingredients, nutraceuticals, and pharmaceuticals.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-07
    Trung T Nguyen,Andrew R Barber,Kendall Corbin,Wei Zhang

    The worldwide annual production of lobster was 165,367 tons valued over $3.32 billion in 2004, but this figure rose up to 304,000 tons in 2012. Over half the volume of the worldwide lobster production has been processed to meet the rising global demand in diversified lobster products. Lobster processing generates a large amount of by-products (heads, shells, livers, and eggs) which account for 50-70% of the starting material. Continued production of these lobster processing by-products (LPBs) without corresponding process development for efficient utilization has led to disposal issues associated with costs and pollutions. This review presents the promising opportunities to maximize the utilization of LPBs by economic recovery of their valuable components to produce high value-added products. More than 50,000 tons of LPBs are globally generated, which costs lobster processing companies upward of about $7.5 million/year for disposal. This not only presents financial and environmental burdens to the lobster processors but also wastes a valuable bioresource. LPBs are rich in a range of high-value compounds such as proteins, chitin, lipids, minerals, and pigments. Extracts recovered from LPBs have been demonstrated to possess several functionalities and bioactivities, which are useful for numerous applications in water treatment, agriculture, food, nutraceutical, pharmaceutical products, and biomedicine. Although LPBs have been studied for recovery of valuable components, utilization of these materials for the large-scale production is still very limited. Extraction of lobster components using microwave, ultrasonic, and supercritical fluid extraction were found to be promising techniques that could be used for large-scale production. LPBs are rich in high-value compounds that are currently being underutilized. These compounds can be extracted for being used as functional ingredients, nutraceuticals, and pharmaceuticals in a wide range of commercial applications. The efficient utilization of LPBs would not only generate significant economic benefits but also reduce the problems of waste management associated with the lobster industry. This comprehensive review highlights the availability of the global LPBs, the key components in LPBs and their current applications, the limitations to the extraction techniques used, and the suggested emerging techniques which may be promising on an industrial scale for the maximized utilization of LPBs. Graphical abstractLobster processing by-product as bioresource of several functional and bioactive compounds used in various value-added products.

  • Detoxification of parthenium (Parthenium hysterophorus) and its metamorphosis into an organic fertilizer and biopesticide.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-07
    Naseer Hussain,Tasneem Abbasi,Shahid Abbas Abbasi

    BACKGROUND Vermicompost of the toxic and allelopathic weed parthenium (Parthenium hysterophorus) was explored for its possible use as an organic fertilizer. Replicated plant growth trials were conducted using four levels of parthenium vermicompost (0, 2.5, 3.75, and 5 t/ha) to assess their effects on the germination, growth, and fruition of a typical food plant ladies finger (Abelmoschus esculentus). Additionally the role of vermicompost in reducing plant pests and disease was evaluated. RESULTS Vermicompost encouraged the germination and growth of ladies finger at all levels of vermicompost application, with best results obtained in 5 t/ha treatments. The positive impact extended up to the fruit yield. Vermicompost application also improved the quality of fruits in terms of mineral, protein, and carbohydrate contents, and reduced the disease incidence and pest attacks. CONCLUSIONS The studies establish the fact that parthenium acquires all the qualities of a good organic fertilizer with concomitant loss of its toxic and allelopathic properties after it gets vermicomposted. The findings raise the prospects of economical and eco-friendly utilization of billions of tons of parthenium biomass which is generated annually but goes to waste at present.

  • Beechwood carbohydrates for enzymatic synthesis of sustainable glycolipids.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-07-07
    Sascha Siebenhaller,Tatjana Hajek,Claudia Muhle-Goll,Miriam Himmelsbach,Burkhard Luy,Frank Kirschhöfer,Gerald Brenner-Weiß,Thomas Hahn,Susanne Zibek,Christoph Syldatk

    Moving away from crude oil to renewable resources for the production of a wide range of compounds is a challenge for future generations. To overcome this, the use of lignocellulose as substrate can contribute to drastically reduce the consumption of crude oil. In this study, sugars from lignocellulose were used as a starting material for the enzymatic synthesis of surface-active sugar esters. The substrates were obtained by an acid-catalyzed, beechwood pretreatment process, which resulted in a fiber fraction that is subsequently hydrolyzed to obtain the monosaccharides. After purification and drying, this glucose- and xylose-rich fraction was used to create a deep eutectic solvent, which acts both as solvent and substrate for the lipase-catalyzed reaction at the same time. Finally, the successful synthesis of glycolipids from a sustainable resource was confirmed by ESI-Q-ToF mass spectrometry and multidimensional NMR experiments. Moreover, conversion yields of 4.8% were determined by LC-MS/MS.

  • Green synthesis of enzyme/metal-organic framework composites with high stability in protein denaturing solvents.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-06-10
    Xiaoling Wu,Cheng Yang,Jun Ge

    OBJECTIVES Enzyme/metal-organic framework composites with high stability in protein denaturing solvents were reported in this study. RESULTS Encapsulation of enzyme in metal-organic frameworks (MOFs) via co-precipitation process was realized, and the generality of the synthesis was validated by using cytochrome c, horseradish peroxidase, and Candida antarctica lipase B as model enzymes. The stability of encapsulated enzyme was greatly increased after immobilization on MOFs. Remarkably, when exposed to protein denaturing solvents including dimethyl sulfoxide, dimethyl formamide, methanol, and ethanol, the enzyme/MOF composites still preserved almost 100% of activity. In contrast, free enzymes retained no more than 20% of their original activities at the same condition. This study shows the extraordinary protecting effect of MOF shell on increasing enzyme stability at extremely harsh conditions. CONCLUSION The enzyme immobilized in MOF exhibited enhanced thermal stability and high tolerance towards protein denaturing organic solvents.

  • Mineralization of a sulfonated textile dye Reactive Red 31 from simulated wastewater using pellets of Aspergillus bombycis.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-06-06
    Razia Khan,M H Fulekar

    BACKGROUND Reactive Red 31, applied extensively in the commercial textile industry, is a hazardous and persistent azo dye compound often present in dye manufacturing and textile industrial effluents. Aspergillus bombycis strain was isolated from dye contaminated zones of Gujarat Industrial Development Corporation, Vatva, Ahmedabad, India. The decolorization potential was monitored by the decrease in maximum absorption of the dye using UV-visible spectroscopy. Optimization of physicochemical conditions was carried out to achieve maximum decolorization of Reactive Red 31 by fungal pellets. RESULTS Pellets of A. bombycis strain were found to decolorize this dye (20 mg/L) under aerobic conditions within 12 h. The activity of azoreductase, laccase, phenol oxidase and Manganese peroxidase in fungal culture after decolorization was about 8, 7.5, 19 and 23.7 fold more than before decolorization suggesting that these enzymes might be induced by the addition of Reactive Red 31 dye, and thus results in a higher decolorization. The lab-scale reactor was developed and mineralization of Reactive Red 31 dye by fungal pellets was studied at 6, 12 and 24 h of HRT (hydraulic retention time). At 12 h of HRT, decolorization potential, chemical oxygen demand (COD) and total organic carbon reduction (TOC) was 99.02, 94.19, and 83.97%, respectively, for 20 mg/L of dye concentration. CONCLUSIONS Dye decolorization potential of A. bombycis culture was influenced by several factors such as initial dye concentration, biomass concentration, pH, temperature, and required aerated conditions. Induction of azoreductase, laccase, phenol oxidase, and Mn-peroxidase enzymes was observed during dye decolorization phase. A. bombycis pellets showed potential in mineralization of dye in the aerobic reactor system. Isolated fungal strain A. bombycis showed better dye decolorization performance in short duration of time (12 h) as compared to other reported fungal cultures.Graphical abstractDegradation of RR31 dye in developed aerobic fungal pelleted reactor.

  • Comprehensive reconstruction and evaluation of Pichia pastoris genome-scale metabolic model that accounts for 1243 ORFs.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-05-27
    Rui Ye,Mingzhi Huang,Hongzhong Lu,Jiangchao Qian,Weilu Lin,Ju Chu,Yingping Zhuang,Siliang Zhang

    BACKGROUND Pichia pastoris is one of the most important cell factories for production of industrial enzymes and heterogenous proteins. The genome-scale metabolic model of high quality is crucial for comprehensive understanding of the P. pastoris metabolism. METHODS In this paper, we upgraded P. pastoris genome-scale metabolic model based on the combination of latest genome annotations and literatures. Then the performance of the new model was evaluated using the Cobra Toolbox v2.0. RESULTS Compared with the recently published model iMT1026, the reaction number in the new model iRY1243 was increased from 2035 to 2407 and the metabolite number was increased from 1018 to 1094. Accordingly, the unique ORF number was increased from 1026 to 1243. To improve the metabolic functions of P. pastoris genome-scale metabolic model, the biosynthesis pathways of vitamins and cofactors were carefully added. iRY1243 showed good performances when predicting the growth capability on most of the reported carbon and nitrogen sources, the metabolic flux distribution with glucose as a sole carbon source, the essential and partially essential genes, and the effects of gene deletion or overexpression on cell growth and S-adenosyl-l-methionine production. CONCLUSION iRY1243 is an upgraded P. pastoris genome-scale metabolic model with significant improvements in the metabolic coverage and prediction ability, and thus it will be a potential platform for further systematic investigation of P. pastoris metabolism.

  • Biofibres from biofuel industrial byproduct-Pongamia pinnata seed hull.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-03-10
    Puttaswamy Manjula,Govindan Srinikethan,K Vidya Shetty

    BACKGROUND Biodiesel production using Pongamia pinnata (P. pinnata) seeds results in large amount of unused seed hull. These seed hulls serve as a potential source for cellulose fibres which can be exploited as reinforcement in composites. METHODS These seed hulls were processed using chlorination and alkaline extraction process in order to isolate cellulose fibres. Scanning electron microscopy (SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR) analysis demonstrated the morphological changes in the fibre structure. RESULTS Cellulose microfibres of diameter 6-8 µm, hydrodynamic diameter of 58.4 nm and length of 535 nm were isolated. Thermal stability was enhanced by 70 °C and crystallinity index (CI) by 19.8% ensuring isolation of crystalline cellulose fibres. CONCLUSION The sequential chlorination and alkaline treatment stemmed to the isolation of cellulose fibres from P. pinnata seed hull. The isolated cellulose fibres possessed enhanced morphological, thermal, and crystalline properties in comparison with P.pinnata seed hull. These cellulose microfibres may potentially find application as biofillers in biodegradable composites by augmenting their properties.

  • Efficient expression of sortase A from Staphylococcus aureus in Escherichia coli and its enzymatic characterizations.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-03-07
    Zhimeng Wu,Haofei Hong,Xinrui Zhao,Xun Wang

    BACKGROUND Sortase A (SrtA) is a transpeptidase found in Staphylococcus aureus, which is widely used in site-specific protein modification. However, SrtA was expressed in Escherichia coli (E. coli) in rather low level (ranging from several milligrams to 76.9 mg/L at most). The present study aims to optimize fermentation conditions for improving SrtA expression in E. coli. RESULTS Under the optimized media (0.48 g/L glycerol, 1.37 g/L tryptone, 0.51 g/L yeast extract, MOPS 0.5 g/L, PBS buffer 180 mL/L) and condition (30 °C for 8 h) in a 7-L fermentor, the enzyme activity and the yield of SrtA reached 2458.4 ± 115.9 U/mg DCW and 232.4 ± 21.1 mg/L, respectively, which were higher by 5.8- and 4.5-folds compared with initial conditions, respectively. The yield of SrtA also represented threefold increase than the previously reported maximal level. In addition, the enzymatic characterizations of SrtA (optimal temperature, optimal pH, the influence of metal irons, and tolerance to water-soluble organic solvents) were determined. CONCLUSIONS Enhanced expression of SrtA was achieved by optimization of medium and condition. This result will have potential application for production levels of SrtA on an industry scale. Moreover, the detailed enzymatic characterizations of SrtA were examined, which will provide a useful guide for its future application.

  • Techno-economic analysis of extraction-based separation systems for acetone, butanol, and ethanol recovery and purification.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-03-03
    Víctor Hugo Grisales Díaz,Gerard Olivar Tost

    BACKGROUND Dual extraction, high-temperature extraction, mixture extraction, and oleyl alcohol extraction have been proposed in the literature for acetone, butanol, and ethanol (ABE) production. However, energy and economic evaluation under similar assumptions of extraction-based separation systems are necessary. Hence, the new process proposed in this work, direct steam distillation (DSD), for regeneration of high-boiling extractants was compared with several extraction-based separation systems. METHODS The evaluation was performed under similar assumptions through simulation in Aspen Plus V7.3® software. Two end distillation systems (number of non-ideal stages between 70 and 80) were studied. Heat integration and vacuum operation of some units were proposed reducing the energy requirements. RESULTS Energy requirement of hybrid processes, substrate concentration of 200 g/l, was between 6.4 and 8.3 MJ-fuel/kg-ABE. The minimum energy requirements of extraction-based separation systems, feeding a water concentration in the substrate equivalent to extractant selectivity, and ideal assumptions were between 2.6 and 3.5 MJ-fuel/kg-ABE, respectively. The efficiencies of recovery systems for baseline case and ideal evaluation were 0.53-0.57 and 0.81-0.84, respectively. CONCLUSIONS The main advantages of DSD were the operation of the regeneration column at atmospheric pressure, the utilization of low-pressure steam, and the low energy requirements of preheating. The in situ recovery processes, DSD, and mixture extraction with conventional regeneration were the approaches with the lowest energy requirements and total annualized costs.

  • Advances in industrial microbiome based on microbial consortium for biorefinery.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-03-03
    Li-Li Jiang,Jin-Jie Zhou,Chun-Shan Quan,Zhi-Long Xiu

    One of the important targets of industrial biotechnology is using cheap biomass resources. The traditional strategy is microbial fermentations with single strain. However, cheap biomass normally contains so complex compositions and impurities that it is very difficult for single microorganism to utilize availably. In order to completely utilize the substrates and produce multiple products in one process, industrial microbiome based on microbial consortium draws more and more attention. In this review, we first briefly described some examples of existing industrial bioprocesses involving microbial consortia. Comparison of 1,3-propanediol production by mixed and pure cultures were then introduced, and interaction relationships between cells in microbial consortium were summarized. Finally, the outlook on how to design and apply microbial consortium in the future was also proposed.

  • Changes of membrane fatty acids and proteins of Shewanella putrefaciens treated with cinnamon oil and gamma irradiation.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-02-17
    Fei Lyu,Fei Gao,Qianqian Wei,Lin Liu

    BACKGROUND In order to detect the antimicrobial mechanism of combined treatment of cinnamon oil and gamma irradiation (GI), the membrane fatty acids and proteins characteristics of Shewanella putrefaciens (S. putrefaciens) treated with cinnamon oil and GI, and the distribution of cinnamon oil in S. putrefaciens were observed in this study. RESULTS The membrane lipid profile of S. putrefaciens was notably damaged by treatments of cinnamon oil and the combination of cinnamon oil and GI, with significantly fatty acids decrease in C14:0, C16:0, C16:1, C17:1, C18:1 (p < 0.05). The SDS-PAGE result showed that GI did not have obvious effect on membrane proteins (MP), but GI combined with cinnamon oil changed the MP subunits. Cinnamaldehyde, the main component of cinnamon oil, can not transport into S. putrefaciens obviously. It was transformed into cinnamyl alcohol in the nutrient broth with the action of S. putrefaciens. This indicated that the antimicrobial action of cinnamon oil mainly happened on the membrane of S. putrefaciens. CONCLUSION Cinnamon oil could act on the membrane of S. putrefaciens with the damage of fatty acids and proteins, and GI would increase the destructive capability of cinnamon oil on the membrane fatty acids and proteins of S. putrefaciens.

  • A food-grade expression system for d-psicose 3-epimerase production in Bacillus subtilis using an alanine racemase-encoding selection marker.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-02-14
    Jingqi Chen,Zhaoxia Jin,Yuanming Gai,Jibin Sun,Dawei Zhang

    BACKGROUND Food-grade expression systems require that the resultant strains should only contain materials from food-safe microorganisms, and no antibiotic resistance marker can be utilized. To develop a food-grade expression system for d-psicose 3-epimerase production, we use an alanine racemase-encoding gene as selection marker in Bacillus subtilis. RESULTS In this study, the d-alanine racemase-encoding gene dal was deleted from the chromosome of B. subtilis 1A751 using Cre/lox system to generate the food-grade host. Subsequently, the plasmid-coded selection marker dal was complemented in the food-grade host, and RDPE was thus successfully expressed in dal deletion strain without addition of d-alanine. The selection appeared highly stringent, and the plasmid was stably maintained during culturing. The highest RDPE activity in medium reached 46 U/ml at 72 h which was comparable to RDPE production in kanamycin-based system. Finally, the capacity of the food-grade B. subtilis 1A751D2R was evaluated in a 7.5 l fermentor with a fed-batch fermentation. CONCLUSION The alanine racemase-encoding gene can be used as a selection marker, and the food-grade expression system was suitable for heterologous proteins production in B. subtilis.

  • An efficient multi-stage fermentation strategy for the production of microbial oil rich in arachidonic acid in Mortierella alpina.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-02-07
    Wen-Jia Wu,Ai-Hui Zhang,Chao Peng,Lu-Jing Ren,Ping Song,Ya-Dong Yu,He Huang,Xiao-Jun Ji

    BACKGROUND Fungal morphology and aeration play a significant role in the growth process of Mortierella alpina. The production of microbial oil rich in arachidonic acid (ARA) in M. alpina was enhanced by using a multi-stage fermentation strategy which combined fed-batch culture with precise control of aeration and agitation rates at proper times. RESULTS The fermentation period was divided into four stages according to the cultivation characteristics of M. alpina. The dissolved oxygen concentration was well suited for ARA biosynthesis. Moreover, the ultimate dry cell weight (DCW), lipid, and ARA yields obtained using this strategy reached 41.4, 22.2, 13.5 g/L, respectively. The respective values represent 14.8, 25.8, and 7.8% improvements over traditional fed-batch fermentation processes. CONCLUSIONS This strategy provides promising control insights for the mass production of ARA-rich oil on an industrial scale. Pellet-like fungal morphology was transformed into rice-shaped particles which were beneficial for oxygen transfer and thus highly suitable for biomass accumulation.

  • Fungal pretreatment of raw digested piggery wastewater enhancing the survival of algae as biofuel feedstock.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-01-31
    Junying Liu,Wen Qiu,Yunpu Wang

    BACKGROUND Understanding about the impact of white rot fungi on indigenous bacterial communities, NH4+ and turbidity in digested piggery wastewater, will allow the optimization of wastewater treatment methods and its use as a feasible medium for algal growth. Here, the white rot fungi were inoculated into undiluted and unsterilized digested piggery wastewater under different temperatures and pH regimes in order to lower the pretreatment cost. Diversity and abundance of the bacterial communities in the pretreated wastewater were assessed by PCR-denaturing gradient gel electrophoresis coupled with 16S rDNA sequencing. RESULTS The research showed a significant reduction on the microbial diversity with the presence of white rot fungi which occur at pH 6. The distribution and presence of bacteria taxa were strongly correlated with NH4+ concentration, pH, and the presence of white rot fungi. Variance partition analysis also showed that the effect on the chlorophyll content of algae in fungi-filtered wastewater was as the following hierarchy: bacterial diversity > NH4+ > turbidity. Therefore, the algae in treated wastewater with less abundance of bacteria proliferated more successfully, indicating that bacterial community not only played an important role in algal growth but also imposed a strong top-down control on the algal population. The algae grown in wastewater treated with fungi reached the highest specific growth rate (0.033 day-1), whereas the controls displayed the negative specific growth rate. The fatty acid composition varied markedly in C16:0 and C18:0 between these treatments, with a higher content of C16:0. CONCLUSIONS This study firstly showed that Chlorella can grow as cost-effective biofuel feedstocks in undiluted and unsterilized digested wastewater with high ammonium concentration and dark brown color because the bacterial abundance of digested piggery wastewater could be reduced greatly by the white rot fungi.

  • Hydrolysis of carotenoid esters from Tagetes erecta by the action of lipases from Yarrowia lipolytica.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-01-31
    Abraham Figueiras Abdala,Alfonso Pérez Gallardo,Lorenzo Guevara Olvera,Eleazar Máximo Escamilla Silva

    The present study was conducted to evaluate the feasibility of enzymatic hydrolysis of carotenoid esters from Tagetes erecta using lipases from the yeast of Yarrowia lipolytica, with the aim of obtaining free lutein. The optimal concentrations of seven nutrients, considering the production of lipases relative to biomass (Yp/x) as the response variable, were determined in flask fermentations. In addition, we studied the effect on hydrolysis of growing Y. lipolytica in the presence of the oleoresin of the marigold flower in flask and stirred tank. Furthermore, hydrolysis of the oleoresin using the lipases from this microorganism was compared with the hydrolysis using lipases from Rhizopus oryzae. Cultured in the presence of marigold oleoresin, Y. lipolytica showed an increase in free carotenoids of 12.41% in flask and 8.8% in stirred tank, representing a fourfold and a threefold increase compared to the initial value in the fermentation, respectively. When lipases from the supernatant from both microorganisms were used for only 14 h hydrolysis experiments, a slight increase was achieved compared to a blank. We concluded that carotenoid esters of the oleoresin could not be completely hydrolyzed in 14 h by these lipases, but that growing Y. lipolytica in the presence of marigold oleoresin gives until fourfold production of free carotenoids in 72 h fermentations.

  • Investigation of spiral-wound membrane modules for the cross-flow nanofiltration of fermentation broth obtained from a pilot plant fermentation reactor for the continuous production of lactic acid.
    Bioresour. Bioprocess. (IF 0) Pub Date : 2017-01-31
    Hendrik Laube,Roland Schneider,Joachim Venus

    BACKGROUND The separation performance of seven polymer membranes for the nanofiltration of sodium lactate in fermentation broth was investigated. Each module was introduced into the test stand, and the system curve was obtained by recording the permeate flow velocity at different pump head levels. Performance benchmarks were good permeate quality, as determined by high permeate flow velocity, high sodium lactic concentration, low ion impurity concentration, and low organic impurity concentration. Market research has shown that three companies, DOW (TW30, SW30, NF45), General Electric (DK73, DL73), and Microdyn-Nadir (NP30), distributed spiral-wound membrane modules for cross-flow filtration in a 2.5 by 40-in. module size, suitable for operation in the filtration test stand. RESULTS The measured permeate flow velocity was found to vary widely between the membranes. At a pump head of 250 m, DK73, NP30, and DL73 generated more than 200, 300, and 400% higher permeate flow velocities, respectively, than TW30 and NF45. A key benchmark, lactate rejection, was also highly dependent upon membrane type. The NP30, NF45, and TW30 membranes showed a decrease in lactate permeate flow velocity of 117, 83, and 348% starting at 205, 250, and 300 m, respectively. CONCLUSIONS The DL73 had the overall best performance according to the measured fermentation broth and lactic acid permeability. The presented method for the graphical analysis of the membrane performance proofed to be a useful tool for the filtration engineer.

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上海纽约大学William Glover