Process for the successive production of calcium galactonate crystals by Gluconobacter oxydans Bioresource Technol. (IF 5.651) Pub Date : 2018-04-12 Xin Zhou, Xia Hua, Xuelian Zhou, Yong Xu
Galactonic acid and its salts can be potentially used in foodstuffs and as specialty chemicals. So far, the researches on microbial conversion of galactose to galactonate is still scarce. In this study, we initially used Gluconobacter oxydans strain NL 71 to convert galactose to galactonic acid via aerobic fermentation by fed-batch and product separation process in shaken flasks, finally 390 g/L galactonic acid could be obtained after 96 h fermentation. To harvest calcium galactonate product, an aeration-agitation bioreactor with product drain port was used. The lower solubility of calcium galactonate aided its crystallization and after 96 h of fermentation, approximately 720 g calcium galactonate crystals were produced from 1 L broth. The results showed that a successive bioprocess for the crystallization and production of calcium galactonate was put forward to efficiently improve galactonic acid bioconversion.
Discernment of Synergism in Pyrolysis of Biomass Blends using Thermogravimetric Analysis Bioresource Technol. (IF 5.651) Pub Date : 2018-04-12 Debarshi Mallick, Maneesh Kumar Poddar, Pinakeswar Mahanta, Vijayanand S. Moholkar
This study reports pyrolysis kinetics of biomass blends using isoconversional methods, viz. Friedman, FWO and KAS. Blends of three biomasses, viz. saw dust, bamboo dust and rice husk, were used. Extractives and volatiles in biomass and minerals in ash had marked influence on enhancement of reaction kinetics during co-pyrolysis, as indicated by reduction in activation energy and increase in decomposition intensity. Pyrolysis kinetics of saw dust and rice husk accelerated (positive synergy), while that of bamboo dust decelerated after blending (negative synergy). Predominant reaction mechanism of all biomass blends was 3-D diffusion in lower conversion range (α ≤ 0.5), while for α ≥ 0.5 pyrolysis followed random nucleation (or nucleation and growth mechanism). Higher reaction order for pyrolysis of blends of rice husk with saw dust and bamboo dust was attributed to catalytic effect of minerals in ash. Positive ΔH and ΔG was obtained for pyrolysis of all biomass blends.
Sustainable green pretreatment approach to biomass-to-energy conversion using natural hydro-low-transition-temperature mixtures Bioresource Technol. (IF 5.651) Pub Date : 2018-04-12 Chung Loong Yiin, Armando T. Quitain, Suzana Yusup, Yoshimitsu Uemura, Mitsuru Sasaki, Tetsuya Kida
Utilization of acetone-butanol-ethanol-water mixture obtained from biomass fermentation as renewable feedstock for hydrogen production via steam reforming: Thermodynamic and energy analyses Bioresource Technol. (IF 5.651) Pub Date : 2018-04-12 Brajesh Kumar, Shashi Kumar, Shishir Sinha, Surendra Kumar
A thermodynamic equilibrium analysis on steam reforming process to utilize acetone-butanol-ethanol-water mixture obtained from biomass fermentation as biorenewable fuel has been performed to produce clean energy carrier H2 via non-stoichiometric approach namely Gibbs free energy minimization method. The effect of process variables such as temperature (573-1473 K), pressure (1-10 atm), and steam/fuel molar feed ratio (FABE=5.5-12) have been investigated on equilibrium compositions of products, H2, CO, CO2, CH4 and solid carbon. The best suitable conditions for maximization of desired product H2, suppression of CH4, and inhibition of solid carbon are 973 K, 1 atm, steam/fuel molar feed ratio=12. Under these conditions, the maximum molar production of hydrogen is 8.35 with negligible formation of carbon and methane. Furthermore, the energy requirement per mol of H2 (48.96 kJ), thermal efficiency (69.13%), exergy efficiency (55.09%), exergy destruction (85.36 kJ/mol), and generated entropy (0.29 kJ/mol.K) have been achieved at same operating conditions.
Chemo-enzymatic synthesis of furfuralcohol from chestnut shell hydrolysate by a sequential acid-catalyzed dehydration under microwave and Escherichia coli CCZU-Y10 whole-cells conversion Bioresource Technol. (IF 5.651) Pub Date : 2018-04-12 Junhua Di, Cuiluan Ma, Jianghao Qian, Xiaolong Liao, Bo Peng, Yucai He
In this study, chemo-enzymatic synthesis of furfuralcohol from biomass-derived xylose was successfully demonstrated by a sequential acid-catalyzed dehydration under microwave and whole-cells reduction. After dry dewaxed chestnut shells (CNS, 75 g/L) was acid-hydrolyzed with dilute oxalic acid (0.5 wt%) at 140 oC for 40 min, the obtained CNS-derived xylose (17.9 g/L xylose) could be converted to furfural at 78.8% yield with solid acid SO42-/SnO2-Attapulgite (2.0 wt% catalyst loading) in the dibutyl phthalate-water (1:1, v:v) under microwave (600 W) at 180 oC for 10 min. In the dibutyl phthalate-water (1:1, v/v) media at 30 oC and pH 6.5, the furfural liquor (47.0 mM furfural) was biologically converted to furfuralcohol by recombinant Escherichia coli CCZU-Y10 whole-cells harboring an NADH-dependent reductase (PgCR) without extra addition of NAD+ and glucose, and furfural was completely converted to furfuralcohol after 2.5 h. Clearly, this one-pot synthesis strategy can be effectively used for furfuralcohol production.
Production of R,R-2,3-butanediol of ultra-high optical purity from Paenibacillus polymyxa ZJ-9 using homologous recombination Bioresource Technol. (IF 5.651) Pub Date : 2018-04-11 Li Zhang, Can Cao, Ruifan Jiang, Hong Xu, Feng Xue, Weiwei Huang, Hao Ni, Jian Gao
The present study describes the use of metabolic engineering to achieve the production of R,R-2,3-butanediol (R,R-2,3-BD) of ultra-high optical purity (> 99.99%). To this end, the diacetyl reductase (DAR) gene (dud A) of Paenibacillus polymyxa ZJ-9 was knocked out via homologous recombination between the genome and the previously constructed targeting vector pRN5101-L′C in a process based on homologous single-crossover. PCR verification confirmed the successful isolation of the dud A gene disruption mutant P. polymyxa ZJ-9-△dud A. Moreover, fermentation results indicated that the optical purity of R,R-2,3-BD increased from about 98% to over 99.99%, with a titer of 21.62 g/L in Erlenmeyer flasks. The latter was further increased to 25.88 g/L by fed-batch fermentation in a 5-L bioreactor.
Influence of biomass pretreatment on upgrading of bio-oil: comparison of dry and hydrothermal torrefaction Bioresource Technol. (IF 5.651) Pub Date : 2018-04-11 Xu Xiwei, Tu Ren, Sun Yan, Li Zhiyu, Jiang Enchen
The dry and hydrothermal torrefacation of on Camellia Shell (CS) was carried on three different devices- batch autoclave, quartz tube, and auger reactor. The torrefied bio-char products were investigated via TGA, elemental analysis and industrial analysis. Moreover, the pyrolysis and catalytic pyrolysis properties of torrefied bio-char were investigated. The results showed torrefaction significantly influenced the content of hemicellulose in CS. And hydrothermal torrefaction via batch autoclave and dry torrefaction via auger reactors promoted the hemicellulose to strip from the CS. Quartz tube and auger reactor were beneficial for devolatilization and improving heat value of torrefied bio-char. The result showed that the main products were phenols and acids. And hydrothermal torrefction pretreatment effectively reduced the acids content from 34.5% to 13.2% and enriched the content of phenols (from 27.23% to 60.05%) in bio-oil due to the decreasing of hemicellulos in torrefied bio-char. And the catalyst had slight influence on the bio-oil distribution.
Evaluation of phase separation in a single-stage vertical anaerobic reactor: performance and microbial composition analysis Bioresource Technol. (IF 5.651) Pub Date : 2018-04-11 Longyi Lv, Weiguang Li, Jiyong Bian, Yang Yu, Donghui Li, Zejia Zheng
In order to explore whether the acidogenic phase and methanogenic phase could be separated vertically into a single-stage anaerobic reactor, a controlled double circulation (CDC) anaerobic reactor was proposed for treating traditional Chinese medicine (TCM) wastewater in this study. The results showed that most of the organic pollutants and refractory were removed in the first reaction area where most of the amount of sludge existed. The organic acids were accumulated in the first reaction area, and larger specific methanogenic activity (SMA) and coenzyme F420 values were found in the second reaction area. Bacterial and archaeal community structures in the two reaction areas of the CDC reactor were analysised by Illumina MiSeq Sequencing, which revealed that the archaeal community showed larger difference compared with the bacterial community. Differences in the performance and microbial composition of the two reaction areas confirmed that phase separation was implemented in the CDC reactor.
Investigating the adsorption behavior and the relative distribution of Cd2+ sorption mechanisms on biochars by different feedstock Bioresource Technol. (IF 5.651) Pub Date : 2018-04-10 Rong-Zhong Wang, Dan-Lian Huang, Yun-Guo Liu, Chen Zhang, Cui Lai, Guang-Ming Zeng, Min Cheng, Xiao-Min Gong, Jia Wan, Hao Luo
The objective of this study was to investigate the adsorption behaviour and the relative distribution of Cd2+ sorption mechanisms on biochars by different feedstock. Bamboo biochars (BBCs), corn straw biochars (CBCs) and pig manure biochars (PBCs) were prepared at 300-700 °C. Adsorption results showed PBCs have the best adsorption capacity for Cd2+, the extra adsorption capacity of PBCs mainly attributed to the precipitation or cation exchange, which played an important role in the removal of Cd2+ by PBCs. The contribution of involved Cd2+ removal mechanism varied with feedstock due to the different components and oxygen-containing functional groups. Cd2+-π interaction was the predominant mechanism for Cd2+ removal on biochars and the contribution proportion significantly decreased from 82.17% to 61.83% as the ash content increased from 9.40% to 58.08%. Results from this study may suggest that the application of PBC is a feasible strategy for removing metal contaminants from aqueous solutions.
Co-digestion of food waste and sewage sludge for methane production: Current status and perspective Bioresource Technol. (IF 5.651) Pub Date : 2018-04-10 Sanjeet Mehariya, Anil Kumar Patel, Parthiba Karthikeyan Obulisamy, Elumalai Punniyakotti, Jonathan W.C. Wong
Food waste (FW) is a valuable resource which requires sustainable management avenues to reduce the hazardous environmental impacts and add-value for better economy. Anaerobic digestion (AD) is still reliable, cost-effective technology for waste management. Conventional AD was originally designed for sewer sludge digestion, is not effective for FW due to mainly high organics and volatile fatty acid (VFA) accumulation, hence better technical aptitudes and biochemical inputs are required for optimal biogas production. Besides, to overcome these challenges, FW co-digestion with complementary organic waste e.g. sewage sludge (SS) mixed which complement each other for better process design. The main aim of this article is to summarize the recent updates and review different holistic approaches for efficient anaerobic co-digestion (AcoD) of FW and SS to provide a comprehensive review on the topic. Moreover, to demonstrate the status and perspectives of AcoD at present scenario for Hong Kong and rest of the world.
Determination of the optimal aeration for nitrogen removal in biochar-amended aerated vertical flow constructed wetlands Bioresource Technol. (IF 5.651) Pub Date : 2018-04-10 Xu Zhou, Lei Gao, Hai Zhang, Haiming Wu
Nitrogen removal in vertical flow constructed wetlands (VFCWs) is still a key problem especially for treating low C/N wastewaters. In this study, nitrogen removal and nitrous oxide (N2O) emission in biochar-amended aerated VFCWs were evaluated under the varying intermittent aeration (different aeration times and aeration rates). The results indicated that the optimal aeration time and rate were 2 h d-1 and 0.6 L min-1, which could create alternant of aerobic and anaerobic conditions for the simultaneous nitrification and denitrification in VFCWs. Much higher removal efficiency of COD (95.9%), NH4+-N (96.6%), and TN (74.7%) was achieved under the optimal conditions, and moderate N2O emission (282 μg·m-2·h-1) was observed simultaneously. The results can be used to select the optimal aeration in the further design and application of biochar-amended aerated CW treatments.
Role of Ca-bentonite to improve the humification, enzymatic activities, nutrient transformation and end product quality during sewage sludge composting Bioresource Technol. (IF 5.651) Pub Date : 2018-04-10 Mukesh Kumar Awasthi, Sanjeev Kumar Awasthi, Quan Wang, Mrigendra Kumar Awasthi, Junchao Zhao, Hongyu Chen, Xiuna Ren, Meijing Wang, Zengqiang Zhang
This study was aimed to examine the response of Ca-bentonite (CB) amendment to improve the sewage sludge (SS) composting along with wheat straw (WS) as bulking agent. Five treatments (SS+WS) were mixed with or without blending of discrepant concentration of CB (2%, 4%, 6%, and 10%), respectively, and without CB added treatment applied as the control. The results showed that compared to control and 2%CB blended treatments, while the 6 to 10%CB -amended treatment indicated maximum enzymatic activities with the composting progress and highest organic matter degradation and loss. The amendment of 6 to 10%CB increased the humic acid, HA/FA ratio, DON, NH4+-N, NO3 and DOC but reduced the fulvic acids content and the maturity period by 2 weeks as compared to control. In addition, maturity parameters also confirmed that the highest seed germination was observed with the 10%CB applied compost followed by 6%CB, 4%CB and 2%CB applied treatments, respectively.
Generating cycle flow between dark and light zones with double paddlewheels to improve microalgal growth in a flat plate photo-bioreactor Bioresource Technol. (IF 5.651) Pub Date : 2018-04-09 Jun Cheng, Junchen Xu, Hongxiang Lu, Qing Ye, Jianzhong Liu, Junhu Zhou
Double paddlewheels were proposed to generate cycle flow for increasing horizontal fluid velocity between dark and light zones in a flat plate photo-bioreactor, which strengthened the mass transfer and the mixing effect to improve microalgal growth with 15% CO2. Numerical fluid dynamics were used to simulate the cycle flow field with double paddlewheels. The local flow field measured with particle image velocimetry fitted well with the numerical simulation results. The horizontal fluid velocity in the photo-bioreactor was markedly increased from 5.8×10-5 m/s to 0.45 m/s with the rotation of double paddlewheels, resulting in a decreased dark/light cycle period. Therefore, bubble formation time and diameter reduced by 24.4% and 27.4%, respectively. Meanwhile, solution mixing time reduced by 31.3% and mass transfer coefficient increased by 41.2%. The biomass yield of microalgae Nannochloropsis Oceanic increased by 127.1% with double paddlewheels under 15% CO2 condition.
Nuclease expression in efficient polyhydroxyalkanoates-producing bacteria could yield cost reduction during downstream processing Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Rodríguez G. Jesús E, Favaro Lorenzo, Pizzocchero Valentino, Lomolino Giovanna, Basaglia Marina, Casella Sergio
Industrial manufacturing of polyhydroxyalkanoates (PHAs) requires purification of PHAs granules from high-cell-density cultures. Cells are broken by homogenization and PHAs granules are cleansed and treated to obtain PHAs latexes. However, cell lysis releases large amounts of DNA which results in an increasing viscosity of the medium, hampering the following downstream steps. Drop in viscosity is generally achieved by costly procedures such as heat treatment or the supplementation of hypochlorite and commercially available nucleases. Searching for a cost-effective solution to this issue, a nuclease gene from Staphylococcus aureus has been integrated into two efficient PHAs-producing bacteria: Cupriavidus necator DSM 545 and Delftia acidovorans DSM 39. Staphylococcal nuclease has been proficiently expressed in both microbial hosts without affecting PHAs production. Moreover, the viscosity of the lysates of recombinant C. necator cells was greatly reduced, indicating that the engineered strain is expected to yield large reduction cost in PHAs downstream processing.
Enhanced bioreduction synthesis of ethyl (R)-4-chloro-3-hydroybutanoate by alkalic salt pretreatment Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Ganggang Chong, Junhua Di, Cuiluan Ma, Dajing Wang, Chu Wang, Lingling Wang, Pengqi Zhang, Jun Zhu, Yucai He
In this study, biomass-hydrolysate was used for enhancing the bioreduction of ethyl 4-chloro-3-oxobutanoate (COBE). Firstly, dilute alkalic salt pretreatment was attempted to pretreat bamboo shoot shell (BSS). It was found that enzymatic in situ hydrolysis of 20-50 g/L BSS pretreated with dilute alkalic salts (0.4% Na2CO3, 0.032% Na2S) at 7.5% sulfidity by autoclaving at 110 °C for 40 min gave sugar yields at 59.9%-73.5%. Moreover, linear relationships were corrected on solid recovery-total delignification-sugar yield. In BSS-hydrolysates, xylose and glucose could promote the reductase activity of recombinant E. coli CCZU-A13. Compared with glucose, hydrolysate could increase the reductase activity by 1.35-folds. Furthermore, the cyclohexane-hydrolysate (10:90, v/v) biphasic media containing ethylene diamine tetraacetic acid (EDTA,40 mM) and L-glutamine (150 mM) was built for the effective biosynthesis of ethyl (R)-4-chloro-3-hydroxybutanoate [(R)-CHBE] (94.6% yield) from 500 mM COBE. In conclusion, this strategy has high potential for the effective biosynthesis of (R)-CHBE (>99% e.e.).
Thermogravimetric kinetic modelling of in-situ catalytic pyrolytic conversion of rice husk to bioenergy using rice hull ash catalyst Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Adrian Chun Minh Loy, Darren Kin Wai Gan, Suzana Yusup, Bridgid Lai Fui Chin, Man Kee Lam, Muhammad Shahbaz, Pornkamol Unrean, Menandro N. Acda, Elisabeth Rianawati
The thermal degradation behaviour and kinetic parameter of non-catalytic and catalytic pyrolysis of rice husk (RH) using rice hull ash (RHA) as catalyst were investigated using thermogravimetric analysis at four different heating rates of 10, 20, 50 and 100 K/min. Four different iso conversional kinetic models such as Kissinger, Friedman, Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) were applied in this study to calculate the activation energy (EA) and pre-exponential value (A) of the system. The EA of non-catalytic and catalytic pyrolysis was found to be in the range of 152 to 190 kJ/mol and 146 to 153 kJ/mol, respectively. The results showed that the catalytic pyrolysis of RH had resulted in a lower EA as compared to non-catalytic pyrolysis of RH and other biomass in literature. Furthermore, the high Gibb’s free energy obtained in RH implied that it has the potential to serve as a source of bioenergy production.
Fermentation of Undetoxified Sugarcane Bagasse Hydrolyzates using a Two Stage Hydrothermal and Mechanical Refining Pretreatment Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Zhaoqin Wang, Bruce S. Dien, Kent D. Rausch, M.E. Tumbleson, Vijay Singh
In this study, liquid hot water pretreatment was combined with disk milling for pretreatment of sugarcane bagasse. Sugarcane bagasse was pretreated using liquid hot water (LHW) at 140 to 180°C for 10 min (20%w/w solids content) and then disk milled. Disk milling improved glucose release 41 to 177% and ethanol production from glucose/xylose cofermentation by 80% compared to only using LHW pretreatment. The highest ethanol conversion efficiency achieved was 94%, which was observed when bagasse was treated at 180°C with LHW and disk milled. However, a small amount of residual xylose (3g/L) was indicative that further improvement could be achieved to increase ethanol production.
Stable carbon isotope fractionation of chlorinated ethenes by a microbial consortium containing multiple dechlorinating genes Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Na Liu, Longzhen Ding, Haijun Li, Pengpeng Zhang, Jixing Zheng, Chih-Huang Weng
The study aimed to determine the possible contribution of specific growth conditions and community structures to variable carbon enrichment factors (Ɛ-carbon) values for the degradation of chlorinated ethenes (CEs) by a bacterial consortium with multiple dechlorinating genes. Ɛ-carbon values for trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride were −7.24% ± 0.59%, −14.6% ± 1.71%, and −21.1% ± 1.14%, respectively, during their degradation by a microbial consortium containing multiple dechlorinating genes including tceA and vcrA. The Ɛ-carbon values of all CEs were not greatly affected by changes in growth conditions and community structures, which directly or indirectly affected reductive dechlorination of CEs by this consortium. Stability analysis provided evidence that the presence of multiple dechlorinating genes within a microbial consortium had little effect on carbon isotope fractionation, as long as the genes have definite, non-overlapping functions.
Kinetic study of thermal degradation of olive cake based on a scheme of fractionation and its behavior impregnated of metals Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 L. Quesada, A. Pérez, M. Calero, G. Blázquez, M.A. Martín-Lara
This research aims to provide a better knowledge of the thermal decomposition of the olive cake as well as this lignocellulosic material loaded, in a previous stage of biosorption, with heavy metals for its use in processes of energy recovery. Firstly, isolation of constituents of the olive cake was carried out. Then, experiments were performed by thermogravimetric analysis (TGA) and differential thermogravimetry (DTG) under inert and oxidative atmosphere at a heating rate of 15 K/min for each isolated fraction. Next, adequate reactions schemes were proposed to find kinetic parameters. Validation of these schemes were verified by the goodness of fitting between experimental and simulated data. Also, some important combustion characteristics such as ignition and burnout temperatures were determined. With regard to the effect of metals, cadmium, copper, chromium, nickel and lead present in metal-loaded olivecake did not modify values of kinetic parameters which described the thermal decomposition processes.
Promoting helix pitch and trichome length to improve biomass harvesting efficiency and carbon dioxide fixation rate by Spirulina.sp in 660 m2 raceway ponds under purified carbon dioxide from a coal chemical flue gas Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Jun Cheng, Wangbiao Guo, Kubar Ameer Ali, Qing Ye, Guiyong Jin, Zhanshan Qiao
The helix pitch and trichome length of Spirulina.sp were promoted to improve the biomass harvesting efficiency and CO2 fixation rate in 660 m2 raceway ponds aerated with food-grade CO2 purified from a coal chemical flue gas. The CO2 fixation rate was improved with increased trichome length of the Spirulina.sp in a raceway pond with double paddlewheels, baffles, and CO2 aerators (DBA raceway pond). The trichome length has increased by 33.3 μm, and CO2 fixation rate has increased by 42.3% and peaked to 51.3 g/m2/d in a DBA raceway pond. Biomass harvesting efficiency was increased with increased helix pitch. When the day-average greenhouse temperature was 33 °C and day-average sunlight intensity was 72,100 lux, the helix pitch of Spirulina.sp was increased to 56.2 μm. Hence the biomass harvesting efficiency was maximized to 75.6% and biomass actual yield was increased to 35.9 kg in a DBA raceway pond.
Value-Added Biotransformation of Cellulosic Sugars by Engineered Saccharomyces cerevisiae Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Stephan Lane, Jia Dong, Yong-Su Jin
The substantial research efforts into lignocellulosic biofuels have generated an abundance of valuable knowledge and technologies for metabolic engineering. In particular, these investments have led to a vast growth in proficiency of engineering the yeast Saccharomyces cerevisiae for consuming lignocellulosic sugars, enabling the simultaneous assimilation of multiple carbon sources, and producing a large variety of value-added products by introduction of heterologous metabolic pathways. While microbial conversion of cellulosic sugars into large-volume low-value biofuels is not currently economically feasible, there may still be opportunities to produce other value-added chemicals as regulation of cellulosic sugar metabolism is quite different from glucose metabolism. This review summarizes these recent advances with an emphasis on employing engineered yeast for the bioconversion of lignocellulosic sugars into a variety of non-ethanol value-added products.
Adsorption removal of natural organic matters in waters using biochar Bioresource Technol. (IF 5.651) Pub Date : 2018-04-07 Duu-Jong Lee, Ya-Ling Cheng, Ruei-Jyun Wong, Xiao-Dong Wang
This work concerns the adsorption of aromatic organic matter from river water using various doses of a simulated biochar. The water yielded five UV254 peaks associated with organic matters in size exclusion chromatography (SEC), corresponding to molecular weights (MW) of 10000, 6500, 4800, 3000, and 1500 Da. Biochar removes all of these peaks with an overall adsorption of 6.4 mg-DOC/g-C, and preferentially removes organic matter with high MW. Physisorption control in a pseudo-second-order type model fits the adsorption kinetics. Biochar can therefore be used as an efficient adsorbent of organic matter in water.
Biodegradation of acrylamide by a novel isolate, Cupriavidus oxalaticus ICTDB921: identification, and characterization of the acrylamidase produced Bioresource Technol. (IF 5.651) Pub Date : 2018-04-06 Dattatray K. Bedade, Rekha S. Singhal
Hydrothermal processing as pretreatment for efficient production of ethanol and biogas from municipal solid waste Bioresource Technol. (IF 5.651) Pub Date : 2018-04-06 Peyman Mahmoodi, Keikhosro Karimi, Mohammad J. Taherzadeh
Organic fraction of municipal solid waste (OFMSW) is dominated by carbohydrates, including starch-based and lignocellulosic materials. The OFMSW was hydrothermally pretreated at 100–160 °C for 0–60 min, and then assessed for enzymatic ethanol production, followed by biogas production from the stillage. The highest glucose yield of 520 g/Kg of dry OFMSW, corresponding to 131% increase compared to that of the untreated OFMSW, was obtained after the pretreatment and enzymatic hydrolysis. Through ethanolic fermentation by an inhibitory tolerant fungus, Mucor indicus, 191.10 g ethanol/Kg of dry OFMSW was obtained, which was a 140.9% improvement in the ethanol yield compared to that from the untreated one. Methane production from the stillage (waste residues) resulted in 156 L/Kg OFMSW. In other words, a total of 10774 KJ energy/Kg of dry OFMSW was generated at the best conditions.
Aerobic granules cultivated with simultaneous feeding/draw mode and low-strength wastewater: performance and bacterial community analysis Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Qibin Wang, Renda Yao, Quan Yuan, Hui Gong, Heng Xu, Nasir Ali, Zhengyu Jin, Jiane Zuo, Kaijun Wang
Sequence batch reactors (SBR) with simultaneous feeding/draw mode and low-strength wastewater were used for the cultivation of aerobic granules, and analysis of bacterial community diversity were conducted. Results revealed that the ratio of chemical oxygen demand/total nitrogen removal amount for R1 with real wastewater and R2 with synthetic wastewater decreased from 9.9 to 8.7 and, 29.9 to 21.1, respectively, when volumetric exchange ratio (VER) decreased from 90% (stage I) to 50% (stage II), indicating that organic matter in real and low-strength wastewater was fully utilized with lower VER by denitrifying bacteria. Relative abundances of the genus Dechloromonas, Pseudomonas, Bacillus in R1, which are responsible for denitrifying phosphorus removal, were much higher than that in R2, accounting for the high efficiency of nitrogen and phosphorus removal from real wastewater with low influent C/N ratio of 3.6 on average. These results provide useful information for improving wastewater treatment efficiency in the future.
Evaluation of the mass transfer effects on delignification kinetics of atmospheric acetic acid fractionation of sugarcane bagasse with a shrinking-layer model Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Xuebing Zhao, Ruchun Wu, Dehua Liu
A shrinking-layer model by modification of classical shrinking-core model was developed based on cell wall multi-layered structure for delignification of sugarcane bagasse with sulfuric acid (SA) catalyzed atmospheric acetic acid (AA) fractionation. The general model for overall rate of delignification was obtained and further employed to evaluate the mass transfer effects on delignification. It was found that the external diffusion could be neglected under the studied fractionation conditions, while internal diffusion appeared to play an important role. The effective diffusion coefficient for lignin within the biomass was estimated as 6.7×10-14∼1.6×10-12 m2/s depending on temperature, solid content in the system and molecular weight of lignin. However, surface reaction also seems to be a limiting step to the overall rate of delignification. At the early stage of delignification, both internal diffusion and reaction were controlling steps, while at the late stage reaction seems to be the controlling step.
Improving hydrocarbon yield from catalytic fast co-pyrolysis of hemicellulose and plastic in the dual-catalyst bed of CaO and HZSM-5 Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Kuan Ding, Zhaoping Zhong, Jia Wang, Bo Zhang, Liangliang Fan, Shiyu Liu, Yunpu Wang, Yuhuan Liu, Daoxu Zhong, Paul Chen, Roger Ruan
The high concentration of oxygenated compounds in pyrolytic products prohibits the conversion of hemicellulose to important biofuels and chemicals via fast pyrolysis. Herein a dual-catalyst bed of CaO and HZSM-5 was developed to convert acids in the pyrolytic products of xylan to valuable hydrocarbons. Meanwhile, LLDPE was co-pyrolyzed with xylan to supplement hydrogen during the catalysis of HZSM-5. The results showed that CaO could effectively transform acids into ketones. A minimum yield of acids (2.74%) and a maximum yield of ketones (42.93%) were obtained at a catalyst to feedstock ratio of 2:1. The dual-catalyst bed dramatically increased the yield of aromatics. Moreover, hydrogen-rich fragments derived from LLDPE promoted the Diels-Alder reactions of furans and participated in the hydrocarbon pool reactions of non-furanic compounds. As a result, a higher yield of hydrocarbons was achieved. This study provides a fundamental for recovering energy and chemicals from pyrolysis of hemicellulose.
Exploring the potential of lactic acid production from lignocellulosic hydrolysates with various ratios of hexose versus pentose by Bacillus coagulans IPE 22 Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Yujue Wang, Weifeng Cao, Jianquan Luo, Yinhua Wan
The aim of this study was to investigate the feasibility of utilizing different lignocellulosic hydrolysates with various hexose versus pentose (H:P) ratios to produce lactic acid (LA) from Bacillus coagulans IPE 22 by fermentations with single and mixed sugar. In single sugar utilization, glucose tended to promote LA production, and xylose preferred to enhance cell growth. In mixed sugar utilization, glucose and pentose were consumed simultaneously when glucose concentration was lower than 20 g/L, and almost the same concentration of LA (50 g/L) was obtained regardless of the differences of H:P values. Finally, LA production from corn cob hydrolysates (CCH) contained 60 g/L mixed sugar verified the mechanisms found in the fermentations with simulated sugar mixture. Comparing with single glucose utilization, CCH utilization was faster and the yield of LA was not significantly affected. Therefore, the great potential of producing LA with lignocellulosic materials by B. coagulans was proved.
Mathematical model to appraise the inhibitory effect of phenolic compounds derived from lignin for biobutanol production Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Wen-Hsing Chen, Yan-Ru Zeng
This study aimed to establish a mathematical modeling to evaluate the inhibitory effect of phenolic derivatives on acetone-butanol-ethanol (ABE) fermentation by Clostridium saccharoperbutylacetonicum N1-4. Vanillin, 4-hydroxybenzoic acid, and syringaldehyde were selected to represent guaiacyl, hydroxyphenyl, and syringyl phenols, respectively, to be examined in a series of fed-batch experiments. Results show the presence of phenolic derivatives blocked the pathway of the assimilation of organic acids and reduced cell growth and glucose utilization. The inhibition model projected that the levels of 0.13, 0.14, and 0.04 g L-1 for vanillin, 4-hydroxybenzoic acid, and syringaldehyde, respectively, resulted in 25% inhibition of butanol production, whereas 100% inhibition was predicted at the levels of 4.94, 4.37, and 4.20 g L-1 for vanillin, 4-hydroxybenzoic acid, and syringaldehyde, respectively. Syringaldehyde was more toxic than the other two compounds. The established model described that the phenolic compounds derived from different phenyl propane monomers of lignin severely obstructed biobutanol production.
Removal of hexavalent chromium from aqueous solution by different surface-modified biochars: Acid washing, nanoscale zero-valent iron and ferric iron loading Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Yuen Zhu, Hua Li, Guixiang Zhang, Fanjian Meng, Lifen Li, Shan Wu
Willow residue biochar (BC) and modified biochars (hydrochloric acid washing (HBC), HBC loaded with nanoscale zero-valent iron (nZVI-HBC), and HBC loaded with ferric iron (Fe3+-HBC)) after aging were used for aqueous Cr(VI) removal. HBC (> 98.67%), nZVI-HBC (> 98.86%), and Fe3+-HBC (> 99.64%) kept high Cr(VI) removal rates under the acidic conditions within a wide pH range (< 7.0), indicating their good adaptability to pH change because of aging. Cr(VI) reduction to Cr(III) was the dominant removal mechanism. The formation of –COOH on BC, HBC, and nZVI-HBC indicates the oxidation of surface functional groups by Cr(VI) and simultaneous Cr(VI) reduction. The disappearance of nZVI peaks indicates the reduction of Cr(VI) to Cr(III) by nZVI. The color reaction result demonstrated that the converted Fe2+ in Fe3+-HBC contributed to Cr(VI) reduction. Taking into account the removal efficiency, recyclability, cost, preparation process, and stability of adsorbents, Fe3+-HBC was recommended for Cr(VI) removal.
Dynamics of bacterial composition and the fate of antibiotic resistance genes and mobile genetic elements during the co-composting with gentamicin fermentation residue and lovastatin fermentation residue Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Yuanwang Liu, Yao Feng, Dengmiao Cheng, Jianming Xue, StevenWakelin, Zhaojun Li
Dynamics in bacterial community composition, along with 13 antibiotic resistance genes (ARGs) and eight mobile genetic elements (MGEs), were assessed during co-composting with gentamicin and lovastatin fermentation residue (GFR and LFR, respectively). Using next generation sequencing, the key bacterial taxa associated with the different stages of composting were identified. Most importantly, Bacillus, belonging to Phylum Firmicutes, was associated with enhanced degradation of gentamicin, decomposition of organic matter (OM) and dissolved organic carbon (DOC), and also extension of the thermophilic phase of the composting cycle. During the course of composting, the patterns of different ARGs/MGEs varied. However, the total and the normalized (to bacterial numbers) copies both remained high. The abundance of various ARGs was related to bacterial abundance and community composition, and the changing pattern of individual ARGs was influenced by the selectivity of MGEs and bacteria.
Enhancing microalgae biofilm formation and growth by fabricating microgrooves onto the substrate surface Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Yun Huang, Yaping Zheng, Jun Li, Qiang Liao, Qian Fu, Ao Xia, Jingwei Fu, Yahui Sun
Attachment of cells to substrate surface is the premise for biofilm formation. To shelter microalgae cells from fluid shear stress and offer larger areas for microalgae attachment, the inerratic microgrooves, which can act as anchor points that offer larger areas for microalgae attachment and induce vortex to protect cells from hydraulic shear stress, were designed and fabricated into substrate surface. The results indicated that the shear stress on the surface with V-grooves was weaker than that on the surface with U-grooves, and 45° V-grooves with the width of 200 μm were benefit for cells attachment. The initial attachment time was shortened to 50 minutes under the hydraulic shear stress of 0.02 Pa compared to that of 135 minutes on the surface without microgrooves. Subsequently, the biofilm biomass concentration on the surface with 45° V-grooves increased by 14.29% to 165.84 g m-2 compared with that on flat substrates.
Efficient degradation of lignin in raw wood via pretreatment with heteropoly acids in γ-valerolactone/water Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Libo Zhang, Wenxiu Zheng, Ziming Wang, Yubo Ma, Ling Jiang, Tianfu Wang
The aim of this work was to study the degradation of lignin in raw wood via pretreatment with heteropoly acids as substitutes for traditional H2SO4 in γ-valerolactone/water. By optimizing catalyst concentration, reaction time and temperature, the optimal lignin degradation conditions are obtained (130 °C, 3 hours and 20 mM silicotungstic acid). SEM and FTIR measurements demonstrated the efficient lignin degradation ability of HPAs in the GVL/H2O solvent, with negligible damage to cellulose within the raw wood. Furthermore, an elaborated enzymatic hydrolysis study of the thus obtained cellulosic feedstock revealed its suitability for enzymatic digestion, with great potential as starting material for the production of fermentable sugar from biomass in future biorefinery applications.
Facile one-pot hydrothermal synthesis of cubic spinel-type manganese ferrite/biochar composites for environmental remediation of heavy metals from aqueous solutions Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Kyung-Won Jung, Seon Yong Lee, Young Jae Lee
This study reports the facile synthesis of cubic spinel-type manganese ferrite (MnFe2O4)/biochar (MF/BC) composites via a one-pot hydrothermal technique. Multiple characterizations demonstrated that the MnFe2O4 spinel nanoparticles were successfully grown on the biochar, which provides magnetic separability with superparamagnetic behavior and effective adsorption performance for heavy metals (Pb(II), Cu(II), and Cd(II)). The adsorption kinetics and isotherms can be well described with a pseudo-second-order and Sips isotherm models, respectively. Comparative adsorption in multi-heavy metal systems (binary and ternary) indicated that the adsorption affinity of MF/BC composites toward heavy metals followed the sequence of Pb(II) > Cu(II) > Cd(II), which followed the order of their covalent indexes. Thermodynamic analysis revealed that the adsorption process was endothermic and primarily governed by physisorption. This study provides a feasible and simple approach for the preparation of high-performance materials for the remediation of heavy metal-contaminated wastewater in a cost-effective manner.
Response of greenhouse gas emissions and microbial community dynamics to temperature variation during partial nitrification Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Wenlin Jia, Yunfan Chen, Jian Zhang, Cong Li, Qian Wang, Guangchao Li, Weihua Yang
This study investigated the greenhouse gas emission characteristics and microbial community dynamics with the variation of temperature during partial nitrification. Low temperature weakened nitrite accumulation, and partial nitrification would shift to complete nitrification easily at 15 °C. Based on CO2 equivalents (CO2-eq), partial nitrification process released 2.7 g of greenhouse gases per gMLSS per cycle, and N2O accounted for more than 98% of the total CO2-eq emission. The total CO2-eq emission amount at 35 °C was 45.6% and 153.4% higher than that at 25 °C and 15 °C, respectively. During partial nitrification, the microbial community diversity greatly declined compared with seed sludge. However, the diversity was enhanced at low temperature. The abundance of Betaproteobacteria at class level increased greatly during partial nitrification. Proteobacteria abundance declined while Nitrospira raised at low temperature. The nosZ community abundance was not affected by temperature, although N2O emission was varied with the operating temperature.
Comparison of liquid hot water, very dilute acid and alkali treatments for enhancing enzymatic digestibility of hazelnut tree pruning residues Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Kevser Sabanci, Ali Oguz Buyukkileci
The effect of pretreatments on the composition of the hazelnut tree pruning residue (HTPR) and on the digestibility of the cellulose was investigated. The liquid hot water (LHW) and the very dilute acid (VDA) treatments were effective in solubilizing hemicellulose. The cellulose conversion increased up to around 60% (corresponding to 32-36 g/L glucose) with decreasing hemicellulose concentration in the pretreated HTPR. The alkali treatment provided partial delignification, however, the glucose production was comparably lower. Combining the hemicellulose removal and the delignification effect of different pretreatments in two-stage processes (LHW-alkali and VDA-alkali treatments) enhanced the cellulose concentration in the solids, but not the amount of glucose released in the enzymatic digestion. These results suggested that the hemicellulose was the main barrier against the conversion of cellulose in the LHW and VDA treated HTPR and the glucose in the hydrolysis medium inhibited the cellulase activity, which prevented the complete conversion of cellulose.
A simple respirogram-based approach for the management of effluent from an activated sludge system Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Zhi-Hua Li, Yuan-Mo Zhu, Cheng-Jian Yang, Tian-Yu Zhang, Han-Qing Yu
Managing wastewater treatment plant (WWTP) based on respirometric analysis is a new and promising field. In this study, a multi-dimensional respirogram space was constructed, and an important index Res/t (ratio of in-situ respiration rate to maximum respiration rate) was derived as an alarm signal for the effluent quality control. A smaller Res/t value suggests better effluent. The critical R’es/t value used for determining whether the effluent meets the regulation depends on operational conditions, which were characterized by temperature and biomass ratio of heterotrophs to autotrophs. With given operational conditions, the critical R’es/t value can be calculated from the respirogram space and effluent conditions required by the discharge regulation, with no requirement for calibration of parameters or any additional measurements. Since it is simple, easy to use, and can be readily implemented online, this approach holds a great promise for applications.
Bioaugmentation strategy for enhancing anaerobic digestion of high C/N ratio feedstock with methanogenic enrichment culture Bioresource Technol. (IF 5.651) Pub Date : 2018-04-05 Ying Li, Lianhua Li, Yongming Sun, Zhenhong Yuan
To investigate whether bioaugmentation could improve the digestion performance of high C/N ratio feedstock without co-digestion with nitrogen-rich substrate, different forms of enriched methanogenic culture were introduced to the continuous feed digesters. The performance efficiency of bioaugmentation on digestion improvement was compared. The effect of bioaugmentation on microbial community composition was revealed as well. Results demonstrated that routine bioaugmentation with liquid culture (containing the microbes and the medium remains) showed the best performance, with the organic loading rate (OLR), methane percentage, volumetric methane production (VMP) and volatile solid methane production (VSMP) higher at 1.0 g L-1d-1, 24%, 0.22 L L-1 d-1 and 0.23 Lg-1VSd-1 respectively, compared to the non-bioaugmentation control. Whole genome pyrosequencing analysis suggested that consecutive microbial consortium addition could reconstruct the methanogens community by increasing the populations of acetoclastic methanogens Methanothrix, which could accelerate the degradation of acetate and methane production.
Effect of ciprofloxacin on methane production and anaerobic microbial community Bioresource Technol. (IF 5.651) Pub Date : 2018-04-04 Thi Mai Do, David C. Stuckey, Seungdae Oh
This study investigated the effects and fate of CIP on anaerobic sludge over a wide range of concentrations (0.05–50 mg/L), and 0.5–50 mg/L significantly inhibited organic removal and methanogenic activity, increased volatile fatty acids accumulation and low molecular weight soluble microbial products (SMPs), including p-cresol and nitrogen-containing compounds. Although microbial communities exposed to CIP did not differ significantly from the control in species diversity indices, Syntrophobacter and Methanothrix associated with acetogenesis and acetoclastic methanogenesis, respectively, were underrepresented in the CIP-exposed communities. Our study advances understanding of how environmentally relevant concentrations of CIP disrupts anaerobic digestion, which has important implications for anaerobic engineered systems treating CIP-bearing waste streams.
Combined bioaugmentation with anaerobic ruminal fungi and fermentative bacteria to enhance biogas production from wheat straw and mushroom spent straw Bioresource Technol. (IF 5.651) Pub Date : 2018-04-03 Alberto Ferraro, Giulia Dottorini, Giulia Massini, Valentina Mazzurco Miritana, Antonella Signorini, Giuseppe Lembo, Massimiliano Fabbricino
Biocatalytic strategies for the production of high fructose syrup from inulin Bioresource Technol. (IF 5.651) Pub Date : 2018-04-03 R.S. Singh, Kanika Chauhan, Ashok Pandey, Christian Larroche
The consumption of natural and low calorie sugars has increased enormously from the past few decades. To fulfil the demands, the production of healthy sweeteners as an alternative to sucrose has recently received considerable interest. Fructose is the most health beneficial and safest sugar amongst them. It is generally recognised as safe (GRAS) and has become an important food ingredient due its sweetening and various health promising functional properties. Commercially, high fructose syrup is prepared from starch by multienzymatic process. Single-step enzymatic hydrolysis of inulin using inulinase has emerged as an alternate to the conventional approach to reduce complexity, time and cost. The present review, outlines the enzymatic strategies used for the preparation of high fructose syrup from inulin/inulin-rich plant materials in batch and continuous systems, and its conclusions.
High-frequency, high-intensity electromagnetic field effects on Saccharomyces cerevisiae conversion yields and growth rates in a reverberant environment Bioresource Technol. (IF 5.651) Pub Date : 2018-04-03 Emmanuel Bertrand, Christophe Pasquier, David Duchez, Sebastien Girard, Agnès Pons, Pierre Bonnet, Catherine Creuly, Claude-Gilles Dussap
Studies of the effects of electromagnetic waves on Saccharomyces cerevisiae emphasize the need to develop instrumented experimental systems ensuring a characterization of the exposition level to enable unambiguous assessment of their potential effects on living organisms. A bioreactor constituted with two separate compartments has been designed. The main element (75% of total volume) supporting all measurement and control systems (temperature, pH, agitation, and aeration) is placed outside the exposure room whereas the secondary element is exposed to irradiation. Measurements of the medium dielectric properties allow the determination of the electromagnetic field at any point inside the irradiated part of the reactor and are consistent with numerical simulations. In these conditions, the growth rate of Saccharomyces cerevisiae and the ethanol yield in aerobic conditions are not significantly modified when submitted to an electromagnetic field of 900 and 2400 MHz with an average exposition of 6.11 V.m-1 and 3.44 V.m-1 respectively.
Electricity generation and removal performance of a microbial fuel cell using sulfonated poly (ether ether ketone) as proton exchange membrane to treat phenol/acetone wastewater Bioresource Technol. (IF 5.651) Pub Date : 2018-04-03 Hao Wu, Yu Fu, Chunyu Guo, Yanbo Li, Nanzhe Jiang, Chengri Yin
Conversion and recovery of saponifiable lipids from microalgae using a nonpolar solvent via lipase-assisted extraction Bioresource Technol. (IF 5.651) Pub Date : 2018-04-01 Sam Q.K. Law, Ronald Halim, Peter J. Scales, Gregory J.O. Martin
An integrated membrane bioreactor system with iron-dosing and side-stream co-fermentation for enhanced nutrient removal and recovery: System performance and microbial community analysis Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Ruo-hong Li, Bing Li, Xiao-yan Li
An integrated membrane bioreactor (MBR) system was developed for enhanced nutrient (N and P) removal and effective P recovery in wastewater treatment. The system consisted of an iron-dosing MBR and side-stream fermentation for P removal and recovery and side-stream denitrification for N removal. Around 98.1% of the total phosphorus (TP) in wastewater was removed by ferric iron-induced precipitation and membrane filtration in the aerobic MBR, and nearly 53.4% of the TP could be recovered via anaerobic fermentation from the MBR sludge. In addition, the fermenter that allowed acidogenic co-fermentation with food waste provided sufficient soluble organics for biological denitrification, and an overall 91.8% total N removal was achieved through the side-stream denitrification. High-throughput sequencing was applied to analyse the microbial communities in the integrated system, and important functional bacteria were identified for nitrification, denitrification, acidogenic fermentation and dissimilatory iron reduction through the different components of the system.
The mechanism of enhanced wastewater nitrogen removal by photo-sequencing batch reactors based on comprehensive analysis of system dynamics within a cycle Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Jianfeng Ye, Junyu Liang, Liang Wang, Giorgos Markou
To understand the mechanism of enhanced nitrogen removal by photo-sequencing batch reactors (photo-SBRs), which incorporated microalgal photosynthetic oxygenation into the aerobic phases of a conventional cycle, this study performed comprehensive analysis of one-cycle dynamics. Under a low aeration intensity (about 0.02 vvm), a photo-SBR, illuminated with light at 92.27 μ·mol·m-2·s-1, could remove 99.45% COD, 99.93% NH4+-N, 90.39% TN, and 95.17 % TP, while the control SBR could only remove 98.36% COD, 83.51% NH4+-N, 78.96% TN, and 97.75% TP, for a synthetic domestic sewage. The specific oxygen production rate (SOPR) of microalgae in the photo-SBR could reach 6.63 fmol O2·cell-1·h-1. One-cycle dynamics shows that the enhanced nitrogen removal by photo-SBRs is related to photosynthetic oxygenation, resulting in strengthened nitrification, instead of direct nutrient uptake by microalgae. A too high light or aeration intensity could deteriorate anoxic conditions and thus adversely affect the removal of TN and TP in photo-SBRs.
Effects of bean dregs and crab shell powder additives on the composting of green waste Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Lu Zhang, Xiangyang Sun
Composting is an effective and economic technology for the recycling of organic waste. In this study, bean dregs (BD) (at 0, 35, and 45%) and crab shell powder (CSP) (at 0, 15, and 25%) were evaluated as additives during the two-stage composting of green waste (GW). The GW used in this experiment mainly consisted of branch cuttings collected during the maintenance of the urban green landscape. Combined additions of BD and CSP improved composting conditions and compost quality in terms of composting temperature, specific surface area, average pore diameter, pH and EC values, carbon dioxide release, ammonia and nitrous oxide emissions, E4/E6 ratio, elemental composition and atomic ratios, organic matter degradation, microbial numbers, enzyme activities, compost phytotoxicity, and environmental and economic benefits. The combined addition of 35% BD and 25% CSP to the two-stage composting of GW resulted in the highest quality compost product in only 22 days.
Enhancing the Fock reactivity of dissolving pulp by the combined prerefining and Poly dimethyl diallyl ammonium chloride- assisted cellulase treatment Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Shuo Yang, Yangbing Wen, Hongjie Zhang, Jianguo Li, Yonghao Ni
Dissolving pulp is an important source of cellulose raw material, and its key quality parameter is the Fock reactivity for viscose rayon application. Cellulase treatment is an effective method for improving the Fock reactivity of kraft-based dissolving pulp. In this study, a novel process concept of improving the cellulase treatment for this purpose was developed, and it consists of mechanical pre-refining and PDADMAC-assisted cellulase treatment. The hypothesis is based on: 1) opening up the fiber structures to improve the cellulase accessibility by pulp prerefining, 2) the addition of cationic poly DADMAC to the subsequent cellulase stage enhances the cellulase adsorption onto anionic fibers due to favorable electrostatic interactions. The results showed that the Fock reactivity of the resultant pulp from the combined treatment is much higher than that of the control, yet, achieved at a much lower cellulase dosage.
Sodium thiosulphate induced immobilized bacterial disintegration of sludge: an energy efficient and cost effective platform for sludge management and biomethanation Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 U. Ushani, S. Kavitha, R. Yukesh Kannah, M. Gunasekaran, Gopalakrishnan Kumar, Dinh Duc Nguyen, Soon Woong Chang, J. Rajesh banu
Drinking water treatment sludge as an effective additive for biogas production from food waste; kinetic evaluation and biomethane potential test Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Mohammadali Ebrahimi-Nik, Ava Heidari, Shamim Ramezaniazghandi, Fatemeh Asadi Mohammadi, Habibollah Younesi
Enhanced Hydrolysis of Mechanically Pretreated Cellulose in Water/CO2 System Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Kejing Wu, Guangrong Feng, Yingying Liu, Changjun Liu, Xingyilong Zhang, Shijie Liu, Bin Liang, Houfang Lu
The aim of this work was to study promotion of ball milling and CO2 assistance on cellulose hydrolysis kinetics in water medium. Kinetic behaviors were analyzed based on first-order and shrinking core models. The results showed that cellulose hydrolysis is enhanced by ball milling and CO2 assistance. Ball milling reduced crystallinity and particle size of cellulose, resulting in high cellulose conversion, while hydrolysis promoted by CO2 assistance was weaker. Double-layer hydrolysis was observed for ball-milled cellulose, and rate constant in active layer is higher. Based on double-layer shrinking core model (DL-SCM), activation energy of cellulose conversion decreased from 73.6 to 39.8 kJ/mol when ball milling and CO2 assistance were applied. Hydrolysis active layer was about 0.9 μm, representing activated thickness of ball-milled cellulose. Hydrolysis promotion by crystallinity and particle size reduction was distinguished via DL-SCM, and crystal evolution possesses greater improvement than particle size decrease on hydrolysis of ball-milled cellulose.
Paracoccus versutus KS293 adaptation to aerobic and anaerobic denitrification: Insights from nitrogen removal, functional gene abundance, and proteomic profiling analysis Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Haihan Zhang, Zhenfang Zhao, Shengnan Chen, Pengliang Kang, Yue Wang, Ji Feng, Jingyu Jia, Miaomiao Yan, Yan Wang, Lei Xu
Magnetic bionanoparticles of Penicillium sp. yz11-22N2 doped with Fe3O4 and encapsulated within PVA-SA gel beads for atrazine removal Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Jiaping Yu, Huijun He, William L. Yang, Chunping Yang, Guangming Zeng, Xin Wu
A novel magnetic bionanomaterial, Penicillium sp. yz11-22N2 doped with nano Fe3O4 entrapped in polyvinyl alcohol-sodium alginate gel beads (PFEPS), was successfully synthesized. The factors including nutrient substance, temperature, pH, initial concentrations of atrazine and rotational speeds were presented and discussed in detail. Results showed that the highest removal efficiency of atrazine by PFEPS was 91.2% at 8.00 mg/L atrazine. The maximum removal capacity for atrazine was 7.94 mg/g. Meanwhile, it has been found that most of atrazine were removed by metabolism and degradation of Penicillium sp. yz11-22N2, which could use atrazine as the sole source of either carbon or nitrogen. Degradation kinetics of atrazine conformed to first-order kinetics model. The intermediates indicated that the possible pathway for atrazine degradation by PFEPS mainly included hydrolysis dechlorination, dealkylation, side-chain oxidation and ring-opening.
Hydrochars from Bamboo Sawdust through Acid Assisted and Two-Stage Hydrothermal Carbonization for Removal of Two Organics from Aqueous Solution Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Yin Li, Arun Meas, Shengdao Shan, Ruiqin Yang, Xikun Gai, Hongpeng Wang, Nyamkhand Tsend
Addition of granular activated carbon and trace elements to favor volatile fatty acid consumption during anaerobic digestion of food waste Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Gabriel Capson-Tojo, Roman Moscoviz, Diane Ruiz, Gaëlle Santa-Catalina, Eric Trably, Maxime Rouez, Marion Crest, Jean-Philippe Steyer, Nicolas Bernet, Jean-Philippe Delgenès, Renaud Escudié
Environmentally persistent free radicals mediated removal of Cr(VI) from highly saline water by corn straw biochars Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Nan Zhao, Zheng Yin, Feng Liu, Meiyi Zhang, Yizhong Lv, Zhengping Hao, Gang Pan, Jing Zhang
Hydrothermal synthesis of hierarchically structured birnessite-type MnO2/biochar composites for the adsorptive removal of Cu(II) from aqueous media Bioresource Technol. (IF 5.651) Pub Date : 2018-03-31 Kyung-Won Jung, Seon Yong Lee, Young Jae Lee
Symbiotic relationship between hydrothermal carbonization technology and anaerobic digestion for food waste in China Bioresource Technol. (IF 5.651) Pub Date : 2018-03-30 Ying Zhou, Nils Engler, Michael Nelles
Food waste (FW) is traditionally disposed through landfills and incineration in China. Nowadays, there are some promising methods, such as anaerobic digestion (AD) or feeding and composting, which are being applied in pilot cities. However, the inherent characteristics of Chinese FW may be regarded as a double-edged sword in the practical applications of these disposal methods. To overcome these challenges, two modes of the hydrothermal carbonization (HTC) process were reviewed as innovative strategies in this article. Meanwhile, the “symbiotic relationship” between Chinese FW and HTC technologies was highlighted. To improve treatment efficiency of FW, we should not only try different methods and develop existing technologies, but also pay more attention to the utilization and “1+1>2” synergistic effect of their combinations, such as the combination of HTC and AD as a co-treatment method for saving on the construction cost and avoiding redistribution of social resources.
Synthetic Escherichia coli-Corynebacterium glutamicum consortia for l-lysine production from starch and sucrose Bioresource Technol. (IF 5.651) Pub Date : 2018-03-30 Elvira Sgobba, Anna K. Stumpf, Marina Vortmann, Nina Jagmann, Martin Krehenbrink, Mareike Dirks-Hofmeister, Bruno Moerschbacher, Bodo Philipp, Volker F. Wendisch
In the biorefinery concept renewable feedstocks are converted to a multitude of value-added compounds irrespective of seasonal or other variations of the complex biomass substrates. Conceptionally, this can be realized by specialized single microbial strains or by co-culturing various strain combinations. In the latter approach strains for substrate conversion and for product formation can be combined. This study addressed the construction of binary microbial consortia based on starch- and sucrose-based production of l-lysine and derived value-added compounds. A commensalism-based synthetic consortium for l-lysine production from sucrose was developed combining an l-lysine auxotrophic, naturally sucrose-negative E. coli strain with a C. glutamicum strain able to produce l-lysine that secretes fructose when grown with sucrose due to deletion of the fructose importer gene ptsF. Mutualistic synthetic consortia with an l-lysine auxotrophic, α-amylase secreting E. coli strain and naturally amylase-negative C. glutamicum strains was implemented for production of valuable fine chemicals from starch.
Performance of pilot scale anaerobic biofilm digester (ABD) for the treatment of leachate from a municipal waste transfer station Bioresource Technol. (IF 5.651) Pub Date : 2018-03-30 Y. Arij, S. Fatihah, A.R. Rakmi
The anaerobic treatment of leachate from a municipal waste transfer station in Malaysia was tested using a pilot scale anaerobic biofilm digester system that was operated under HRT sequence of 30-day, 25-day, 20-day and 10-day for 163 days under mesophilic conditions. Despite the leachate’s complex characteristics, the system showed great performance given its maximum COD, BOD5 and total phosphorus removal efficiencies of 98±1%, 99±1% and 92±9% respectively. The system was stable throughout its operation and showed optimal average values for the monitored parameters such as pH (7.53±0.14), total VFA (79±66 mg HOAc/L), alkalinity (10,919±1556 mg CaCO3/L) and a non-toxic value for accumulated ammonia (960±106 mg NH3-N/L). Measurement of the average daily biogas production yielded a value of 25±1 m3/day throughout the system’s operation with a composition of 57±12% methane and 26±6% carbon dioxide.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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