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Medium-Chain Fatty Acid Synthesis by "Candidatus Weimeria bifida" gen. nov., sp. nov., and "Candidatus Pseudoramibacter fermentans" sp. nov.
Applied and Environmental Microbiology ( IF 4.4 ) Pub Date : 2020-01-21
Scarborough, M. J., Myers, K. S., Donohue, T. J., Noguera, D. R.

Chain elongation is emerging as a bioprocess to produce valuable medium-chain fatty acids (MCFA; 6 to 8 carbons in length) from organic waste streams by harnessing the metabolism of anaerobic microbiomes. Although our understanding of chain elongation physiology is still evolving, the reverse β-oxidation pathway has been identified as a key metabolic function to elongate the intermediate products of fermentation to MCFA. Here, we describe two uncultured chain-elongating microorganisms that were enriched in an anaerobic microbiome transforming the residues from a lignocellulosic biorefining process. Based on a multi-omic analysis, we describe "Candidatus Weimeria bifida" gen. nov., sp. nov., and "Candidatus Pseudoramibacter fermentans" sp. nov., both predicted to produce MCFA but using different substrates. The analysis of a time series metatranscriptomic data set suggests that "Ca. Weimeria bifida" is an effective xylose utilizer since both the pentose phosphate pathway and the bifid shunt are active. Furthermore, the metatranscriptomic data suggest that energy conservation during MCFA production in this organism is essential and occurs via the creation of an ion motive force using both the RNF complex and an energy-conserving hydrogenase. For "Ca. Pseudoramibacter fermentans," predicted to produce MCFA from lactate, the metatranscriptomic analysis reveals the activity of an electron-confurcating lactate dehydrogenase, energy conservation via the RNF complex, H2 production for redox balance, and glycerol utilization. A thermodynamic analysis also suggests the possibility of glycerol being a substrate for MCFA production by "Ca. Pseudoramibacter fermentans." In total, this work reveals unknown characteristics of MCFA production in two novel organisms.

IMPORTANCE Chain elongation by medium-chain fatty acid (MCFA)-producing microbiomes offers an opportunity to produce valuable chemicals from organic streams that would otherwise be considered waste. However, the physiology and energetics of chain elongation are only beginning to be studied, and many of these organisms remain uncultured. We analyzed MCFA production by two uncultured organisms that were identified as the main MCFA producers in a microbial community enriched from an anaerobic digester; this characterization, which is based on meta-multi-omic analysis, complements the knowledge that has been acquired from pure-culture studies. The analysis revealed previously unreported features of the metabolism of MCFA-producing organisms.



中文翻译:

用“ Candidatus Weimeria bifida”基因合成中链脂肪酸。十一月,sp。十一月号,和“发酵假单胞菌”。十一月

通过利用厌氧微生物的新陈代谢,链伸长正在作为一种生物过程从有机废物流生产有价值的中链脂肪酸(MCFA;长度为6至8个碳),正在兴起。尽管我们对链延长生理学的理解仍在发展,但反向β氧化途径已被确定为将发酵中间产物延长为MCFA的关键代谢功能。在这里,我们描述了两个未培养的链延长微生物,它们富含厌氧微生物组,可转化木质纤维素生物精制过程中的残留物。基于多组学分析,我们描述了“ Candidatus Weimeria bifida”基因。十一月,sp。十一月和“念珠菌Pseudoramibacter发酵氨基酸“属十一月,既预期可产生MCFA,但使用不同的底物。时间序列metatranscriptomic数据组的分析表明,”。Weimeria bifida”是有效的木糖利用者,因为戊糖磷酸途径和bifid分流器都是活跃的。此外,超转录组学数据表明,在该生物体中MCFA产生过程中的能量守恒是必不可少的,并且通过使用两者产生离子动力来实现的RNF络合物和节能氢化酶。对于“。发酵假单胞菌”,预计会从乳酸中产生MCFA,后转录组学分析揭示了一种电子化的乳酸脱氢酶的活性,通过RNF络合物的节能,生产氧化还原平衡和甘油利用率。的热力学分析还表明甘油是用于生产MCFA通过衬底的可能性“的Ca。Pseudoramibacter发酵氨基酸”。总的来说,这项工作揭示了两种新型生物中MCFA产生的未知特征。

重要信息产生中链脂肪酸(MCFA)的微生物群的链延长作用提供了从有机流中生产有价值的化学物质的机会,否则这些化学物质将被视为废物。但是,链伸长的生理学和能量学才刚刚开始被研究,并且其中许多生物仍未培养。我们分析了两种未经培养的微生物的MCFA产生,这两种微生物被确定为富含厌氧消化池的微生物群落中主要的MCFA生产者;这种基于元多组学分析的特征补充了从纯培养研究中获得的知识。该分析揭示了生产MCFA的生物的代谢以前未报道的特征。

更新日期:2020-01-22
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