Tharak Athmakuri, Mohan S Venkata
Bioengineering and Environmental Science Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, India.
Micromachines (Basel). 2022 Jun 21;13(7):980. doi: 10.3390/mi13070980.
Microbial electrosynthesis system (MES; single-chambered) was fabricated and evaluated with carbon cloth/graphite as a working/counter electrode employing an enriched microbiome. Continuous syngas sparging (at working electrode; WE) enabled the growth of endo electrogenic bacteria by availing the inorganic carbon source. Applied potential (-0.5 V) on the working electrode facilitated the reduction in syngas, leading to the synthesis of fatty acids and alcohols. The higher acetic acid titer of 3.8 g/L and ethanol concentration of 0.2 g/L was observed at an active microbial metabolic state, evidencing the shift in metabolism from acetogenic to solventogenesis. Voltammograms evidenced distinct redox species with low charge transfer resistance (R; Nyquist impedance). Reductive catalytic current (-0.02 mA) enabled the charge transfer efficiency of the cathodes favoring syngas conversion to products. The surface morphology of carbon cloth and system-designed conditions favored the growth of electrochemically active consortia. Metagenomic analysis revealed the enrichment of phylum/class with Actinobacteria, Firmicutes/Clostridia and Bacilli, which accounts for the syngas fermentation through suitable gene loci.
构建了微生物电合成系统（MES；单室），并以碳布/石墨作为工作电极/对电极，利用富集的微生物群落进行评估。通过在工作电极（WE）处持续鼓入合成气，利用无机碳源促进了内生电细菌的生长。在工作电极上施加的电势（-0.5 V）促进了合成气的还原，从而导致脂肪酸和醇类的合成。在活跃的微生物代谢状态下，观察到较高的乙酸滴度为3.8 g/L，乙醇浓度为0.2 g/L，这证明了代谢从产乙酸转变为产溶剂。伏安图表明存在具有低电荷转移电阻（R；奈奎斯特阻抗）的不同氧化还原物种。还原催化电流（-0.02 mA）使阴极的电荷转移效率有利于合成气转化为产物。碳布的表面形态和系统设计条件有利于电化学活性菌群的生长。宏基因组分析揭示了放线菌门、厚壁菌门/梭菌纲和芽孢杆菌纲的富集，这通过合适的基因位点解释了合成气发酵过程。
