Biochar-mediated enhanced ethanol fermentation (BMEEF) in Zymomonas mobilis under furfural and acetic acid stress

• Published in: Biotechnology for biofuels Vol. 13; no. 1; p. 28
• Main Authors: Wang, Wei-Ting, Dai, Li-Chun, Wu, Bo, Qi, Bu-Fan, Huang, Tian-Fang, Hu, Guo-Quan, He, Ming-Xiong
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 26.02.2020; BioMed Central; BMC
• Subjects: Acetic acid; Acidification; Acids; Alternative energy sources; Biochar; Biomass energy research; Charcoal; Chemical properties; Ethanol; Fermentation; Furfural; Genetic engineering; Glucose; Lignocellulose; Lignocellulosic hydrolysate; Methods; Organic acids; Production management; Production processes; Productivity; Proteobacteria; Soil amendments; Zymomonas mobilis; China; Furfural; Acetic acid; Biochar; Lignocellulosic hydrolysate; Zymomonas mobilis
• ISSN: 1754-6834; 1754-6834
• DOI: 10.1186/s13068-020-1666-6

Pretreatment of lignocellulosic biomass generates different types of inhibitors (e.g., furfural and acetic acid), which could remarkably inhibit subsequent ethanol fermentation. Here, biochar as an additive in the fermentation broth was first applied to enhance ethanol production by wild-type strain ZM4 in the presence of typical inhibitors. This study showed that the biochar-mediated tolerance to furfural and acetic acid for the strain  ZM4 was the highest reported level, resulting in much higher ethanol productivity under stress conditions than that in non-treated conditions. Further analysis showed that adsorptive detoxification was not the controlling factor for enhanced ethanol production under stress conditions, attributed to its low removal of furfural (< 20%) and incapability of acetic acid removal. When biochar was filtered from the biochar-treated inhibitor-containing broth, it still showed enhanced ethanol production. Furthermore, immobilized on biochar was also observed. Thus, biochar extracts in the fermentation broth and cell immobilization on biochar might be the controlling factors for enhanced ethanol production under stress conditions. These results indicate that biochar-mediated enhanced ethanol fermentation (BMEEF) might be a promising strategy for ethanol production from lignocellulosic biomass.