Advances towards the understanding of microbial communities in dark fermentation of enzymatic hydrolysates: Diversity, structure and hydrogen production performance

• Published in: International journal of hydrogen energy 2021-08, Vol.46 (54), p.27459-27472
• Main Authors: Palomo-Briones, Rodolfo, Montoya-Rosales, José de Jesús, Razo-Flores, Elías
• Format: Article
• Language: English
• Subjects: Biohydrogen; Dark fermentation; Enzymatic hydrolysates; Microbial communities; Microbial diversity
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.06.016

Microbial communities involved in hydrogen (H2) production from enzymatic hydrolysates of agave bagasse were analyzed through 16S rRNA sequencing. Two types of reactor configurations and four different enzymatic hydrolysates were evaluated. Trickling bed reactors led to highly-diverse microbial communities, but low volumetric H2 production rates (VHPR, maximum: 5.8 L H2/L-d). On the contrary, well-controlled environments of continuous stirred-tank reactors favored the establishment of low diverse microbial communities composed by Clostridium-Sporolactobacillus leading to high-performance H2-production (VHPR maximum: 13 L H2/L-d). Cellulase-Viscozyme and Celluclast-Viscozyme hydrolysates led to the co-dominance of Clostridium and Sporolactobacillus, possibly due to the presence of xylose and hemicellulose-derived carbohydrates. Cellulase hydrolysates were linked to communities dominated by Clostridium, while maintaining low abundance of Sporolactobacillus. Stonezyme hydrolysates favored microbial communities co-dominated by Clostridium-Lachnoclostridium-Leuconostoc. Moreover, contrary to the prevailing theory, it was demonstrated that H2 production performance was inversely related to microbial diversity. [Display omitted] •Microbial communities performed hydrolysis, primary and secondary fermentation.•Clostridium and Lachnoclostridium perform H2 production from enzymatic hydrolysates.•Controlled environments in CSTR favored low diverse microbial communities.•Trickling bed reactors lead to high diversity microbial communities.•H2 production rate was inversely related to the microbial diversity.