Impact of culture source and linoleic acid (C18:2) on biohydrogen production from glucose under mesophilic conditions

Genomic and statistical methods were used to demonstrate the effects of linoleic acid (LA) on hydrogen (H2) production in mixed anaerobic cultures from two sources (designated as A and B). The microbial composition of the control cultures CA and CB were statistically different. Bacteroidaceae (26%) and Clostridiaceae (10%) dominated CA whereas Clostridiaceae (33%) and Bacteroidaceae (10%) dominated CB. Homoacetogens directed 42% of the electron equivalents to acetate production and decreased the H2 yield by 50% in CA compared to CB. The maximum H2 yields (3.11 ± 0.02 and 3.11 ± 0.07 mol H2 mol−1 glucose in LA-treated cultures ALA and BLA, respectively) were statistically the same. Cultures ALA and BLA followed the acetate-butyrate pathway while CA and CB followed propionate and homoacetogenic pathways. LA-treated and control cultures were statistically different based on the type and quantity of metabolites; the differences were also confirmed by principal component analysis (PCA).

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Impact of linoleic acid on hydrogen yield using different anaerobic cultures. ► Same maximum H2 yield for the two microbial cultures fed the same LA concentration. ► Propionate production was dominant in controls. ► Butyrate pathway was central in cultures fed LA. ► Cultures fed LA statistically different than controls based on genomic and statistical tools.