Potentialities of biotechnological recovery of hydrogen and short- and medium-chain organic acids from the co-fermentation of cheese whey and Yerba Mate (Ilex paraguariensis) waste

Co-fermentation of cheese whey (CW) and thermal-alkaline pre-treated Yerba Mate (Ilex paraguariensis) waste (YMW) was performed aiming to produce biohydrogen and/or short- medium-chain organic acids. Central Composite Designs (CCD) chosen as the experimental design for evaluating combinations three independent variables namely YMW concentration, pH inoculum concentration in hydrogen yield (H2Y; response variable). The increase concentrations had positive effect production (H2Ymax 1.35 mmolH2. g−1 VS added) whereas initial no significant on it. Hydrogen produced a coproduct butyrate mainly. Acetate from homoacetogenesis accounted all conditions evaluated. CCD also indicated operating moderate-to-high short acids such (∼135 mM), caproate (∼45 mM) lactate (∼140 mM). 16S rRNA gene sequences analysis revealed five groups microorganisms related hydrogen, production, ethanol-hydrogen co-production consumption.