Producing hydrogen from the fermentation of cheese whey and glycerol as cosubstrates in an anaerobic fluidized bed reactor

This study aimed to evaluate the effect of the organic loading rate (OLR) (60, 90, and 120 g Chemical Oxygen Demand (COD). L-1.d(-1)) on hydrogen production from cheese whey and glycerol fermentation as cosubstrates (50% cheese whey and 50% glycerol on a COD basis) in a thermophilic fluidized bed reactor (55 degrees C). The increase in the OLR to 90 gCOD.L-1.d(-1) favored the hydrogen production rate (HPR) (3.9 L H2 center dot L-1.d(-1)) and hydrogen yield (HY) (1.7 mmol H(2 center dot)gCOD(app)(-1)) concomitant with the production of butyric and acetic acids. Employing 16S rRNA gene sequencing, the highest hydrogen production was related to the detection of Thermoanaerobacterium (34.9%), Pseudomonas (14.5%), and Clostridium (4.7%). Conversely, at 120 gCOD.L-1.d(-1), HPR and HY decreased to 2.5 L H2 center dot L-1.d(-1) and 0.8 mmol H(2 center dot)gCOD(app)(-1), respectively, due to lactic acid production that was related to the genera Thermoanaerobacterium (50.91%) and Tumebacillus (23.56%). Cofermentation favored hydrogen production at higher OLRs than cheese whey single fermentation. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.