Significance of acclimatization for biohydrogen production from synthetic lignocellulose hydrolysate in continuous-flow systems

This study investigated the response of acclimatized anaerobic hydrogen-producing cultures to feed changes in continuous-flow systems. Two identical integrated biohydrogen reactor clarifier systems (IBRCS) which were used for biohydrogen production from glucose at a concentration of 10 g/L (phase 1) and then switched to a mixture of xylose, arabinose, glucose, and cellobiose at a concentration of 2.5 g/L each (phase 2) prior to reverting to glucose at a concentration of 10 g/L (phase 3) exhibited hydrogen yields in phases 1, 2, and 3 of 2.3, 1.1, and 1.0 mol H2/mol sugar, respectively. Acetate was the main soluble product in phase 1 while propionate was predominant in phases 2 and 3. The genus Ethanoligenes, Clostridium, Bulleidia, and Ruminococcus were dominant in phase 1, while Coriobacteriaceae family and genera Megasphaera and Bifidobacterium were dominant in phases 2 and 3, in addition to Ethanoligenes in phase 3 in both reactors.