Catalyzing the metabolism through CoFe2O4 magnetic photocatalyst for photo fermentative biohydrogen production: Selectivity and recyclability across diverse strains

The interaction between the photo-induced charges from photo nanocatalysts (PNCs) and biohydrogen production strains plays a key role in controlling the metabolism mechanism in fermentative biohydrogen production from lignocellulosic biomass wastes. Thus, in the present study, two strains of Rhodopseudomonas palustris (PNSB) and a mixed consortium of HAU-M1 were evaluated for their biohydrogen production potential from corn stover (CS), whereas metabolism was catalyzed through photo-induced electrons from magnetic PNCs of cobalt ferrite (CoFe 2 O 4 ). The threshold concentration of CoFe 2 O 4 (400 mg/L) produced 428.62 mL and 373.30 mL biohydrogen in PNSB and HAU-M1, which is 129.0 % and 81.12 % higher as compared to respective control groups (CGs), respectively. The presence of PNCs provides the photo-induced electrons, which catalyze the metabolic processes as butyric acid increases by 96.29 % and 94.87 % in PNSB and HAU-M1, respectively, hence increasing hydrogen production. The results were supported by microbial community investigation, which showed that the incorporation of the appropriate concentration of PNCs effectively changes the bacterial community dynamics and diversifies the phyla ( Firmicutes , Proteobacteria , and Bacteroidetes ) and hydrogen-producing genus Clostridium . The recovered yield of CoFe 2 O 4 PNCs from PNSB and HAU-M1 fermentative mediums in three consecutive cycles was (90.87 %, 88.94 %), (80.25 %, 72.25 %), and (69.75 %, 60.80 %) respectively showing potential for recycling catalysts during the fermentation process. Thus, selecting the right photocatalysts and strain can affect metabolism and biohydrogen production, while recyclability reduces environmental leaching.