Аңдатпа
Various pretreatment methods for the valorization of sunflower husks (SHs) for H2 gas generation through fermentation by Escherichia coli were investigated. We analyzed thermal treatment (TT), acid hydrolysis (AH), and alkaline hydrolysis (AlkH) at different substrate concentrations (50 g L−1, 75 g L−1, 100 g L−1, and 150 g L−1) and dilution levels (undiluted, 2× diluted, and 5× diluted). A concentration of 75 g L−1 SH that was acid-hydrolyzed and dissolved twice in the medium yielded optimal microbial growth, reaching 0.3 ± 0.1 g cell dry weight (CDW) L−1 biomass. The highest substrate level enabling effective fermentation was 100 g L−1, producing 0.37 ± 0.13 (g CDW) × L−1 biomass after complete fermentation, while 150 g L−1 exhibited pronounced inhibitory effects. It is worth mentioning that the sole alkaline treatment was not optimal for growth and H2 production. Co-fermentation with glycerol significantly enhanced both biomass formation (up to 0.42 ± 0.15 (g CDW) × L−1)) and H2 production. The highest H2 yield was observed during batch growth at 50 g L−1 SH hydrolysate with 5× dilution, reaching up to 5.7 mmol H2 (g sugar)−1 with glycerol supplementation. This study introduces a dual-waste valorization strategy that combines agricultural and biodiesel industry residues to enhance clean energy generation. The novelty lies in optimizing pretreatment and co-substrate fermentation conditions to maximize both biohydrogen yield and microbial biomass using E. coli, a widely studied and scalable host.