Enhanced biohydrogen production by an acid-tolerant strain isolated from food wastewater

Biohydrogen production from food waste leachate (FWL) was investigated using microbial strains inherently tolerant to environments abundant in volatile fatty acids (VFAs). Four hydrogen-producing isolated strains (IS #1-4) were obtained from large-scale food waste digesters (>100 tons/day) in South Korea. Among them, IS #1 and IS #3 exhibited 28 % and 18 % higher hydrogen yields than their type strains (TS) when cultivated with FWL. The best performing strain, P. bifermentans (IS #1), was selected for evaluation of the acid-tolerance using simulated FWL (0-50 g/L VFAs). As a result, hydrogen productivity was found to be 244 %, 145 %, 171 %, and 260 % higher than that of the TS at concentrations of 0, 30, 35, and 40 g/L VFAs, respectively. These results showed that microbial adaptation to the environment enhances resistance. Consequently, the application of resistant strains can be utilized as a cost-effective and easily accessible strategy for commercializing biohydrogen production processes.