Yonghua Luo and Mary Ann Bruns
The Pennsylvania State University
Biohydrogen production from organic wastes can provide a relatively inexpensive source of renewable energy. Many bacterial species produce H2 gas as a fermentation byproduct from diverse organic substrates. The effects of L-cysteine addition on H2 production and bacterial community composition were tested in batch systems of artificial wastewater inoculated with pre-heated soil. Addition of L-cysteine (0.5 g l-1) resulted in Eh reduction of the medium from +100 to -90 mV and resulted in a bacterial community dominated by Clostridium spp. Cultures grown without L-cysteine were dominated by members of Enterobacteriaceae. Growth with L-cysteine was associated with higher amounts of H2 and higher glucose-to-H2 conversion efficiencies.