The effects of metal ions and l-cysteine on hydA gene expression and hydrogen production by Clostridium beijerinckii RZF-1108

Abstract

The effects of Fe2+, Mg2+ ions and l-cysteine on hydrogen production and cell growth of Clostridium beijerinckii RZF-1108 were investigated, and [FeFe]-hydrogenase (hydA) gene expression under different conditions was evaluated using quantitative reverse transcription PCR (qRT-PCR). Best concentration of Fe2+ stimulated hydrogen production, cell biomass and hydA gene expression in C. beijerinckii RZF-1108. Mg2+ increased cell growth and hydrogen evolution, but negatively facilitated hydrogen production rate and hydA gene expression. l-cysteine slightly stimulated hydA gene expression, but not hydrogen production in strain RZF-1108. A maximum hydrogen yield of 1.96 mol H2/mol glucose and production rate of 106.0 ml H2/l medium·h−1 were obtained using optimized culture medium supplemented with 0.2 g/l FeSO4·7H2O and 0.1 g/l MgCl2·6H2O. These experimental results suggested that the effects of metal ions on hydrogen production by C. beijerinckii RZF-1108 was complicated. Hydrogen production was highly dependent on the cooperation of cell growth and hydrogenase gene expression.