Effects of Iron on Hydrogen-producing Capacity,Hydrogenase and NADH-fd Reductase Activities of a Fermentative Hydrogen-producing Bacterial Strain B49

Iron plays an important role in hydrogen production, cell growth, hydrogenase and NADH-fd reductase activities of hydrogen-producing bacterial strain B49 (AF481148 in EMBL). At the end of fermentation from 10 g/L glucose, for the culture containing 10 mg/L FeSO4*7H2O the cell growth in terms of optical density (OD) at 600nm was 1.13, the ratio of ethanol amount (mg/L) to acetate amount (mg/L) was 1.55, and the accumulated hydrogen volume was 1816.3 ml H2/L culture; whereas for the culture of 80 mg/L FeSO4*7H2O OD600nm was increased to 1.34, the accumulated hydrogen volume was increased to 2360.5 ml H2/L culture, and the ratio of ethanol amount (mg/L) to acetate amount (mg/L) decreased to 1.31. Moreover, the iron addition to the medium at different fermentation time could affect hydrogen-producing ability. However, the later the addition time of FeSO4*7H2O was postponed, the less the effect on hydrogen evolution was. In the course of fermentation, the specific activities of hydrogenase and NADH-fd reductase of hydrogen-producing bacterial strain B49 decreased with the consumption of iron.