Construction and physiological studies of hydrogenase depleted mutants of Desulfovibrio fructosovorans.

ABSTRACT

Desulfovibrio fructosovorans possesses two periplasmic hydrogenases (a nickel-iron and an iron hydrogenase) and a cytoplasmic NADP-dependent hydrogenase. The hydAB genes encoding the periplasmic iron hydrogenase were replaced, in the wild-type strain as well as in single mutants depleted of one of the other two hydrogenases, by the acc1 gene encoding resistance to gentamycin. Molecular characterization and remaining activity measurements of the resulting single and double mutants were performed. All mutated strains exhibited similar growth when H(2) was the electron donor but they grew differently on fructose, lactate or pyruvate as electron donors. Our results indicate that the loss of one enzyme might be compensated by another even though hydrogenases have different localization in the cells.