Hydrogenase and ribulose-1, 5-bisphosphate carboxylase activities of Alcaligenes eutrophus ATCC 17706 associated with an indigenous plasmid

Abstract

Mutants of Alcaligenes eutrophus ATCC 17706 defective in hydrogen uptake (hydrogen oxidation) were isolated following treatment with the plasmid-curing agents Mitomycin C and Acridine orange. These mutants were devoid of hydrogenase and D-ribulose-1, 5-bisphosphate carboxylase activities, but were able to utilize formate. A single-plasmid species was identified in ATCC 17706, which was absent in all Hup− mutants, and was shown to confer hydrogen-uptake proficiency in A. eutrophus. This plasmid, pRMB1, was not self-transmissible, but was conjugative in a strain carrying a self-transmissible plasmid, RK2.