C-TYPE CYTOCHROMES AND MANGANESE OXIDATION IN PSEUDOMONAS-PUTIDA MNB1

Pseudomonas putida MnB1 is an isolate from an Mn oxide-encrusted pipel ine that can oxidize Mn(II) to Mn oxides, We used transposon mutagenes is to construct mutants of strain MnB1 that are unable to oxidize mang anese, and we characterized some of these mutants. The mutants were di vided into three groups: mutants defective in the biogenesis of c-type cytochromes, mutants defective in genes that encode key enzymes of th e tricarboxylic acid cycle, and mutants defective in the biosynthesis of tryptophan, The mutants in the first two groups were cytochrome c o xidase negative and dill not contain c-type cytochromes. Mn(II) oxidat ion capability could be recovered in a c-type cytochrome biogenesis-de fective mutant by complementation of the mutation.