Isolation of Azospirillum lipoferum 4T Tn 5 Mutants Affected in Melanization and Laccase Activity

Abstract

Azospirillum lipoferum 4T has original properties such as nonmotility, melanin synthesis, and laccase activity. Following random Tn 5 mutagenesis in A. lipoferum 4T, we obtained 10 mutants which were affected in melanization and laccase activity. The class 1 mutants, with intermediate levels of laccase activity, showed some coloration; the class 2 mutants, which were completely negative for laccase activity, were also colorless. The Tn 5 localization on the chromosome or on the cryptic 300-MDa plasmid of A. lipoferum 4T was proven by hybridization for all class 1 mutants or for most class 2 mutants, respectively.