Patterns of Enzymic Adaptation in Species of the Genus Azotobacter

Abstract

Fourteen strains of the Azotobacter agilis-A. vinelandii group were classified into one or another of these sp. by the usual methods. Whole cell suspensions and standard manometric procedures were used to measure rate of O2 uptake on sucrose and acetate, malate, succinate, alpha-keto-glutarate, and citrate. The rates of respiration could not be correlated with the sp., but there were differences in the pattern of adaptability to some of the substrates, notably succinate, which could be used to differentiate between the 2 sp. These patterns of adaptability were stable over a 2-year period, were the same whether freshly isolated or old laboratory cultures were used, and it is suggested that the ability to adapt to such a substrate might be a useful criteria for differentiating between members of the 2 sp.