Abstract
The relationships between growth conditions and degradability of 4 isolated strains of the herbicide molinate (S-ethyl perhydroazepin-1-carbothioate)-degrading microorganisms, Mycobacterium sp. (B-1), Flavobacterium sp. (B-2), Streptomyces sp. (A-1), and Fusarium sp. (F-1), and the mechanisms of molinate degradation by them were investigated. None of these microorganisms could utilize molinate as a sole source of carbon and energy for growth and they needed other carbon sources. The three strains of microbes, B-2, A-1 and F-1, also needed other nutrient sources for the degradation of molinate while B-1 did not. The mode of molinate metabolism by these strains was found to be co-metabolism. Excess concentrations of the nutrient sources repressed the degradation by B-1 and B-2, but promoted by A-1. Adaptive enzymes seemed to be responsible for the first step of the molinate metabolism by A-1, whereas both constitutive and adaptive enzymes by B-1 and B-2. These four strains also responded differently to pH and temperature conditions.
