Activity and evolution of mixed microbial culture degrading molinate

A laboratory study on molinate degrading activity of a microbial enriched population, obtained from pesticide-treated soil and slurries from a molinate production plant, was conducted. The degradation rate of molinate was determined in batch cultures by analyses with gas and liquid chromatography (GLC and HPLC). The oxidative activity of microorganisms was measured by a Warburg microrespirometer. The results showed: (1) the inability of microorganisms to use molinate as the only carbon source; (2) the co-oxidation of molinate by mixed microbial population when present with saccharose; co-oxidation was not supported by glucose; (3) the reduction of molinate co-metabolizing ability by mixing microbial populations, when the cultures were repeatedly transferred to fresh medium; (4) the high degradation activity by a Streptomyces sp. and Arthrobacter sp. mixed culture growing on glucose: molinate loss (42% in 21 days) appeared significantly as the glucose level decreased to around 20 mg/l.