Microbial degradation of a macrotetrolide miticide in soil

Macrotetrolide, a miticide consisting of tetranactin, trinactin, and dinactin, was readily biodegradable and hence did not accumulate in soil. [U-C]macrotetrolide was rapidly degraded via its constituent hydroxycarboxylic acids to carbon dioxide and water. In culture media, however, the mixture was hydrolyzed to homononactic and nonactic acids by three strains of Bacillus sp. and two of Micrococcus sp. The latter strains were able to hydrolyze 500 mug of the antibiotic per ml within a few days and to grow in the presence of 4,000 mug of the antibiotic per ml. However, they were unable to assimilate the constituent acids which accumulated in the culture medium.