Screening and identification of gossypol-degraded strains isolated from a soil microcosm.

Two new strains named MM-2 and RP-3 were isolated from a soil microcosm and investigated due to the finding that they could degrade free-gossypol on agar plates.Through the morphological and molecular biological identification,MM-2 was confirmed homologous with Fusarium oxysporum as high as 93%,presumably that it might belong to Fusarium.RP-3 was confirmed homologous with Rhodotorula mucilaginosa as high as 92%,presumably that it might belong to Rhodotorula.The growth characters of gossypol-degraded strains in different carbon sources,at different temperatures were compared.The results showed that the optimal incubation conditions of MM-2 were 48～72 h at 30℃ in glucose medium and 60～84 h at 30℃ in gossypol medium.The optimum growth conditions of RP-3 were 24～48 h at 25～30℃ in glucose medium.The OD value of RP-3 in gossypol medium could not be studied exactly because of the presence of gossypol which is a yellow pigment,however,the degradation of gossypol by strain RP-3 was in evidence.