Study on the structure and function of a stable methane-oxidizing mixed microbial consortium

From an agricultural sample taken in Chongqing, a stable methane-oxidizing mixed microbial consortium was established by enrichment culture with methane as a sole source of carbon and energy. The mixed consortium showed high capability of phenol degradation and 1,2-epoxypropane production from propene. More than 99% of phenol at an initial concentration of 600mg/L could be degraded by the mixed microbial consortium after 11 h of cultivation. The productivity of 1,2-epoxypropane could be increased with the decrease of phosphate concentration. The concentration of 1,2-epoxypropane produced could reach to 5.0mmol/L. The bacterial structure of the methane-oxidizing mixed microbial consortium was analyzed by pure culture isolation combining with 16S rRNA and PCR of the related MMO functional genes. The results showed that the methane-oxidizing mixed microbial consortium was composed of a type Ⅱ methanotroph identified as Methylosinus trichosporium and at least 4 kinds of heterotrophs (Comamonas testosteroni,Cupriavidus metallidurans, Acinetobacter junii and Stenotrophomonas maltophilia). M. trichosporium Y9, isolated from the mixed consortium, harbored both sMMO and pMMO genes.