RESUMO
Objective To identify a strain screen which utilize dibutyl phthalate (DBP) as the sole carbon source and to explore the optimal conditions for the degradation of DBP. Methods The solid leachate was inoculated in minimal salt medium (MSM) supplemented with DBP as the sole carbon and energy source to isolate the targeted strain. The strain was identified through colony phenotype, transmission electron microscope and 16SrDNA gene sequence analysis. The targeted strain was inoculated to the above medium with different pH and temperature. The optimal temperature and pH of the microbial degradation of DBP were studied with determination of the DBP residue and bacterial biomass. Results One bacterial strain named L6 was isolated from the solid with adding DBP as the sole carbon source. Based on its morphology, physiochemical characteristics, and 16SrDNA sequence, the strain was identified as Methylobacterium sp. The optimal pH and temperature for its biodegradation activities were 7 and 30℃, respectively. The targeted strain could degrade 85% of 800 mg/L DBP within 120 hours. Conclusion Based on the high removal rate, the isolated Methylobacterium sp. L6 has a potential for bioremediation technology of DBP pollution.