Biodegradation of paclobutrazol by a microbial consortium isolated from industrially contaminated sediment

Abstract

Biodegradability of the plant growth retardant paclobutrazol by a microbial consortium in which Pseudomonas was the predominant strain was investigated in batch culture. The consortium which had been isolated from an industrially contaminated sediment was proven to be useful for the treatment of effluents containing paclobutrazol. Paclobutrazol was degraded by the pure isolated strain of Pseudomonas sp. as well as the microbial consortium. Paclobutrazol was utilized as the sole source of carbon and energy. Sixty percent of the paclobutrazol was degraded by the microbial consortium from an initial concentration of 54 mg L⁻¹ within 48 h and more than 98% of an initial concentration of 3.4 mg L⁻¹ was degraded within 36 h. The optimum temperature and pH were determined to be 30°C and 7.0, respectively. A pure strain of a bacterium, isolated from the enrichment culture was identified as Pseudomonas sp. The microbial consortium was tolerant of high pH and could degrade paclobutrazol faster than the pure strain. The degradation rate of this plant growth regulator in an aerobic environment was greater than that under anaerobic conditions.

Keywords:

• industrial effluent
• adaptation
• plant growth regulator
• soil
• wastewater treatment
• removal
• aerobic

Acknowledgments

This study was supported by National Natural Science Foundation of China (39270152). Prof. Giesy was supported by the Canada Research Chair program and at large Chair Professorship at the Department of Biology and Chemistry and Research Centre for Coastal Pollution and Conservation, City University of Hong Kong. The research was supported by a Discovery Grant from the National Science and Engineering Research Council of Canada (Project No. 6807).