Characterization of pentachlorophenol degrading Bacillus strains from secondary pulp-and-paper-industry sludge

Pentachlorophenol (PCP) degrading Bacillus strains CL3 CL5 and CL11 were isolated from the secondary sludge of a pulp paper mill and characterized These isolates were identified as Bacillus megaterium Bacillus pumilus and Bacillus thuringensis based on their 16S rRNA sequence analysis These isolates were able to grow and utilize PCP as a carbon and energy source HPLC analysis and stoichiometric release of chloride in the medium confirmed the degradation ability of these isolates The removal efficiency of PCP by these bacterial isolates was highly significant and they were able to degrade more than 90% of PCP when grown at high concentration of PCP (600 mg l(-1)) Consortia of these isolates removed 77% of PCP from the sludge The removal efficiency of PCP by the bacterial isolate used in this study was found to be more efficient than what has been reported with other Bacillus species These results suggest that the bacterial isolates are very effective PCP degraders and can be used in remediation of PCP-contaminated sites (C) 2010 Elsevier Ltd All rights reserved