Evaluation of biphenyl- and polychlorinated-biphenyl (PCB) degrading Rhodococcus sp. MAPN-1 on growth of Morus alba by pot study

Abstract

This study focused on isolation of bacteria with biphenyl/polychlorinated biphenyl (PCB) degrading ability from the rhizosphere of Morus alba (mulberry plant). Repetitive enrichment of rhizospheric soil samples with biphenyl resulted in the isolation of Rhodococcus sp. MAPN-1, identified by 16S rRNA gene sequence analysis. The bacterium showed growth on five different aromatic compounds (naphthalene, salicylic acid, benzoic acid, dibenzofuran and anthracene). Benzoic acid was detected as the major metabolite during biphenyl degradation using high-performance thin-layer chromatography (HPTLC) with R_f 0.42 at 254 nm. Further GC-MS/MS study showed 95% and 15% degradation of biphenyl and dichlorobiphenyl, respectively. A pot study was conducted to evaluate the effect of presence of biphenyl on M. alba and the role of biphenyl degrader Rhodococcus sp. MAPN-1 in relation to phytoremediation. Morus alba twigs in biphenyl spiked soil (100 mg/kg and 300 mg/kg) inoculated with Rhodococcus sp. MAPN-1 showed growth, whereas, growth of plants (control) was adversely affected in biphenyl-spiked uninoculated soil. It is the first report of isolation of Rhodococcus sp. MAPN-1 from the rhizosphere of Morus alba, its capability to degrade biphenyl, thereby showing a positive effect on the plant growth grown in biphenyl spiked soil.

Keywords:

• Biodegradation
• biphenyl/PCB
• phytoremediation
• rhizoremediation

Acknowledgments

Our special thanks belong to Birla Institute of Technology and Science (BITS), Pilani for providing infrastructure and the facilities required during the research work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Department of Science and Technology under Women Scientist Scheme B [Grant number DST/Disha/SoRF-IM/009/2015/01 to MS].