Journal of Pure and Applied MicrobiologyVol. 8 No. 2

Biodegradation of Pentachlorophenol by Endophytic Bacteria Isolated from PCP-Tolerant Plant Species

Avita K. Marihal1, K.S. Jagadeesh1 and Sarita Sinha2

1Department of Agricultural Microbiology,University of Agricultural Sciences, Dharwad 580 005 Karnataka, India. 2Ecotoxicology and Bioremediation Group, National Botanical Research Institute, Lucknow 226 001, India.

Received on 19 June 2013 and accepted on 24 August 2013

 

ABSTRACT

Pentachlorophenol (PCP) is widely used as a pesticide and a wood preservative. It is highly persistent in soils and is lethal to wide variety of beneficial microorganisms, insects and animals. The present investigation was carried out with the aim of developing an endophytic microbial system for bioremediation of Pentachlorophenol (PCP) polluted soils. A number of plant species were evaluated for their ability to tolerate pentachlorophenol in the soil spiked with different concentrations under pot culture conditions. The toxic effect of pentachlorophenol on plants was studied by monitoring seed germination, plant growth and biomass. In general, pentachlorophenol significantly inhibited the seed germination and growth of all plants at 25 ?g ml-1. As the concentration was increased to 50 ?g ml-1, there was further inhibitory influence on seed germination and plant growth. Although PCP had a negative effect on all the plant species tested, however, maize and groundnut showed maximum tolerance to PCP. Other tolerating plants included wheat, safflower, sunflower, and soybean. From the PCP tolerating plant species, bacterial endophytes from roots and leaves were isolated and screened for their PCP degradation potentials. It was interesting to note that most of the isolates degraded PCP. The bacterial isolate, GRN (root) 4 was found to be the most efficient PCP degrader, which degraded 94.12 % of PCP as analyzed through HPLC, and holds promise in bioremediation of PCP polluted soils.

Keywords : Pentachlorophenol, endophytes, degradation, bioremediation, HPLC.