Arsenic Bioremediation And Bioactive Potential Of Endophytic Bacterium Bacillus Pumilus Isolated From Pteris Vittata L.

Endophytic microorganisms have been found to colonize virtually every healthy plant species that exist on the earth. In an attempt to study the endophytic bacterial diversity, the common fern Pteris vittata L. were collected from the different regions of West Bengal including Darjeeling hills. A total of 15 phenotypically distinguishable bacterial endophytes were isolated from surface sterilized frond, rhizome and root tissues of P. vittata using nutrient agar (NA), tryptic soy agar (TSA) and glycerol aspargine agar (GA) media. Shannon Weaver diversity index has clearly revealed more diverse types of endophytes in rhizome (1.75) than in roots (1.72) and frond (1.09). The isolated endophytes were screened for their heavy metal tolerance and the isolate DSKP8 was found to tolerate 8 mM of As, Ni, Co and Cd. Based on morphological, physiological and biochemical characters along with 16S rDNA sequence analysis, the isolate was identified as Bacillus pumilus (Genbank Accession No. KJ881418). To determine the role of the endophytic bacterium DSKP8 on arsenic remediation P. vittata L. was grown in arsenic spiked soil inoculated with the bacterium DSKP8 and plant growth and arsenic uptake were analyzed. The uptake of arsenic was significantly higher in bacterial inoculated plants, 2.58 mg kg(-1) in shoot and 1.06 mg kg(-1) in root in comparison to non-inoculated arsenic treated plants. It is apparent that the integrated use of P. vittata with the microbe B. pumilus can enhance the plant growth and uptake of arsenic, and have potential application for the remediation of arsenic contaminated sites.