Isolation and Molecular Characterization of Arsenite-Tolerant Alishewanella sp. GIDC-5 Originated from Industrial Effluents

Abstract

An As-hypertolerant Alishewanella sp. GIDC-5 (Accession no. HQ659190) was isolated from an effluent treatment plant of the industrial area near Sachin, Gujarat (India). In vitro studies revealed that GIDC-5 can tolerate 18 mM of arsenite [As(III)] and 220 mM of arsenate [As(V)]. PCR analysis confirmed the presence of arsenite transporters [arsB and ACR3(1)] and arsenite oxidase gene [aioB]. Specific activities of arsenite oxidase and arsenate reductase, located on membrane and cytoplasmic fractions respectively, increased in dose dependent manner with arsenite concentration. Also, specific activities of antioxidant enzymes viz., catalase, ascorbate peroxidase, superoxide dismutase and glutathione S-transferase increased in presence of arsenite. Increased exposure to arsenite changes enzyme activities of the glycolysis, Krebs and glyoxylate branches dramatically. These results reveal that along with ars operon, metabolic adaptation and antioxidant activities participate in As(III) tolerance in Alishewanella sp. GIDC-5.

Keywords:

• Alishewanella
• arsenite
• antioxidant enzymes
• ars operon
• central carbon metabolism

Acknowledgments 

This work was supported by the Department of Biotechnology, Ministry of Science and Technology, Government of India and Gujarat State Biotechnology Mission (GSBTM), Gujarat. No author has any conflict of interest.