Multiple Metal Resistant Bacillus cereus 3.1S Isolated from Industrial Effluent has Promising Arsenite Oxidizing Potential
Multiple Metal Resistant Bacillus cereus 3.1S Isolated from Industrial Effluent has Promising Arsenite Oxidizing Potential
Ayesha Noreen1, Amina Elahi1, Dilara Abbas Bukhari2 and Abdul Rehman1*
ABSTRACT
The arsenite resistant Bacillus cereus 3.1S, isolated from pesticide industry effluent, showed maximum growth at pH 7 at 37 °C in LB medium after 24 h of incubation. The strain tolerated As3+ up to 40 mM and also showed resistance against Pb2+ (8mM), Cd2+ (6mM), Cr6+ (6mM), and Cu2+ (10mM). The arsenite oxidase is responsible for the conversion of arsenite (As3+) into arsenate (As5+) and the predominant form of arsenite oxidase was intracellular and its optimum activity recorded was determined as 730 and 750µM/min (calculated by both Safranine O spectrophotometric and molybdene blue methods) at pH 7 and 37°C in the presence of Zn2+ as cofactor. The protein profile of B. cereus 3.1S, showed two bands of approximately 14 and 70 kDa, which had their possible role in arsenite oxidation. This was confirmed by transforming E. coli DH5α with plasmid DNA of B. cereus 3.1S. This arsenite resistant bacterial strain oxidized 76 and 86.5% As3+ from the original industrial wastewater after 3 and 6 days of incubation, respectively. This bacterially treated wastewater, when used for plant growth, revealed an improved growth of Vigna radiata as compared to the original (untreated) wastewater. This multiple metal resistant bacterium’s ability to convert toxic arsenite into relatively less toxic form may find potential application in environmental biotechnology.
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December 2020
Vol. 52, Iss. 6, Pages 2027-2426
