Sodium Alginate/Polyvinyl Alcohol Immobilization of Brevibacillus brevis OZF6 Isolated from Waste Water and Its Role in the Removal of Toxic Chromate

Abstract

Aim: In this study we wanted to determine bacteria for chromium (VI) removal under pH, chromium concentration, carbon source and immobilizing agents. Place and Duration of Study: This study was carried out in the Department of Biological Sciences, College of Natural and Applied Sciences, Crescent University, Abeokuta, Nigeria in the year 2015. Methodology: Isolation of bacteria was done from industrial waste water of Abeokuta, Nigeria which is often released into water bodies and thus contaminates water during 2015. Nutrient agar added with 100 µg/ml Cr (VI) was used to isolate resistant bacterial strains. Resistance of the strains for Cr (VI) was evaluated on nutrient agar media. Natural material [sodium aliginate (SA)] and synthetic material (PVA)] immobilized bacterial cells for Cr (VI) removal experiment was done by 1, 5–diphenyl carbazide method. Results: The strain OZF6 was characterized as Brevibacillus brevis using 16S rRNA gene sequence. All isolates (8 strains) were tolerant to chromium (VI). Among all strains, only Brevibacillus brevis OFZ6 reduced Chromium (VI). Brevibacillus brevis OZF6 reduced maximum Cr (VI) (72.5%) at pH 7. Brevibacillus brevis OFZ6 also reduced chromium (VI) significantly under various concentrations of chromium. Brevibacillus brevis OZF6 detoxified the metal 81% at 50 μg Cr/ ml, 75% at a concentration of 100 μg/ ml and 68% at 150 μg/ ml respectively. Among electron donors, maximum reduction was observed under influence of lactose. Among different matrices combinations for whole cell immobilization of OZF6, combination of 10% PVA, 10% sodium alginate (SA) proved to be best combination for Cr (VI) reduction. Conclusion: Due to above properties, bacteria will be utilized for Cr (VI) detoxification in contaminated industrial waste water and thus will protect environment from contamination. There needs a proper regulation and treatment of these effluents prior their release into water bodies or into soil and thus ultimately protect population from carcinogenesis and other ill hazards.