Effect of Brevibacillus brevis OZF6 on Reduction of Chromium (VI) and Pea Growth

Abstract

Aim: Hexavalent chromium (Cr (VI)) is toxic due to its high solubility in water and permeability through biological membranes and Cr (VI) interacts with proteins and nucleic acids which makes it more toxic and carcinogenic than trivalent. Microbes converting toxic chromium Cr (VI) to stable and less soluble Cr (III) can be used for detoxification of Cr (VI) from contaminated environment. In this study the authors wanted to evaluate the effect of chromium (VI) reducing Brevibacillus brevis OZF6 on the growth, photosynthestic pigments, nodulation and metal accumulation in pea crop. Place and Duration of Study: This study was carried out at the Department of Biological Sciences, Crescent University, Abeokuta, Ogun State, Nigeria in 2015. Methodology: Cr (VI) reduction in both free and immobilized cells was evaluated by 1, 5-Diphenyl Carbazide method. Pigments, plant growth, and metal accumulation were determined as per the standard methods as described in materials and methods. Results: Brevibacillus brevis OZF6 significantly reduced Cr (VI) when bacteria were immobilized by sodium alginate as compared to the free cells. Seed germination, pea growth, nodulation, photosynthetic pigments, and protein increased in pea plants after inoculation with Brevibacillus brevis OZF6 compared to un-inoculated pea plants amended with metal. OZF6 significantly decreased accumulation of chromium in roots and shoots compared to only metal-amended plants. Conclusions: Due to above properties, B. brevis OZF6 could therefore be used as bioremediator of Cr (VI) in chromium contaminated environment and thus will protect the environment.