BIOREMEDIAL APPROACH TO DEGRADE HEXAVALENT CHROMIUM FROM PULP AND PAPER INDUSTRY EFFLUENTSONIKA SAXENA, ABHAY DEV TRIPATHI, KAJAL KACHHAWAHA, BABY SHARMA, RINKI MISHRA AND SUDIPTI ARORAAbstract One of the greatest problems that the world is facing today is that of environmental pollution, increasing with every passing year and causing grave and irreparable damage to the earth. Chromium is one of the important metals used in the pulp & paper industry, tannery industry etc. Chromium (VI) is of particular environmental concern and is recognized as one of the most dangerous pollutants due to its toxicity and ability to cause mutation, irritation, corrosion of the skin and cause lung carcinoma in humans. But Cr (III) forms insoluble precipitates, and also an essential nutrient in trace amounts in humans for glucose metabolism. Thus, reducing Cr (VI) to Cr (III) simplifies its removal from effluent and also reduces its toxicity and mobility. Different bacterial species had been identified and reported to reduce Cr (VI) under aerobic and anaerobic conditions. Hence in the present investigation, the chromium degrading bacterial strains were isolated from pulp and paper industry effluent. Based on the morphological, microscopic and biochemical characterization, they were identified as Bacillus sp. according to Bergeys manual. Chromium (VI) reduction in the effluent was monitored with 0.25% of Cr (VI) at 37°C in aerobic condition under shaking at 150 rpm with three inoculum size i.e. 0.1%, 0.5%, 1%. The rate of Cr (VI) reduction was increased with increasing the time intervals. Maximum degradation was observed with 1% inoculum size of K3 strain at 15th day. Optimum growth conditions for K3 strain were observed as temperature 37°C and pH 8. Thus this stain shows its potential use as bioremedial agent for detoxification of hexavalent chromium.
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