Bioremediation of Chromium in Pulp and Paper Processing Industrial Effluents by Indigenous Microbes

摘要

The present study was conducted with the goal of elimination of chromium toxicity in the pulp and paper processing industrial effluents. The physicochemical analysis of effluents showed that some of the parameters were exceeded and some were within the permissible limits as per the WHO standards. Based on the isolation, identification and biochemical characterization study the isolated strains (P1, P2, P3 and P4) were identified as Lactobacillus sps (P1) and Bacillus sps (P2, P3 and P4) according to Bergy’s Manual of Systematic Bacteriology. The MICs and MBCs study showed that all the bacterial isolates exhibited Cr tolerance for 1 ppm, 2 ppm, 5 ppm and 10 ppm. The bacterial isolates showed very high degree of resistance to the chromium. The growth studies showed that all bacterial strains exposed to high level of the chromium metal concentration in the environment which have adapted to this stress by developing various resistant mechanism. The rate of Cr (VI) reduction increased with decreasing concentration of Cr (VI) and increasing time interval for all the bacteria isolates. All the bacterial isolates showed the best chromate reduction for different concentration of Cr (VI).