ISOLATION, SCREENING AND CHARACTERIZATION OF HEAVY METAL RESISTANCE BACTERIA FOR THEIR POTENTIAL USE IN BIOREMEDIATION OF POLLUTED WATER.

Abstract

Native species of microorganism provides a potential system for the treatment of metal contaminated water. Present study was conducted to screen and characterize heavy metal resistance bacteria in order to remediate the effluent waste water. Nine strains were isolated and designated as WAs1, WCd2, WCo3, WCr4, WCu5, WHg6, WNi7, WPb8 & WZn9 based on their maximum threshold level of tolerance to each metal. These values for respective metal are Arsenic (1000 ppm), Cadmium (200 ppm), Cobalt (400 ppm), Chromium (20 ppm), Copper (100 ppm), Mercury (20 ppm), Nickel (50 ppm), Lead (1000 ppm) and Zinc (1000 ppm). The highest values with respect to arsenic and lead observed during this study are not reported so far showing the importance of the work. Maximum growth of these strains was observed at pH 7 and 37 0 C temperature. These strains were further characterized by biochemical and morphological methods. Introduction:-Environmental contamination by heavy metals from anthropogenic and industrial activities has caused considerable irreparable damage to aquatic ecosystems. Industrial wastes containing toxic metals can arise from a wide variety of industrial processes (Mohammed and Normala 2015). According to the World Health Organization (WHO), metals of most immediate concern include cadmium, chromium, cobalt, copper, lead, nickel, mercury and zinc. These metals have exacting consequences on human such as brain damage, reproductive failure, nervous system failure and tumor formation (Gleick 2014). Industrial effluent is usually collected at a common place for its treatment. Waste water from Common Effluent Treatment Plant (CETP), Navi Mumbai industrial area was characterized and used to make it suitable for land applications. For this purpose different bacteria tolerant to heavy metal were isolated and were screened for their ability to decontaminate the effluent. This effluent was characterized by high BOD, COD and higher levels of TDS making it unsuitable for flora and fauna of the ecosystem. Bioremediation, which is essentially the use of microbial metabolism, seems to offer a viable, safer, more efficient and less expensive alternative to physiochemical methods for pollution abatement (Pandey and Jain, 2002).