Luteimonas aestuarii SA13A as a novel chromium reducing strain isolated from activated sludge

Satisfactory Essays
1. Introduction
Industrialization is a hallmark of civilization but nowadays it is becoming matter of great concern. Industrial emissions unfavorably affect the environment, leading to the large-scale worldwide destruction of agricultural land along with water bodies (1, 2). Various toxic substances are released that accumulate in the environment and food chains, thereby affecting many biological processes. Chromium (Cr) is one the important metal being employed far and wide in numerous industrial processes, including chrome leather tanning, chrome plating, ceramics, dyes, paints and pigments manufacturing, textile processing, metal finishing etc.(3-6). Leather processing industry is one of the major industries utilizing chromium in the form of chrome liqueur or chrome powder. Residual chromium is thus discharged in solid as well as liquid effluent. It exists in various oxidation states ranging from -2 to +6 but the most persistent forms are hexavalent (Cr6+) and trivalent (Cr3+) species. Hexavalent chromium is the most toxic form, mainly available as oxyanions, whereas trivalent chromium is hundred-fold less toxic, less soluble and less mobile, mostly found as oxides, hydroxides or sulfates (7, 8). Hexavalent chromium is a strong oxidizing agent, mutagen and teratogen (4, 9). Its oxyanionic form (CrO42−), analogous in structure to sulfate and phosphate ions, readily permeate through bacterial and eukaryotic cells resulting in intracellular reduction leading to chromate-induced toxicity (4, 8, 10). The presence of chromate in the environment inhibits most microorganisms, but it also promotes the selection of metal resistant bacteria (2, 11).
In Kanpur, about 400 leather processing industries at Jajmau, discharge both liquid as wel...

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...munity. Normally, it is assumed that the heavy metal exposure leads to the establishment of a tolerant microbial population. A gram negative bacilli strain SA13A isolated in this study has shown high chromium (100 mgL-1) reducing efficiency (100%, 16 h). Further, chromium reduction was also found to be dependent on both pH and temperature. The optimal values of temperature and pH for reduction were 37 oC and 8.0, respectively. As per literature surveyed, this is the first compilation of data in conviction with chromate reduction by Luteimonas aestuarii SA13A. Moreover, the isolate SA13A has also shown resistance against various heavy metals. As Luteimonas aestuarii SA13A possess heavy metal resistance along with chromate reduction potential, therefore it may serve as potent novel bacteria for bioremediation applications especially in heavy metal contaminated sites.
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