Chromium, a heavy metal, is a major xenobiotic element found in electroplating effluents. It is a recalcitrant of concern as it is highly toxic and carcinogenic. It exists as Cr (VI) which is highly soluble and bioavailable. Various conventional treatment technologies like adsorption, ion exchange, filtration, reverse osmosis and electrodialysis have been used but they generate lot of sludge and residue. Hence, there is a need for an economical, faster and ecofriendly means of remediation for which bioremediation is preferred. In this study we attempted chromium removal by employing improved indigenous isolate Bacillus amyloliquifaciens sourced and identified from a previous study from chrome plating effluent collected from Peenya industrial area, Bengaluru, India. Strain improvement was achieved using physical mutagen (UV radiation) and chemical mutagens (ethidium bromide, ethyl methane sulphonate and acrylamide). A comparative study was carried out to screen the chromium remediation potential of wild type and mutants in chromium spiked sample and the electroplating effluent. The mutant generated using acrylamide (150 µg/mL) in comparison with wild type and other mutants was more capable of remediating chromium. At the end of 18 days, from the chrome electroplating effluent containing chromium (490 mg/100mL), the wildtype could remove 74% (362.6 mg/100 mL), UV radiation induced mutant removed 83% (406.7 mg / 100 mL) whereas acrylamide induced mutants removed 96.67% (470.4 mg/100 mL) of chromium. Enzyme assays confirmed involvement of enzymes at sub cellular level in chromium remediation.

中文翻译：

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野生和突变解淀粉芽孢杆菌菌株对电镀废水中六价铬的生物修复

铬是一种重金属，是电镀废水中发现的主要异种生物元素。由于它具有剧毒和致癌性，因此令人担忧。它以高溶解度和生物利用度的Cr（VI）的形式存在。已经使用了各种常规处理技术，例如吸附，离子交换，过滤，反渗透和电渗析，但它们会产生大量的污泥和残留物。因此，需要一种经济的，更快的和生态友好的修复方法，其中优选生物修复。在这项研究中，我们尝试通过使用改良的本地分离株解淀粉芽孢杆菌来去除铬来源于先前的研究，该研究来自印度班加罗尔Peenya工业区收集的镀铬废水。使用物理诱变剂（紫外线辐射）和化学诱变剂（溴化乙锭，甲烷磺酸乙酯和丙烯酰胺）可实现菌株改良。进行了一项比较研究，以筛选铬加标样品和电镀废水中野生型和突变体的铬修复潜力。与野生型和其他突变型相比，使用丙烯酰胺（150 µg / mL）产生的突变型更能修复铬。在第18天结束时，从含铬的铬电镀废水（490 mg / 100mL）中，野生型可以去除74％（362.6 mg / 100 mL），紫外线辐射诱导的突变体可以去除83％（406.7 mg / 100 mL），而丙烯酰胺诱导的突变体去除了96.67％（470。4 mg / 100 mL）中的铬。酶分析证实了亚细胞水平的酶参与了铬的修复。