Microbiology Division, Central Leather Research Institute, (CSIR, New Delhi), Adyar, Chennai 600020, Tamil Nadu, India.
Colloids Surf B Biointerfaces. 2010 Sep 1;79(2):334-9. doi: 10.1016/j.colsurfb.2010.04.007. Epub 2010 Apr 22.
The present study demonstrates hexavalent chromium reduction and trivalent chromium tolerance behavior of marine Bacillus sp., MTCC 5514 through its extracellular enzyme reductase and biosurfactants production. The isolate reduces 10-2000 mg/L of hexavalent chromium to trivalent chromium with in 24-96 h respectively and the release of extracellular chromium reductase, found responsible for the reduction. Upon reduction, the concentration of trivalent chromium in the medium found comparatively less. Experimental results reveal, biosurfactants activity found responsible for the less concentration of Cr(III). Hypothetically, trivalent chromium upon formation get entrapped in the micelle of biosurfactants, prevents microbial cells from exposure towards trivalent chromium. Thus, the chosen isolate exhibit tolerance and growth with the increasing concentration of chromium.
本研究通过海洋芽孢杆菌 MTCC 5514 的胞外酶还原酶和生物表面活性剂的产生，展示了其对六价铬的还原和三价铬的耐受性。该分离物在 24-96 小时内将 10-2000mg/L 的六价铬分别还原为三价铬，并且释放出胞外铬还原酶，该酶负责还原。还原后，培养基中三价铬的浓度相对较低。实验结果表明，生物表面活性剂的活性负责降低 Cr(III)的浓度。从理论上讲，形成的三价铬会被困在生物表面活性剂的胶束中，防止微生物细胞暴露在三价铬中。因此，所选的分离物在铬浓度增加的情况下表现出耐受性和生长。
