Koçberber Nur, Dönmez Gönül
Ankara University, Faculty of Science, Department of Biology, 06100 Beşevler, Ankara, Turkey.
Bioresour Technol. 2007 Aug;98(11):2178-83. doi: 10.1016/j.biortech.2006.08.017. Epub 2006 Oct 16.
Enrichment mixed cultures tolerating relatively high concentrations of chromium and salt ions were isolated and their bioaccumulation properties improved by adaptation. Mixed cultures were enriched in Nutrient Broth media containing 25-300 mg l(-1) Cr(VI) and 0%, 2%, 4%, 6% (w/v) NaCl. Bioaccumulation of Cr(VI) was studied in a batch system as a function of initial pH (7, 8 and 9), Cr(VI) and NaCl concentrations. Increasing NaCl and Cr(VI) concentrations led to significant decreases in percentage uptake and dried weight of mixed cultures but increased maximum specific chromium uptake. The maximum specific chromium uptake value at pH 8 was 58.9 mg g(-1) for 316.1 mg l(-1) Cr(VI) in the absence of NaCl, while at pH 9 it was 130.1 mg g(-1) in media including 194.5 mg l(-1) Cr(VI) and 2% NaCl concentrations. At 4% NaCl, the maximum Cr(VI) uptake of 127.0 mg g(-1) for 221.1 mg l(-1) Cr(VI) occurred at pH 9, while at 6% NaCl the maximum Cr(VI) uptake of 114.9 mg g(-1) for 278.1 mg l(-1) Cr(VI) was found at pH 7.
分离出了能够耐受相对高浓度铬和盐离子的富集混合培养物，并通过适应性培养提高了它们的生物累积特性。在含有25 - 300 mg l(-1) Cr(VI)以及0%、2%、4%、6%（w/v）NaCl的营养肉汤培养基中富集混合培养物。在间歇系统中研究了Cr(VI)的生物累积与初始pH值（7、8和9）、Cr(VI)和NaCl浓度的关系。NaCl和Cr(VI)浓度的增加导致混合培养物的摄取百分比和干重显著下降，但最大比铬摄取量增加。在不存在NaCl的情况下，pH值为8时，对于316.1 mg l(-1) Cr(VI)，最大比铬摄取值为58.9 mg g(-1)；而在pH值为9时，在含有194.5 mg l(-1) Cr(VI)和2% NaCl浓度的培养基中，该值为130.1 mg g(-1)。在4% NaCl时，对于221.1 mg l(-1) Cr(VI)，最大Cr(VI)摄取量127.0 mg g(-1)出现在pH值为9时；而在6% NaCl时，对于278.1 mg l(-1) Cr(VI)，最大Cr(VI)摄取量114.9 mg g(-1)出现在pH值为7时。
