Polti Marta A, García Roberto O, Amoroso María J, Abate Carlos M
Planta Piloto de Procesos Industriales y Microbiológicos PROIMI, CONICET, Av. Belgrano y Pasaje Caseros, Tucumán, Argentina.
J Basic Microbiol. 2009 Jun;49(3):285-92. doi: 10.1002/jobm.200800239.
This work provides quantitative information on Cr(VI) reduction in soil samples by an indigenous actinomycete. Streptomyces sp. MC1, previously isolated from sugarcane, has shown ability to reduce Cr(VI) in liquid minimal medium. A reduction of 100 and 75% was obtained at initial Cr(VI) concentrations of 5 and 50 mg l(-1), respectively, after 48 h of incubation. Bioremediation ability of Streptomyces sp. MC1 was assayed in soil extracts and soil samples. Relative growth of Streptomyces sp. MC1 was 77 and 38% when grown in soil extract with 10 and 50 mg l(-1) of Cr(VI), respectively. MC1 was able to reduce 30% of Cr(VI) after 96 h of incubation with 10 mg l(-1) of Cr(VI), and reduction coincided with the exponential growth phase at pH 7 and 30 degrees C.In soil samples, Streptomyces sp. MC1 was able to reduce up to 94% of the Cr(VI) bioavailability (50 mg kg(-1)) after 7 d. These results were compared with non-inoculated soil samples with Cr(VI). Bioremediation activity of Streptomyces sp. MC1 was not inhibited by natural soil microbial flora. Besides, Streptomyces sp. MC1 growth was not inhibited by 50 mg kg(-1) of Cr(VI). In contrast to findings obtained by other authors, our results showed almost complete Cr(VI) removal from soil without any previous treatment, and without addition of any substrate and with a normal soil humidity level. These results confirm the Cr(VI)-contaminated soil bioremediation potential of Streptomyces sp. MC1.
这项工作提供了关于一种本地放线菌对土壤样品中六价铬还原的定量信息。链霉菌属MC1，先前从甘蔗中分离得到，已显示出在液体基本培养基中还原六价铬的能力。在初始六价铬浓度分别为5和50 mg l(-1)的情况下，培养48小时后，六价铬的还原率分别达到100%和75%。对链霉菌属MC1在土壤提取物和土壤样品中的生物修复能力进行了测定。当在含有10和50 mg l(-1)六价铬的土壤提取物中生长时，链霉菌属MC1的相对生长率分别为77%和38%。在与10 mg l(-1)六价铬孵育96小时后，MC1能够还原30%的六价铬，且还原与pH值为7、温度为30℃时的指数生长期一致。在土壤样品中，链霉菌属MC1在7天后能够将高达94%的六价铬生物有效性（50 mg kg(-1)）还原。将这些结果与含有六价铬的未接种土壤样品进行了比较。链霉菌属MC1的生物修复活性未受到天然土壤微生物群落的抑制。此外，50 mg kg(-1)的六价铬未抑制链霉菌属MC1的生长。与其他作者的研究结果不同，我们的结果表明，无需任何预处理、不添加任何底物且在正常土壤湿度水平下，土壤中的六价铬几乎能被完全去除。这些结果证实了链霉菌属MC1对受六价铬污染土壤的生物修复潜力。
