Aslam Sumaira, Hussain Ali, Qazi Javed Iqbal
Department of Zoology, Government College Women University, Faisalabad, Pakistan.
Department of Wildlife & Ecology, University of Veterinary & Animal Sciences, Lahore, Pakistan.
3 Biotech. 2016 Dec;6(2):125. doi: 10.1007/s13205-016-0443-5. Epub 2016 Jun 7.
We conducted a study for enhanced biological rehabilitation of chromium-contaminated soils using a chromium-reducing and nitrogen-fixing bacterial species (Bacillus megaterium-ASNF3). The bacterial species was isolated from a chromium-rich land area, characterized, and employed under optimum conditions for the treatment of artificially prepared chromium-rich soil. The bacterium reduced Cr(VI) up to 86 % in a 60-day trial of incubation in the soil bioreactor. The nitrogenase activity of the bacterium yielded up to 486 nmol of ethylene/mL/h after an incubation period of 40 days when it was optimally cultured in growth medium at neutral pH and 30 °C. Although the nitrogen-fixing ability of the bacterium reduced significantly in the presence of 1000 ppm of Cr(VI), yet, the bacterium was proved to be a potential bio-fertilizer for enhancing nitrogen contents of the contaminated soil even under the higher chromium stress, together with the metal reduction. In the biologically treated soil, higher values of wheat growth variables were achieved. Application of metal-resistant B. megaterium-ASNF3 in selected situations rendered chromium-laden soils arable with significant increment in crop-yield parameters.
我们开展了一项研究，利用一种铬还原兼固氮细菌（巨大芽孢杆菌-ASNF3）来强化受铬污染土壤的生物修复。该细菌从富含铬的陆地区域分离得到，经过鉴定，并在最佳条件下用于处理人工制备的富铬土壤。在土壤生物反应器中进行的60天培养试验中，该细菌将Cr(VI)还原了高达86%。当该细菌在中性pH值和30°C的生长培养基中进行最佳培养时，培养40天后其固氮酶活性产生的乙烯量高达486 nmol/mL/h。尽管在1000 ppm的Cr(VI)存在下该细菌的固氮能力显著降低，然而，即使在较高的铬胁迫下，该细菌也被证明是一种潜在的生物肥料，可在还原金属的同时提高受污染土壤的氮含量。在经过生物处理的土壤中，小麦生长变量的值更高。在特定情况下应用抗金属的巨大芽孢杆菌-ASNF3使含铬土壤变得适于耕种，作物产量参数显著增加。
