Khan Mohammad Tariq Ali, Al-Battashi Huda, Al-Hinai Mahmood, Almdawi Malak, Pracejus Bernhard, Elshafey El-Said I, Abed Raeid M M
Biology Department, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman.
Department of Earth Sciences, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman.
Appl Biochem Biotechnol. 2025 Jan;197(1):94-112. doi: 10.1007/s12010-024-05023-0. Epub 2024 Aug 5.
Water pollution with toxic hexavalent chromium, Cr(VI), is an environmental threat that has a direct impact on living organisms. The use of microorganisms from microbial mats to remove Cr(VI) has scarcely been investigated. Here, we isolated aerobic heterotrophic bacteria from a Cr-polluted microbial mat found in a mining site in Oman, and investigated their ability to remove Cr(VI), and the underlying mechanism(s) of removal. All isolates fell phylogenetically into the genera Enterobacter, Bacillus, and Cupriavidus, and could completely remove 1 mg L Cr(VI) in 6 days. The strains could tolerate up to 2000 mg L Cr(VI), and exhibited the highest Cr(VI) removal rate at 100 ± 9 mg L d. Using scanning electron microscopy (SEM) coupled with elemental analysis, the strains were shown to adsorb Cr(VI) at their cell surfaces. The functional groups OH, NH, Alkyl, Metal-O, and Cr(VI)-O were involved in the biosorption process. In addition, the strains were shown to reduce Cr(VI) to Cr(III) with the involvement of chromate reductase enzyme. We conclude that the aerobic heterotrophic bacteria isolated from Cr-polluted microbial mats use biosorption and bioreduction processes to remove Cr(VI) from wastewater.
有毒的六价铬（Cr(VI)）造成的水污染是一种环境威胁，对生物有直接影响。利用微生物席中的微生物来去除Cr(VI)的研究几乎没有。在此，我们从阿曼一个矿区发现的受铬污染的微生物席中分离出好氧异养细菌，并研究了它们去除Cr(VI)的能力以及潜在的去除机制。所有分离菌株在系统发育上均属于肠杆菌属、芽孢杆菌属和贪铜菌属，并且能够在6天内完全去除1 mg/L的Cr(VI)。这些菌株能够耐受高达2000 mg/L的Cr(VI)，在100±9 mg/(L·d)时表现出最高的Cr(VI)去除率。通过扫描电子显微镜（SEM）结合元素分析表明，这些菌株在其细胞表面吸附Cr(VI)。官能团OH、NH、烷基、金属 - O和Cr(VI) - O参与了生物吸附过程。此外，这些菌株在铬酸盐还原酶的作用下将Cr(VI)还原为Cr(III)。我们得出结论，从受铬污染的微生物席中分离出的好氧异养细菌利用生物吸附和生物还原过程从废水中去除Cr(VI)。
