Anaerobic methane oxidation coupled to chromate reduction in a methane-based membrane biofilm batch reactor
Chromate can be reduced by methanotrophs in a membrane biofilm reactor (MBfR). In this study, we cultivated a Cr(VI)-reducing biofilm in a methane (CH4)-based membrane biofilm batch reactor (MBBR) under anaerobic conditions. The Cr(VI) reduction rate increased to 0.28 mg/L day when the chromate concentration was ≤ 2.2 mg/L but declined sharply to 0.01 mg/L day when the Cr(VI) concentration increased to 6 mg/L. Isotope tracing experiments showed that part of the 13C-labeled CH4 was transformed to 13CO2, suggesting that the biofilm may reduce Cr(VI) by anaerobic methane oxidation (AnMO). Microbial community analysis showed that a methanogen, i.e., Methanobacterium, dominated in the biofilm, suggesting that this genus is probably capable of carrying out AnMO. The abundance of Methylomonas, an aerobic methanotroph, decreased significantly, while Meiothermus, a potential chromate-reducing bacterium, was enriched in the biofilm. Overall, the results showed that the anaerobic environment inhibited the activity of aerobic methanotrophs while promoting AnMO bacterial enrichment, and high Cr(VI) loading reduced Cr(VI) flux by inhibiting the methane oxidation process.
KeywordsChromate Methane AnMO Remediation
The authors greatly thank the National Natural Science Foundation of China (grant nos. 21577123, 51878596) and Natural Science Funds for Distinguished Young Scholar of Zhejiang Province (LR17B070001) for their financial support.
- Cakir FY, Stenstrom MK (2005) Greenhouse gas production: a comparison between aerobic and anaerobic wastewater treatment technology. Water Res 39(17):4197–4203Google Scholar
- Dragun J (1988) The soil chemistry of hazardous materials. Hazardous Materials Control Research Institute, Silver SpringGoogle Scholar
- Maeda H, Fujimoto C, Haruki Y, Maeda T, Kokeguchi S, Petelin M, Arai H, Tanimoto I, Nishimura F and Takashiba S, (2003) Quantitative real-time PCR using TaqMan and SYBR Green for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, tetQ gene and total bacteria. FEMS Immunology & Medical Microbiology, 39(1):81–86Google Scholar
- Meyer KJ, Swaim P D, Bellamy WD, Rittmann BE, Tang YN, Scott R (2010) Biological and ion exchange nitrate removal: performance and sustainability evaluation, Final Project Report, Water Research Foundation: Denver, COGoogle Scholar
- Moran JJ, House CH, Freeman KH, Ferry JG (2014) Trace methane oxidation studied in several euryarchaeota under diverse conditions. Archaea 5:303Google Scholar
- Rittmann, McCarty (2002) Environmental biotechnology: principles and applications. McGraw-HillGoogle Scholar
- Sun Y, Wolcott RD, Dowd SE (2011) Tag-encoded FLX amplicon pyrosequencing for the elucidation of microbial and functional gene diversity in any environment. In: Kwon Y, Ricke S (eds) High-throughput next generation sequencing. Methods in molecular biology (Methods and Protocols) 733. Humana Press, TotowaGoogle Scholar
- World Health Organization (2011) Guidelines for drinking-water quality, 4th edn. WHO Press, GenevaGoogle Scholar
- Zehnder AJB, Brock TD (1979) Methane formation and methane oxidation by methanogenic bacteria. J Bacteriol 137:420–432Google Scholar