Duluth WRS Seminar

Using Microbiology to Clean up Environmental Contaminants


Susma Bhattarai Gautam
UMD's Natural Resources Research Institute

September 28, 2020


image of Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (AOM-SR)Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (AOM-SR) is a biological process mediated by anaerobic methanotrophs (ANME) and sulfate reducing bacteria. It has scientific and societal relevance in regulating the global carbon cycle and biotechnological application for treating sulfate-rich wastewater. We aimed to enhance the recent knowledge on ANME distribution and understand its growth and kinetics in different bioreactor configurations. We explored the coastal lake sediment from Lake Grevelingen, the Netherlands and depicted that the shallow sediment of water depth around 45 m host unique ANME and sulfate reducing microbial community. Marine sediment from Ginsburg mud volcano (900 m below sea level), Gulf of Cadiz was inoculated in the biotrickling filter and membrane bioreactor. The biotricking filter operation showed the enrichment of ANME in the biofilm, especially ANME-1 (40%) and ANME-2 (10%), whereas, the dominancy of ANME-2 and Desulfosarcina aggregates was observed in the membrane bioreactor. Moreover, high pressure enrichment was performed by using highly enriched ANME-2 community from Captain Arutyunov mud volcano, Gulf of Cadiz in high pressure bioreactor system up to 400 bar. During the incubation at high pressure gradient, the incubation at 100 bar pressure and 15oC was observed to be the most suitable condition for the studied AOM-SR community. Our research in different bioreactor configurations showed the slow-growing AOM community can be benefited by continuous supply of methane and biomass retention by allowing the biofilm growth, which can be further up-scaled to larger bioreactor system.

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