초록
<P><B>Abstract</B></P> <P>The microbial reduction of CO<SUB>2</SUB> into value-added products is gaining considerable attention and can play a significant role in the field of environment and energy research. A novel strategy for biotransformation of CO<SUB>2</SUB> was tested with zero valent iron (ZVI) and enrichment cultures for methane and acetate production under anaerobic conditions at room temperature. The favorable performance of CO<SUB>2</SUB> conversion (81.67% of conversion rate) was achieved in ZVI-amended treatments by enhanced methanogenesis and acetogenesis simultaneously. The enrichment consortium of microorganisms containing <I>Methanosarcina</I> spp. and <I>Clostridiaceae</I> was responsible for methane and acetate production, and accounted for 25.89% and ∼4.83% of CO<SUB>2</SUB> conversion, respectively. Scanning electron microscopy (SEM) observation and mass balance analysis of hydrogen detected in the headspace indicated that direct electron transfer and utilization possibly occurred with these microbes, especially methanogens. Interestingly, X-ray Photoelectron Spectroscopy (XPS) confirmed carbonation mineral (FeCO<SUB>3</SUB>) as the major strategy of CO<SUB>2</SUB> consumption under the experimental conditions. These observations collectively revealed that supplementation of ZVI can be a favorable electron donor to stimulate and accelerate the biotransformation of CO<SUB>2</SUB> into methane and acetate by the enrichment culture of microorganisms, and the information presents available alternative biochemical pathways for energy recovery from greenhouse gas under anaerobic conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Accelerated methanogenesis and acetogenesis were achieved simultaneously. </LI> <LI> <I>Methanosarcina</I> spp. and <I>Clostridiaceae</I> were contributors to methane and acetate production respectively. </LI> <LI> Direct electron transfer and utilization occurred in microbes. </LI> <LI> Improved conversion rate of CO<SUB>2</SUB> (81.67%) was obtained by ZVI addition. </LI> <LI> Mineral carbonation might be the major CO<SUB>2</SUB> consumption pathway in ZVI-amended cultures. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>