Hydrogen fermentation of food waste by alkali-shock pretreatment: Microbial community analysis and limitation of continuous operation

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>In the study, at first, batch tests were performed to investigate the effect of alkali-shock on H<SUB>2</SUB> production from food waste (FW). After alkali-pretreatment of FW at pH 9.0–13.0, the FW was cultivated under mesophilic condition at pH 6.0 for 30h without external inoculum addition. The amount of H<SUB>2</SUB> production from FW pretreated at pH 11.0 and 12.0 was higher than that achieved in other pretreatment pH. The main metabolite was butyrate, and <I>Clostridium</I> were dominant at pH 11.0 and 12.0. Meanwhile, lactate was the main metabolite with <I>Enterococcus</I> and <I>Streptococcus</I> being the dominant genus at other pretreatment pH. When the batch process was switched to a continuous mode, H<SUB>2</SUB> production was significantly dropped due to the increased activity of H<SUB>2</SUB>-consumers. The reliability of alkali-pretreatment at pH 11.0 was proven by repeating the scale-up batch process, recording 1.57±0.11molH<SUB>2</SUB>/mol hexose<SUB>added</SUB> (17±2LH<SUB>2</SUB>/kg FW) and 4.39±0.32LH<SUB>2</SUB>/L/d.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Increased H<SUB>2</SUB> production from food waste by alkali-pretreatment. </LI> <LI> High H<SUB>2</SUB> production and dominance of <I>Clostridium</I> sp. at pH 11.0 and 12.0. </LI> <LI> Limited performance in continuous operation due to H<SUB>2</SUB>-consuming reactions. </LI> <LI> The repeated batch performance: 1.6±0.1molH<SUB>2</SUB>/mol hexose<SUB>added</SUB> and 4.4±0.3LH<SUB>2</SUB>/L/d. </LI> </UL> </P>