Shortening\nthe Storage Duration of Food Waste and\nAdding Ammonia Nitrogen to Food Waste to Increase Hydrogen Yield in\nMicrobial Electrolysis Cells

Acidification occurs during the temporal storage and\nlong-distance\ntransportation of food waste (FW). It can influence FW physicochemical\nproperties and even subsequent treatment and disposal. In this study,\nmicrobial electrolysis cells were constructed to evaluate hydrogen\n(H<sub>2</sub>) production and biodegradation behaviors of rice slurry\n(R) and fermented rice liquid (FR). Carbohydrate, as the main component\nin R, was more prone to be acidified into acetate and subsequently\nstart H<sub>2</sub> generation. While the dominant component in FR\nwas butyrate, it became a rate-limiting step during anaerobic fermentation,\nleading to its lower H<sub>2</sub> productivity. Results showed that\nthe H<sub>2</sub> yield of R was 1.48 times higher than that of FR.\nThe microbial community and molecular dynamics simulation revealed\nthat R was readily utilized by <i>g_Aeromonas</i>. This\nwas a more efficient pathway for producing H<sub>2</sub>. The additional\nsupply of NH<sub>4</sub><sup>+</sup>-N exerted a more remarkable effect\non improving H<sub>2</sub> yield through enriching <i>g_Geobacter</i> and <i>g_Enterococcus.</i> The increasing of <i>g_Flavobacterium</i> accelerated the degradation of starch to generate more H<sub>2</sub>.