Using watermelon rind and nitrite-containing wastewater for electricity production in a membraneless biocathode microbial fuel cell

Waste-to-energy is a promising approach for environmental sustainability. We examined the usage of watermelon rind waste coupled with nitrite-containing wastewater electricity production in membraneless biocathode microbial fuel cell (MB-MFC). Results showed that maximum voltage output internal nitrite circulation fed-batch mode was 294 mV, which 1.4 and 1.3 times without continuous mode, respectively. Watermelon quickly fermented to organic acids dominated acetate lactate during generation. The most dominant genus cathodic biofilm Lactobacillus relative abundance 74%, while two dominative genera Clostridium sensu stricto Bacteroides anodic had similar approximately 18%. Three microbes cooperated well producing converting nitrogen gas. Additionally, we found key genes nirS/K, conrB nosZ involved reduction. Our results suggest feasibility harnessing electrical energy from MB-MFC as substrates electron acceptor.