LAUSR

Resource efficient and novel practices to produce proteinaceous food and feed sources can partially alleviate the protein scarcity problem. The conversion of low-value waste streams into single cell protein (SCP) seems a potent solution. This study evaluated the possibility of urban biowaste valorization through coupling anaerobic digestion and SCP production, and feeding a methanotroph mixed-culture with raw and upgraded biogas. In respect to nitrogen supply, the mixed-culture could grow well providing nutrients by direct addition of pasteurized centrifuged-filtered digestate or by adding electrochemically extracted ammonium from the digestate. The SCP yield on methane varied from 0.59 to 0.76 g cell dry weight (CDW)/g CH4. A high yield on methane (0.87 g CDW/g CH4) proved that biogas is a good substitute for natural gas for scaled-up microbial protein production. In addition, the produced SCP was rich in essential amino acids, marking the produced biomass comparable with other protein sources.