Assessment of biogas production and microbial ecology in a high solid anaerobic digestion of major California food processing residues

High-solids anaerobic digestion (HSAD) was performed using mixtures of tomato or grape pomace, dry bovine manure and mature green waste compost at a total solids content of 28%. Various feedstock loading levels (FLL) were tested over multiple fed-batch cycles. TP showed greater methane yield at 201.61 mL/g dry pomace when digested at a mesophilic temperature with 5% (by dry weight) FLL. Methane yield from GP was approximately 132 mL/g_dry pomace in both thermophilic and mesophilic conditions with up to 5% FLL. 16S rRNA gene sequencing of the different HSAD systems was used to profile bacteria and archaea. The results showed shifts between Methanoculleus and Methanosarcina genera in response to feedstock and operating temperature. These data can enable additional studies to scale up HSAD of these waste streams, optimize HSAD conditions for improved yield and stability, and understand the microbiota structures that relate to HSAD performance.