Bioaugmentation with Propionate-Degrading Methanogenic Cultures to Boost the Start-Up of Food Waste Anaerobic Digestion at High Organic Loading Rate

This study investigated whether bioaugmentation can boost the start-up of anaerobic digestion (AD) of food waste at high organic loading rate (OLR), and the effects of addition dosage and frequency on bioaugmentation performance. The results showed that the start-up efficiency of all bioaugmented reactors was better than that of non-bioaugmentation control at the high OLR of 3.0 g VS L-1 d-1, no matter what dose and frequency. Besides, relatively high dosages or frequencies promoted methane production. Adding 0.675 g VS L-1 of bioaugmentation seed (BS) each 5 days during the first HRT, the digester performed the best among the three bioaugmented systems, which remained relatively stable for next 3 HRTs without BS introduction. Metagenomic sequencing analysis indicated that bioaugmentation maintained aceticlastic Methanothrix at a high abundance and avoided volatile fatty acids (VFAs) accumulation, particularly acetate and propionate, which contributed to a successful start-up of AD at high OLR.