Influence of Microbial Agents Based on Biochar in Post-Consumption Food Waste Composting

Abstract

Recycling nutrients by post-consumption food waste (PCFW) composting is impeded by slow composting process because of high perishability and moisture content of PCFW. Concerning this issue, a biochar-based microbial agent with trehalose as a protectant was developed, and was evaluated as inoculum in PCFW composting. Inoculation effectively ameliorated acidic condition, accelerated organics degradation resulting in quick temperature rising, shortened maturation from 28 to 14 days and altered the succession of bacterial community structure. The combination of microbial consortium and biochar effectively inhibited the acid-producing bacteria Weissella and increased Bacillus, which contributed to better condition for indigenous microbes by ameliorated acidic condition of PCFW. This further expedited temperature rising that selectively enriched Firmicutes (Bacillus, Compostibacillus, Novibacillus) and Actinobacteria (Pseudonocardia) at thermophilic stage. Moreover, C cycle was strengthened by chemoheterotrophy and aerobic chemoheterotrophy, while fermentation was inhibited, which was in favor of organic material degradation. The addition of 5% trehalose further enhanced positive effect, and increased GI value to 152.21% at day 14. This study suggested that biochar-based microbial agent was an efficient inoculant specifically for PCFW composting.

Keywords: post-consumption food waste, Composting, biochar-based microbial agent, trehalose