A comparative study of composting the solid fraction of dairy manure with or without bulking material: Performance and microbial community dynamics

•Composting of the solid fraction of dairy manure with or without bulking material.•Both composting processes allowed mature end-product in 48days.•Both composting processes presented similar bacterial community succession.•Composting phase, rather than compost type, affected bacterial composition.•Feasibility of composting using only the solid fraction of dairy manure was confirmed. The present study compared the development of various physicochemical properties and the composition of microbial communities involved in the composting process in the solid fraction of dairy manure (SFDM) with a sawdust-regulated SFDM (RDM). The changes in several primary physicochemical properties were similar in the two composting processes, and both resulted in mature end-products within 48days. The bacterial communities in both composting processes primarily comprised Proteobacteria and Bacteroidetes. Firmicutes were predominant in the thermophilic phase, whereas Chloroflexi, Planctomycetes, and Nitrospirae were more abundant in the final mature phase. Furthermore, the succession of bacteria in both groups proceeded in a similar pattern, suggesting that the effects of the bulking material on bacterial dynamics were minor. These results demonstrate the feasibility of composting using only the SFDM, reflected by the evolution of physicochemical properties and the microbial communities involved in the composting process.