Co-digestion of oat straw and cow manure during anaerobic digestion: Stimulative and inhibitory effects on fermentation.

Impacts of adding different amounts of cow manure (CM) on the anaerobic digestion (AD) of oat straw (OS) with total solids content (TS) values of 4%, 6%, 8% and 10% was assessed over 50 days using batch experiments. A modified Gompertz model was introduced to predict the methane yield and determine the kinetic parameters. The optimum addition was a 1:2 ratio of CM to the OS added, which resulted in a suitable C/N ratio of 27 and a higher degradation rate of lignocellulose. The best cumulative methane yield of 841.77 mL/g volatile solids added (VSadded) was 26.64% greater than that of digesting OS alone. In addition, the amount of CM added produced larger effects than that of changes in the TS. However, higher CM concentrations were found to be inhibitory. Clustering analysis could provide significant guidance for demonstrating project process and combining farming and animal husbandry.

Methane production and characteristics of the microbial community in the co-digestion of spent mushroom substrate with dairy manure.

Spent mushroom substrate (SMS) is a potential biomass material generated during mushroom cultivation. In this study, the methane yield and microbial community resulting from co-digestion of SMS and dairy manure (DM) at different mixing ratios (0:4, 1:1, 3:1, and 1:3), were evaluated. Co-digestion analysis showed that the methane yield from the mixtures was 6%-61% higher than the yield from SMS or DM alone, indicating a synergistic effect of co-digestion of SMS with DM. For the SMS of F.velutipes (SFv) and P.erygii var. tuoliensis (SPt), co-digestion of DM/SMS at a ratio of 1:1 was optimal, but for the SMS of P. eryngi (SPe), co-digestion of DM/SMS at a ratio of 3:1 was ideal. The pH at all co-digestion ratios was in the range of 6.8-8.0, indicating that adding DM could increase the systemic buffering capacity. Methanosaetaceae was shown to be the predominant methanogens present during the co-digestion of DM/SMS.

Effect of pig manure on the chemical composition and microbial diversity during co-composting with spent mushroom substrate and rice husks.

In this study, the impact of pig manure on the maturity of compost consisting of spent mushroom substrate and rice husks was accessed. The results showed that the addition of pig manure (SMS-PM) reached 50°C 5days earlier and lasted 15days longer than without pig manure (SMS). Furthermore, the addition of pig manure improved nutrition and germination index. High-throughput 16S rRNA pyrosequencing was used to evaluate the bacterial and fungal composition during the composting process of SMS-PM compared to SMS alone. The SMS treatment showed a relatively higher abundance of carbon-degrading microbes (Bacillaceae and Thermomyces) and plant pathogenic fungi (Sordariomycetes_unclassified) at the end of the compost. In contrast, the SMS-PM showed an increased bacterial diversity with anti-pathogen (Pseudomonas). The results indicated that the addition of pig manure improved the decomposition of refractory carbon from the spent mushroom substrate and promoted the maturity and nutritional content of the compost product.