Relationship between maturity and microbial communities during pig manure composting by phospholipid fatty acid (PLFA) and correlation analysis

The dynamic of microbial community plays vital role during composting. We therefore conducted a combined study on the maturity of compost (by pig manure composting with covering matured compost) and the successions of microbial communities (via phospholipid fatty acid (PLFA)). Our results showed that pH, electrical conductivity (EC), NH4-N, and germination index (GI) were suitable indicators for compost maturity evalument. In addition, there was a closer correlation between maturity indexes (NH4-N and GI) and the microbial compositions (as evaluated by microbial PLFA). The regression predicting model for NH4-N used bacteria PLFA 15:0 and fungi PLFA 18:1ω9t (R2 = 0.98, P < 0.01) and for GI used fungi PLFA 18:1ω9t and 18:1ω9, 12 (R2 = 0.94, P < 0.01) as the evidences of good predictive ability. It also indicated that PLFA 18:1ω9t has a good relationship with the changes of NH4-N and GI during the composting. Our results revealed the potential of using microbial PLFA for evaluating the maturity during pig manure composting.