Relating quinone profile to the aerobic biodegradation in thermophilic composting processes of cattle manure with various bulking agents

Cattle manure was composted aerobically with various bulking agents (rice straw, vermiculite, sawdust or waste paper) at a constant incubation temperature of 60 degrees C. Increased quinone content (IQC) was used to assess microbial biomass in the composted material. IQC was proportional to mass reduction (MR) (R = 0.812) and cumulative O-2 consumption (COC) (R = 0.810) irrespective of the bulking agent used, indicating that the yield of quinone was constant. Quinone yields were 0.44 +/- 0.03 mu mol quinone/g MR and 0.34 +/- 0.02 mu mol quinone/g COC. The material that was decomposed by microorganisms was considered to be mainly cattle manure. Bulking agents were not degraded within the 14 day trial period and did not affect microbial succession because composting runs with various bulking agents exhibited similar quinone yields.