Improving enzyme activity by compound microbial agents in compost with mixed fruit tree branches and pig manure during composting

The effects of compound microbial agents in compost with mixed fruit tree branches and pig manure during composting in a thermophilic aerobic state were examined.The research used the inoculants compound microbial agents and control compost. The changes of temperature, enzyme activity, and the microbial community functional diversity in compost materials during composting were determined. The results showed the temperature during the composting period was increased and the high temperature(above 55℃) maintaining period was three days longer. Besides, inoculation treatment and control treatment are all carried out to achieve compost maturity, what was more, when added to the compound microbial agents composting process, we can easily find that the number of the seed germination in inoculants treatment is obviously higher than it is in the control treatment(P0.05), so we can find that this process caused the decrease of the pH value and the C/N ratio. Of course, they promoted the compost maturity. The activities of the enzymes were improved by adding compound microbial agents. The tested enzymes Cellulose, laccase(Lac), Manganese peroxidase(Mn P), and lignin peroxidase(Li P) activities were higher in the treatment with microorganism agent than those in the control treatment by 15.0%-19.8%, 1.0%-11.0%, 4.1%-26.8%, and 4.0%-22.2%, respectively. The research showed that the activity of Cellulose, Laccase(Lac), and the lignin peroxidase(LiP) rose at the beginning of the experiment and then dropped gradually under the inoculants agent processing, and reached the peak value in the seventh day. Their numerical values were 0.96 mg/(g·d) and 72.6 U/g respectively. However, the Manganese peroxidase(Mn P) and Lignin peroxidase(Li P) reached their peak in the second day. Their numerical peak values were 927.2 and 726.4 U/g respectively. In addition, the activity of Manganese peroxidase(Mn P) which was dealt with the inoculation treatment and control treatment was rising a little at the last period, and it may be affected by the content of the nitrogen in the last period. The average well color development(AWCD) value of microbes in compost was improved significantly, and six kinds of carbon sources used by the microbes during the high temperature period and cooling period were also significantly changed by the inoculation compound microbial agents. The research showed that the use of the inoculation agent processing to sugar and polyamine is obviously higher than the control treatment in the high temperature period. They are improved by 50.0% and 77.0% respectively. However, the use of carboxylic acid, polymer, and the polyphenolic substance were obviously lower than the control treatment, and their utilization rates were reduced by 23.5%, 44.7%, and 39.3% respectively. In the cooling temperature period, the use of the inoculants agent processing to the other five carbon sources, except polyamine, were all higher than that in the control treatment(P0.05). Principal component analysis clearly revealed that adding compound microbial agents plays a main role in the high temperature period during the composting, and the metabolic characteristics of micro flora during these two treatments were changing along with the composting process and the differentiation in the six utilizations of carbon sources were mainly sugars and amino acids.