Evolution of alkaline phosphatase and protease activities, total organic carbon and CO2 evolved during composting

The changes in the activity of two enzymes (protease and alkaline phosphatase) and CO2 evolution rate were monitored during composting a mixture of horse and poultry manure and wheat straw. The relationships between them were investigated. Absolute and relative CO2 (CO2-C/TOC) evolution and phosphatase activity decreased as composting progressed. Protease activity increased sharply during the second week, then decreased and remained without significant differences. There was a close relationship between the activity of the two enzymes and the CO, evolution suggesting that the synthesis of these enzymes was related to the growth of beterotrophic microorganisms.