HYDROLASES AS A MEASURE OF MICROBIAL ACTIVITIES OF VERMICOMPOSTING SUBSTRATES
Hydrolase's activities as measured by fluorescein diacetate (FDA) assay was used to quantify microbial activity in composts and vermicomposts using the earthworms, Eisenia fetida andrei, Aporrectodea caliginosa and A. rosea made of cattle manure, leaves and turf. It was found that effectiveness of hydrolases (the Michaelis-Menten constant, Km) was lower in the vermicomposts as compared to composts which correlated to a decrease in fungal hyphal length. It is proposed to use measurement kinetics of FDA activity along with fungal hyphal length to characterize vermicomposting process by functional (activities) and structural (microbial biomass) approaches.