Quantifying the relative role of phytase and phosphatase enzymes in phosphorus mineralization during vermicomposting of fibrous tea factory waste

Tea factory waste (TFW) is a difficult-to-degrade and fibrous waste material generated in tonnes during tea manufacturing. Though TFW contains high amount of nutrients; high phenolic compound content and fibrous nature limit its direct use in agriculture. In this study, TFW was mixed with cattle manure at different proportions for evaluating possibility of recycling TFW through vermicomposting. It was observed that earthworms (Eudrilus euginae used in this study) could only survive when TFW was mixed with cattle manure at least in 1:1 proportion (w/w basis). The quality of vermicompost prepared from 25% TFW and 75% cattle manure combination was comparable to the vermicompost of sole cattle manure. Phosphorus (P) is one of the major nutrients required for plant growth. Though the effect of phosphatase enzyme in P mineralization during vermicomposting is well established, phytase enzyme in the vermicomposted organic substrate was not quantified before. In this study, phytase enzyme, measured in vermicomposting materials, was positively related to the amount of P mineralized. Both acid phosphatase and phytase enzymes were responsible for P-mineralization during vermicomposting. It was observed that acid phosphatase enzyme contributed to the P-mineralization in the first 50 days, while phytase enzyme contributed in the latter part of vermicomposting.