Objective Cellulose-degrading microbes in pomelo compost were identified to evaluate potential of the waste utilization for fertilizing tea plants.

Method Soils containing decomposed pomelo waste from Pinghe County, Fujian Province were sampled to isolate cellulose-degrading microbes using the plate clearing zone method followed by cellulase activity determination. Potential candidates were identified by morphological characteristics and ITS sequence. Compost using discarded pomelo parts as the primary substrate was fermented with the isolated cellulose-degrading fungi to prepare the pomelo compost fertilizer (F) for the experimentation on 5-year-old Huangdan tea plants. Along with water as control, soils were mixed with F at 150x dilution (150xF), with F at 300x dilution (300xF), or a conventional compound fertilizer (CF). At end of the experiment, leaf yield and quality of the tea plants were determined.

Result The highly efficient cellulose-degrading PHFG1220 was isolated and identified to be Penicillium oxalicum. The 150xF or 300xF soil significantly improved the bud length and density as well as the length, width, thickness, and yield of the leaves of the tea plants grown on them. They also significantly elevated the quality indices of oolong tea, such as the contents of water extract, caffeine, catechins, tea polyphenols, and free amino acids. Specifically and respectively in comparison with control, bud density significantly increased by 5.45% and 1.82%, fresh leaf yield by 29.80% and 21.25%, water extract by 2.80% and 1.00%, caffeine by 12.29% and 8.47%, catechins by 13.00% and 5.38%, tea polyphenols by 3.59% and 1.50%, and free amino acids by 11.00% and 9.00% (P＜0.05).

Conclusion P. oxalicum PHFG1220 was highly efficient in degrading pomelo waste. Application of the pomelo compost fertilizer significantly increased the yield and quality of tea leaves. The green practice could materially utilize the waste material and reduce the need for chemical fertilizer at tea plantations.