Valorization of pruned tea leaves based on the accumulated metabolites: Current techniques and prospects towards sustainable production

China ranks first in tea cultivation (62.6%), production (49.1%), and consumption (44.2%) in 2022 over the world. Increasing output of tea leaves produces profit for China’s tea farmers, however, current tea production from such prosperous market aims for premium and special tea, which results in over 60% tea leaves being wasted in tea garden after pruning. Herein, comprehensive research on the pruned tea leaves termed as tea waste biomass (TWB) is conducted to draw a balance between simple consumption and cross-frontier waste management. Current research on tea biomass is reviewed by bibliometric analysis and further investigation into the physiological accumulation patterns in TWB are concluded. Vigorous photosynthesis promotes the accumulation of valuable and characteristic metabolites in TWB such as sugars and flavonoids. The valorization of this underestimated resource is positively pronounced through three cost-effective approaches, namely two-stage enzymatic extraction, biological and thermochemical conversion. Two-stage enzymatic extraction transforms PTB into food, agricultural, chemical, and medical products. Biological fermentatation, ensiling and composting convert CTB into enzymes, feed and fertilizer. Through thermochemical pyrolysis, the fixed carbon in CTB is beneficial for soil improvement, bio-fuel production, and energy storage. This review promotes current valorization methods of TWB based on the accumulated metabolites in tea plants, and sheds light into continual production of tea plants and other C 3 cash crops.