Abstract: This study examined the effect of fermentation with Phomopsis liquidambari B3 on increasing the resveratrol content in the peanut wastes. The resveratrol biosynthesis pathway was elucidated by identifying metabolites and analyzing the key enzyme genes in this pathway using real-time quantitative PCR. The results showed that B3 could secrete β-glucosidase to transform piceid in peanut wastes to resveratrol. It could also transform p-coumaric acid in peanut wastes to resveratrol via de novo synthesis. On this basis, the optimization of fermentation conditions for improved resveratrol conversion efficiency was carried out using one-factor-at-a-time method and response surface methodology. A ratio of solid to liquid of 1:30 (g/mL), an initial medium pH value of 5.2, an inoculum amount of 9%, a fermentation temperature of 28.6 ℃ and a rotating speed of 204 r/min were found to be the optimal conditions to obtain a higher yield of reveratrol. After 36 h fermentation in a 5 L fermentor, the content of resveratrol was increased by 1.9 times as compared with that before fermentation. The results confirmed that fermentation with P. liquidambari B3 could significantly increase the content of resveratrol in peanut wastes. This study is of great guiding significance for the development of high value-added products from peanuts and for wider comprehensive utilization of peanuts.

Key words: Phomopsis liquidambari B3, peanut wastes, resveratrol, response surface analysis, fermentation process