Optimization for the production of a polyketone 3S,4S-DMD from Panus lecomtei (Agaricomycetes) by submerged fermentation.

3,4-Dihydroxy-2,2-dimethyl-chroman derivatives have diverse physiological properties. A polyketone (3S,4S)-3,4-Dihydroxy-6-methoxy-2,2-dimethylchromom (3S,4S-DMD) with antibacterial activity was isolated from the solid culture of rare edible fungus Panus lecomtei. However, the yield of 3S,4S-DMD in solid culture of P. lecomtei is very low and the production period are too long. In this work, efficient accumulation of 3S,4S-DMD in P. lecomtei by submerged fermentation is studied. The key fermentation factors of P. lecomtei for 3S,4S-DMD production were optimised by single-factor experiment successively, and then a Box-Behnken design (BBD) experiment was carried out to further enhance 3S,4S-DMD production. A maximum 3S,4S-DMD yield of 196.3 mg/L was obtained at 25.78 g/L glucose, 1.67 g/L MgSO₄ · 7H₂O, 40°C and 197 r/min, respectively, which increased by 1.3-fold in comparison with that in the non-optimised fermentation conditions. Furthermore, an enhanced yield of 3S,4S-DMD (261.6 mg/L) was obtained in 5-L agitated fermenter. The 3S,4S-DMD productivity in flask and fermenter reached to 7.26 and 8.07 mg/g per day, respectively, which considerably increased by over 121-fold in comparison with that in the solid fermentation (0.06 mg/g per day). This study presents a potential method for the production of 3S,4S-DMD by submerged fermentation.