Efficient conversion of cane molasses into Tremella fuciformis polysaccharides with enhanced bioactivity through repeated batch culture

Tremella fuciformis polysaccharide (TFPS) is a natural mushroom mucopolysaccharide widely used in health foods, medical care, cosmetic and surgical materials. In this study, we developed an efficient strategy for the repeated batch production of highly bioactive TFPS from the agro-industrial residue cane molasses. Cane molasses contained 39.92 % sucrose (w/w), 6.36 % fructose and 3.53 % glucose, all of which could be utilized by T. fuciformis spores, whereas, the TFPS production efficiency only reached 0.74 g/L/d. Corn cobs proved to be the best immobilized carrier that could tightly absorb spores and significantly shorten the fermentation lag period. The average yield of TFPS in eight repeated batch culture was 5.52 g/L with a production efficiency of 2.04 g/L/d. The average fermentation cycle after optimization was reduced by 61.61 % compared with the initial conditions. Compared to glucose as a carbon source, cane molasses significantly increased the proportion of low-molecular-weight TFPS (TFPS-2) in total polysaccharides from 3.54 % to 17.25 % (w/w). Moreover, TFPS-2 exhibited potent antioxidant capacity against four free radicals ([rad]O₂⁻, ABTS[rad]⁺, [rad]OH, and DPPH[rad]). In conclusion, this study lays the foundation for the efficient conversion of cane molasses and production of TFPS with high bioactivity.