Effects of Carbon and Nitrogen Sources in the Medium on Tremella mesenterica Retz.:Fr. (Heterobasidiomycetes) Growth and Polysaccharide Production

The effects of different carbon and nitrogen sources, as well as of the initial medium pH, on Tremella mesenterica growth and polysaccharide production in submerged cultivation was investigated. Maximal biomass and extracellular polysaccharide (EPS) production was achieved when using sucrose, maltose, or mannitol as the only carbon source and peptone or corn steep liquor as the nitrogen source (yield of crude mycelium-polysaccharide ethanol precipitate reached 21–23 g/L). It has been shown that the yield of biomass and polysaccharides correlates with carbon source concentration in the medium. The EPS production improved threefold with increasing initial sucrose concentration from 1 to 6%. The levels of EPS production by the fungus grown at an initial pH of 5.0, 6.0, and 7.0 were, respectively, 11.7, 11.0, and 6.7 g/L. The cultivation process in shake flasks could be successfully reproduced in a laboratory bioreactor. The maximum mycelium-polysaccharide precipitate yield reached in 3 and 4 days of fermentation was 28.3 and 31.4 g/L, respectively.