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Abstract: For the first time, a fed-batch fermentation process of Tuber melanosporum was developed for the efficient production of bioactive mycelia and Tuber polysaccharides. Each 1.67g/L of peptone and 8.33g/L of yeast extract were added on day 3, 6, and 9, respectively, and sucrose was fed to maintain its concentration around 35–5g/L when its residual level decreased to 10–5g/L. Then, the maximal biomass, the production of extracellular polysaccharides (EPS) and intracellular polysaccharides (IPS) reached 53.72±2.57g DW/L, 7.09±0.62 and 4.43±0.21g/L, respectively. Compared with the batch culture conducted in the enriched medium, the biomass, the production of EPS and IPS were enhanced by 55.8%, 222.3% and 103.2%, respectively. Not only the cell density but also the production of EPS and IPS were the highest ever reported in truffle fermentation, and the biomass was also the highest as ever reported in mushroom fermentation. [Copyright &y& Elsevier]

Abstract: During the submerged fermentation of medicinal mushroom Chinese truffle Tuber sinense, there was no significant effect of metal ion on the cell growth and the production of intracellular polysaccharides, while metal ion and its concentration significantly affected the production of extracellular polysaccharides (EPS). By using the approach of “one-variable-at-a-time”, 50mM Mg2+ was identified to be the most favorable for EPS production, and the next was 10mM K+. A mathematical model, constructed by response surface methodology combination with full factorial design, was applied to study the synergic effect of Mg2+ and K+. EPS production reached its peak value of 5.86g/L under their optimal combination of 30mM Mg2+ and 5mM K+ predicted by the model, which was higher by 130.7% compared with the basal fermentation medium without metal ion. The validation experiment showed the experimental values agreed with the predicted values well. EPS production obtained in this work was the highest reported in the culture of T. sinense. [Copyright &y& Elsevier]