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Uniform design and partial least squares regression were adopted to quantitatively analyze the effects of plant oil and fatty acid as well as their addition amount and addition time on the performance of Tuber melanosporum submerged fermentation. The regression models showed the optimal scheme was the addition of 1.2 mL soybean oil on day 9, which was validated by experiment. The maximal biomass of 25.89 ± 1.01 g/L and extracellular polysaccharides (EPS) production of 6.51 ± 0.68 g/L were obtained, which were enhanced by 18.5% and 86%, respectively. Palmitic acid was identified to be the key component to stimulate the cell growth and EPS biosynthesis, and stearic acid was beneficial for the production of intracellular polysaccharides. Not only the biomass but also EPS production obtained in this work are the highest reported in the batch fermentation of truffle. [ABSTRACT FROM AUTHOR]

Abstract: A novel method using Plackett–Burman design (PBD) coupled with Draper–Lin small composite design (SCD) and desirability function (DF) was developed to optimize Tuber melanosporum fermentation medium. Firstly, sucrose, yeast extract, peptone and Mg2+ were identified to be key medium components by PBD. Secondly, in order to evaluate the relationships between responses and the identified key components, mathematical models were developed by SCD. Finally, by using DF, the responses were optimized simultaneously and the optimal concentration was located to be 73g/L sucrose, 11g/L yeast extract, 8g/L peptone, and 46mM Mg2+. Under the identified optimal conditions, the maximal biomass, the production of extracellular (EPS) and intracellular (IPS) polysaccharides was 25.10±0.12g/L, 3.88±0.23g/L and 2.87±0.32g/L, respectively, which agreed with the predicted values well. Compared with the basic medium, the biomass, the production of EPS and IPS was enhanced by 54.4%, 71.7% and 124.2%, respectively. [Copyright &y& Elsevier]

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]