KOREASCHOLAR

We studied the effects of initial pH, different nitrogen sources, and cultivation methods (shake flask and static culture) on biomass production, exopolysaccharides (EPS), and adenosine by Paecilomyces tenuipes. Relatively low pH levels were optimal for mycelial growth and EPS production. Yeast extract was the most effective organic nitrogen source for EPS production, whereas soybean extract was the best for adenosine production. A high C/N ratio was beneficial for adenosine production; however, excessively high C/N ratios reduced adenosine production. Static fermentation significantly increased adenosine production. A Box-Behnken design was used to optimize adenosine production; the optimal conditions for adenosine production by P. tenuipes were pH 7.0, soybean concentration of 3%, and a static culture period of 20 days, with the maximum adenosine production of 141.10 mg/L (predicted value: 128.05 mg/L).

INTRODUCTION
MATERIALS AND METHODS
    Mycelium and seed culture
    Flask culture conditions
    Determination of mycelia dry weight, pH and residual sugar
    Measurements of exopolysaccharide
    Measurement of adenosine by HPLC
    Response surface methodology (RSM), the Box–Behnken design
    Statistical Analyses
RESULTS AND DISCUSSION
    Effect of pH on cell growth and the production of metabolites
    Effect of nitrogen sources on cell growth and the production of metabolites
    Shake-flask and static culture of P. tenuipes
    Optimization of adenosine production by RSM (Box–Behnken design)
ACKNOWLEDGEMENTS
REFERENCES

• Si Young Ha(Department of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Republic of Korea)
• Hyeon Cheol Kim(Department of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Republic of Korea)
• Woo Seok Lim(Department of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Republic of Korea)
• Jae-Kyung Yang(Department of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Republic of Korea) Corresponding author