Ren Xueyong, He Liang, Cheng Junwen, Chang Jianmin
College of Materials Science and Technology, Beijing Forestry University, Beijing, P.R. China.
Key Laboratory of Biological and Chemical Utilization of Zhejiang Forest Resources, Institute of Biological Technology, Zhejiang Forestry Academy, Hangzhou, P.R. China.
PLoS One. 2014 Feb 3;9(2):e87578. doi: 10.1371/journal.pone.0087578. eCollection 2014.
The culture conditions for the yield of a polysaccharide (PCPS) produced by Paecilomyces cicadae (Miquel) Samson on solid-state fermentation were investigated using response surface methodology (RSM). Plackett-Burman design (PBD) was applied to screen out significant factors, followed by the paths of steepest ascent to move to the nearest region of maximum response. Then Box-Behnken design (BBD) was conducted to optimize the final levels of the culture conditions. After analyzing the regression equation and the response surface contour plots, relative humidity 56.07%, inoculum 13.51 mL/100 g and temperature 27.09°C were found to be the optimal key parameters for PCPS production. The maximum predicted yield of PCPS was 10.76 mg/g under the optimized conditions. The resulting PCPS (FPCPS) generated at optimal conditions was purified by chromatography column and found to be composed of mannose (43.2%), rhamnose (32.1%), xylose (14.5%) and arabinose (10.2%). Based on the size exclusion chromatography combined with multi-angle laser light scattering (SEC-MALLS) analysis, FPCPS adopted a Gaussian coil conformation in 0.1 M NaNO3 solution with 3.75 × 10(6) g/mol of the weight-average molar mass (Mw) and 41.1 nm of the root-mean square radius (Rg(2))z (1/2). Furthermore, both of the polysaccharides were revealed to have strong antioxidant activities by evaluating in DPPH radical, superoxide radicals and hydroxyl radical assay. These data suggest the polysaccharides of Paecilomyces cicadae (Miquel) Samson produced by solid-state fermentation could be explored as potential natural antioxidants.
采用响应面法（RSM）研究了蝉拟青霉（Paecilomyces cicadae (Miquel) Samson）固态发酵生产多糖（PCPS）的培养条件。运用Plackett-Burman设计（PBD）筛选出显著因素，随后通过最速上升路径移至最接近最大响应的区域。然后进行Box-Behnken设计（BBD）以优化培养条件的最终水平。通过分析回归方程和响应面等高线图，发现相对湿度56.07%、接种量13.51 mL/100 g和温度27.09°C是PCPS生产的最佳关键参数。在优化条件下，PCPS的最大预测产量为10.76 mg/g。在最佳条件下产生的所得PCPS（FPCPS）通过色谱柱纯化，发现其由甘露糖（43.2%）、鼠李糖（32.1%）、木糖（14.5%）和阿拉伯糖（10.2%）组成。基于尺寸排阻色谱结合多角度激光光散射（SEC-MALLS）分析，FPCPS在0.1 M NaNO3溶液中呈高斯卷曲构象，重均摩尔质量（Mw）为3.75×10(6) g/mol，均方根半径（Rg(2))z (1/2)为41.1 nm。此外，通过DPPH自由基、超氧阴离子自由基和羟基自由基测定评估，发现这两种多糖均具有较强的抗氧化活性。这些数据表明，固态发酵产生的蝉拟青霉（Paecilomyces cicadae (Miquel) Samson）多糖可作为潜在的天然抗氧化剂进行开发。
