响应面法优化普通小球藻混合营养培养基组成生产生物质

Optimization of the Mixotrophic Culture Medium Composition for Biomass Production by Chlorella vulgaris Using Response Surface Methodology

利用响应面法优化了混合营养培养普通小球藻生产生物质的培养基组成。首先采用Plackett-Burman设计对11个相关营养因素的效应进行了评价,并筛选出影响小球藻细胞生长的3个主要因素为KNO3、葡萄糖和NaCl;然后结合Box-Behnken设计建立了以小球藻浓度为响应值的二次回归方程模型,获得优化的培养基组成为KNO31.64g/L、葡萄糖45g/L、NaCl 1.57g/L;模型预测的最大浓度为5.28g/L,验证值为5.68g/L;验证结果表明,所建立模型预测精度较好,可用于优化小球藻的混养培养基组成。优化条件下混养小球藻细胞的蛋白质和色素含量较优化前降低,而可溶性糖和油脂含量提高,脂肪酸以棕榈酸和油酸为主;细胞组分分析结果显示,混养培养所得小球藻生物质具有作为生产微藻生物能源原料的潜力。

Response surface methodology was adopted to optimize the mixotrophic culture medium composition for biomass production. In the first optimization step, KNO3, glucose and NaCl were screened from eleven related nutrients as the major factors influence the mixotrophic growth of Chlorella vulgaris significantly using Plackett-Burman design. Subsequently, quadratic regression equation model was established based on the Box-Behnken design, and the optimized nutrients contents were that KNO3 was 1.64g/L, glucose was 45g/L and NaCl was 1.57g/L. The predicted maximum biomass content of 5.28g/L was obtained from the model, and the actual validation value was 5.68g/L. The validation results indicated that the model can be used to optimize the mixotrophic culture medium of C. vulgaris for its high prediction accuracy. Under the optimum conditions, the biochemical composition of mixotrophic C. vulgaris displayed that the protein and total pigments content were reduced and the soluble carbohdyrate and lipid content were increased, compared with the un-optimized algal biomass. The major fatty acids of the alga lipid were oleic acid and palmitic acid. The results from biochemical composition analysis suggested that the mixotrophic biomass of C. vulgaris can be used as a potential feedstock for microalgae biofuel production.