响应面法优化暹罗芽孢杆菌产大环内酯的发酵培养条件

Optimization of Fermentation Culture Conditions for Macrolactins Yield of Bacillus siamensis Using Response Surface Methodology

【目的】大环内酯(MLNs)是一类由聚酮链环化而成的新型化合物,具有显著的抗菌、抗病毒和抗肿瘤活性,但因传统发酵的大环内酯产量较低而限制了其广泛应用。旨在提高暹罗芽孢杆菌K53合成MLNs的产量,以期为MLNs的批量生产提供科学依据。【方法】基于前期研究发现,通过单因素试验研究碳源、氮源、氨基酸等营养成分对菌株K53中MLNs发酵产量的影响,确定关键营养因子,运用响应面分析法对关键营养因子进行优化,获得发酵MLNs的最佳工艺参数。【结果】单因素试验中,菌株K53的发酵培养基中葡萄糖为最优碳源,酵母提取物和(NH_(4))_(2)SO_(4)分别为最优有机氮源和无机氮源,额外添加组氨酸和缬氨酸可提高MLNs的产量。响应面优化中,菌株K53的最佳发酵培养基:22.0 g/L葡萄糖、3.0 g/L(NH_(4))_(2)SO_(4)、1.0 g/L酵母提取物、6.1 g/L缬氨酸和5.9 g/L组氨酸,其中缬氨酸和组氨酸为合成MLNs的前体物质。在该培养基中MLNs的产量达到5.37×10^(2)μg/mL,与理论预测的最大值(5.46×10^(2)μg/mL)非常接近,与优化前的菌株合成MLNs产量(1.31×10^(2)μg/mL)相比提高4.10倍。【结论】响应面法优化后的发酵培养基有利于提高菌株K53的MLNs产量,为菌株MLNs的后续开发应用提供参考。

【Objective】Macrolactins(MLNs)are a class of 24-membered macrolides formed by cyclization of polyketones,which have a variety of biological activities such as antibacterial,antifungal,antiviral,and anti-tumor.However,due to the low yield of macrolides in traditional fermentation,its development and application are limited.Therefore,this article aims to increase the yield of MLNs synthesized by Bacillus siamensis K53,in order to provide scientific basis for the mass production of MLNs.【Method】Based on previous research,single factor experiments was used to study the effects of carbon,nitrogen and amino acids on the MLNs yield of strain K53 and to determine the key nutritional factors.Response surface analysis was used to optimize the key nutritional factors for obtaining the optimal parameters in fermenting MLNs.【Result】In the single factor experiment,glucose was the optimal carbon source in the fermentation medium of strain K53.The yeast extract and(NH_(4))_(2)SO_(4) were the optimal organic and inorganic nitrogen sources,respectively.The addition of histidine and valine increased the yield of MLNs.In response surface optimization,the optimal fermentation medium for strain K53 was 22.0 g/L glucose,3.0 g/L(NH_(4))_(2)SO_(4),1.0 g/L yeast extract,6.1 g/L valine,and 5.9 g/L histidine.The valine and histidine were precursors for the synthesis of MLNs.The MLNs yield in this medium reached 5.37×10^(2)μg/mL,which was very close to the maximum value(5.46×10^(2)μg/mL)predicted by theory,and 4.10 times higher than that in the non-optimized medium(1.31×10^(2)μg/mL).【Conclusion】The optimized medium formula by response surface methodology is conducive to the MLNs yield of the strain K53,and the results provide theoretical bases for the consequent development and application of the strain K53.