响应面法优化诺尔斯链霉菌发酵条件以提高谷氏菌素产量

Optimization of fermentation conditions of Streptomyces noursei using response surface methodology to improve the gougerotin yield

诺尔斯链霉菌Streptomyces noursei的次级代谢产物丰富,抑菌谱广,在农业上具有潜在的应用前景。作者实验室筛选到一株诺尔斯链霉菌S. noursei NK27,其次级代谢产物对番茄灰霉病的防治效果显著。为了提高NK27次级代谢产物中谷氏菌素的产量,以NK27发酵液中谷氏菌素产量为响应值,采用单因素试验、Plackett-Burman (PB)试验、最陡爬坡试验以及响应面法中的Box-Behnken试验设计,对NK27的发酵条件进行了优化。结果表明,诺尔斯链霉菌种龄、接种量及初始pH值3个因素对发酵效果影响最为显著。优化后的发酵条件为:初始pH值7.6,种龄32.6 h,接种量2.6%,转速220 r/min,发酵时间144 h。与原始发酵条件相比,优化后谷氏菌素含量提高了约3倍。本研究可为诺尔斯链霉菌大规模工业化发酵提供理论依据和技术支撑。

Streptomyces noursei was rich in secondary metabolites and had a broad-spectrum antifungal activity. A strain of S. noursei NK27, whose secondary metabolites had significant control effect on Botrytis cinerea was screened in our laboratory. In order to improve the ability of NK27 to produce gougerotin, single-factor tests, Plackett-Burman (PB) tests, the steepest climb tests and Box-Behnken tests were designed to optimize the fermentation conditions of NK27. From the five fermentation conditions, the three factors of inoculum age, inoculation amount and the initial pH showed the most significant influence on the yield of gougerotin. The fermentation conditions after the optimization of response surface were as follows: initial pH 7.6, inoculum age 32.6 h, inoculation amount 2.6%, rotation speed 220 r/min, fermentation time 144 h. The content of gougerotin was 3 times higher than that under the original fermentation condition. This study provided a theoretical basis for the industrial fermentation of S. noursei.