对红曲霉ZL307产γ-氨基丁酸的固态发酵工艺进行了优化,旨在探寻豆渣的综合利用方式,降低γ-氨基丁酸的生产成本。在单因素试验的基础上,通过Plackett-Burman设计从6个因素中筛选出了有显著影响的大米粉、MgSO4、KH2PO4三个因素。通过最陡爬坡实验、中心复合实验设计及响应面分析确定主要影响因素的最佳浓度及回归模型,并经实验验证模型的可行性。最佳培养基组成和培养条件为:基质豆渣12.28 g,大米粉为7.72g,(NH4)2SO40.20%,MgSO40.23%,KH2PO40.37%,CaCl20.25%,谷氨酸钠0.45%(均为占固体基质的质量分数),初始含水量60%,初始pH值5.5,温度32℃。在优化条件下,γ-氨基丁酸产量达到0.417mg/g,含量比优化前提高13.4%。

In order to reduce the production cost of γ-aminobutyric acid and make the best of bean dregs,the fermentation conditions for Monascus ZL307 to produce γ-aminobutyric acid with bean dregs as raw material in solid-state fermentation were optimized.Based on the study of single factor tests,we used Plaekett-Burman design to evaluate the influence of six related factors.Rice flour,MgSO4,KH2PO4 were affirmed the important factors in the medium.After identifying three critical factors,the optimal region of γ-aminobutyric acid production was found by steepest ascent approach.Then response surface methodology was also used to develop a mathematical model to identify the optimum concentrations of the key nutrients for higher γ-aminobutyric acid production,and to confirm its experimental validity.The results showed that the optimal fermentation conditions were as follows: bean dregs 12.28g,rice flour 7.72 g,(NH4)2SO4 0.20%,MgSO4 0.23%,KH2PO4 0.37%,CaCl2 0.25%,sodium glutamate 0.45%,initial water content 60%,initial pH 5.5,temperature 32 ℃.Under the optimum conditions,the yield of γ-aminobutyric acid reached 0.417 mg/g,which was 13.4% higher than before.