响应面法优化复合菌种发酵豆粕条件

Optimization of Conditions for the Compound Strains Fermented Soybean Meal Using the Response Surface Methodology

以豆粕、麸皮、糖蜜为原料,利用米曲霉和酿酒酵母混菌发酵生产高蛋白饲料。通过单因素试验研究了菌液接种量、温度、发酵时间、料水比、麸皮添加量、糖蜜添加量对粗蛋白含量的影响。在此基础上进行响应面优化,得出最佳发酵工艺条件:装料量25 g(其中91%豆粕、7%麸皮、2%糖蜜),1.5%MgSO_4,1%(NH_4)_2SO_4,1%尿素,1%K_2HPO_4,料水比1∶1.1,接种13%的菌液,在31.3℃发酵78.6 h。在最佳发酵条件下,粗蛋白含量达到56%,比发酵前提高13.96%;真蛋白含量达到52.43%,比发酵前提高21.39%;活菌数达到1.38×109;脲酶活性降低了95.93%。该复合菌株发酵模式可以有效提高产品的蛋白含量,降低脲酶活性,降解大分子蛋白质和抗原蛋白,且发酵过程中产生曲香味和酒香味,适用于豆粕发酵的工业化生产。

With soybean meal,bran and molasses as raw materials,Aspergillus oryzae and Saccharomyces cerevisiae as strains fermented for production of high-protein fodder. This paper investigated inoculation quantity,temperature,fermentation time,material-water ratio,the bran addition quantity and the molasses addition quantity on the influence of the total protein content through single factor experiment. On this basis,it is concluded that the best fermentation condition as followed,charge 25 g（ 91% of soybean meal,7% of bran,2% of molasses）,addition of 1. 5% MgSO_4,1%（ NH_4）_2SO_4,1% urea,1% K_2HPO_4,the ratio of material to water was 1∶ 1. 1,inoculation quantity was 13%,the temperature was 31. 3℃,the fermentation time was 78. 6 h by using the response surface optimization. Under the optimum fermentation conditions,the total protein content was56%,13. 96% higher than that of before fermentation. True protein content reached 52. 43%,21. 39% higher than that of before fermentation. The viable count achieved 1. 38 × 109. Urease activity was reduced by 95. 93%. The compound strains fermentation mode could effectively increase the protein content of products,reduce the activity of urease,degrade macromolecular protein and antigen protein,is suitable for soybean meal fermentation of industrial production with the fermentation process of aroma and wine flavor.