响应面优化黑曲霉和酿酒酵母发酵豆粕的条件

Optimization of soybean meal fermentation conditionsby using response surface methodology

摘要:

以豆粕、麸皮和糖蜜为发酵原料,利用黑曲霉和酿酒酵母复合菌发酵生产饲料蛋白。首先利用单因素试验优化了豆粕蛋白发酵条件(接种量、温度和发酵时间)和发酵培养基成分(料水比、麸皮和糖蜜添加量),再利用响应面法进一步优化了发酵条件。优化结果为:装料量为25 g(其中豆粕、麸皮和糖蜜分别为90%、7%和3%),MgSO₄ 0.375 g, (NH4)2SO₄ 0.25 g,尿素0.25 g, K₂HPO₄ 0.25 g,料水比1∶1,菌液接种量16%,33.2℃发酵86.6 h。优化后粗蛋白和真蛋白含量分别为57.59%和53.65%,比优化前分别提高17.42%和24.59%;活菌数达到3.62×109cfu/g;脲酶活性降低了92.41%。经过优化的复合菌发酵豆粕可以提高豆粕的蛋白含量,有效地降解了抗原蛋白和营养抑制因子,提高了畜禽对豆粕的消化利用率,该发酵工艺可为发酵豆粕工业化生产提供优化依据。

Abstract:

Soybean meal,bran and molasses were used as raw materials to ferment protein feed with Aspergillus niger and Saccharomyces cerevisiae.The effects of inoculation amount,temperature,fermentation time,ratio of raw material to water,amount of bran and molasses on crude protein content were studied through single factor experiment.The response surface method based optimal fermentation conditions were as follows: 25g (90% soybean meal,7% bran,3% molasses) loaded raw material,0.375g MgSO₄,0.25 g (NH4)2SO4,0.25 g urea and 0.25 g K₂HPO₄;The ratio of raw material to water was 1∶1,and the microbial inoculation amount was 16%;The fermentation temperature and time were 33.2℃ and 86.6 hours.Under the optimal fermentation conditions,the crude protein and true protein content reached 57.59% and 53.65% respectively,which was 17.42% and 24.59% higher than the control.The number of viable microbe reached 3.62×109 cfu/g.Urease activity decreased by 92.41%.The optimized combined fermentation could effectively increase the protein content,degrade the macromolecular protein and antigen protein,and improve digestibility of soybean meal,which was suitable for the industrial production of soybean meal fermentation.