食品科学 ›› 2019, Vol. 40 ›› Issue (20): 185-191.doi: 10.7506/spkx1002-6630-20180808-073

• 生物工程 • 上一篇    下一篇

产蛋白酶芽孢杆菌的筛选及其发酵对豆粕的影响

郑丽,李达,牛红红,苗欣宇,王景会,苏颖   

  1. (吉林省农业科学院农产品加工研究所,吉林 长春 130033)
  • 出版日期:2019-10-25 发布日期:2019-10-25
  • 基金资助:
    吉林省农业科技创新工程杰出青年项目(CXGC2017JQ009); 吉林省农业科技创新工程自由创新项目(CXGC2017ZY018;CXGC2018ZY003)

ZHENG Li, LI Da, NIU Honghong, MIAO Xinyu, WANG Jinghui, SU Ying

ZHENG Li, LI Da, NIU Honghong, MIAO Xinyu, WANG Jinghui, SU Ying   

  1. (Institute of Agro-Food Technology, Jilin Academy of Agricultural Sciences, Changchun 130033, China)
  • Online:2019-10-25 Published:2019-10-25

摘要: 筛选高产蛋白酶芽孢杆菌并评价其发酵对豆粕的影响,从吉林省猪饲料中分离出1 株蛋白酶产量为(519.1±4.7)U/g的需氧芽孢杆菌JL8。通过生化实验和16S rDNA基因分析,鉴定其为暹罗芽孢杆菌(Bacillus siamensis)。通过分析不同发酵时间芽孢杆菌产芽孢数量、豆粕中可溶性还原糖含量、总蛋白含量、可溶性蛋白与总蛋白的比值以及蛋白过敏源降解情况,确定最佳发酵时间,并在最佳发酵时间下,通过扫描电镜(scanning electron microscopy,SEM)和X射线衍射(X-ray diffraction,XRD)分析芽孢杆菌发酵对豆粕蛋白微观结构的影响。结果表明:在37 ℃、物料含50%水的条件下,24 h为最佳发酵时间。发酵24 h后,SEM结果显示发酵显著改变了豆粕蛋白的微观结构,使其结构更加疏松。XRD结果显示发酵改变了蛋白质的主链结构,并且使β-折叠结构在二级结构中的占比大幅度提高,可能会提高豆粕蛋白的溶解性。

关键词: 芽孢杆菌, 蛋白酶, 发酵豆粕, 扫描电镜, X射线衍射

Abstract: In this study, we screened out a strain with high protease activity and evaluated its effect on soybean meal. The strain, coded as JL8, was an aerobic spore-forming Bacillus isolated from pig feed in Jilin province, which could produce (519.1 ± 4.7) U/g protease. This isolate was identified as Bacillus siamensis by physiological and biochemical tests and 16S rDNA sequence analysis. The optimal fermentation time was determined based on the spore quantity of JL8, and soluble reducing sugar content, total protein content, the ratio of soluble to total protein and the degradation degree of allergenic proteins in soybean meal. Then, the microstructure of soybean meal protein was investigated by scanning electron microscopy (SEM) and X-ray diffraction before and after fermentation. Results showed the optimal fermentation time was 24 h at 37 ℃ and at a water content of 50%. Moreover, the SEM images revealed that fermentation significantly changed the microstructure of soybean meal protein, making it looser. The X-ray diffraction patterns showed that the backbone of soybean meal protein was changed and the content of β-sheet was significantly increased by Bacillus fermentation, which may improve the solubility of soybean meal protein.

Key words: Bacillus, protease, fermented soybean meal, scanning electron microscopy, X-ray diffraction

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