棉籽饼粕微生物法降棉酚及其蛋白多肽制备研究

发布时间：2018-04-27 00:12

  本文选题：棉籽饼粕 + 微生物降解　； 参考：《湖南农业大学》2015年硕士论文

【摘要】：本文以棉籽饼粕为原料,开展了微生物法降棉酚以及利用蛋白酶水解棉籽蛋白制备棉籽多肽的工艺研究。本文从棉田土壤中分离得到以棉酚为唯一碳源的芽孢细菌菌株106株。经过复筛,从中筛选得到了1株对棉酚降解性能较好的菌株,命名为菌株M57-1,通过初步鉴定该菌为芽孢杆菌属(Bacillus)。其对棉籽饼中棉酚降解率高达67.52%,能有效降解棉籽饼中的游离棉酚,达到使棉籽饼脱毒的效果。通过优化,确定了该菌最适生长条件以及利用该菌制备种子发酵液和固态发酵的最优条件。利用该菌作为种子液培养的时间为18h,种子液发酵培养基可采用营养肉汤培养基。固态发酵时,固态发酵培养基中的辅料可使用蔗糖渣,棉籽饼与蔗糖渣比例为4：1,加入棉籽饼与蔗糖渣总质量的77%的水制成。接入至固态发酵培养基中种子发酵液的接种量为3%,发酵温度为36℃,发酵时间为11d,对棉籽饼中棉酚降解率可达78.96%。经发酵条件优化后,其对棉酚的降解率得到了进一步提高。本文还对降棉酚后的棉籽饼进行了酶水解工艺条件优化研究,利用其制备棉籽多肽。确定了酶解溶液的料液比为1：4(w/w),水解用酶为碱性蛋白酶。通过响应面优化,建立了酶解条件中加酶量、温度、酶解时间3个因素对多肽转化率影响的二次模型。通过优化模型,最终得到碱性蛋白酶水解棉籽蛋白制备多肽的工艺条件为：料液比1：4、加酶量1.48%、温度51.5℃、酶解时间8 h、pH值8.2,采用上述优化的参数酶解棉籽蛋白,多肽转化率可达84.52%,优化效果明显,可在实际生产中起到指导作用。
[Abstract]:In this paper, using cottonseed cake as raw material, the process of reducing gossypol by microorganism and hydrolyzing cottonseed protein with protease to prepare cottonseed polypeptide was studied. In this paper, 106 Bacillus strains with gossypol as the sole carbon source were isolated from cotton soil. After screening, a strain with good degradation of gossypol was obtained and named as strain M57-1. The strain was identified as Bacillus sp. The degradation rate of gossypol in cottonseed cake is as high as 67.52, which can effectively degrade free gossypol in cottonseed cake and detoxify cottonseed cake. Through optimization, the optimum growth conditions and the optimal conditions for the preparation of seed fermentation broth and solid state fermentation were determined. The culture time of the strain was 18 h, and the nutrient broth medium could be used in the fermentation medium of the seed liquid. During solid state fermentation, sucrose residue was used as auxiliary material in solid fermentation medium. The ratio of cottonseed cake to sucrose residue was 4: 1, and 77% of the total mass of cottonseed cake and sucrose residue was added. The inoculation amount of seed fermentation broth was 3, the fermentation temperature was 36 鈩，

本文编号：1808304