关键词: 寡肽, 胶原蛋白, 酸性蛋白酶, 碱性蛋白酶

Abstract: In this paper, the feasibility of making collagen oligopeptides from the synergetic hydrolysis of pigskin by Bacillussubtilis alkaline protease and Aspergillus niger acidic protease under condition of spontaneous drop of pH value in broth has beenstudied. On the basis of finding the optimum conditions for both enzymes via mono-factor investigations by selecting an one-time-all-enzymes feeding manner, the orthogonal test was carried out to further optimize the synergetic hydrolysis conditionsdetermined as follows: hydrolyzing temperature 60℃,ratio of alkaline protein enzyme/substrate 25μl/g, ratio of acid proteinenzyme/ substrate 4%(g/g ), concentration of substrate 60g/L and total hydrolysis time 12h. Under these conditions the degradationpercentage of the pigskin could reach 94.7%, while the hydrolysis degree of collagen protein (i.e., the ratio of the peptide bondscleavaged/total peptide bonds in protein) could reach 17.7% accounted for a 42.5% oligopeptides (viz. molecular weight less than1000 ) selectivity versus total protein hydrolysates.The results indicated that the cooperation of acidic protease with alkalineprotease clearly favored the degradation of pigskin and the preparation of collagen oligopeptides. Thus the hydrolysis could beperformed without using additional alkali.

Key words: oligopeptide, collagen, acid protease, alkaline protease