Study On Characteristics Of Enzyme Production And Probiotics By17Bacillus Strain

Probiotic Bacillus has widely used as a feed additive in animal husbandry and aquaculture. The main researches of probiotics focus on the mechanisms of regulating micro-ecology balance on intestine and ntagonistic effect on pathogenic bacteria. But there are few researches focus on the mechanism of promoting feed conversion. This paper was focused on the characteristics of enzyme production in a series of probiotic Bacillus.This paper choosed17probiotic Bacillus strains. Their capabilities of producing protease, cellulase, amylase and lipase were studied using the qualitative detection. The results showed that most of them could peoduce protease, cellulase and amylase, only5strains could produce lipase.According to quantitative detection methods for protease, cellulase, hemicellulase and amylase, the enzymes characteristics of17Bacillus strains were studied.3strains, labeled Js-1, N-2and NN, which were capable on producing protease, cellulase, hemicellulase, amylase were selected. To perform an digestion experiment. The result showed that hemicellulose digestions were significant in all of the4compound feeds, and there were better effects in the corn-wheat bran feeds. The vitro of hemicellulose reached23.5%(Js-1),18.7%(N-2),10.0%(NN). While cellulose digestions were insignificant. The maximum digestion amount of cellulose was only0.8%. The reducing sugar content increased significantly in all of the compound feeds. All of the3strains had best effects in the corn-wheat bran feeds. The contents increased by23.7mg/g (Js-1),22.5mg/g (N-2),22.3mg/g (NN). The research also showed that Bacillus were effective in promoting protein digestion. The amino acid concentration was increased significantly. The contents of digested protein,which were discounted by increment of amino acid contents, were more than4.1mg/g. Js-1and N-2strains made better jobs. When add Js-1, the minimum content of digested protein of compound feeds was7.7mg/g; while the maximum content is5.9mg/g when NN were added into compound feeds. N-2also made good jobs in corn-wheat bran and corn-soybean meal with large increments of11.0mg/g and11.4mg/g. Analysis indicated that probiotic Bacillus makes a positive role in promoting digestion of compound feeds. It is also combination with the strains itself. According to study on curve of enzyme production by17strains of probiotic Bacillus,3strains, labeled N-2, N-5, YCB, which were capable in producing protease,were selected. Then a enzymatic hydrolysis experiment was performed. The results showed that the amino acid contents were increased while crude enzyme solution were added into feed materia There were better results in all of the3strains while treat with wheat. The minimum increment was0.98mg/ml,20.8%of the total protein. The were no significant differences among them.Through the antagonistic test of17probiotic Bacillus strains, it discovered that most of them inhibit the growth of S.raureus, while only4strains inhabit E.coli. Study on bile tolerance test of17probiotic Bacillus strains. The result showed that most of them have wesk bile tolerance properties. Their can grow on0.05%bile salt, while Js-1and N-2can grow on0.1%bile salt.Detections on survival rate of Js-1, N-2and NN, the results showed that all of the3strains have good acid properties. The survival rate of the3strains were more than90%while treat with pH2.0HC1for30min.