西农萨能奶山羊瘤胃产蛋白酶酵母菌的筛选研究

Screening of Protease-producing Yeast in Rumen of Xinong Saanen Dairy Goat

试验旨在从西农萨能奶山羊瘤胃液中分离出产蛋白酶的酵母菌株,并对其产酶能力进行测定。以蛋白酶的活性进行筛选,得到高产蛋白酶酵母菌,对其产酶条件进行优化。经形态学观察及26S rDNA序列分析鉴定出5株产蛋白酶酵母菌,分别对各菌株产酶条件进行优化,在最佳产酶条件下,菌株库德毕赤酵母Y1(时间48 h、接菌量3%、温度30℃、pH值9)产酶活力达229.89 U/mL,东方伊萨酵母Y5(时间48 h、接菌量4%、温度37℃、pH值9)产酶活力达212.63 U/mL,马克斯克鲁维酵母Y16(时间48 h、接菌量3%、温度37℃、pH值9)产酶活力达208.44 U/mL,近平滑假丝酵母Y20(时间48 h、接菌量4%、温度37℃、pH值9)产酶活力达211.74 U/mL,单孢酿酒酵母Y21(时间48 h、接菌量4%、温度30℃、pH值9)产酶活力达209.96 U/mL。同时对五株酵母菌产水解酶的效果进行了探究,发现库德毕赤酵母Y1、马克斯克鲁维酵母Y16、单孢酿酒酵母Y21具有较高的植酸酶活性,达到14.38、15.34、15.63 U/mL;五株菌株均表现出较高的果胶酶活性,其中单孢酿酒酵母Y21显著高于其他菌株(P<0.05),达到15.18 U/mL;五株菌株均表现出较高的纤维素酶活性,均超过180 U/mL,其中近平滑假丝酵母Y20显著高于其他菌株(P<0.05),达到199.08 U/mL。试验成功分离出5株产蛋白酶菌。库德毕赤酵母Y1、马克斯克鲁维酵母Y16、单孢酿酒酵母Y21具有较高的植酸酶活性。五株菌株均表现出较高的果胶酶活性、纤维素酶活性。

The aim of this study was to isolate and determine the enzyme production capacity of the yeast strains from the ruminal contents of Xinong Saanen dairy goat.High-yielding yeast was obtained by screening the activity of protease,and the enzyme production conditions were optimized.Five strains of protein-producing yeast were identified by morphological observation and 26S rDNA sequence analysis,and the enzyme production conditions of each strain were optimized.Under the optimal enzyme production conditions,the enzyme activities of Pichiakudriavzevii Y1(48 h,3%inoculation,30℃,pH 9),Issatchenkiaorientalis Y5(48 h,4%inoculation,37℃,pH 9),Kluyveromycesmarxianus Y16(48 h,3%inoculation,37℃,pH 9),Candidaparapsilosis Y20(48 h,4%inoculation,37℃,pH 9),Saccharomycescerevisiae Y21(48 h,4%inoculation,30℃,pH 9)was 229.89 U/mL,212.63 U/mL,208.44 U/mL,211.74 U/mL,and 209.96 U/mL,respectively.At the same time,the hydrolytic enzyme activity of five strains of yeast was investigated,and Pichiakudriavzevii Y1,Kluyveromycesmarxianus Y16 and Saccharomycescerevisiae Y21 showed high phytase activity,which reaching 14.38 U/mL,15.34 U/mL and 15.63 U/mL.All the five strains showed higher pectinase activity,among which Saccharomycescerevisiae Y21 was significantly higher than that of other strains(P<0.05),reaching 15.18 U/mL.All the five strains showed higher cellulase activity than 180 U/mL,among which Candidaparapsilosis Y20 was significantly higher than other strains(P<0.05),reaching 199.08 U/mL.In this experiment,5 strains of protease producing bacteria were successfully isolated,and Pichiakudriavzevii Y1,Kluyveromycesmarxianus Y16 and Saccharomycescerevisiae Y21 had higher phytase activity.All the five strains showed higher pectinase and cellulase activities.