产单宁酶海洋短梗霉的分离筛选及酶学性质的研究

Isolation and screening of cellulase-producing marine Aureobasidium subglaciale and its enzymatic characteristics

单宁酶能水解单宁物质中的酯键,在食品和饲料工业中有重要应用价值。该研究从海洋微生物中获得了几株高产单宁酶菌株,其中菌株95水解圈与菌落(直径)大小的比值最大,对其进行生理生化鉴定,并扩增内转录间隔区(ITS)序列作进化树分析,鉴定菌株95号为Aureobasidium subglaciale,其在发酵培养基中发酵72 h达到最大酶活力323.2 U/mL。考察了温度和pH对酶促反应影响,同时考察了粗酶的热稳定性和pH稳定性。结果表明,菌株95号所产单宁酶最适反应温度为50℃,该酶在30℃、40℃、50℃水浴保温4 h,相对酶活80%以上,具有较好的热稳定性;最适反应和最稳定pH均为6.0,在pH 3.0~7.0之间均有较高的酶活,表示其具有较广的pH值稳定性。

Tannase can hydrolyze ester bonds in tannin substances and have important applications in the food and feed industry.Several strains with high yield tannase were isolated from marine microorganism,by selecting the ratio of the hydrolytic circle and colony diameter ratio,strain 95#was selected for physiological,biochemical and molecular biological identification,The internal transcribed spacer(ITS)sequence was amplified and phylogenetic tree was analyzed,and results showed that strain 95#was identified as Aureobasidium subglaciale.The maximum enzyme activity of the strain was 323.2 U/ml.The effects of temperature and pH on extracellular enzyme activity were investigated,and thermal stability of crude enzyme was researched.The results showed that the optimum reaction temperature of tannase from A.subglaciale 95 was 50℃,the enzyme at 30℃,40℃and 50℃water bath for 4 h,the relative enzyme above 80%,which showed good thermal stability.The optimum pH and the most stable pH of tannase was 6.0,and the relative enzyme activity was high with pH 3.0-7.0,which showed that the enzyme had a wide range of pH stability.