中文摘要：

对一株产酸性果胶酶的菌株Penicillium sp.JF09的发酵条件、酶学特性及其在苹果汁澄清中的应用潜力进行研究。该菌株发酵产果胶酶的培养基优化后,碳源为1.0%的柚子皮粉,氮源为0.5%的蛋白胨,起始pH值为5.5,发酵时间75~147h,产果胶酶酶活力为16.5U/mL,比活力为199.5U/mg。该果胶酶最适反应温度为60℃,在10~70℃范围内具有活性;最适反应pH值为5.0,酶在pH3.0~5.5范围内活性保持83%以上并在pH3.0~8.0范围内保持稳定;10mmol/L的Hg2＋、Pb2＋、Cu2＋、Fe2＋、Ag＋及SDS对该酶有不同程度的抑制作用,10mmol/L的Mg2＋、Mn2＋对该酶有略微的促进作用,不同浓度的Ca2＋对酶活力有较大影响（最适浓度为0.2mmol/L）。在低温和高温下（10~60℃）添加JF09果胶酶对鲜榨苹果汁都有显著澄清作用,反应1h后澄清率可达88.8%。

英文摘要：

The fermentation optimization, enzymatic characterization and potential for application in apple juice clarification of the crude acid pectinase from a newly isolated Penicillium sp. JF09 were studied. The highest （16.5 U/mL, 199.5 U/mg） production of the crude acid pectinase was obtained under the optimized conditions （w/v）： 1.0% pomelo peel power, 0.5% tryptone, initial pH5.5, incubation time 75-147 h. The pectinase showed activity at 10-70℃ and pH3.0-5.5 （more than 83%）, optimal activity at 60 ℃ and pH5.0, and good stability at pH3.0-8.0. The presence of 10 mmol/L Hg^2＋, Pb^2＋, Cu2＋, Fe^2＋, Ag＋ and SDS inhibited the activity of the pectinase, while 10 mmol/L Mg^2＋ and Mn^2＋ slightly enhanced the activity. Furthermore, the concentration of Ca2＋ had a great influence on the pectinase activity （the optimum concentration was 0.2 retool/L）. Addition of JF09 pectinase significantly clarified the fresh apple juice at low to high temperature （10-60 %）. The clarification efficiency could reach 88.8% after incubating the pectinase and the fresh apple juice for 1 h.