da Silva Evânia Geralda, de Fátima Borges Maria, Medina Clara, Piccoli Roberta Hilsdorf, Schwan Rosane Freitas
Biology Department, Federal University of Lavras, MG, Brazil.
FEMS Yeast Res. 2005 Jun;5(9):859-65. doi: 10.1016/j.femsyr.2005.02.006. Epub 2005 Mar 30.
Three hundred yeasts isolated from tropical fruits were screened in relation to secretion of pectinases. Twenty-one isolates were able to produce polygalacturonase and among them seven isolates could secrete pectin lyase. None of the isolates was able to secrete pectin methylesterase. The pectinolytic yeasts identified belonged to six different genera. Kluyveromyces wickerhamii isolated from the fruit mangaba (Hancornia speciosa) secreted the highest amount of polygalacturonase, followed by K. marxianus and Stephanoascus smithiae. The yeast Debaryomyces hansenii produced the greatest decrease in viscosity while only 3% of the glycosidic linkages were hydrolysed, indicating that the enzyme secreted was an endo-polygalacturonase. The hydrolysis of pectin by polygalacturonase secreted by S. smithiae suggested an exo-splitting mechanism. The other yeast species studied showed low polygalacturonase activity.
对从热带水果中分离出的300株酵母进行了果胶酶分泌相关的筛选。21株分离株能够产生多聚半乳糖醛酸酶，其中7株分离株能够分泌果胶裂解酶。没有分离株能够分泌果胶甲酯酶。鉴定出的果胶分解酵母属于六个不同的属。从曼加巴果（Hancornia speciosa）中分离出的威克汉姆克鲁维酵母分泌的多聚半乳糖醛酸酶量最高，其次是马克斯克鲁维酵母和史密斯斯蒂芬酵母。汉逊德巴利酵母产生的粘度降低最大，而只有3%的糖苷键被水解，这表明分泌的酶是一种内切多聚半乳糖醛酸酶。史密斯斯蒂芬酵母分泌的多聚半乳糖醛酸酶对果胶的水解表明了一种外切裂解机制。所研究的其他酵母物种显示出较低的多聚半乳糖醛酸酶活性。
