Properties of a new fungal b-galactosidase with potential application in the dairy industry

Revista de Microbiologia

Cruz, Vinícius D'Arcádia¹  Khenayfes, Marcelo de Oliveira¹  Cruz, Rubens¹  Dorta, Claudia¹  Universidade Estadual de São Paulo, Assis, Brasil¹  Belote, Juliana Gisele¹  Oliveira, Luiza Helena dos Santos¹ 

关键词: : b-Galactosidase;    galactosyltransferase;    galactooligosaccharides;    lactose;    prebiotic effect;   

DOI  :  10.1590/S0001-37141999000300014

学科分类：农业科学（综合）

来源: Sociedade Brasileira de Microbiologia / Brazilian Society for Microbiology

【 摘 要 】

b-Galactosidase or b-D-galactoside-galactohydrolase (EC. 3.2.1.23) is an important enzyme industrially used for the hydrolysis of lactose from milk and milk whey for several applications. Lately, the importance of this enzyme was enhanced by its galactosyltransferase activity, which is responsible for the synthesis of transgalactosylated oligosaccharides (TOS) that act as functional foods, with several beneficial effects on consumers. Penicillium simplicissimum, a strain isolated from soil, when grown in semi-solid medium showed good productivity of b-galactosidase with galactosyltransferase activity. The optimum pH for hydrolysis was in the 4.04.6 range and the optimum pH for galactosyltransferase activity was in the 6.07.0 range. The optimum temperature for hydrolysis and transferase activity was 5560°C and 50°C, respectively, and the enzyme showed high thermostability for the hydrolytic activity. The enzyme showed a potential for several industrial applications such as removal of 67% of the lactose from milk and 84% of the lactose from milk whey when incubated at their original pH (4.5 and 6.34, respectively) under optimum temperature conditions. When incubated with a 40% lactose solution in 150 mM McIlvaine buffer, pH 4.5, at 55°C the enzyme converted 86.5% of the lactose to its component monosaccharides. When incubated with a 60% lactose solution in the same buffer but at pH 6.5 and 50°C, the enzyme can synthetize up to 30.5% TOS, with 39.5% lactose and 30% monosaccharides remaining in the preparation.

【 授权许可】

Unknown