Properties of a new fungal <FONT FACE=Symbol>b</font>-galactosidase with potential application in the dairy industry

Abstract

ABSTRACTβ-Galactosidase or β-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 semisolid medium showed good productivity of β-galactosidase with galactosyltransferase activity. The optimum pH for hydrolysis was in the 4.0-4.6 range and the optimum pH for galactosyltransferase activity was in the 6.0-7.0 range. The optimum temperature for hydrolysis and transferase activity was 55-60°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.

Use of Whey Permeate for Cultivating Ganoderma lucidum Mycelia

“…This reported value is much smaller than the 2). The optimum pH and temperature of purified fungal β-galactosidase lactose hydrolysis are pH 4.0 to 4.6 and 55 to 60°C (Cruz et al, 1999). This pH agrees well with that at which the maximum radial extension rate occurred in the present experiment, but the temperature does not.…”

The comparison of commercially available β-galactosidases for dairy industry : review

“…Cruz and co-authors (1999) noted that Penicillium simplicissimum β-galactosidase optimal pH for hydrolysis was in the range 4.0 -4.6. The enzyme reached great results, hydrolysed 67% lactose from milk and 84% lactose from milk whey which show a potential of using for food production (Cruz et al, 1999). El-Kader and co-authors (2012) discovered that at pH 8.0 the activity of Bacillus subtilis increased rapidly till 1278 UI•mL -1 at 30 minutes, while enzyme activity at pH 8.5 rise to 1387 UI•mL -1 at 10 minutes (El-Kader et al, 2012).…”

“…The optimal temperature and pH of enzyme action at 60 °C, pH 4.75 can be used for lactose hydrolysis in whey. Benefit of this β-galactosidase from a technological viewpoint is its comparative stability at high temperature what is very important for controlling and preventing microbial risk during the hydrolysis process (Cruz et al, 1999).…”

New β-galactosidase producers with potential for prebiotic synthesis

“…(Gargova et al, 1995;Gonzalez and Monsan, 1991;O'Connell and Walsh, 2008;Tonelotto et al, 2014;Roal et al, 2015), Penicillium spp. (Watanabe et al, 1979;Cruz et al, 1999;Nagy et al, 2001) and Mucor spp. (Ismail et al, 1997;Shaikh 1999).…”