Hydrolysis of whey lactose using CTAB-permeabilized yeast cells

Abstract

Disposal of lactose in whey and whey permeates is one of the most significant problems with regard to economics and environmental impact faced by the dairy industries. The enzymatic hydrolysis of whey lactose to glucose and galactose by beta-galactosidase constitutes the basis of the most biotechnological processes currently developed to exploit the sugar content of whey. Keeping this in view, lactose hydrolysis in whey was performed using CTAB permeabilized Kluyveromyces marxianus cells. Permeabilization of K. marxianus cells in relation to beta-galactosidase activity was carried out using cetyltrimethyl ammonium bromide (CTAB) to avoid the problem of enzyme extraction. Different process parameters (biomass load, pH, temperature, and incubation time) were optimized to enhance the lactose hydrolysis in whey. Maximum hydrolysis (90.5%) of whey lactose was observed with 200 mg DW yeast biomass after 90 min of incubation period at optimum pH of 6.5 and temperature of 40 degrees C.

Immobilization of Aspergillus oryzae β galactosidase on zinc oxide nanoparticles via simple adsorption mechanism

“…␤ Galactosidases have been exploited as a drug to treat infants with a genetic deficiency of intestinal lactase. Thus, the technological importance of this enzyme arises mainly due to the problems associated with whey disposal, lactose crystallization in frozen concentrated desserts and milk consumption by lactose-intolerant populations [4][5][6][7].…”

Thermotolerant Yeast Strains Producers of Galacto-Oligosaccharides

“…The β-galactosidase enzyme, isolated from K. marxianus and/or K. lactis strains, is important for the dairy industry because of the benefits derived from lactose hydrolysis such as reduction of lactose intolerance and prevention of lactose crystallization in concentrated milk and ice cream (2,26). Furthermore, Kluyveromyces yeasts are also employed for the enzymatic hydrolysis of the lactose in milk whey, a polluting by-product of the dairy industry, which constitutes the basis of most biotechnological processes currently developed to exploit sugar content of milk whey (13,18).…”

“…The enzymatic hydrolysis of whey lactose to glucose and galactose by β-galactosidase constitutes the basis of most biotechnological processes that are currently developed to exploit the sugar content of the whey (2,13,18,25,26). Moreover, employment of transgalactosylation activity of β-galactosidase enzymes and production of prebiotic GOS will further enhance the value of the process.…”

“…β-Galactosydases from E. coli or Aspergillus niger exerts strong hydrolytic activity, whereas β-galactosydase from Aspergillus oryzae and Bacillus circulans possess strong transgalactosylation activity (17). Moreover, amongst other microorganisms, yeasts have emerged as an important source of β-galactosydase, since the yeast enzyme has an optimum pH suitable for lactose hydrolysis in milk and cheese-whey (13,26). Furthermore, yeasts belonging to genus Kluyveromyces, offer several great advantages such as good growth yield, acceptability as safe microorganisms for human (GRAS status), thermotolerancy, utilization of cheese-whey and higher β-galacytosydase activity than other yeasts.…”

Functionalized agarose as an effective and novel matrix for immobilizing Cicer arietinum β-galactosidase and its application in lactose hydrolysis

“…In another study, the half-life of Talaromyces thermophilus β-galactosidase was determined to be 8 h and 27 h at 50°C for the free and immobilized enzymes, respectively (Nakkharat and Haltrich, 2006). Other major problems generally associated with immobilized β-galactosidase systems include product mediated inhibition, microbial contamination, protein adherence and channeling (Kaur et al, 2009). Figure 3 shows the inhibitory eff ect of galactose on the activity of soluble and immobilized β-galactosidase.…”