Production of Galacto-Oligosaccharides from Lactose and whey Permeate by β-Glycosidase from Sporotrichum Thermophile ATCC 34628

ABSTRACT

β-Glycosidases catalyze not only the hydrolysis reactions, but also the transglycosylation ones, producing different oligosaccharides. The production of galactooligosaccharides using intracellular β'-glycosidase from Sporotrichum thermophile ATCC 34628 and toluene-treated cell suspensions was investigated. Enzymatic hydrolysis of lactose and synthesis of galactooligosaccharides (Gal-OS) by intracellular p-glycosidase reached an yield of 5.9% when 20% (w/v) lactose was used as substrate at 50 °C and pH 6.0. The production of Gal-OS by toluene-treated cells of Sporotrichum thermophile ATCC 34628 revealed an increasing of the trisaccharides content from 4% after 2 hours of incubation up to 13.5% after 72 hours at a lactose concentration of 20% (w/v). When whey permeate (10%, w/v) was used as substrate for the transglycosylation reaction, mainly trisaccharides were produced. The results from TLC and HPLC analyses suggested a transfer of glucose to lactose and formation of glucosyllactose, because of the lack of glucose on the chromatograms as a product of lactose hydrolysis at 22h of incubation. The produced Gal-OS were purified and their potential role as prebiotics and growth factors for Bifidobacteria strains was established.

Keywords:

• β-glycosidases
• galacto-oligosaccharides
• whey permeate