Researching Of Fermenting Galacto-Oligosaccharides Technology

Galactooligosaccharide catalyticed connect1~4galactose with lactose,, is themiscellaneous oligosaccharides composited by glucose and galactose.Galactooligosaccharide has the special physical and chemical properties, and had beenused in many fields.It’s developed and applicatedare broadly.The methods of producing galactooligosaccharide have been summarized in threemolds, such as chemical method, enzymatic method and fermentation. Fermention hasbeen summarized in three molds, such as free enzymatic reaction, immobilized enzymecontinuous reaction and the water phase enzyme reaction. At present, enzymaticmethod has been used the most broading. The fermentation of producinggalactooligosaccharide which has been studied lackly is the emphasis of this paper.Use lactose as the only carbon source, the X-gal as color agent, a strain ofmucedine producing galacto-oligosaccharides, which was screened from spoiled milk,was identified as Penicillium decumberns by its morphological characteristics,Physiological and Biochemical Characteristics and the result of18s rDNA sequence.The culture condition of the stain producing galacto-oligosaccharides was optimizedby orthogonal test. The effect of pH, temperature, the concentration of lactose andfermentation time on the galacto-oligosaccharides production of the whole cell Strainhas been studied, using lactose as the only carbon source. It was determined that thisstrain has the ability of producing galacto-oligosaccharides by analyzing thegalactosylation production of the optimization reaction with TLC and HPLC. Theproduction of GOS is between31.883g/L and46.793g/L. The best fermentationconditions: fermented liquid3.0L, inoculation amount20%, temperature35℃, speed800r/min，ventilation8L/min, flow the50%NaOH to keep the pH6.5of fermentedliquid.