Production of galacto-oligosaccharide from lactose by Sterigmatomyces elviae CBS8119.
Our stock cultures were screened for microorganisms that can produce galacto-oligosaccharide (Gal-OS) from lactose. Of the 574 strains of bacteria and yeasts tested, Sterigmatomyces elviae CBS8119, Rhodotorula minuta IFO879, and Sirobasidium magnum CBS6803 were found to be efficient producers of Gal-OS from lactose and S. elviae CBS8119 was selected as a representative, high-level producing strain. With toluene-treated resting S. elviae CBS8119 cells, 135 mg of Gal-OS per ml was produced from 360-mg/ml lactose. During this reaction, the by-product glucose was found to inhibit Gal-OS production. Therefore, in order to remove the glucose from the reaction mixture, a culture method in which cell growth followed the enzymatic reaction was devised, which increased the yield of Gal-OS considerably because of the consumption of glucose for cell growth. Under such conditions, 232 mg of Gal-OS per ml was produced from 360-mg/ml lactose after incubation at 30 degrees for 60 h. The structure of the major product was identified as O-beta-D-galactopyranosyl-(1-->4)-O-beta-D-galactopyranosyl-(1-->4)-D- glucopyranose (4'-galactosyl-lactose) by 13C nuclear magnetic resonance spectroscopy.
Central Research Laboratories of Ajinomoto Co. Inc., Kawasaki-shi, Japan.
N
N
Onishi
A
A
Yamashiro
K
K
Yokozeki
D001419:Bacteria / Q000378:metabolism; D001644:Bifidobacterium / Q000378:metabolism; D002240:Carbohydrate Sequence; D005285:Fermentation; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007422:Intestines / Q000382:microbiology; D007785:Lactose / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D003904:Mitosporic Fungi / Q000187:drug effects / Q000378:metabolism*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry; D014312:Trisaccharides / Q000096:biosynthesis / Q000737:chemistry; D015003:Yeasts / Q000378:metabolism
D009844:Oligosaccharides; D014312:Trisaccharides; C023872:mannotriose; D005947:Glucose; D007785:Lactose