Lactulose production from lactose and fructose by a thermostable β-galactosidase from Sulfolobus solfataricus

Identification and Characterization of a NovelTerrabacter ginsenosidimutanssp. nov. β-Glucosidase That Transforms Ginsenoside Rb1 into the Rare Gypenosides XVII and LXXV

“…strain GL1 ␤-glucosidase. To date, only two ginsenoside-hydrolyzing glycoside hydrolases have been successfully cloned: a ␤-glucosidase from a soil metagenome (16) and a ␤-galactosidase from archaeon Solfolobus solfataricus (18). However, both of these genes code for family 1 glycoside hydrolases.…”

Ginsenoside Compound K Production from Ginseng Root Extract by a Thermostable β-Glycosidase fromSulfolobus solfataricus

“…Although the enzyme from S. solfataricus in the present study has been used as -galactosidase, 17,21) it is considered to be -glycosidase due to its hydrolyzing activity for -1,2, -1,3, -1,4, and -1,6 linked glycosides containing glucose or/and galactose (Table 2). -Glycosidase, having broad specificity, can hydrolyze ginsenosides containing glucoside and arabinoside binds.…”

“…Esherichia coli ER2566 cells containing the -glycosidase/pET-24a gene from Sulfolobus solfataricus were grown in Luria-Bertani (LB) medium containing 20 mg/ml of kanamycin at 37 C with agitation at 200 rpm until an optical density (OD) at 600 nm of 1.0 was reached. 17) Isopropyl--D-thiogalactopyranoside (IPTG) was added to the culture medium at a final concentration of 0.1 mM, and incubation continued with agitation at 150 rpm at 30 C for 16 h. The induced cells were harvested and disrupted by sonication in McIlvaine buffer of pH 5.5 (200 mM Na 2 HPO 4 and 100 mM citric acid). Unbroken cells and cell debris were removed by centrifugation at 13;000 Â g for 20 min, and the supernatant was treated at 90 C for 10 min to remove proteins derived from E. coli.…”

Lactulose biosynthesis by β-galactosidase from a newly isolated Arthrobacter sp.

“…Since b-galactosidase genes have been successfully expressed in recombinant E. coli and the purified enzymes have been used in lactulose production [8,11], the expressing of b-galactosidases genes from other microbes such as Arthrobacter sp. LAS in E. coli might change the condition for lactulose production and minimize the byproducts.…”

“…Although b-galactosidases from different sources either in the form of whole cells or purified enzymes are described, the promising ones are limited to those from Kluyveromyces lactis, Sulfolobus solfataricus, and Pyrococcus furiosus [8,9,11] whose optimum temperatures for lactulose production are relatively high (60, 80, and 75°C, respectively). High temperature with the high concentration of reducing sugars (lactose, fructose) induces nonenzymatic browning [10].…”