title: Immobilization of Bacillus licheniformis L-arabinose isomerase for semi-continuous L-ribulose production.
abstract: Bacillus licheniformis L-arabinose isomerase (BLAI) with a broad pH range, high substrate specificity, and high catalytic efficiency for L-arabinose was immobilized on various supports. Eupergit C, activated-carboxymethylcellulose, CNBr-activated agarose, chitosan, and alginate were tested as supports, and Eupergit C was selected as the most effective. After determination of the optimum enzyme concentration, the effects of pH and temperature were investigated using a response surface methodology. The immobilized BLAI enzyme retained 86.4% of the activity of the free enzyme. The optimal pH for the immobilized BLAI was 8.0, and immobilization improved the optimal temperature from 50 degrees C (free enzyme) to a range between 55 and 65 degrees C. The half life improved from 2 at 50 degrees C to 212 h at 55 degrees C following immobilization. The immobilized BLAI was used for semi-continuous production of L-ribulose. After 8 batch cycles, 95.1% of the BLAI activity was retained. This simple immobilization procedure and the high stability of the final immobilized BLAI on Eupergit C provide a promising solution for large-scale production of L-ribulose from an inexpensive L-arabinose precursor.
authors.affiliation: Department of Chemical Engineering, Konkuk University, Seoul, Korea.
authors.forename: Ye-Wang
authors.initials: YW
authors.lastname: Zhang
authors.forename: Ponnandy
authors.initials: P
authors.lastname: Prabhu
authors.forename: Jung-Kul
authors.initials: JK
authors.lastname: Lee
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000737:chemistry* / Q000378:metabolism*; D001089:Arabinose / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology*; D055162:Biocatalysis; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism*; D010429:Pentoses / Q000096:biosynthesis*; D011108:Polymers / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D004800:Enzymes, Immobilized; D010429:Pentoses; D011108:Polymers; C100182:ribulose; C065843:Eupergit C; D001089:Arabinose; D019747:Aldose-Ketose Isomerases; C019715:L-arabinose isomerase