Purification and immobilization of dextranase

Abstract

An enzymic characteristi of Novo dextranase wa presented. In addition to a high dextranolytic activity (7,200 U/ml), the crude enzyme also contained small amounts of protease, glucoamylase, polygalacturonase, carboxymethylcellulase, laminarinase and chitinase. A highly purified dextranase was then simply separated from a commercial preparation by column chromatographies on DEAESepharose. CM-Sepharose, and by chromatofocussing on Polybuffer Exchanger PBE-94. The enzyme was recovered with an over 200-fold increase in specific activity and a yield of 84%. The final preparation was homogeneous, as observed during high performance liquid chromatography (HPLC). Size-exclusion HPLC indicated that dextranase had a molecular mass of 35 kDa and its isoelectric point, established by chromatofocussing. was 4.85. Analysis of the dextran break-down products indicated that purified dextranase represents an endolytic mode of action, and isomaltose and isomaltotriose were identified as the main reducing sugars of dextran hydrolysis. The enzyme was then covalently coupled to the silanized porous glass beads modified by glutataldehyde (Carrier I) or carbodiimide (Carrier II). It was shown that immobilization of dextranase gave optimum pH and temperature ranges from 5.4 to 5.7 and from 50 "C to 60 O C . respectively. The a f f~t y of the enzyme to the substrate decreased by a factor of more than 13 for dextranase immobilized on Carrier I and increased slightly (about 1.4-times) for the enzyme bound to Carrier II.

Microbial Dextran-Hydrolyzing Enzymes: Fundamentals and Applications

“…Dextranases reduce the molecular mass and therefore the viscosity of juices (22,32,81,118,233). Trademarks like Novo dextranase of P. lilacinum (Denmark) and dextranase Hutten DL-2 of Chaetomium gracile (Japan) have been successfully used to treat dextran-contaminated sugar process streams (169,233). Even at relatively low levels of dextran in raw juice (i.e., 75 mg/liter) the filtration rate is markedly dropped and, consequently, the slicing capacity is decreased by 50%.…”

Purification and properties of extracellular dextranase from a Bacillus sp.

“…Further purification involved a combination of chromatographic steps. The purification factor achieved ranged from 4 [24] to 202 [25].…”

Production and use of mutanase from Trichoderma harzianum for effective degradation of streptococcal mutans

“…The activities of all the accompanying hydrolytic enzymes present in mutanase preparation, such as dextranase, laminarinase, pullulanase, amylase, invertase, chitinase and protease were quantified under the optimized reaction conditions by measuring the reducing sugars, N-acetylglucosamine or diazotized aromatic amino acids released by these enzymes from the respective carbohydrates or azocasein (2,7,23,30). One microgram of reducing sugars or N-acetyl- The same as C but with the addition of peptone proteose (0.1%).…”