Shizu Fujishima

Production of N-Acetylglucosamine Deacetylase by Vibrio cholerae Non-O1

Vibrio cholerae non-O1 (1148 A) produced β-N-acetylglucosamini-dase and N-acetylglucosamine (GlcNAc) deacetylase intracellularly when grown in chitin or GlcNAc containing medium. It also secreted chitinase only in the chitin-containing medium. The partially purified GlcNAc deacetylase deacetylated GlcNAc but not chitin oligosaccharides, the dimer to hexamer of GlcNAc. We also detected the reaction product by capillary electrophoresis.

Purification and Characterization of N-Acetylglucosamine-6-phosphate Deacetylase from a Psychrotrophic Marine Bacterium, Alteromonas Species.

Abstract: A psychrotrophic bacterium, strain Mct-9, which produced an N-acetylglucosamine-6-phosphate deacetylase, was isolated from a deep-seawater sample in the Mariana Trough. The Mct-9 strain was identified as Alteromonas sp. The native enzyme had a molecular mass of 164,000 Da, and was predicted to be composed of four identical subunits with molecular masses of 41,000 Da. The purified enzyme hydrolyzed N-acetylglucosamine (GlcNAc), GlcNAc-6-phosphate, and GlcNAc-6-sulfate. Considering the low Km and high kcat/Km for GlcNAc-6-phosphate, it probably acts as a GlcNAc-6-phosphate deacetylase in vivo. The enzyme was functional in the temperature range of 5° to 70°C and displayed optimal activity at 55°C. The optimal temperature was higher than that of the deacetylase from the mesophilic bacterium Vibrio cholerae non-O1. The characteristics of the GlcNAc-6-phosphate deacetylase from Alteromonas sp. are unique among psychrotrophs and psychrophiles, whose intracellular enzymes are mostly thermolabile.

Immobilization of β-Glucosidase using Wood Residue for Enzymatic Hydrolysis

ABSTRACT A significant amount of β-glucosidase and other cellulase components were adsorbed on the residue remaining after enzymatic hydrolysis of cellulosic materials. The wet wood-residue separated from an enzymatic degradation mixture hydrolyzed cellobiose to glucose in a yield of about 100% and retained the activity even after the 30th treatment. These residues were able to be used as an immobilized β-glucosidase preparation. By drying the wet wood residue, only β-glucosidase was retained on it, and the stability of immobilized β-glucosidase increased, although the specific activity decreased significantly.