Depolymerization of β-chitin to mono- and disaccharides by the serum fraction from the para rubber tree, Hevea brasiliensis

The serum fraction of latex from Hevea brasiliensis, the para rubber tree, is known to contain an endo-chitinolytic enzyme, hevamine. Herein the activity of the rubber serum towards beta-chitin is investigated. The serum contained 6mg/mL of protein and a chitinolytic activity of 18mU per mg of protein. The optimum ratio of enzyme to chitin was 0.22mU/mg, and the optimum substrate concentration was 60 mg/mL. The optimum pH range was pH 2-4, and the optimum temperature was 45degreesC. At these conditions both (GlcNAc)(2) and GlcNAc were produced in a molar ratio of approximately 2:1. The hydrolysis of 300 mg of chitin with 64 mU of the rubber serum for 8 days under the optimum conditions gave 39 mg of GlcNAc and 108 mg of (GlcNAc)(2) as determined by HPLC. Mixing the rubber serum preparation with an Aspergillus niger pectinase preparation containing beta-N-acetylhexosaminidase can be used to produce almost exclusively the GlcNAc monomer in about 50% yield. (C) 2004 Elsevier Ltd. All rights reserved.