Martin C. Cadmus

Laboratory production of a phosphorylated mannan by Hansenula holstii

Abstract Conditions for the production of a phosphorylated mannan by strains of the yeast Hansenula holstii were investigated. Polysaccharide was produced from glucose in media containing organic nitrogen and inorganic salts. The ratio of mannose to phosphate in the polymer was not altered by changes in medium constituents. Yields of polymer in the range of 50–55% based on glucose were realized in shaken-flask experiments.

High-temperature, salt-tolerant xanthanase

SummaryA new high-temperature, salt-tolerant xanthanase suitable as an enzymic viscosity breaker for xanthanbased hydraulic fracture fluids was obtained by soil enrichment growth on xanthan gum incubated at 45°C in the presence of 3% NaCl. The mixed culture produces exoenzymes functional up to 65°C in the presence of salts. Degradation products include the pyruvic acetal of mannose and branched oligosaccharides derived from cleavage of main-chain β-(1→4)-d-glucosyl linkages. Release of the terminal pyruvic acetal ofd-mannose leads to oligosaccharide products that evidently contain the ene-4,5-unsaturated glucuronic acid residue.

An extracellular fungal polysaccharide composed of 2-acetamido-2-deoxy-d-glucuronic acid residues☆

The black yeast-like fungus NRRL YB-4163, now tentatively identified as Rhinocladiella elatior Mangenot, has been found to produce an extracellular microbial polysaccharide composed mainly of 2-acetamido-2-deoxy-D-glucuronic acid residues. Polysaccharide (PS) YB-4163, when isolated in good yield as the neutral potassium salt, dissolves readily in water to produce extremely viscous solutions, which form stable foams and emulsions. By depolymerizing PS YB-4163 with [14C]methanol-HCl, the polysaccharide can be both identified and quantitated radiochemically by determining the individual [14C]methyl glycosides after their separation by paper chromatography. When the methyl glycosides of PS YB-4163 were reduced with NaB3H4, only the methyl glycosides of 2-acetamido-2-deoxy-D-[6-3H]glucose were found. Analysis of the monosaccharide released from carboxyl-reduced PS YB-4163 by acid hydrolysis or methanolysis also showed 2-acetamido-2-deoxy-D-glucuronic acid to be the main constituent. Previously, the only polysaccharides known to be composed entirely or hexosaminuronic acid have been cellular products from pathogens. Of these, the antigenic polysaccharide (SPSA) from Staphylococcus aureus is composed entirely of 2-amino-2-deoxy-D-glucuronic acid, but its amino groups are substituted equally with acetyl and N-acetylalanyl groups. The specific optical rotation of PS YB-4163, [alpha]20D -75 degrees (c 0.5, water), is similar to that of SPSA (-91 degrees), and suggests beta-D-linkages that must be either (1 leads to 3) or (1 leads to 4).

Enzymic hydrolysis of rhizobial 4-O-methyl-d-glucurono-l-rhamnan

Abstract A Bacillus sp. obtained from soil-enrichment culture excretes a depolymerase that degrades rhizobial 4-O-methylglucuronorhamnan. The enzyme was purified to homogeneity. According to SDS gel electrophoresis, it is a polypeptide chain of Mr ∼ 210,000. As determined by methylation analysis and n.m.r. spectroscopy, the sole product of enzymolysis is the linear tetrasaccharide 4-O-Me-β- d -GlcpA-(1→3)-α- l -Rhap-(1→3)-β- l -Rhap- (1→4)- l -Rha.