Optional production and utilization of polysaccharide by Aeromonas hydrophila

Glucans from the fish pathogen Aeromonas hydrophila have been extracted and purified by a method utilizing phenol/water followed by sodium deoxycholate rather than the traditional sodium hydroxide extraction. Presence of substantial amounts of these glucans was shown to be dependant on whether or not the substrate contained dextrose, a point which had import because of the low carbohydrate environment in which this species must survive and multiply. These glucans, produced in the log phase, were utilized during the growth period. The structures of the two purified glucans were examined by methylation analysis, periodate oxidation, and enzymatic degradation. The results indicated that A. hydrophila under low-carbohydrate growth conditions produced two similar but distinguishable alpha 1 leads to 4 linked glucans substituted alpha 1 leads to 6 by single monosaccharide residues or short chains to give an amylopectinglucogen type of polysaccharide.