Nutritional versatility of a starch-utilizing Flavobacterium at low substrate concentrations

Abstract

A starch-utilizing yellow-pigmented bacterium, isolated from tap water, was tested for the utilization of 64 natural compounds at a concentration of 1 g/liter by measuring colony growth on agar media. Only 12 carbohydrates and glycerol promoted growth. Growth experiments with the organism in pasteurized tap water supplied with mixtures of substrates at concentrations of 1 or 10 micrograms of C of each substrate per liter, followed by separate experiments with a number of carbohydrates at 10 micrograms of C per liter showed that of these 64 natural compounds only sucrose, maltose, raffinose, starch, and glycerol promoted growth at very low concentrations. Also maltotriose, -tetraose, -pentaose, -hexaose, and stachyose, which were not included in the mixtures, enhanced growth, and generation times of 3 to 5 h at 10 micrograms of C per liter were observed. The organism, which was tentatively identified as a Flavobacterium species, thus appeared to be highly specialized in the utilization of glycerol and a number of oligo- and polysaccharides at very low concentrations.