Detection of Gentiobiose and Sophorose in Cultures of Certain Micro-organisms growing in Defined Glucose-containing Media

Abstract

THE ability of cellulose-forming species of Acetobacter to produce from glucose a mixture of melibiose, cellobiose, cellotriose, cellotetraose and fructose, together with higher oligosaccharides some of which yield fructose on hydrolysis, has been reported in recent communications^1–3. We have now examined the behaviour, in comparable conditions, of Acetobacter aceti N.C.I.B. 8554, Acetobacter rancens N.C.I.B. 7214, Acetobacter acidum-mucosum N.C.I.B. 8133, and Acetobacter acetosum var. nairobiense N.C.I.B. 7212, none of which produces cellulose. A. aceti was grown in a medium containing (gm./l.): (NH₄)₂SO₄, 3; MgSO₄.7H₂O, 2; KH₂PO₄, 3; glucose, 30. The same ingredients with addition (gm./l.) of: DL-alanine, 0.1; asparagine, 0.1; calcium D-pantothenate, 0.002; riboflavin, 0.002 and biotin, 0.0003, were employed to make up the medium for the three other species. These media were dispensed in volumes of 200 ml. in sixteen Glaxo flasks, four flasks for each species. After inoculation and incubation for 10 days at 28° C. the contents of each set of four flasks were Seitz-filtered and concentrated to about 50 ml. in presence of a little barium carbonate in vacuo at 35°. Each concentrate was filtered and treated in the following manner in all four cases. It was added to a column (4.5 cm. diameter) filled with a charcoal–‘Celite’ (50 : 50, w/w) mixture. The column was eluted with water (5 l.) and then with aqueous ethanol solutions containing, respectively, 5, 15, 20 and 35 per cent (v/v) of ethanol. The aqueous ethanolic eluates were combined (4 l.), concentrated under low pressure at 35° C. to 500 ml. and treated successively with ‘Zeo-Karb 225’ (H⁺ form) and ‘De-Acidite E’ (OH⁻ form).