| 摘要 |
1400691 Yeast BRITISH PETROLEUM CO Ltd 31 Jan 1974 [8 Feb 1973] 6213/73 Heading C6F [Also in Division C3] A process for reducing the quantity of nucleic acids present in a proteinaceous material involves treating the material with an organic solvent and thereafter subjecting the solvent-treated material to an aqueous alkali under conditions which solubilize nucleic acids. The proteinaceous material is exemplified by hydrocarbon assimilating yeasts of the species Candida lipolytica and Candida tropicalis. The organic solvent may be a C 1 -C 4 alcohol admixed with water in a ratio by volume of between 4 and 10:1, particularly the azeotropic mixture of isopropanol and water. Ketones, hydrocarbons and organic halogenated compounds are also mentioned in the context. After drying, the solvent-treated material is subjected to an aqueous alkali solution (pH 8À5-9À5) typically of strength 0.01-0À1Nper 100 grams dry weight per litre, at a temperature in the range 50 to 90‹C. The alkali may be potassium or sodium hydroxide, ammonia or ammonium hydroxide. The protein of reduced nucleic acid content is recovered by centrifugation, filtration or sedimentation. The solubilized nucleic acids contained in the aqueous phase can be recovered together with some protein and polysaccharide by precipitation in acid media, reverse osmosis, ultrafiltration, dialysis or enzymic attack. |
