| 摘要 |
1,175,912. Hydrolysis of protein. BRITISH PETROLEUM CO. Ltd. 23 March, 1967 [15 April, 1966], No. 16536/66. Heading C3H. [Also in Division C6] Material consisting of, or containing, cells of a micro-organism having a cell wall constructed at least in part of at least one compound having a carbohydrate component and a protein component, are treated with a proteolytic enzyme such that degeneration of the protein component takes place and the carbohydrate component is rendered susceptible to enzymic attack, the proteolytic enzyme which is present in the cell walls is then deactivated or removed (e.g. by washing), the treated material or a fraction therefrom is further treated with an enzyme capable of attacking a carbohydrate present in the cell wall whereby degeneration of the carbohydrate takes place, and with or without an intermediate step for the further attack on or rupturing of the cell wall, there is recovered an aqueous fraction containing nitrogenous compounds in solution or suspension. The proteolytic enzyme, which should have activity for breaking only a bond between two specific amino acids present in a protein component of the cell wall, is employed under conditions such that a substantial proportion of the nitrogenous component of the cell wall is solubilized but only at most a minor proportion of the cytoplasmic protein is degraded. Suitable proteolytic enzymes are pepsin, trypsin, bromelain, ficin and papain. Papain may be employed in an amount constituting 0À2-0À3% of the dry cell weight of the micro-organism. According to an example, 25 Kg. of an aqueous yeast cream containing 15% by weight of the yeast Candida tropicalis which had been grown on gas oil, then washed with a non-ionic detergent, was brought to pH 7À6 by addition of a 2N soda solution, disodium phosphate and citric acid were added and the temperature was brought to 70‹ C. The mixture was digested with 15 g. papain and 15 g. cysteine hydrochloride at this temperature for an hour, after which the material was centrifuged, washed and recentrifuged. The resulting residue was taken up by 15 1. of distilled water, the pH was adjusted to 5 by addition of 2N hydrochloric acid, disodium phosphate and citric acid were added and this new mixture was heated and kept at 40‹ C. for 2 hours in the presence of 25 g. cellulose and 25 g. lipase. The product was centrifuged and the liquid product obtained was added to the liquid products previously obtained by centrifuging. The mixture of liquids was dried by spray drying. 2À25 Kg. of dry product containing 11% by weight of nitrogen was obtained. A further example is directed to the treatment of baker's yeast (Saccharomyces cerevisiae). Many species of microorganisms are particularly mentioned.
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