GB1224174A - Improvements in or relating to the production of fibrous material from micro-organism cells - Google Patents

Abstract

1,224,174. Extracting protein. BRITISH PETROLEUM CO. Ltd. 2 May, 1968 [6 June, 1967], No. 26095/67. Heading C3H. [Also in Division C6] Cells of micro-organisms are extracted with a solvent which consists of or contains formic acid, the extraction being carried out under conditions such that all, or a substantial proportion, of the protein and carbohydrate content of the cells passes into the extract phase, thereafter, any solid phase still present is separated from the extract phase and (whether or not a solid phase has been separated) the extract phase is mixed with an aqueous phase whereby a fibrous material is precipitated and recovered. The micro-organism cells are typically obtained by the aerobic culture of specified normal paraffin-consuming yeasts, moulds or bacteria on a hydrocarbon substrate. Under preferred conditions of operation: the micro-organism is in a dry state when subjected to the extraction, formic acid is employed in the anhydrous state or in aqueous dilution containing at least 80% of formic acid, and the extraction is carried out at a temperature of at least 60‹ C. with a contact time of at least 2 hours. The extract phase is mixed with aqueous caustic soda solution or sodium citrate buffer to give a pH in the range 3À5 to 4À2, the resulting solid fibrous phase is dried in an oven, and the remaining aqueous phase is spray dried as such, or the proteins are precipitated and a fraction containing the proteins is mixed with the fibrous material, with or without treatment to achieve bonding. According to an example, 100 g. of dry Candida yeast was stirred with 1 kg. of 85% aqueous formic acid at a temperature of 90‹ C. for 5 hours, and at the end of this period the solution thereby obtained was added to three times its volume of cold water. The mass of solid fibrous material which formed in the aqueous medium was removed by filtration on a 0À5 mm. mesh nylon screen using reduced pressure. The filtered material was dried in a vacuum oven at 45‹ C., whereby there was obtained 25 g. of a fibrous material having a nitrogen content of 2À7% by weight. The filtrate contained in solution 75 g. of solid material having a nitrogen content of 11%. In a further example, the solution in formic acid was added to N/5 aqueous caustic soda instead of to cold water.