| 摘要 |
1,224,882. Yeast &c. BRITISH PETROLEUM CO. Ltd. June 5, 1968 [July 19, 1967], No.33088/67. Heading C6F. A micro-organism capable of growth on a hydrocarbon is cultivated in the presence of a feedstock which consists of or contains a hydrocarbon and on which the micro-organism is capable of growth, in the presence of an aqueous nutrient medium and in the presence of a gas containing free oxygen and thereafter part of the aqueous medium is separated, the remaining product (or part thereof) comprising the micro-organism in admixture with at least part of the residual hydrocarbon and at least part of the residual nutrient medium is treated with a surface active agent having the formula:- where n is an integer from 11 to 14, m is from 4 to 12 and X is sodium or potassium, and the mixture so obtained is subjected to a separation treatment for the recovery of a fraction in which hydrocarbon predominates and a fraction consisting of or containing a mixture of micro-organism and water. The aqueous medium separated off may be replaced with fresh water to reconstitute the original mixture. The surface active agent is added in proportions within the range 0À02-0À5%, based on the weight of the mixture of micro-organism, aqueous nutrient medium and hydrocarbon. The surface agent is exemplified by an oxyethylenated lauric alcohol sulphate having on average 7 ethylene oxide groups per molecule and a sulphur content of 1.4% by weight. The recovered fraction in which hydrocarbons predominate, containing aqueous medium held in emulsion, may be treated to separate the surface active agent, as follows: (1) with a compound containing a metal ion which forms a water insoluble salt with the surface active agent e. g. calcium or barium hydroxides or carbonates, or salts of zinc and heavy metals; (2) with a mineral acid e.g. HC1 or H 2 SO 4 , under conditions such that the surface active agent is hydrolysed; (3) by cooling to a temperature in the range-10 degrees to +10‹ C.; or (4) with a solvent e.g. 15-25% by weight of isopropanol. Examples are directed to the cultivativation of Candida tropicalis upon a gas obtained from Middle-East crude petroleum and to the recovery of the product yeast. |
