Patent GB-1049929-A (GB)
Title: Improvements in or relating to the treatment of micro-organisms and/or to the treatment of products derived from said micro-organisms
Inventor: CHAMPAGNAT ALFRED
IPC: C21C/
Filed: 1964-02-04
Abstract: A petroleum fraction especially a gas oil containing waxes is used as substrate for the growth of a mould, yeast or bacterium; straight-chain components such as waxes are preferentially consumed by the micro-organism.ALSO:A micro-organism capable of growing on a feedstock consisting of or containing straight chain hydrocarbons is cultivated in the presence of such a feedstock, aqueous nutrient medium and a gas containing free oxygen, thereafter a fraction containing the micro-organism is subjected to conditions (autolysis, plasmolysis or hydrolysis) such that cell rupture takes place, and there is then recovered a fraction consisting of or containing proteins, polypeptides and/or amino-acids (a) which have been produced by the micro-organism in the course of its metabolism and which have been released from the micro-organism or (b) which have been derived from nitrogen-containing compounds of the micro-organism in the course of cell rupture.  The fraction containing the microorganism may be subjected to a series of alternate washing and separation stages, employing an aqueous solution of a surface active agent (e.g. stearyl-trimethyl ammonium chloride, a condensate of oleic acid and ethylene oxide, or sodium alkyl sulphates) in the first washing stage and in the last washing stage an aqueous medium free of surface active agent, whereby the micro-organism finally separated has a hydrocarbon content of less than 7% by weight.  The proteins &c. may be separated from cell wall material consisting of cell walls and/or material which constituted the cell walls.  The cell wall material may be treated by solvent extraction to recover at least part of the unmodified hydrocarbon feedstock for recycling to the cultivation, employing a solvent mixture of 80% n-hexane and 20% ethanol, an azeotropic mixture of n-hexane and iso-propanol, or ethanol and n-hexane sequentially.  The solvent extracted cell wall material, containing about 4% by weight of fixed nitrogen, is suitable as a cattle feedstuff.  Autolysis of the cells, to which enzymes and sodium chloride may have been added, involves heating at 45-55 DEG C. for 3 hours down to 40-50% dry matter (for use as an animal feedstuff) or heating for 10-20 hours down to 55-65% dry matter (for human consumption).  The autolysate may be concentrated or dried under reduced pressure at a temperature below 70 DEG C. Plasmolysates are obtained by the diffusion of the proteins &c. out of the cells as a result of a change in osmotic pressure produced by the addition of, for example, sodium chloride.  Hydrolysates are obtained by the action of acids or alkalis on the cells.  Separation is carried out by filtration or centrifuging.  Of the many species and strains of yeasts, moulds and bacteria particularly mentioned, Candida lypolytica, Penicillium expansum, Bacillus megatherium, Bacillus subtilis and Pseudomonas aeruginosa are preferred.  An example is directed to the cultivation of an inoculum of Candida lypolytica on mixed C9-C16 normal hydrocarbons, on heavy petroleum gas oil.