Microorganisms with low nucleic acid content are produced by acid treating of the microorganism. One embodiment relates to the extraction of so treated microorganisms after their separation from the acid treating fluid, using a strong base for the extraction. Another embodiment relates to the neutralization of the acid treating fluid containing nucleic acids prior to the introduction of this fluid into the fermentation zone, the anion of the acid and the metal cation used in the neutralization step forming minerals desirable for the growth medium in the fermentation step.
Yeast cells containing useful substances accumulated therein are contacted with a divalent copper ion in aqueous suspension, thereby discharging low-molecular-weight compounds in the cytoplasm out of the cells. Useful substances can be efficiently recovered both from the discharged compounds and the remaining cells.
A methanol-utilizing bacterium selected from the group consisting of Methylophilus KISRI 5 (NCIB 12135), Methylophilus KISRI 6.1 (NCIB 12136), Methylophilus KISRI 512 (NCIB 12137), Methylophilus KISRI 5112 (NCIB 12138) and mutants and variants thereof. Also, bacterial cultures comprising these novel strains of Methylophilus and a method of producing single cell protein comprising culturing one or more of the Methylophilus strains of the invention in a methanol-containing aqueous culture medium, preferably in the culture medium of the invention which has been optimized for culturing these novel Methylophilus strains. The culture method preferably further comprises the recycling of spent culture medium.
Substances producing an undesired odor and taste can be removed from microbial protein materials if these materials are treated with aqueous solutions which contain a phosphate and/or a hydrophilic low molecular weight aliphatic compound which contains at least two functional groups from the series comprising hydroxy, formyl, keto and carboxy. Preferred aliphatic extraction auxiliaries are flavoring acids, sugars and polyols, and phosphates are orthophosphates and diphosphates. The extraction can also be carried out in association with reducing the nucleic acid content of defatted cell aggregates.
A comestible whipped protein product produced by treating yeast cells for nucleic acid reduction under basic and acidic conditions followed by treating the nucleic reduced cells with a relatively high temperature short-time heat-shock, and whipping.
A comestible whipped protein product produced by treating yeast cells for nucleic acid reduction followed by treating the nucleic acid-reduced cells with a relatively high temperature short-time heat-shock, and whipping.
