Process for reducing the contents of lipids and nucleic acid in microbial cell masses

Claim 1

A process for reducing the content of lipids and nucleic acid in a microbial cell mass, which comprises first extracting said cell mass at a temperature not exceeding 50° C. for a time from 5 minutes to 120 minutes with a liquid extractant comprising ammonia or ammonium hydroxide and isopropanol or an organic solvent of the formula R 1 --(CH 2 ) n --OR 2 , wherein either R 1 and R 2 are hydrogen, and n is 1, 2, or 3, or R 1 is hydroxy, R 2 is hydrogen, methyl, or ethyl and n is 2 or 3, the NH 3 -content of said liquid extractant being from 1 to 10 percent by weight of said organic solvent, the weight ratio of solvent to cell mass being between 3:1 and 12:1, and the total amount of water present during said extraction, as contributed by the cell mass, solvent, and ammonium hydroxide, being from 0 to 10 percent by weight of said solvent, separating the liquid extractant from the solvent-extracted microbial cell mass, and then extracting the separated solvent-extracted cell mass with water at a pH from 6 to 7.5 for a time from 5 minutes to 120 minutes, separating the water from the water-extracted cell mass, and drying the water-extracted cell mass.