Today in 1975, US Patent 3887431 A was issued, an invention of Ernest Aleck Robbins, Robert William Sucher Jr., Erich Henry Schuldt, Daniel Robert Sidoti, Robert Dudley Seeley, and Jon Albert Newell, assigned to Anheuser Busch, for their “Yeast Protein Isolate with Reduced Nucleic Acid Content and Process of Making Same.” Here’s the Abstract:

This disclosure relates to a yeast protein isolate (IYP) with less than 9% nucleic acid (RNA) and a Protein Equivalence Ratio (PER) of greater than 1. The yeast protein is made by a process which involves rupturing yeast cells, removing the cell wall residue from an alkaline medium, incubating in such a manner that the endogenous nuclease contained in the solubles portion degrades the nucleic acid present to a soluble form, insolubilizing the protein to separate it from the hydrolyzed nucleic acid, and separating the insoluble protein from the fraction containing soluble nucleic acid.