1. Field of the Invention
This invention relates to the recovery of proteinaceous matter from such waste protein-containing liquids as whey and tannery unhairing waste.
2. Description of the Prior Art
Precipitation of proteins from whey by heat denaturation is an old and straightforward procedure. In fact, the various whey proteins have been shown to be heat-denatured at different rates (J. Dairy Sci. 38, 351, 1955). However, the major whey proteins, .alpha.-lactalbumin and .beta.-lactoglobulin are rather resistant to denaturation by heat at the pH and concentration at which they occur in acid whey (J. Dairy Sci. 49, 694, 1966; J. Dairy Res. 37, 233, 1970). Both of these proteins are stabilized in their native conformations by internal disulfide bonds (Biochem. Biophys. Acta 200, 184, 1970; J. Dairy Sci. 57, 1152, 1974) and, at least in the case of .beta.-lactoglobulin, irreversible denaturation and the simultaneous appearance of new sulfhydryl groups has been thoroughly established (J. Dairy Sci. 33, 890, 1950; JACS 79, 126, 1957; J. Dairy Sci. 52, 585, 1969).
Tannery unhairing waste is an opaque, noxious liquid that has a 5-day biological oxygen demand (BOD) of over 19,000 ppm (JALCA 69, 50, 1974). Methods of disposing of this waste, which contains quantities of proteinaceous materials, are the subject of world wide studies (J. Water Pollut. Contr. Fed. 44, 1080, 1972; ibid 43, 998, 1971).