Autolytic reduction of the nucleic acid content in Candida utilis

Abstract

The nucleic acid content in Candida utilis was autolytically reduced only after previous lyophilization of yeast cells or pretreatment of the cells with ethyl acetate. These pretreatments provided a sufficient permeability of the cell membrane system and thus enabled a reduction of the nucleic acid content. While deep freezing of the cells (-35 degrees C) had no positive effect on the degradation of nucleic acids, lyophilization of yeast cells led to a 75% decrease of the nucleic acid content. Furthermore, a 55% reduction of the nucleic acid content was proceeded without a concomitant loss of proteins. Similar results were obtained by using ethyl acetate.

Utilization of Food Industries Wastes for The Production of Single Cell Protein by Yeasts

“…These include activation of endogenous RNAase by brief heat treatment up to 60-70 °C for 20 min, alkaline hydrolysis of nucleic acids, modifications of cultural conditions with respect to nitrogen, carbon, phosphorous and zinc content or chemical extraction and removal of nucleic acids (Anupama and Ravindra, 2000). Several methods have been reported in the literature for this purpose such as a heat shock treatment to activate the endogenous nucleases (Abu-Ruwaida et al, 1988;Kurbanoglu and Algur, 1996), the use of pancreatic ribonuclease (Martinez et al 1990), a heat shock followed by a RNase treatment (Kunhi and Rao, 1995), lyophilization (Kossaczka et al, 1990), alkaline treatment with NH 4 OH at 65 C (Alvarez and Enriquez, 1988) and use of ion exchange (Lewis et al, 1982).…”