Production of high‐quality edible protein from Candida yeast grown in continuous culture

Abstract

SummaryC'oirtlitlrr rctilis NRRL Y-900 was grown in aerobic continuous culture with cane molasses a s the source of the growth-limiting carbon. At 1% reducing sugar in the chemostat (10 liter working volume) feed medium. addition of Zn (25pM) to a minimal salts medium resulted in an increase in the biomass productivity of the chemostat from 1.7 to 2.6 glliterihr with a growth yield of 0.55 g dry biomassig reducing sugar utilized at D,,,. On the average, the yeast biomass was 50-55% protein. At S R > 2% sugar. the biomass productivity was limited by the oxygen supply. With 0,-supplemented aeration (at S R = 4.2%) the maximum biomass productivity was 7.45 glliterihr. Aerobic ethanol production was not observed. A highquality undenatured protein fraction was isolated from the yeast homogenate by isoelectric precipitation at pH 4.5. Contaminating nucleic acid was removed as,an insoluble complex by chelation with an organic cation (cetavlon). The final protein product contained about 3% RNA (DWB) and was suitable for use a s a food additive.

A transformation system for the yeast Candida utilis: use of a modified endogenous ribosomal protein gene as a drug-resistant marker and ribosomal DNA as an integration target for vector DNA

“…It has been suggested that C. utilis is diploid (14,25); this is supported by our observation that it was difficult to obtain auxotrophic mutants by chemical mutagenesis. Southern analysis of transformants in which the linearized pCLRE4 was integrated at the L41 gene locus indicated that there are two copies of the L41 gene per wild-type cell (Fig.…”

“…It is used in the production of a number of biologically useful materials, such as glutathione, and certain amino acids and enzymes. It is also a promising source of nutrients through the large-scale production of single-cell protein from biomass-derived sugars, such as sugar molasses and spent sulfite liquor (2,14). Since C. utilis is a Crabtree-negative yeast, ethanol formation does not occur in strict aerobic culture; thus, large-scale production of single-cell protein is possible in efficient continuous-culture conditions (2).…”

Effect of Physiochemical Treatments on Brevibacterium flavum for Production of Lysine

“…Khan et al (1990) observed that addition of 5% molasses after 48 hours of incubation enhanced the total protein from 7.71 to 11.97 mg/ml. The result of present study are substantiated by Lawford et al (1979) who used can molasses as source of growth limiting carbon in the fermentation media for the production of single cell protein using Candida utilis NRRL Y-900. At one percent reducing sugar with the addition of zinc powder resulted in an increase in biomass productivity from 1.7 to 2.6 g/l/h with the growth yield of 0.55g dry biomass/g reducing sugar utilized at the maximum dilution rate.…”

Using Black Liquor from the Soda Pulping Process for Protein Production by Candida utilis

“…Moreover, they can also supply feed with vitamins, minerals, and other nutrients (Raa 1990). Candida utilis has a relatively high concentration of essential amino acids in its proteins (Lawford et al 1979) and possesses the ability to metabolize a wide range of saccharides (Shay and Wegner 1985). However, to date, there has been no publication that reports the use of Candida utilis in black liquor from the soda pulping process for the production of SCP.…”