Abstract

EFFECT OF VARIOUS FACTORS (CARBON SOURCES, NITROGEN SOURCES, TEMPERATURE, AND PH) ON GROWTH OF YEAST ISOLATED FROM CURD AND CHEESE

G. Venkatesh*, G. Vijaya Geetha and N. Mounika Reddy

ABSTRACT

Yeast is single-celled fungi. Some yeast is beneficial, being used to produce bread or allow the fermentation of sugars to ethanol that occurs during beer and wine production (e.g., Saccharomyces cerevisiae). Other species of yeasts are detrimental to human health. An example is Candida albicans, the cause of vaginal infections, diaper rash in infants and thrush in the mouth and throat. Among the samples screened for of yeast, 6 isolates were selected i.e., four from curd and two from cheese sample. Isolation and Screening of the thermotolerant yeasts was performed by culturing each isolate of the yeast on YPD culture medium. The isolated cultures were tested for their antimicrobial property, antibiotic sensitivity and the effect of different carbon sources, nitrogen sources, pH levels, and temperatures were also tested in vitro. Results indicated that the Enteropathogens like E.coli, Enterococcus and Klebsiella are sensitive to yeast where as proteus vulgarius and s.aureus resistant to saccharomyces spp and it was resistance to Gentamycin, Flucanazole, Ceftazidime and sensitive to Ampicillin, tetracycline, streptomycin antibiotics. The maximum growth of saccharomyces spp. was found to be in glucose (1.51), beef extract (1.43), pH 6.5 (1.64) and temperature 350c compared with reference strain baker’s yeast. Further, the strain was found to vary morphologically with the baker’s yeast under the study.

Keywords: Yeast, saccharomyces spp, baker’s yeast, antimicrobial property, antibiotic sensitivity test, temperature, pH.