Abstract

MANOVACIA MORENO, Nohora Patricia; MORENO CARDENAS, Angélica María; MAYORGA MOGOLLON, Olga Lucía  and  BARAHONA ROSALES, Rolando. EVALUATION OF THE NUTRIENT CONTENT AND BIOMASS PRODUCTION IN COLOMBIAN AND COMMERCIAL YEAST STRAINS. Rev. Fac. Nac. Agron. Medellín [online]. 2008, vol.61, n.2, pp.4542-4553. ISSN 0304-2847.

In the present study biomass production and nutrient (selenium, total carbohydrate and microbial protein) were evaluated in both commercial and native yeast isolates from the Colombian Germplasm Bank managed by the Colombian Corporation of Agricultural Research, CORPOICA. In an initial phase, three randomly chosen yeast isolates were grown under different conditions of pH, temperature and time of fermentation using liquid malt extract culture medium. The best responses in biomass yield were observed at a pH of 4.5, or temperature of 25 °C and a fermentation period of 24 hours. Using these conditions, 100 native and 4 commercial yeast isolates, were evaluated for their biomass production, content of selenium, total carbohydrates and microbial protein and nutrient intake. According to these variables, a cluster analysis was used to distribute the 104 isolates in homogeneous groups. Great variability in biomass production was observed among isolates, probably due to the existing biological variability in the population studied. Biomass yields varied from 0.101 to 0.480 g of biomass/ g of sugar consumed and rate of biomass production ranged between 0.040 to 0.185 g L^-1 h^-1. Average nutrient intake (g of consumed nutrients/ g of available nutrients) was of 91.6% in the case of carbohydrates and of 17.8% in the case of protein. Ten yeast isolates with superior growth and nutrient content were identified for future screening for prebiotic and probiotic potential.

Keywords : Native yeast isolates; yeast biomass production; selenium; protein; carbohydrates.

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