Effect of selenium uptake on growth metabolism in yeasts for the production of enriched single-cell protein using agro-industrial by-products

Abstract

The use of agro-industrial by-products as feedstock for selenium-enriched yeast biomass production is an innovative and low-cost method. Thus, the present study aims for the utilization of sugarcane bagasse and corn bran hydrolysates for the production of selenium-enriched yeast and the evaluation of the effect of selenium in growth and cell composition. The hydrolysates were obtained using acid pretreatment, and yeasts were evaluated in different medium compositions. All evaluated yeasts were able to grow in the presence of 15 mg/L selenium. S. cerevisiae strains presented the major tolerance to selenium and better relation between selenium uptake and cell growth, with maximum cell biomass production of 7.97 ± 0.24 g/L and maximum selenium uptake of 1193 ± 336 ppm and 99% cell viability. Selenium also enhanced the lipid and protein concentration in cell extracts obtained after mechanical disruption. Regarding agro-industrial hydrolysates, corn bran hydrolysate allowed a better growth, with the production of 4.25 ± 0.49 g/L of biomass enriched with 167 ± 18 ppm selenium and 100% of viability. Starchy and lignocellulosic biomasses presented potential as low-cost alternatives for single-cell protein contributing to the development of sustainable and economically viable technologies.