RESUMEN
OBJECTIVE: To produce an alcoholic beverage containing anthocyanins that can act as antioxidants and have anticarcinogenic activities and antihypertensive effects. RESULTS: High starch-assimilating sake yeast strain of Saccharomyces cerevisiae co-expressing the glucoamylase and α-amylase genes from Debaryomyces occidentalis using the double rDNA-integration system was developed. The new strain grew substantially using 5 % (w/v) purple sweet potato flour as the sole carbon source. Its cell yield reached 14.5 mg ml(-1) after 3 days. This value was 2.4-fold higher than that of the parental wild-type strain. It produced 12 % (v/v) ethanol from 20 % (w/v) purple sweet potato flour and consumed 98 % of the starch content in purple sweet potato flour after 5 days of fermentation. CONCLUSION: We have produced a health-promoting alcoholic beverage abundant in anthocyanins from purple sweet potato.
Asunto(s)
Bebidas Alcohólicas/análisis , Antocianinas/metabolismo , Ipomoea batatas/metabolismo , Saccharomyces cerevisiae/metabolismo , Antocianinas/análisis , Debaryomyces/enzimología , Debaryomyces/genética , Fermentación , Glucano 1,4-alfa-Glucosidasa/genética , Glucano 1,4-alfa-Glucosidasa/metabolismo , Saccharomyces cerevisiae/genética , Almidón/metabolismo , alfa-Amilasas/genética , alfa-Amilasas/metabolismoRESUMEN
Industrial strains of a polyploid, distiller's Saccharomyces cerevisiae that produces glucoamylase and α-amylase was used for the direct fermentation of raw starch to ethanol. Strains contained either Aspergillus awamori glucoamylase gene (GA1), Debaryomyces occidentalis glucoamylase gene (GAM1) or D. occidentalis α-amylase gene (AMY), singly or in combination, integrated into their chromosomes. The strain expressing both GA1 and AMY generated 10.3% (v/v) ethanol (80.9 g l(-1)) from 20% (w/v) raw corn starch after 6 days of fermentation, and decreased the raw starch content to 21% of the initial concentration.