Adaptative laboratory evolution to reduce acetic acid yield by Saccharomyces cerevisiae wine yeast strains under aerobic conditions

Autor: Martín-Guindal, Andrea, Roodink, Jorik S., Morales, Pilar, González García, Ramón, Tronchoni, Jordi
Rok vydání: 2020
Předmět:
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
instname
Popis: Resumen del trabajo presentado en el EMBL Conference Molecular Mechanisms in Evolution and Ecology, celebrado de forma virtual del 30 de septiembre al 2 de octubre de 2020
Respiro-fermentative metabolism has been proposed as a tool to decrease the alcoholic content in wines. Saccharomyces cerevisiae strains -despite the Crabtree effect- can reduce significantly their ethanol yield under aerobic conditions, as compared to standard fermentation settings. However, an exacerbated acetic acid production associated with this condition limits the usefulness of this species for this application. In previous works, recombinant wine yeast strains defective for some carbon catabolite repression related genes showed a reduced acetic acid yield in the presence of oxygen (Curiel et al., 2016). But the GMO status also precludes its general applicability in winemaking. In this work, we used Adaptative Laboratory Evolution (ALE) to obtain partially derepressed S. cerevisiae wine strains from four different backgrounds -three of them commercially available. This was expected to act as an indirect selection for strains showing reduced acetic acid yield under aerobic conditions. The selective pressure was established by 2-deoxy-D-glucose (2-DG), using galactose as the only carbon source. The experiment was run in three replicates for each genetic background by repeated batch subculture for ~100 generations with growing concentrations of 2-DG. All the evolved populations showed improved growth on different carbon sources under carbon catabolite repression control -both fermentable and non-fermentable-, in the presence of either 2-DG or glucosamine (another non-metabolizable glucose analogue). Almost all the evolved populations were able to perform a complete fermentation of natural must, being slightly slower compared with the parental strain. In addition, all the evolved populations showed reduced acetic acid yield and a slight but significant increase in glycerol production. Singlecolony isolated from grape juice fermentations were tested for tolerance to the most common wine-industry factor stresses. Selected candidates were confirmed for acetic acid production under aerobic conditions significantly lower than the parental strain and for some of them lower than the original evolved population, below commercial wine standard thresholds. We show here a methodology to obtain in a quick manner industrial strains suitable to ferment under aerobic conditions by using a combined ALE and fermentation screening techniques. This work was funded by the Spanish Government through grant PCI2018¿092949 (cofunded by ERA¿CoBioTech). JT is funded by FGCSIC by the COMFUTURO program. AMG holds a training contract funded by La Rioja Government. Curiel JA, Salvadó Z, Tronchoni J, Morales P, Rodrigues AJ, Quirós M. Microb Cell Fact.2016;15:156
Databáze: OpenAIRE
Externí odkaz: