First aspects on acetate metabolism in the yeast Dekkera bruxellensis: a few keys for improving ethanol fermentation

Abstract

Dekkera bruxellensis is continuously changing its status in fermentation processes, ranging from a contaminant or spoiling yeast to a microorganism with potential to produce metabolites of biotechnological interest. In spite of that, several major aspects of its physiology are still poorly understood. As an acetogenic yeast, minimal oxygen concentrations are able to drive glucose assimilation to oxidative metabolism, in order to produce biomass and acetate, with consequent low yield in ethanol. In the present study, we used disulfiram to inhibit acetaldehyde dehydrogenase activity to evaluate the influence of cytosolic acetate on cell metabolism. D. bruxellensis was more tolerant to disulfiram than Saccharomyces cerevisiae and the use of different carbon sources revealed that the former yeast might be able to export acetate (or acetyl-CoA) from mitochondria to cytoplasm. Fermentation assays showed that acetaldehyde dehydrogenase inhibition re-oriented yeast central metabolism to increase ethanol production and decrease biomass formation. However, glucose uptake was reduced, which ultimately represents economical loss to the fermentation process. This might be the major challenge for future metabolic engineering enterprises on this yeast.

Fermentation profiles of the yeast Brettanomyces bruxellensis in d‐xylose and l‐arabinose aiming its application as a second‐generation ethanol producer

“…The ability to ferment d ‐xylose and l ‐arabinose by B. bruxellensis strains was evaluated under aerobic conditions. In a glucose‐based medium, the three strains presented a fermentative performance (ethanol yield and productivity, Figure 2 and Table 3) similar to previous studies (Galafassi et al, 2011; Peña‐Moreno et al, 2019; Teles, da Silva, Mendonça, de Morais Junior, & de Barros, 2018). When d ‐xylose was the sole carbon source, B. bruxellensis completely consumed this sugar, yet none of the three strains was able to produce ethanol in this condition (Figure 2 and Table 3).…”

“…This is similar to those observed for M. guilliermondii PYCC 3012 and C. arabinofermentans PYCC 5603 (Fonseca et al, 2007). This observation might be related to the fact that, despite being a Crabtree positive yeast, B. bruxellensis has a preference for oxidative metabolism, with high biomass yield and low ethanol values in environments with high oxygenation (Leite et al, 2013; Teles et al, 2018). In fact, that is also the explanation for the differences in the growth rates for d ‐xylose and glucose found in the previous section.…”

“…Strains (a) TB457A, (b) JP206M and (c) JP19M. Glucose (square), mixed medium (triangle), Larabinose (diamond) and D-xylose (circle) metabolism, with high biomass yield and low ethanol values in environments with high oxygenation(Leite et al, 2013;Teles et al, 2018).…”

Review on a Potential of Antibiotics

“…The survival of bacteria often results from an inheritable resistance, but the growth of resistance to antibacterial also occurs through horizontal gene transfer. 34 Antibacterial resistance may impose a biological cost, thereby reducing the fitness of resistant strains, which can limit the spread of antibacterialresistant bacteria, for example, in the absence of antibacterial compounds. 35 Additional mutations, however, may compensate for this fitness cost and can aid the survival of these bacteria.…”

Molecular Tools to Exploit the Biotechnological Potential of Brettanomyces bruxellensis: A Review

“…B. bruxellensis strains possess all the characteristics (Table 1) required for a great metabolic potential exploitable in biotechnological applications, such as industrial fermentation processes (beer and wines) and biofuel productions (e.g., first-and secondgeneration ethanol) [27][28][29][30][31][32][33][34][35]. Despite the large amount of information concerning the biotechnological peculiarities of B. bruxellensis in the literature, there have been no reviews focused on the molecular tools that can be used to modify strains for their biotechnological exploitation [27][28][29].…”