Transcriptome of the Alternative Ethanol Production Strain Dekkera bruxellensis CBS 11270 in Sugar Limited, Low Oxygen Cultivation

Abstract

Dekkera bruxellensis can outcompete Saccharomyces cerevisiae in environments with low sugar concentrations. It is usually regarded as a spoilage yeast but has lately been identified as an alternative ethanol production organism. In this study, global gene expression in the industrial isolate D. bruxellensis CBS 11270 under oxygen and glucose limitation was investigated by whole transcriptome sequencing using the AB SOLiD technology. Among other observations, we noted expression of respiratory complex I NADH-ubiquinone reductase although D. bruxellensis is a Crabtree positive yeast. The observed higher expression of NADH-generating enzymes compared to NAD+-generating enzymes might be the reason for the previously observed NADH imbalance and resulting Custer effect in D. bruxellensis. Low expression of genes involved in glycerol production is probably the molecular basis for high efficiency of D. bruxellensis metabolism under nutrient limitation. No D. bruxellensis homologs to the genes involved in the final reactions of glycerol biosynthesis were detected. A high number of expressed sugar transporter genes is consistent with the hypothesis that the competitiveness of D. bruxellensis is due to a higher affinity for the limiting substrate.

Genomics Perspectives on Metabolism, Survival Strategies, and Biotechnological Applications of <b><i>Brettanomyces bruxellensis</i></b> LAMAP2480

“…As might be expected, it was possible to identify 2 putative specific hexose transporters. These results are similar to the findings of Tiukova et al [2013], who described 4 sequences associated with specific hexose transporters B. bruxellensis CBS11270. In addition, we identified the glycolytic pathway of B. bruxellensis LAMAP2480.…”

Brettanomyces bruxellensis, a survivalist prepared for the wine apocalypse and other beverages

“…However, this would only be possible if the affinity of these transporters with their select substrates differed to those of S. cerevisiae. Glucose and hexose transporter genes as well as a high affinity glucose transporter were identified in the aforementioned strain (Tiukova et al, 2013). This would further indicate an evolution-based adaptation of specific strains to live in a low-nutrient medium.…”

“…Therefore, due to the Custers effect in B. bruxellensis, an imbalance in the redox potential of the cell will occur and this could possibly be due to the lack of glycerol 3-phosphate phosphatase activity. The genes involved in this process are indeed poorly expressed in B. bruxellensis (Wijsman et al, 1984;Tiukova et al, 2013). However, B. bruxellensis could utilise other biochemical pathways in order to correct the redox imbalance that occurs during sugar consumption.…”

Microbial acidification, alcoholization, and aroma production during spontaneous lambic beer production

“…When introduced into an anaerobic environment, the redox imbalance cannot be restored by re‐oxidation of NADH + H + to NAD + through the glycerol pathway, because of the lack or limited activity of glycerol 3‐phosphate phosphatase (Fig. ) . The resulting lag phase can eventually be circumvented by B. bruxellensis through the recuperation of NAD + via the production of other reduced metabolites such as ethyl derivatives ( e.g., 4‐ethylguaiacol and 4‐ethylphenol) from hydroxystyrenes, ammonium from nitrate, or through the use of other external electron acceptors such as acetoin to produce 2,3‐butanediol (Fig.…”