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Starmerella bombicola influences the metabolism of Saccharomyces cerevisiae at pyruvate decarboxylase and alcohol dehydrogenase level during mixed wine fermentation.

Milanovic V, Ciani M, Oro L, Comitini F - Microb. Cell Fact. (2012)

Bottom Line: In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata) was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine.The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution.Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation causing variation in the gene expression and enzymatic activity of alcohol deydrogenase and pyruvate decarboxilase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dipartimento Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, 60121 Ancona, Italy.

ABSTRACT

Background: The use of a multistarter fermentation process with Saccharomyces cerevisiae and non-Saccharomyces wine yeasts has been proposed to simulate natural must fermentation and to confer greater complexity and specificity to wine. In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata) was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine. In order to investigate yeast metabolic interaction during controlled mixed fermentation and to evaluate the influence of S. bombicola on S. cerevisiae, the gene expression and enzymatic activity of two key enzymes of the alcoholic fermentation pathway such as pyruvate decarboxylase (Pdc1) and alcohol dehydrogenase (Adh1) were studied.

Results: The presence of S. bombicola immobilized cells in a mixed fermentation trial confirmed an increase in fermentation rate, a combined consumption of glucose and fructose, an increase in glycerol and a reduction in the production of ethanol as well as a modification in the fermentation of by products. The alcoholic fermentation of S. cerevisiae was also influenced by S. bombicola immobilized cells. Indeed, Pdc1 activity in mixed fermentation was lower than that exhibited in pure culture while Adh1 activity showed an opposite behavior. The expression of both PDC1 and ADH1 genes was highly induced at the initial phase of fermentation. The expression level of PDC1 at the end of fermentation was much higher in pure culture while ADH1 level was similar in both pure and mixed fermentations.

Conclusion: In mixed fermentation, S. bombicola immobilized cells greatly affected the fermentation behavior of S. cerevisiae and the analytical composition of wine. The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution. Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation causing variation in the gene expression and enzymatic activity of alcohol deydrogenase and pyruvate decarboxilase.

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Fermentation by-products. By products produced during wine fermentation in mixed culture (▲ dashed lines), in S. cerevisiae pure culture (♦continuous lines) and in immobilized S. bombicola pure culture (○ continuous lines). Production of (a) acetaldehyde, (b) ethyl acetate, (c) propanol, (d) acetoin and (e) amylic alcohols. The data represented are the mean of the three technical repetitions for two independent biological samples ± SD. Values displaying asterisk are significantly different according to the Duncan test (0.05%).
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Figure 4: Fermentation by-products. By products produced during wine fermentation in mixed culture (▲ dashed lines), in S. cerevisiae pure culture (♦continuous lines) and in immobilized S. bombicola pure culture (○ continuous lines). Production of (a) acetaldehyde, (b) ethyl acetate, (c) propanol, (d) acetoin and (e) amylic alcohols. The data represented are the mean of the three technical repetitions for two independent biological samples ± SD. Values displaying asterisk are significantly different according to the Duncan test (0.05%).

Mentions: As expected, pure culture of S. bombicola produced high quantity (11 g l-1) of glycerol, confirming previous results [24,25] (Figure 3a). Mixed culture produced glycerol faster and higher than S. cerevisiae pure culture (7.0 g l-1, 4.4 g l-1 respectively) indicating that immobilized S. bombicola cells positively affect the final amounts of glycerol. Evolution of ethanol showed different kinetics in mixed and pure fermentations (Figure 3b). Immobilized cells of S. bombicola in pure culture produced the smallest amount of ethanol (36.5 g l-1). During the first 72 h of fermentation, mixed culture produced ethanol faster and in higher concentration than that exhibited by S. cerevisiae pure culture, remaining stable until the end of fermentation (58.9 g l-1). Pure culture of S. cerevisiae showed a lower trend of ethanol production, but at the end of fermentation, its concentration was higher than that exhibited by mixed culture (83.6 g l-1). This is a very interesting behavior since the reduction of final ethanol concentration in winemaking is one of the most investigated topics [26-28]. The principal by-products in mixed fermentation were produced mainly due to the metabolic activity of S. cerevisiae strain (Figure 4). Actually, the trend of these compounds is closely related to that showed by S. cerevisiae pure culture, while immobilized S. bombicola cells showed a significantly lower production of acetaldehyde, ethyl acetate and n-propanol (Figures 4a, b and 4c). Mixed fermentation exhibited a significantly higher amount of n-propanol and ethyl acetate (Figures 4b and 4c) even if the final concentration turned out to be far from the sensory threshold level. As regards acetic acid production, we noted that there was a lower level of acetic acid in the mixed culture than that in the pure culture of S. cerevisiae (0.82 g l-1, 0.94 g l-1 respectively), while the pure culture of S. bombicola immobilized cells produced only a small amount of acetic acid (0.23 g l-1).


Starmerella bombicola influences the metabolism of Saccharomyces cerevisiae at pyruvate decarboxylase and alcohol dehydrogenase level during mixed wine fermentation.

Milanovic V, Ciani M, Oro L, Comitini F - Microb. Cell Fact. (2012)

Fermentation by-products. By products produced during wine fermentation in mixed culture (▲ dashed lines), in S. cerevisiae pure culture (♦continuous lines) and in immobilized S. bombicola pure culture (○ continuous lines). Production of (a) acetaldehyde, (b) ethyl acetate, (c) propanol, (d) acetoin and (e) amylic alcohols. The data represented are the mean of the three technical repetitions for two independent biological samples ± SD. Values displaying asterisk are significantly different according to the Duncan test (0.05%).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3295710&req=5

Figure 4: Fermentation by-products. By products produced during wine fermentation in mixed culture (▲ dashed lines), in S. cerevisiae pure culture (♦continuous lines) and in immobilized S. bombicola pure culture (○ continuous lines). Production of (a) acetaldehyde, (b) ethyl acetate, (c) propanol, (d) acetoin and (e) amylic alcohols. The data represented are the mean of the three technical repetitions for two independent biological samples ± SD. Values displaying asterisk are significantly different according to the Duncan test (0.05%).
Mentions: As expected, pure culture of S. bombicola produced high quantity (11 g l-1) of glycerol, confirming previous results [24,25] (Figure 3a). Mixed culture produced glycerol faster and higher than S. cerevisiae pure culture (7.0 g l-1, 4.4 g l-1 respectively) indicating that immobilized S. bombicola cells positively affect the final amounts of glycerol. Evolution of ethanol showed different kinetics in mixed and pure fermentations (Figure 3b). Immobilized cells of S. bombicola in pure culture produced the smallest amount of ethanol (36.5 g l-1). During the first 72 h of fermentation, mixed culture produced ethanol faster and in higher concentration than that exhibited by S. cerevisiae pure culture, remaining stable until the end of fermentation (58.9 g l-1). Pure culture of S. cerevisiae showed a lower trend of ethanol production, but at the end of fermentation, its concentration was higher than that exhibited by mixed culture (83.6 g l-1). This is a very interesting behavior since the reduction of final ethanol concentration in winemaking is one of the most investigated topics [26-28]. The principal by-products in mixed fermentation were produced mainly due to the metabolic activity of S. cerevisiae strain (Figure 4). Actually, the trend of these compounds is closely related to that showed by S. cerevisiae pure culture, while immobilized S. bombicola cells showed a significantly lower production of acetaldehyde, ethyl acetate and n-propanol (Figures 4a, b and 4c). Mixed fermentation exhibited a significantly higher amount of n-propanol and ethyl acetate (Figures 4b and 4c) even if the final concentration turned out to be far from the sensory threshold level. As regards acetic acid production, we noted that there was a lower level of acetic acid in the mixed culture than that in the pure culture of S. cerevisiae (0.82 g l-1, 0.94 g l-1 respectively), while the pure culture of S. bombicola immobilized cells produced only a small amount of acetic acid (0.23 g l-1).

Bottom Line: In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata) was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine.The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution.Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation causing variation in the gene expression and enzymatic activity of alcohol deydrogenase and pyruvate decarboxilase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dipartimento Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, 60121 Ancona, Italy.

ABSTRACT

Background: The use of a multistarter fermentation process with Saccharomyces cerevisiae and non-Saccharomyces wine yeasts has been proposed to simulate natural must fermentation and to confer greater complexity and specificity to wine. In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata) was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine. In order to investigate yeast metabolic interaction during controlled mixed fermentation and to evaluate the influence of S. bombicola on S. cerevisiae, the gene expression and enzymatic activity of two key enzymes of the alcoholic fermentation pathway such as pyruvate decarboxylase (Pdc1) and alcohol dehydrogenase (Adh1) were studied.

Results: The presence of S. bombicola immobilized cells in a mixed fermentation trial confirmed an increase in fermentation rate, a combined consumption of glucose and fructose, an increase in glycerol and a reduction in the production of ethanol as well as a modification in the fermentation of by products. The alcoholic fermentation of S. cerevisiae was also influenced by S. bombicola immobilized cells. Indeed, Pdc1 activity in mixed fermentation was lower than that exhibited in pure culture while Adh1 activity showed an opposite behavior. The expression of both PDC1 and ADH1 genes was highly induced at the initial phase of fermentation. The expression level of PDC1 at the end of fermentation was much higher in pure culture while ADH1 level was similar in both pure and mixed fermentations.

Conclusion: In mixed fermentation, S. bombicola immobilized cells greatly affected the fermentation behavior of S. cerevisiae and the analytical composition of wine. The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution. Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation causing variation in the gene expression and enzymatic activity of alcohol deydrogenase and pyruvate decarboxilase.

Show MeSH
Related in: MedlinePlus