Advances in the Study of Candida stellata

Abstract

Candida stellata is an imperfect yeast of the genus Candida that belongs to the order Saccharomycetales, while phylum Ascomycota. C. stellata was isolated originally from a must overripe in Germany but is widespread in natural and artificial habitats. C. stellata is a yeast with a taxonomic history characterized by numerous changes; it is either a heterogeneous species or easily confused with other yeast species that colonize the same substrates. The strain DBVPG 3827, frequently used to investigate the oenological properties of C. stellata, was recently renamed as Starmerella bombicola, which can be easily confused with C. zemplinina or related species like C. lactis-condensi. Strains of C. stellata have been used in the processing of foods and feeds for thousands of years. This species, which is commonly isolated from grape must, has been found to be competitive and persistent in fermentation in both white and red wine in various wine regions of the world and tolerates a concentration of at least 9% (v/v) ethanol. Although these yeasts can produce spoilage, several studies have been conducted to characterize C. stellata for their ability to produce desirable metabolites for wine flavor, such as acetate esters, or for the presence of enzymatic activities that enhance wine aroma, such as β-glucosidase. This microorganism could also possess many interesting technological properties that could be applied in food processing. Exo and endoglucosidases and polygalactosidase of C. stellata are important in the degradation of β-glucans produced by Botrytis cinerea. In traditional balsamic vinegar production, C. stellata shapes the aromatic profile of traditional vinegar, producing ethanol from fructose and high concentrations of glycerol, succinic acid, ethyl acetate, and acetoin. Chemical characterization of exocellular polysaccharides produced by non-Saccharomyces yeasts revealed them to essentially be mannoproteins with high mannose contents, ranging from 73–74% for Starmerella bombicola. Numerous studies have clearly proven that these macromolecules make multiple positive contributions to wine quality. Recent studies on C. stellata strains in wines made by co-fermentation with Saccharomyces cerevisiae have found that the aroma attributes of the individual strains were apparent when the inoculation protocol permitted the growth and activity of both yeasts. The exploitation of the diversity of biochemical and sensory properties of non-Saccharomyces yeast could be of interest for obtaining new products.

Effect of Sequential Inoculation with Non-Saccharomyces and Saccharomyces Yeasts on Riesling Wine Chemical Composition

“…Higher production of this compound from sequential inoculation with non-Saccharomyces and Saccharomyces spp. has already been shown in the literature [28,[68][69][70][71].…”

The Influence of Non-Saccharomyces Species on Wine Fermentation Quality Parameters

“…Glycerol can increase the softness and body of wine. S. cerevisiae synthesizes glycerol from glucose through glycolysis, where dihydroxyacetone phosphate is reduced to glycerol-3-phosphate and later oxidized to glycerol [58,59]. One of the first reported advantages of using non-Saccharomyces species was the increased glycerol concentration in wine and its influence on wine quality [9,48,60].…”

“…From a biochemical point of view, species other than those of the Saccharomyces genus possess less developed alcohol dehydrogenase enzymatic activity, but more developed glycerol-3-phosphate dehydrogenase enzymatic activity. This metabolism deviates to produce higher final concentrations of glycerol during alcoholic fermentation [59].…”

“…Starmerella bacillaris, formerly Candida stellata [59], produces the highest glycerol concentration (up to 14 g/L) of the non-Saccharomyces yeasts during alcoholic fermentation [9,117,118], while most S. cerevisiae strains have been shown to produce final concentrations that vary from 5 to 8 g/L. These concentrations can improve the mouthfeel sensation and flavor of wine [9].…”

Enological Repercussions of Non-Saccharomyces Species in Wine Biotechnology

“…Moreover, they tend to have an interesting effect on structure by producing full bodied wines [14]. Some of these species, as well as Metschnikowia pulcherrima and C. stellata, are able to release extracellular hydrolytic enzymes, such as β-glucosidases or c-lyases, that help improve the varietal aroma by releasing free terpenes or thiols [15,16]. A wide pool of enzymatic activities can also be found in saprophytic Aureobasidium pullulans, several of these enzymes can be purified with useful applications in enology [17].…”