Torulaspora delbrueckii was one of the first commercial non-Saccharomyces yeast to be released (Jolly et al., 2014). This species has been previously suggested for the vinification of low sugar and acidity musts, and it has been used for the production of red and rosé wines in Italy and for Sauvignon Blanc in South Africa (González-Royo et al., 2015). T. delbrueckii is characterized by high purity fermentation, low production of glycerol, acetaldehyde, acetic acid, and ethyl acetate (Loira et al., 2015). When used in sequential or mixed fermentations with S. cerevisiae, it can contribute to correct certain defects such as the volatile acidity (Loira et al., 2015). In Semillon wine, a mixed T. delbrueckii/S. cerevisiae culture at a 20:1 ratio produced 53% less in volatile acidity and 60% less acetaldehyde than a pure culture of S. cerevisiae (Bely et al., 2008). Some authors showed that the strong β-glucosidase activity of this species enhanced wine aroma by modulating the levels of nor-isoprenoids, terpenols, and lactones by hydrolysing their respective precursors (Renault et al., 2015). Maturano et al. (2012) confirmed the high production of extracellular enzymes of enological relevance by this species. Amarone wines produced by co-inoculation/sequential inoculation with T. delbrueckii and S. cerevisiae were judged to have increased aroma intensity, including ‘ripe red fruit’ aroma, increased sweetness and astringency and decreased intensity for vegetal attributes (Azzolini et al., 2012). Gewurztraminer wines produced by sequential inoculation showed increased concentration of terpenes α-terpineol and linalool (Cus and Jenko, 2013). T. delbrueckii/S. cerevisiae multi starters have been proposed to modulate wine flavor in Sauvignon Blanc and Merlot (Renault et al., 2015), as well as Shiraz wines (Loira et al., 2015).

The growth of T. delbrueckii is often negatively affected by the presence of S. cerevisiae. Indirect interaction, i.e., interaction between strains via components of the medium have been demonstrated. Substrate competition or amensalism (production by S. cerevisiae of metabolites that inhibit T. delbrueckii growth) are examples of the indirect interactions already suggested (Taillandier et al., 2014).

Recently, new killer toxins from T. delbrueckii with potential biocontrol activity of Brettanomyces bruxellensis, Pichiaguilliermondii, P. manshurica and P. membranifaciens wine spoilage were identified and characterized (Comitini et al., 2017).

Lachancea thermotolerans has been investigated for its ability to enhance wine acidity and improve the overall quality (Whitener et al., 2016). L. thermotolerans produces high concentration of L-lactic acid from glucose and fructose as well as low levels of volatile acidity and undesirable flavor compounds (Erten and Tanguler, 2010). This attribute could be of concern to address the problems of increased alcohol content and a reduction in the total acidity of wines associated with global climate change and variations in viticulture and wine-making practices (Balikci et al., 2016). L. thermotolerans was used as starter culture in Airén wine (increase of lactic acid of 3.18 g/L and pH reduction of 0.22) (Benito et al., 2016a), Emir wines (the use of L. thermotolerans in mixed and sequential cultures led to an increase in final total acidity of 5.40–6.28 g/L) (Balikci et al., 2016), Riesling wine (peach/apricot character) (Benito S. et al., 2015), Sangiovese and Cabernet-Sauvignon (spicy attributes) (Gobbi et al., 2013).

Metschnikowia pulcherrima is commonly associated with grapes and wine (Whitener, 2016). It is a high producer of β-glucosidase and its presence in mixed cultures can decrease the volatile acidity and increase the production of medium-chain fatty acids, higher alcohol, esters, terpenols and glycerol (González-Royo et al., 2015). Wines of the grape varieties Chardonnay and Shiraz obtained by sequential fermentation with Caesalpinia pulcherrima and S showed ca. 1% v/v lower ethanol concentration (Varela et al., 2016). In addition, M. pulcherrima has been reported to increase: (1) the levels of methyl butyl-, methyl propyl-, and phenethyl esters production in Sauvignon Blanc (Whitener et al., 2016); (2) the ‘overall impression,’ ‘citrus/grape fruit’ and ‘pear’ attributes of Riesling (Benito S. et al., 2015); (3) foam persistence and ‘smoky’ and ‘flowery’ attributes of Macabeo wine (González-Royo et al., 2015). It has also been reported that M. pulcherrima might have an antagonistic effect toward several yeast. cerevisiaes including S. cerevisiae which leads to delays in fermentation. This phenomenon was the result of a pulcherrimin pigment (Jolly et al., 2014).

The genus Candida is large and extremely diverse with over 50 different identified species several of which have been associated with winemaking (Whitener, 2016). Among the non-Saccharomyces wine yeasts involved in grape juice fermentation, C. stellata has been frequently isolated during the course of must fermentations in different countries (fermentation of botrytized wines and other wines produced by overripe grapes, in cooked musts, and in traditional balsamic vinegars) (Tofalo et al., 2012). Ciani and Maccarelli (1998) suggested that it might be used as a starter culture to increase glycerol levels in Trebbiano Toscano wine, where it 11.76 g/L of glycerol, which is higher than the sensory threshold level for glycerol sweetness, i.e., 5.2 g/L (Jolly et al., 2006). Similarly, wines of the grape variety Syrah obtained by mixed and sequential fermentation with C. cantarellii and S. cerevisiae showed 44.3 to 52.8% glycerol content higher than the control wines (Toro and Vazquez, 2002). C. sake increased concentrations of terpenes and higher alcohols in Pedro Gimenez wines (Maturano et al., 2015).

C. zemplinina (synonym Starmerella bacillaris; Duarte et al., 2012) is a non-Saccharomyces yeast, isolated for the first time in Napa Valley (California, United States) in 2002, under the name EJ1 (Mills et al., 2002). This yeast differs from the other common non-Saccharomyces yeasts, since it can survive and resist until the end of the AF due to its ability to tolerate high concentrations of ethanol (Englezos et al., 2016a).

Candida zemplinina showed some interesting characteristics, such as: (1) high glycerol production (Tofalo et al., 2012; Zara et al., 2014; Englezos et al., 2016b); (2) reduced ethanol yield (Bely et al., 2013; Englezos et al., 2016b); (3) increase of aroma complexity (Tofalo et al., 2016; Whitener et al., 2016); (4) ability to metabolize malic acid (Tofalo et al., 2012); (5) reduction of the acetic acid production in combination with S. cerevisiae (Rantsiou et al., 2012). These applications support the use of C. zemplinina, which could be a good choice to achieve various desired results, mainly due to its fructophilic character and the poor ethanol yield from sugar (Masneuf-Pomarede et al., 2015; Englezos et al., 2016a).

Recently, Mehlomakulu et al. (2014) found two novel killer toxins, CpKT1 and CpKT2, from the wine isolated strains of C. pyralidae, able to control the development of spoilage yeast B. bruxellensis. In addition, these killer toxins inhibited neither the Saccharomyces cerevisiae nor the LAB strains tested.

Pichia fermentans was investigated by Clemente-Jimenez et al. (2005) in lab-scale vinifications of Macabeo wine. Sequential fermentations with P. fermentans and S. cerevisiae produced wines with increased concentrations of acetaldehyde, ethyl acetate, 1-propanol, n-butanol, 1-hexanol, ethyl caprilate, 2,3-butanediol and glycerol.

Sequential inoculum of Riesling must with P. kluyveri and S. cerevisiae increased the ‘overall impression’ and ‘peach/apricot’ character (Benito S. et al., 2015). Co-fermentation of Sauvignon Blanc grape juice with P. kluyveri has been reported to lead to higher levels of 3-mercaptohexyl acetate (Anfang et al., 2009); however, it has also been reported to produce many off odor compounds (Whitener et al., 2016).

Malic acid is sometimes detrimental to the quality of wines when present at high concentrations in some varieties. Several grape varieties contain considerable amounts of malic acid and grapes grown in the cooler regions contain higher amounts of malic acid than those grown in the warmer regions. Excessive amounts of malic acid (15–16 mg/ml) were detected in grapes grown during exceptionally cold summer in cool regions (Kim et al., 2008). In this respect, co-inoculation of P. kudriavzevii enhance the catalysis of malic acid in grape juice fermentation (Kim et al., 2008).

It is reported that P. membranifaciens increased esters production in Muscat wine (Viana et al., 2008).

Schizosaccharomyces pombe was initially considered as a spoilage yeast because of the production of undesirable metabolites with a negative sensory impact; on the other hand, it could be successfully used at an industrial level in cane sugar fermentation during rum making, palm wine production and cocoa fermentation (Mylona et al., 2016). However, Schizosaccharomyces pombe species is highly appreciated in colder regions because of its ability to completely transform the malic acid of the must into ethanol, thanks to its particular metabolism of maloalcoholic fermentation (Loira et al., 2015). In this respect, S. pombe perform effective malic acid deacidification and significantly reduces the levels of biogenic amines and ethyl carbamate precursors without the need for any secondary bacterial MLF (Benito et al., 2014, 2016b). Mylona et al. (2016) confirmed the ability of yeast to produce safe wines.

One new application exploits Schizosaccharomyces ability to increase the formation of vitisins and vinylphenolic pyranoanthocyanin (Loira et al., 2015). In addition, the rapid autolytic release of cell wall polysaccharides after death could reduce the time required to complete aging over lees (Benito et al., 2014).

The apiculate yeast Hanseniaspora uvarum is the non-Saccharomyces found at highest levels in grape must, in fact it is among the relevant contributors to wine quality (Jolly et al., 2014). In single fermentation, H. uvarum produced low volatile acidity and high levels of glycerol (Tofalo et al., 2016). H. uvarum has also been used in mixed fermentations with S. cerevisiae for wine production. Tristezza et al. (2016) assessed the oenological potential of H. uvarum in co-inoculation and in a sequential inoculation with S. cerevisiae for industrial wine production. The mixed starter was able to successfully dominate the different stages of the fermentation process and the H. uvarum strain ITEM8795 contributed to increase the wine organoleptic quality and reduce the volatile acidity. In Solaris wine, mixed fermentations produced higher levels of glycerol, heptyl acetate, and 2-phenylethyl acetate (Liu et al., 2016).

Hanseniaspora vineae has been demonstrated to increase fruity aromas and produce high amounts of acetate esters, such as 2-phenylethyl acetate and ethyl acetate, in wines produced by a sequential fermentation with S. cerevisiae (Lleixà et al., 2016). Co-fermentation of Bobal grape must with H. vineae and S. cerevisiae produced wines that not only showed an increased concentration of 2-phenylethyl acetate (approximately three–ninefold higher) but also exhibited higher ‘fruity’ sensory scores than wines produced with S. cerevisiae pure culture (Viana et al., 2009). Chardonnay wines produced with H. vineae and S. cerevisiae have shown increased aroma and flavor diversity and reduced biogenic amines content (Medina et al., 2013).

Hanseniaspora guilliermondii can contribute to the overall quality of wines. In single-culture this yeast produced high amounts of 2-phenylethyl acetate (Viana et al., 2008). Tinta Roriz grape must inoculated with H. guilliermondii led to the production of wine with higher concentrations of 1-propanol, 2-phenylethyl acetate and 3-(methylthio)propionic acid, and lower amounts of ethyl hexanoate, pentanoic acid, free fatty acids, 2-methyltetrahydrothiophen-3-one and acetic acid-3-(methylthio)propyl ester (Moreira et al., 2011).

The genus Zygosaccharomyces is known, together with Brettanomyces species (Capozzi et al., 2016a), for its ability to spoil wine, namely sweet and sparkling wines (Whitener et al., 2016). Zygosaccharomyces bailii and Zygosaccharomyces rouxii are often the source of spoilage in acidic and shelf-stable foods as well as sweet wines due to their ability to tolerate high acid, salt and sugar conditions (Whitener, 2016). However, selected strains of Zygosaccharomyces spp. might be useful (Garavaglia et al., 2015), because they can yield high levels of ethyl esters in Chardonnay wine (Garavaglia et al., 2015). Ethyl esters are highly interesting because they have a pleasant fruity and floral aromatic note, and are responsible for beer and wine aroma (Garavaglia et al., 2015).

Zygosaccharomyces bailii is fructophilic, and metabolizes fructose more easily than glucose (Garavaglia et al., 2015). This triat could be beneficial in grape musts from over-ripened grapes (Jolly et al., 2006). Zuehlke et al. (2015) used inoculation with Z. bailii to remove residual sugar from Cabernet Sauvignon and Syrah sluggish fermentations.

Zygosaccharomyces kombuchaensis is a newly discovered yeast. It can contribute to increase flavor intensity’ and several ‘fruity’ attributes in Ribolla Gialla (Dashko et al., 2015), as well as benzaldehyde in Sauvignon Blanc and Syrah (Whitener et al., 2015) wines.

Debaryomyces may contribute to the maturation, aroma, and flavor of foods, such as cheese and meat products, but it also might spoil fermented food products (Wrent et al., 2014). In winemaking, two species are of interest: Debaryomyces pseudopolymorphus and Debaryomyces vanriji. Co-fermentation of Chardonnay grape juice with D. pseudopolymorphus and S. cerevisiae resulted in an increased concentration of the terpenols (citronellol, nerol, and geraniol) (Cordero Otero et al., 2003). Sequential fermentation of Muscat of Frontignan grape juice with D. vanriji and S. cerevisiae produced wines with increased concentration of geraniol (Garcia et al., 2002). Sequential fermentation of Pedro Gimenez must with D. vanriji and S. cerevisiae increased the concentrations of esters and fatty acids (Maturano et al., 2015).

The Kazachstania genus as a whole is fairly new; it was first mentioned in literature in 2003. Kazachstania aerobia was first identified in 2004 from corn silage while Kazachstania gamospora was discovered as a species in 2007. Being relatively new yeasts and closely related to S. cerevisiae, the genus is worthy of investigation (Whitener, 2016).

Dashko et al. (2015) used K. gamospora in Ribolla Gialla fermentation, resulting in increased acetate and ethyl ester amounts. In Sauvignon blanc and Syrah musts, this yeast caused a 200-fold increase of phenethyl propionate (Whitener et al., 2015). Sauvignon Blanc wines produced with K. aerobia and S. cerevisiae have shown increased ethyl acetate production (Whitener et al., 2016).

Wickerhamomyces anomalus is a constituent of the normal grape flora in the early phases of fermentation. It could spoil wine by excessive production of acetic acid and ethyl acetate, but also contributes to wine aroma by the production of volatile compounds. This species has gained considerable biotechnological interest due to its tolerance toward environmental stress factors (e.g., low pH, high osmolarity), metabolic versatility and production of exoenzymes (Sabel et al., 2014). Mazuela wines produced by sequential inoculation of W. anomalus and S. cerevisiae showed increased concentration of acetate- and ethyl- esters, along with a significant and panel preference (Cañas et al., 2014).

Williopsis saturnus has been reported to increase the levels of main terpenols (linalool, citronellol, and α-terpineol), produce some terpenoid esters (citronellyl and neryl acetate) and retain the concentration of cis-rose oxide in mango wine with ethanol levels of 2–4% (v/v) (Chen et al., 2015). This specie is not generally found from the natural environment of surfaces of grapes and winery equipments: however, it might potentially enhance the fruity flavor in wines obtained from neutral cultivar characteristics (Erten and Tanguler, 2010).

Emir wines produced by co-inoculation with W. saturnus and S. cerevisiae showed higher concentrations of acetic acid, ethyl acetate and isoamyl acetate (Erten and Tanguler, 2010).

Zygotorulaspora florentina was used in mixed fermentations at different inoculum ratio with S. cerevisiae, and caused an increase of the production of polysaccharides and a modulation of the final concentrations of the various volatile compounds (Domizio et al., 2011). Recently, Sangiovese wines produced by co-inoculation with Zygotorulaspora florentina and S. cerevisiae showed an enhancement of polysaccharides and 2-phenylethanol content, a reduction of volatile acidity, and high concentration of glycerol and esters (Lencioni et al., 2016).