Yeasts associated with the production of distilled alcoholic beverages

Distilled alcoholic beverages are produced firstly by fermenting sugars emanating from cereal starches (in the case of whiskies), sucrose-rich plants (in the case of rums), fructooligosaccharide-rich plants (in the case of tequila) or from fruits (in the case of brandies). Traditionally, such fermentations were conducted in a spontaneous fashion, relying on indigenous microbiota, including wild yeasts. In modern practices, selected strains of Saccharomyces cerevisiae are employed to produce high levels of ethanol together with numerous secondary metabolites (eg. higher alcohols, esters, carbonyls etc.) which greatly influence the final flavour and aroma characteristics of spirits following distillation of the fermented wash. Therefore, distillers, like winemakers, must carefully choose their yeast strain which will be very important in providing the alcohol content and the sensory profiles of spirit beverages. This Chapter discusses yeast and fermentation aspects associated with the production of selected distilled spirits and highlights similarities and differences with the production of wine

Whole cell bioconversion of (+)-valencene to (+)-nootkatone by Yarrowia lipolytica using a three phase partitioning bioreactor

© 2016 Society of Chemical Industry. BACKGROUND: Low permeability of substrates across the cell membrane, cofactor regeneration and product inhibition are some drawbacks of (+)-nootkatone bioconversion. The aim of this work was to evaluate and enhance the bioconversion of (+)-valencene to (+)-nootkatone with Yarrowia lipolytica in a partitioning bioreactor using orange essential oil as the dispersed phase. RESULTS: Preliminary experiments in shake flasks allowed enhancing (+)-nootkatone bioconversion to obtain favorable operating conditions (0.2% w/v of CTAB, 2.0 mmol L-1 of niacin and 11.5 g L-1 of biomass) to produce 420.9 mg L-1. Bioreactor experiments in a two-phase system using 0.2% (w/v) of CTAB, 2.0 mmol L-1 of niacin and 22.5 g L-1 of biomass produced a maximum (+)-nootkatone concentration of 619.8 mg L-1 which was around the product inhibition concentration. Nevertheless, the partitioning three-phase system using orange essential oil overcame product inhibition, obtaining concentrations up to 852.3 mg L-1. CONCLUSIONS: This is the first report of a wild type Y. lipolytica with the enzymatic machinery to carry out this bioconversion. The multiphase partitioning bioreactor concept seems to have good potential for enhancing the productivity of (+)-nootkatone. The bioconversion approach presents an attractive way to produce and recover (+)-nootkatone in situ using a natural (+)-valencene source. © 2015 Society of Chemical Industrystatus: publishe