Bioethanol is a biofuel produced mainly from the fermentation of carbohydrates derived from agricultural feedstocks by the yeast Saccharomyces cerevisiae. One of the most widely adopted strains is PE-2, a heterothallic diploid naturally adapted to the sugar cane fermentation process used in Brazil. Here we report the molecular genetic analysis of a PE-2 derived diploid (JAY270), and the complete genome sequence of a haploid derivative (JAY291). The JAY270 genome is highly heterozygous (;2 SNPs/kb) and has several structural polymorphisms between homologous chromosomes. These chromosomal rearrangements are confined to the peripheral regions of the chromosomes, with breakpoints within repetitive DNA sequences. Despite its complex karyotype, this diploid, when sporulated, had a high frequency of viable spores. Hybrid diploids formed by outcrossing with the laboratory strain S288c also displayed good spore viability. Thus, the rearrangements that exist near the ends of chromosomes do not impair meiosis, as they do not span regions that contain essential genes. This observation is consistent with a model in which the peripheral regions of chromosomes represent plastic domains of the genome that are free to recombine ectopically and experiment with alternative structures. We also explored features of the JAY270 and JAY291 genomes that help explain their high adaptation to industrial environments, exhibiting desirable phenotypes such as high ethanol and cell mass production and high temperature and oxidative stress tolerance. The genomic manipulation of such strains could enable the creation of a new generation of industrial organisms, ideally suited for use as delivery vehicles for future bioenergy technologies.

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The profile of volatile compounds and aging markers in sugar cane spirits aged for 36 months in casks made of 10 types of wood were studied. The ethanol content, volatile acidity, aldehydes, esters, higher alcohols, and methanol were determined. In addition, gallic, vanilic and syringic acids, siringaldehyde, coniferaldehyde, sinapaldehyde, vanillin, 5-hydroxymethylfurfural and furfural were identified and quantified. The profile of volatile compounds characterised aging in each type of wood. The beverage aged in oak cask achieved the highest contents of maturation-related congeners. The Brazilian woods, similar to oak, were jequitibá rosa and cerejeira, which presented the highest contents of some maturation-related compounds, such as vanillin, vanilic acid, syringaldehyde and sinapaldehyde. Although oak wood conferred more chemical complexity to the beverage, Brazilian woods, singly or complementarily, present potential for spirit characterisation and for improving the quality of sugar cane spirits.

A produção de aguardente de cana e de cachaça no Brasil atinge 1,5 bilhões de litros anuais, representando 87% da produção nacional de bebidas alcoólicas destiladas. O consumo médio per capita do brasileiro é de 9,4 L/ano. O setor emprega cerca de 450 mil trabalhadores e movimenta internamente US$ 1,0 bilhão por ano (BOZA; OETERRER, 1999).A aguardente de cana possui uma graduação alcoólica de 38 a 54% em volume, a 20 °C. É obtida de destilado alcoólico simples de cana-de-açúcar (Saccharum officinarum L.) ou pela destilação do mosto fermentado de cana-de-açúcar, podendo ser adicionada de açúcares em até 6 g.L -1 . A aguardente de cana pode conter até 30 g.L -1 de açúcares, devendo, porém, ter sua denominação acrescida da palavra "adoçada" (BRASIL, 2005).A aguardente de cana envelhecida refere-se à bebida que contiver, no mínimo, 50% de aguardente de cana envelhecida em recipiente de madeira apropriado, com capacidade máxima de 700 L, por um período não inferior a um ano. A aguardente de cana Premium é o destilado 100% envelhecido em recipiente de madeira apropriado, com capacidade máxima de 700 L, por um período mínimo de um ano. Já aguardente de cana extra premium é aquela 100% envelhecida em recipiente de madeira apropriado, com capacidade máxima de 700 L, por um período mínimo de três anos (BRASIL, 2005).Além dos seus componentes principais, água e etanol, a aguardente apresenta, ainda que em baixas concentrações, componentes secundários formados principalmente durante a fermentação alcoólica e selecionados pelo processo de destilação e pela etapa de maturação do destilado. Tais componentes pertencem às classes funcionais dos ácidos, ésteres, aldeídos e álcoois, e em proporções menores formam-se também cetonas, compostos fenólicos, aminas e mercaptanas (MAIA, 1994).O envelhecimento da aguardente em tonéis de madeira promove diminuição significativa do sabor alcoólico e da agressividade da bebida, com simultâneo aumento da doçura e do sabor de madeira, proporcionando uma efetiva melhora sensorial do produto (CARDELLO; FARIA, 1999). AbstractThe chemical composition of aguardente -Brazilian sugar cane alcoholic drink -under aging during in 20 L oak casks was evaluated for 390 days. Aging sugar cane aguardente in wood casks improves the sensorial quality of the distillate. The concentrations of ethanol, volatile acidity, esters, aldehydes, furfural, higher alcohols (n-propylic, isobutylic and isoamylics), methanol, copper, dry extract, tannins, and color of the aged sugar cane aguardente were analysed at 0, 76, 147, 228, 314, and 390 days of storage. After 390 days of aging the sugar cane aguardente presented higher concentrations of volatile acidity, esters, aldehydes, furfural, higher alcohols, congeners, dry extract, and tannin. Its color became golden. The concentrations of ethanol and methanol did not change and the copper content decreased slightly. The aging of the sugar cane aguardente in oak casks for 390 days changed the chemical composition of the distillate. However, the aged sugar cane aguardente met ...