Yeast population used in industrial production of fuel-ethanol may vary according to the plant process condition and to the environmental stresses imposed to yeast cells. Therefore, yeast strains isolated from a particular industrial process may be adapted to such conditions and should be used as starter strain instead of less adapted commercial strains. This work reports the use of PCR-fingerprinting method based on microsatellite primer (GTG)5 to characterize the yeast population dynamics along the fermentation period in six distilleries. The results show that indigenous fermenting strains present in the crude substrate can be more adapted to the industrial process than commercial strains. We also identified new strains that dominate the yeast population and were more present either in molasses or sugar cane fermenting distilleries. Those strains were proposed to be used as starters in those industrial processes. This is the first report on the use of molecular markers to discriminate Saccharomyces cerevisiae strains from fuel-ethanol producing process.

Aims:  To identify and characterize the main contaminant yeast species detected in fuel‐ethanol production plants in Northeast region of Brazil by using molecular methods. Methods and Results:  Total DNA from yeast colonies isolated from the fermentation must of industrial alcohol plants was submitted to PCR fingerprinting, D1/D2 28S rDNA sequencing and species‐specific PCR analysis. The most frequent non‐Saccharomyces cerevisiae isolates were identified as belonging to the species Dekkera bruxellensis, and several genetic strains could be discriminated among the isolates. The yeast population dynamics was followed on a daily basis during a whole crop harvesting period in a particular industry, showing the potential of D. bruxellensis to grow faster than S. cerevisiae in industrial conditions, causing recurrent and severe contamination episodes. Conclusions:  The results showed that D. bruxellensis is one of the most important contaminant yeasts in distilleries producing fuel‐ethanol from crude sugar cane juice, specially in continuous fermentation systems. Significance and Impact of the Study:  Severe contamination of the industrial fermentation process by Dekkera yeasts has a negative impact on ethanol yield and productivity. Therefore, early detection of D. bruxellensis in industrial musts may avoid operational problems in alcohol‐producing plants.

Yeast populations used in industrial production of fuel-ethanol may vary according to the plant process conditions and to the environmental stresses imposed on yeast cells. Therefore, yeast strains isolated from a particular industrial process may be adapted to such conditions and should be used as the starter strain instead of less adapted commercial strains. This work reports the use of a PCR-fingerprinting method based on microsatellite primer (GTG) 5 to characterize the yeast population dynamics during the fermentation period in six distilleries. The results show that indigenous fermenting strains present in the crude substrate can be more adapted to the industrial process than commercial strains. We also identified new strains that dominated the yeast population and were more commonly present either in molasses or sugar cane fermenting distilleries. Those strains were proposed to be used as starters in those industrial processes. This is the first report on the use of molecular markers to discriminate Saccharomyces cerevisiae strains from the fuel-ethanol producing process.

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Due to an unfortunate turn of events numeorus corrections were not taken into account therefore this article is reprinted in its entirety and should be treated as definitive by the reader.