Marcos Antônio de Morais

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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(More)
Bacteria may compete with yeast for nutrients during bioethanol production process, potentially causing economic losses. This is the first study aiming at the quantification and identification of Lactic Acid Bacteria (LAB) present in the bioethanol industrial processes in different distilleries of Brazil. A total of 489 LAB isolates were obtained from four(More)
AIMS The present work aimed at identifying the metabolic response to acid stress and the mechanisms that lead to cell tolerance and adaptation. METHODS AND RESULTS Two strategies were used: screening deletion mutants for cell growth at neutral and acid pH compared to wild type and measurement by qPCR of the expression of yeast genes involved in different(More)
AIMS The present work focuses on the possibility to use conserved primers that amplify yeast ITS1-5.8S-ITS2 ribosomal DNA locus (rDNA) to detect the presence of non-Saccharomyces cerevisiae yeast in fermentation must of bioethanol fermentation process. METHODS AND RESULTS Total DNA was extracted from pure or mixed yeast cultures containing different cell(More)
The aims of this work were to obtain, by evolutionary engineering, an industrial strain of Saccharomyces cerevisiae tolerant to high concentrations of HMF and to determine the expression levels of genes previously described as responsible for this tolerance. Cells were grown under anaerobic and oxygen limited conditions, in the presence of glucose or(More)
Dekkera bruxellensis has been described as the major contaminant yeast of industrial ethanol production, although little is known about its physiology. The aim of this study was to investigate the growth of this yeast in diverse carbon sources and involved conducting shake-flask and glucose- or sucrose-limited chemostats experiments, and from the chemostat(More)
The yeast Dekkera bruxellensis has been recently regarded as an important microorganism for bioethanol production owing to its ability to convert glucose, sucrose, and cellobiose to ethanol. The aim of this work was to validate a new set of reference genes for gene expression analysis by quantitative real-time PCR in D. bruxellensis and compare the(More)
UNLABELLED We investigated the presence of the yeast Dekkera bruxellensis in samples collected at three points surrounding the industrial alcoholic fermentation plants of two distilleries where there are often cases of contamination caused by this yeast: this involved sugar cane wash water, feeding sugar cane juice and vinasse from the treatment pond. Total(More)
This study provides the first attempt to analyse the influence of ammonium supplements on sugar-cane juice fermentation and the flavour profile in a cachaça industrial process. The objective was to find a relationship between higher alcohol/ester content and the transcription levels of the main genes involved in production of these compounds under cachaça(More)
The distilled spirit made from sugar cane juice, also known as cachaça, is a traditional Brazilian beverage that in recent years has increased its market share among international distilled beverages. Several volatile compounds produced by yeast cells during the fermentation process are responsible for the unique taste and aroma of this drink. The yeast(More)