Efeitos inibitórios do hidroximetilfurfural na fermentação alcoólica: avaliação...

• Author(s): Baptista, Cátia Vanessa Rodrigues
• Date: 2013
• Persistent ID: http://hdl.handle.net/10400.5/6697
• Origin: Repositório da UTL
• Subject(s): bioethanol; Saccharomyces carlsbergensis; inhibition; hydroxymethylfurfural; multiparametric flow cytometry
• Document Type: Master Thesis
• Language: Portuguese
• Advisor(s): Silva, Maria Teresa Saraiva Lopes da; Passarinho, Paula Cristina Varela; Martins, Maria Luísa Louro

Description

Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia The growing importance of biofuels, such as bioethanol, in today's society as an alternative to oil, was the driving force of this work. The lack of information about the effect of a major alcoholic fermentation inhibitor present in lignocellulosic hydrolysates towards a yeast of the genus Saccharomyces (the most widely used in bioethanol production) justifies the interest and relevance of this study that aim at assessing the inhibitory effect of hydroxymethylfurfural (HMF) during alcoholic fermentation by the yeast Saccharomyces carlsbergensis. The physiological effects evaluation was performed by multiparametric flow cytometry by detecting changes in the cytoplasmic membrane, lipids composition and oxygen reactive species (ROS) production. It was observed that increasing concentrations of HMF inhibit growth (Ki = 0.188 L/g) and ethanol production although in lesser extent in the latter case (20% reduction with 10 g/L). Only in the presence of 15 g/L it was observed neither growth nor ethanol production. The analysis by multiparameter flow cytometry with the use of specific dyes has proved to be an indispensable tool in this study, showing that increasing concentrations of HMF induce loss of cytoplasmic membrane integrity and polarization, production of ROS and changes in the cellular lipid fraction.