Utilização da citometria de fluxo multiparamétrica na monitorização da resposta...

• Author(s): Freitas, Cláudia Sofia da Silva
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.5/4192
• Origin: Repositório da UTL
• Subject(s): bioetanol; Saccharomyces carlsbergensis; acetic acid; inhibition; multiparameter flow citometry
• Document Type: Master Thesis
• Language: Portuguese
• Advisor(s): Silva, Maria Teresa Saraiva Lopes da; Brito, Maria Luísa Lopes de Castro; Passarinho, Paula Cristina Varela

Description

Mestrado em Engenharia de Sistemas Bioenergéticos - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade de Lisboa / Instituto Superior Técnico With the depletion of fossil fuels, instability of oil market and associated environmental impacts, there is a renewed interest in biofuels produced from lignocellulosic substrates, which are a plentiful, cheap and renewable source of biomass for bioethanol production. The aim of this study was the utilization of multi-parameter flow cytometry in monitoring the response to stress of Saccharomyces carlsbergensis yeast in the presence of acetic acid, an inhibitor compound present on lignocellulosic hydrolysates. From this study it was possible to conclude that the presence of acetic acid affects the growth (Ki=0,121 L.g-1) and fermentation capability of this yeast, by promoting the increase of cytoplasmic membrane permeability and depolarization. The results showed that S. carlsbergensis grows in the presence of acetic acid in concentrations up to 15 g.L-1, being inhibited at 20 g L-1. However, concentration levels up to 15 g.L-1 still allow the fermentation to occur with global glucose consumption and ethanol productions at 85% of the assay without inhibitor Also, in this work, flow cytometry proved to be a useful tool in monitoring this bioprocess, allowing to detect quickly, accurately and easily, cell responses to the stress caused by the presence of this inhibitor, and enabling online correction of parameters for improving industrial fermentation performance.