91桃色

Abstract

Glycerol is a well-known product with a large variety of applications in processes and products. Bio-diesel industry generates amounts of glycerol that largely exceed their potential applications. Nevertheless, the crude glycerol does not substitute for glycerin from petrochemical origin since the refining process requires large-scale complex technology and therefore prices do not compete. In consequence, crude glycerol, in opposition to glycerin, is poorly utilized charging the biodiesel industry with a high waste-disposal cost. In this context large amounts/low cost crude glycerol became an interesting carbon source for the biotechnology industry, but this depends on the use of amenable microorganisms with recognized industrial applications. Saccharomyces cerevisiae was genetically engineered aiming to obtain strains that consumed crude glycerol efficiently. For this purpose, several proteins were overexpressed and freed of glucose repression and other tight regulation mechanisms combining several construction strategies. These included proteins from the glycerol consumption pathway, the glycerol plasma membrane high affinity transporter (Stl1p) and kinase (Gut1p) and other proteins indirectly influencing ethanol production flux, the thiamine plasma membrane permease (Thi10p) and pyrophosphokinase (Thi80p) and Pdc2, a transcription factor for thiamine-regulated genes required for expression of the two pyruvate decarboxylase isoforms. Engineered strains were subsequently challenged with biodiesel industry crude glycerol-based culture conditions for proof of concept.

Biography

Email: clucas@bio.uminho.pt