BioChem - DOS

Glycolic acid production in the engineered yeasts Saccharomyces cerevisiae and Kluyveromyces lactis

Microbial cell factories

Koivistoinen, Outi M; Kuivanen, Joosu; Barth, Dorothee; Turkia, Heidi; Pitkä nen, Juha-Pekka; Penttilä , Merja; Richard, Peter

<P><B>Background</B></P><P>Glycolic acid is a C2 hydroxy acid that is a widely used chemical compound. It can be polymerised to produce biodegradable polymers with excellent gas barrier properties. Currently, glycolic acid is produced in a chemical process using fossil resources and toxic chemicals. Biotechnological production of glycolic acid using renewable resources is a desirable alternative.</P><P><B>Results</B></P><P>The yeasts <I>Saccharomyces cerevisiae</I> and <I>Kluyveromyces lactis</I> are suitable organisms for glycolic acid production since they are acid tolerant and can grow in the presence of up to 50&nbsp;g&nbsp;l<SUP>-1</SUP> glycolic acid. We engineered <I>S. cerevisiae</I> and <I>K. lactis</I> for glycolic acid production using the reactions of the glyoxylate cycle to produce glyoxylic acid and then reducing it to glycolic acid. The expression of a high affinity glyoxylate reductase alone already led to glycolic acid production. The production was further improved by deleting genes encoding malate synthase and the cytosolic form of isocitrate dehydrogenase<I>.</I> The engineered <I>S. cerevisiae</I> strain produced up to about 1&nbsp;g&nbsp;l<SUP>-1</SUP> of glycolic acid in a medium containing <SMALL>D</SMALL>-xylose and ethanol. Similar modifications in <I>K. lactis</I> resulted in a much higher glycolic acid titer. In a bioreactor cultivation with <SMALL>D</SMALL>-xylose and ethanol up to 15&nbsp;g&nbsp;l<SUP>-1</SUP> of glycolic acid was obtained.</P><P><B>Conclusions</B></P><P>This is the first demonstration of engineering yeast to produce glycolic acid. Prior to this work glycolic acid production through the glyoxylate cycle has only been reported in bacteria. The benefit of a yeast host is the possibility for glycolic acid production also at low pH, which was demonstrated in flask cultivations. Production of glycolic acid was first shown in <I>S. cerevisiae</I>. To test whether a Crabtree negative yeast would be better suited for glycolic acid production we engineered <I>K. lactis</I> in the same way and demonstrated it to be a better host for glycolic acid production.</P>

2013

BioMed Central

cc-by

1475-2859

12

pp.82-82

10.1186/1475-2859-12-82

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART71748767

https://microbialcellfactories.biomedcentral.com/counter/pdf/10.1186/1475-2859-12-82

Glycolic acid; Glyoxylic acid; Metabolic engineering; Glyoxylate cycle; Glyoxylate reductase; Saccharomyces cerevisiae; Kluyveromyces lactis