Fermentative production of l-glycerol 3-phosphate utilizing a Saccharomyces cerevisiae strain with an engineered glycerol biosynthetic pathway
✍ Scribed by A. Popp; H.T.T. Nguyen; K. Boulahya; C. Bideaux; S. Alfenore; S.E. Guillouet; E. Nevoigt
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 194 KB
- Volume
- 100
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Abstract
Interest in l‐glycerol 3‐phosphate (l‐G3P) production via microbial fermentation is due to the compound's potential to replace the unstable substrate dihydroxyacetone phosphate (DHAP) in one‐pot enzymatic carbohydrate syntheses. A Saccharomyces cerevisiae strain with deletions in both genes encoding specific l‐G3Pases (GPP1 and GPP2) and multicopy overexpression of l‐glycerol 3‐phosphate dehydrogenase (GPD1) was studied via small‐scale (100 mL) batch fermentations under quasi‐anaerobic conditions. Intracellular accumulation of l‐G3P reached extremely high levels (roughly 200 mM) but thereafter declined. Extracellular l‐G3P was also detected and its concentration continuously increased throughout the fermentation, such that most of the total l‐G3P was found outside the cells as fermentation concluded. Moreover, in spite of the complete elimination of specific l‐G3Pase activity, the strain showed considerable glycerol formation suggesting unspecific dephosphorylation as a mechanism to relieve cells of intracellular l‐G3P accumulation. Up‐scaling the process employed fed‐batch fermentation with repeated glucose feeding, plus an aerobic growth phase followed by an anaerobic product accumulation phase. This produced a final product titer of about 325 mg total l‐G3P per liter of fermentation broth. Biotechnol. Bioeng. 2008;100: 497–505. © 2008 Wiley Periodicals, Inc.