Metabolic engineering of yeasts for production of bulk fermentation products from xylose: ethanol and lactic acid

C. Miller, V. Rajgarhia, Marja Ilmen, Kari Koivuranta, Laura Ruohonen, Aristos Aristidou, Merja Penttilä, Pirkko Suominen

Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsScientific

Abstract

Kluyveromyces marxianus, a yeast naturally assimilating but not fermenting xylose, was genetically engineered to produce ethanol from xylose efficiently. Genetic engineering included replacing the natural xylose utilization pathway via xylose reductase and xylitol dehydrogenase to xylulose by a fungal xylose isomerase converting xylose directly to xylulose. Furthermore xylulokinase was overexpressed to improve efficiency of xylose to ethanol fermentation. The resulting strain produced 37 g/L ethanol with a yield of 0.4 g/g xylose used and an ethanol production rate of 0.94 g/L*h in shake flask fermentation tests. The original strain produced xylitol very efficiently in these conditions but did not produce any ethanol. The above strain was further engineered to produce lactic acid from xylose by expressing the L-lactate dehydrogenase (LDH) from Lactobacillus helveticus. The resulting strain produced lactate from xylose in shake flask test conditions with 77% yield and 1 g/L*h productivity. Lactobacillus helveticus LDH was also introduced to Pichia stipitis, a yeast naturally fermenting xylose. Lactate was the main product from xylose in shake flask test and was produced with about 60% yield and 0.4 g/L*h productivity.
Original languageEnglish
Title of host publicationInternational Specialised Symposium on Yeasts ISSY25
Subtitle of host publicationSystems Biology of Yeasts - from Models to Applications
PublisherVTT Technical Research Centre of Finland
Pages45
ISBN (Electronic) 951-38-6308-5
ISBN (Print)951-38-6307-7
Publication statusPublished - 2006
EventInternational Specialised Symposium on Yeasts, ISSY 25 - Espoo, Finland
Duration: 18 Jun 200621 Jun 2006

Publication series

SeriesVTT Symposium
Number242
ISSN0357-9387

Conference

ConferenceInternational Specialised Symposium on Yeasts, ISSY 25
Abbreviated titleISSY 25
CountryFinland
CityEspoo
Period18/06/0621/06/06

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    Miller, C., Rajgarhia, V., Ilmen, M., Koivuranta, K., Ruohonen, L., Aristidou, A., Penttilä, M., & Suominen, P. (2006). Metabolic engineering of yeasts for production of bulk fermentation products from xylose: ethanol and lactic acid. In International Specialised Symposium on Yeasts ISSY25: Systems Biology of Yeasts - from Models to Applications (pp. 45). [T30] VTT Technical Research Centre of Finland. VTT Symposium, No. 242 http://www.vtt.fi/inf/pdf/symposiums/2006/S242.pdf