Tuesday, April 30, 2013
Exhibit Hall
The accumulation of lipids by oleaginous microorganisms can be exploited as a route to biodiesel production. However, so far only sugars and agro-industrial wastes have been used to culture these microorganisms, and the use of these carbon-sources inevitably increases the cost of biofuel production. Recently, Yarrowia lipolytica has been shown to have the potential to become one of the model oleaginous yeasts for the development of biofuels, due to the availability of its genome sequence, a reliable genetic transformation system, and the ability to use a range of substrates that include glycerol and industrial fat wastes. The aim of this study is to express heterologous cellulases in Y. lipolytica and examine their activities and potential for enabling utilization of cellulose. We successfully expressed endoglucanase, cellobiohydrolase and β-glucosidase proteins in Yarrowia, and purified and characterized the individual target cellulases. To test their cellulose-degrading capability, we measured the enzymatic hydrolysis of cellulosic substrates, both in vitro and in vivo, by different combinations of Yarrowia transformants and their expressed cellulases. The results demonstrated that some combinations of Yarrowia transformants and their purified cellulases were more efficient than others in synergistically degrading carboxymethyl cellulose (CMC) and Avicel. This work lays a foundation for further engineering of Yarrowia and other oleaginous microorganisms to become cellulolytic and therefore capable of utilizing cellulosic substrates and converting them to biofuels.