First Patent Granted for Research at Energy Biosciences Institute

Research on improved sugar transport for biofuel production has been recognized with the first patent to be granted to the Energy Biosciences Institute since the collaboration’s establishment in 2007.

The EBI, a public-private research partnership dedicated to the application of bioscience and biotechnology methods to achieve global energy solutions, received U.S. Patent No. 8,431,360 titled  “Methods and Compositions for Improving Sugar Transport, Mixed Sugar Fermentation, and Production of Biofuels.” The application for the patent was filed in July 2010 and the award was granted April 30, 2013, a fairly short processing period for biotechnology inventions.

The patent itself also illustrates the value of interdisciplinary and inter-institutional cooperation that is the hallmark of the EBI, a 10-year program funded by BP. Among the inventors of the patented process are scientists from BP and from the University of California, Berkeley, and the University of Illinois at Urbana-Champaign, who along with Lawrence Berkeley National Laboratory represent the academic component of the collaboration.

The breakthrough discovery resulted from the work of teams at Berkeley and Illinois to optimize sugar conversion yields by yeast to produce bioethanol. Yeasts like Saccharomyces cerevisiae are already successful microbes for producing bioethanol but are not capable of using all plant cell wall sugars efficiently.  All plant walls are made of what are called C5 and C6 sugars.  While yeast can easily import and use the C6 sugars such as glucose, they cannot efficiently import or use C5 sugars that include xylose and arabinose.  Since the C5 sugars can make up to 30 percent of the plant cell wall, it is important to develop methods that concurrently utilize all sugar components of the cell wall to make biofuels commercially viable.

Genes have to be transferred into yeast to make xylose utilization possible.  However, xylose and glucose compete for the same transporter protein to get into the yeast cell, and as such the co-utilization of the C5 and C6 sugars becomes inefficient.  

Since fungi such as Neurospora crassa can and do import and utilize C5 and C6 sugars, EBI scientists studied how fungi use biomass-derived sugars and explored the possibly of transferring of some parts of that process from Neurospora to yeast.   They found a unique transporter from Neurospora than can transport chains of glucose called cellodextrins directly into the cell making them available for conversion into fuel.

The researchers found that expressing these Neurospora cellodextrin transporters in yeast resulted in a significant reduction in the competition for the glucose transporters. Xylose can now use the glucose transporters, and the glucose enters the cell in the form of cellodextrin using the Neurospora crassa transporter.  This makes the co-utilization of the C5 and C6 sugars much more efficient and is one step closer to making biomass-derived fuel more economical.

Inventors include UC Berkeley faculty members N. Louise Glass and Jamie Cate, Illinois faculty members Huimin Zhao and Yong-Su Jin, BP scientist Xiaomin Yang, former Berkeley graduate students William Beeson and Jonathan Galazka, former Berkeley postdoctoral researcher Chaoguang Tian, Illinois graduate student Sijin Li, and Illinois postdoctoral researchers Jing Du, Jin Ho Choi, Suk-Jin Ha, and Soo Rin Kim.

Morrison and Foerster, LLP, an international law firm with offices in in San Francisco, prosecuted the patent on behalf of the University of California and all shareholders.

EBI officials said at least 50 more patents are pending from institute research, including two whose awards are imminent.

The complete patent can be read online here.