Please can you explain how biofuels are currently developed?
The vast bulk of current biofuel produced today comes in the form of ethanol, largely fermented by yeasts from sugars obtained from corn (specifically the corn kernel) or sugar cane.
Are there any challenges or environmental concerns associated with using ethanol to produce biofuels?
It can be reasonably anticipated that increased pressures will come on food production from both increased population as well as increased prosperity in the coming decades. Such pressures represent a challenge even today that often manifests itself in the “food vs fuel” debate. Clearly, any move toward utilizing tailored bioenergy crops, or agricultural waste from food production help resolve such challenges.
The biggest environmental challenge is the world’s dependence on fossil fuels for energy, particularly for transportation. The developments we are working on including C5 FUEL™ are aimed at increasing the range of non-petroleum feedstocks that can be used to economically produce liquid biofuels like ethanol.
How is yeast used to develop biofuels?
Yeast is used extensively today as the process is similar to that used to make alcohol; sugars obtained from various plant sources such as corn, wheat, etc. are fermented by yeast into alcohol, or ethanol.
What is the significance of the new approach Mascoma LLC and the U.S. Department of Energy’s BioEnergy Science Center (BESC) have developed in collaboration with one another?
To understand the significance, it is important to note that the process of biofuel production targeted by this product differs largely in the source of the extracted sugars. Whereas the conventional process for biofuel production involves the use of agricultural crops that are also used for food or feed production (eg, corn, wheat, cane); the process targeted by C5 FUEL™ is based on obtaining sugars from either the waste residue left behind after food/feed production (eg the corn stalk, or stover, wheat straw, etc) or eventually other feedstocks such as grasses, eg switchgrass, or wood.
This process, known as lignocellulosic (or just cellulosic) biofuel production, requires more aggressive (and thus costly) treatment of the plant biomass in order to break down the plant cell wall components into complex sugars such as cellulose, hemi-cellulose and xylose.
The majority of commercial yeasts cannot consume these complex sugars so for the most part these complex sugars must be broken down further into their simple sugar constituents using commercially produced enzymes (again introducing cost into the process). Thus, the ability of C5 FUEL™ to consume xylose as well as glucose introduces additional efficiency and reduces cost into the system.
How will this finding help to both reduce the cost of ethanol production and increase the number of ethanol production facilities?
We are really only seeing a handful of production scale cellulosic biofuel facilities in operation today.
This marks huge progress over the last few years, yet there is still a need to drive the overall cost of production down.
Improvements in feedstock agronomics and traits for improved biofuel yields, improvements in the breakdown or pre-treatment process and improvements in the microbial processes and enzymes used are all potential areas for cost efficiency improvements.
Improved yeasts such as C5 FUEL that can be “plugged-in” to the existing facilities will provide a continuous improvement in cost of production. Continuous improvements in cost and efficiency are essential to growing the biofuels industry.
Most processing methods at the moment only convert cellulose into sugar, what effect does the ability to convert hemicellulose into sugar too have on the level of ethanol production?
It obviates the need to find other means of breaking down the hemicellulose into its component sugars as the yeast can now consume the xylose.
Does the ability for yeast to consume xylose have an effect on the yield of biofuel?
Xylose represents about 20-30% of the total sugars in cellulosic materials; so compared to a conventional yeast which does not ferment xylose, there will be a corresponding yield increase, depending on the feedstock.
What industries do you believe will primarily benefit from C5 FUEL™ and how will they use it?
Specifically the cellulosic biofuel industry. For those industries that already utilize yeast as a part of their production process, this product can be easily substituted in order to realise the gains offered by this yeast.
C5 FUEL™ is used just like a conventional yeast; the producers add it to the biofuel fermentation process.
How important do you believe the combined expertise from both Mascoma and BESC was in the development of this new strain of yeast?
By partnering the intellectual scientific skills and the technical capabilities at both sites and availing of distinct technical and analytical capabilities at each site, the partnership accelerated the translation of basic research finding into a commercially viable product.
The combination of a strong research institution like BESC and the commercial drive of a private company like Mascoma, is a great way to bring a lot of resources to bear on big problems.
What are the next steps in the progression of this new processing approach?
Next steps will include enabling yeast to directly breakdown other complex sugars, such as cellulose, and engineering biofuel fermentation pathways into other microbes already capable of breaking down cellulose and hemi-cellulose.
About Dr. Paul Gilna
Dr. Paul Gilna is the director of the BioEnergy Research Center (BESC) at Oak Ridge National Laboratory. As the BESC Director, Dr. Gilna leads a $25M/yr basic and applied research project underlying the development of more cost effective transformation of biomass products into biofuels.
The research focuses on understanding and overcoming the difficulty in converting cellulosic plant material into biofuels. BESC includes 18 research partners from other national laboratories, universities, and companies.
Dr. Gilna received his Ph.D. in pharmacology from University College Dublin. His postdoctoral work focused on the isolation and sequencing of human steroid hormone receptor proteins.
In 1988, Dr. Gilna joined the GenBank project, the international collection of publicly available gene sequences then managed out of Los Alamos National Laboratory (LANL).
At GenBank, Gilna was instrumental in developing the now widely accepted requirement that authors of journal articles submit gene sequences to GenBank in exchange for an accession number printed with the article.
Gilna has held the position of Program Director at the National Science Foundation’s Division of Biological Infrastructure and is a former Director of the Department of Energy’s Joint Genome Institute (JGI) operations at LANL. Before coming to ORNL and BESC, Gilna was the Executive Director at the Community Cyberinfrastructure for Advanced Marine Microbial Ecology Research and Analysis project (CAMERA) at the University of California, San Diego.
About Dr. Kevin Wenger
Dr. Kevin S. Wenger is the Executive Vice President of Mascoma LLC, a division of Lallemand Inc.
He has been with Mascoma since 2007, leading the company’s biotechnology-based research and development efforts in various roles.
Dr. Wenger led the company’s introduction of TransFerm, the first bioengineered yeast successfully introduced to the corn-based fuel ethanol industry.
He has over 20 years of experience post-Ph.D. in industrial biotechnology product development in the areas of fermentation, industrial enzymes, and biofuels.
Dr. Wenger holds a B.S. degree in chemical engineering from Lehigh University and M.S. and Ph.D. degrees in chemical engineering from Colorado State University.
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