Professor Saddler is a speaker in the AAAS symposium Food, Feed, and Fuel: Optimizing Economic and Sustainable Biofuel Production, Friday, Feb. 17, 1:30 – 4:30 p.m.
Current biofuels derived from sugar cane or starch crops such as corn and wheat have fostered an ongoing food versus fuel debate. This has caused many groups to focus on finding ways to make use of nature’s biggest source of sugars, which is the cellulose in all plants, as a biofuel feedstock, rather than using food crops.
But what stands in the way of making advanced biofuels a reality such that “from the forest to the highway” can be achieved is the ingenuity of Mother Nature herself.
Although both cellulose and starch are made from glucose, nature designed starch (found in potatoes, rice, corn, wheat, etc.) to be broken down easily while cellulose (found in plants, cotton, etc.) does not break down readily at all!
Mother Nature makes it hard to break down plant cellulose
Breaking down cellulose by the mechanisms that decay organisms such as fungi and bacteria use takes too long. If a tree does fall in the forest it typically takes years if not decades for it to finally be metabolized by the myriad of organisms involved in the “deconstruction” process.
The bioconversion sector hopes to make use of the many enzymes that exist in nature to access and use the sugars within biomass. The challenge is to do this while minimizing capital and operational costs while making sure, through tools such as Life Cycle Analyses (LCA), that advanced biofuels production is environmentally sound.
The Forest Products Biotechnology/Bioenergy group at UBC (www.bioenergy.ubc.ca) has been researching what is now generally called the biorefinery area ever since the first OPEC Oil crisis in the late 1970s. It was one of the first groups to show that some form of pretreatment (opening up and fractionation) is typically required before effective enzymatic breakdown of the cellulose can occur.
Steam explosion is a promising method
One of the challenges is to recover the other two main components of biomass, the lignin and hemicellulose, in a useable form while at the same time “opening up” the cellulose so that the enzymes can more effectively break it down to glucose. Building on the UBC group’s familiarity and experience with pulping processes, methods such as “steam explosion” have been developed and are now being commercialized by many of the companies building demonstration plants around the world.
At the same time, by working with the world’s biggest enzyme company, Novozymes, we have been able to develop various “enzyme cocktails” that are more effective on particular biomass materials such as the hundreds of thousands of tons of mountain pine beetle-killed trees in B.C., Alberta, Idaho and Colorado.
Good progress continues to be made in both better understanding the fundamental mechanisms involved in biomass deconstruction and helping drive down the costs. These advancements mean that the International Energy Agency’s (IEA) “Biofuel Road Map” ( www.IEA.org ) prediction of advanced biofuels being commercially viable by 2020 could very likely become a reality.
