Exxon Mobil and Their Move to Cellulosic Biodiesel

by Maithili Joshi

Exxon Mobil has made continuous efforts to look for alternative energy sources in the past few years. Recently, in the last four years, they had invested more than $100 million in developing algae-derived biofuels, and recently have refocused their efforts on researching the production of biodiesel by fermenting renewable cellulosic sugars from sources like agricultural waste. Exxon Mobil has teamed up with Renewable Energy Group (REG) and other universities to find a new source of renewable fuels, focusing on using sugars from non-food sources. Continue reading

Biofuel a Viable Future?

by Ali Siddiqui

An article by Justin Gillis for The New York Times discusses a new report published by World Resources Institute, a global research organization based in Washington, that suggests that biofuels are not the direction policy makers should be heading when considering alternative energy. Biofuels are fuels created by plant matter. Timothy D. Searchinger, a research scholar at Princeton and primary author of this report, was quoted in this article to have said that they were an “inefficient way to convert sunlight to fuel”. Continue reading

How to Find New Enzymes for Making Cellulosic Ethanol

by Emil Morhardt

Nonedible agricultural waste plant material is the most abundant ready source of biomass for making ethanol. But this “cellulosic” ethanol is expensive because breaking down the lignocellulose in plant waste so it can be fermented to ethanol requires either large amounts of energy, or specialized enzymes that are costly to manufacture. Furthermore, the enzymes discovered so far are not as resistant as they might be to the high temperature and high solids (low water) environments that work best for industrial processing.

One way to discover new candidate enzymes is to look for them where they are being produced naturally in an abundant source of agricultural waste; in this case, composting rice straw greenwaste. Genetic engineering technology makes it efficient to look not for the enzymes (proteins) directly, but for the messenger RNA that codes for them—the mRNA that is being actively transcribed from the various microbial genomes present. To distinguish the appropriate genes, a comparison can be made between the RNA products from room temperature (mesophilic) and heated (thermophilic) cultures degrading rice straw. The actual technique is to collect the mRNA, use it to create its complimentary DNA, then sequence the cDNA, looking for genes that code for protein families likely to be involved in degrading lignocellulose. Continue reading

Biomass to Butanol via Engineered Yeast

by Emil Morhardt

Butanol is a four-carbon alcohol, next in size after 1-C methanol (wood alcohol), 2-C ethanol (drinking alcohol), and 3-C propanol (rubbing alcohol), so it shouldn’t come as any surprise that yeast ought to be able to synthesize it out of sugar. And it burns like the other alcohols mentioned, so it is potentially a usable liquid fuel that could be mixed with gasoline (like ethanol, to increase it’s non-fossil-fuel content), processed into other types of fuel, or used as commercial feedstock to make bio-based commercial plastics such as the PET (polyethylene terephthalate) used to make beverage bottles. Gevo, Inc., a company based in Englewood, Colorado but with it’s only [troubled] production facility in Luverne, Minnesota, seems to be gradually overcoming myriad difficulties in commercializing biomass-based isobutanol, and is beginning to license its proprietary genetically-modified yeast, which produce more isobutanol than conventional ethanol-producing commercial varieties. Gevo hopes that these yeast will feel right at home in existing ethanol-production facilities (such as the Luverne plant, where they didn’t do so well initially), and that all Gevo will have to do to get isobutanol out is to bolt on a module that separates the isobutanol from the water in which the yeast are living. Continue reading

Sustainable Bioenergy: Evolving Stakeholder Interests

by Christina Whalen

The diversity of stakeholders’ interest and values complicates the decision-making process involved in the future of sustainable bioenergy production. Johnson et al. explores the different stakeholder perspectives and then examines how this diversity affects research on the subject. Biofuel production has been brought to the public’s attention because of the need to mitigate greenhouse gas (GHG) emissions, increase energy security, support farm production, and improve economic growth in rural areas. The recent increase in biofuel consumption has resulted in stakeholders questioning environmental, economic, and social benefits of using agriculture to produce ethanol and biodiesel. As a result, policy makers have passed legislation and modified regulations about renewable fuel production in order to promote the use of alternative biomass feedstocks. The general research community is looking for ways to convert this feedstock to a usable fuel source in vehicles. The expansion of biofuel production coincides with Continue reading