Butanol is an alcohol that can be used as a transport fuel. It is a higher member of the series of straight chain alcohols with each molecule of butanol (C4H10O) containing four carbon atoms rather than two as in ethanol.
Butanol can be produced by traditional ABE fermentation - the anaerobic conversion of carbohydrates by strains of Clostridium into acetone, butanol and ethanol. However, cost issues, the relatively low-yield and sluggish fermentations, as well as problems caused by end product inhibition and phage infections, meant that ABE butanol could not compete on a commercial scale with butanol produced synthetically and almost all production ceased as the petrochemical industry evolved.
However, there is now increasing interest in use of biobutanol as a transport fuel. 85% Butanol/gasoline blends can be used in unmodified petrol engines. It can be transported in existing gasoline pipelines and produces more power than ethanol. Biobutanol can be produced from cereal crops, sugar cane and sugar beet, etc, but can also be produced from cellulosic raw materials.
To take advantage of these potential benefits, new production processes need to be developed.
Development of biobutanol
A number of companies are now investigating novel alternatives to traditional ABE fermentation, which would enable biobutanol to be produced on an industrial scale. These are summarised below.
The two leading technology developers in this area, Gevo and Butamax, are currently involved in a patent dispute. Up-to-date information on the respective positions of each company is available from their websites. The purpose of this web page is only to provide general background information on advanced biobutanol production and related areas of research. The information presented on this page was believed to be accurate at the time of writing. However, neither the members of the European Biofuels Technology Platform, the Secretariat, the European Commission, nor any other individual or organisation involved with this activity, accept responsibility or liability whatsoever with regard to the material on this web page or the use to which it is put.
Gevo white paper on iso-butanol (2.2.Mb)
On 24 May 2012, announced that it has commenced production at the world's first commercial-scale 18 MGPY biobutanol plant, developed by conversion of the former Agri-Energy corn ethanol plant in Luverne. Ground was broken at the plant in May 2011, and Gevo aims to be producing 1m gallons of isobutanol per month by the end of this year (2012).
As at June 2012, a further seven ethanol plants had expressed an interest in retrofiting isobutanol production technology.
In September 2009, Gevo, Englewood, CO announced that Gevo Integrated Fermentation Technology (GIFT™) will be used in an ICM demonstration plant in St. Joseph, Missouri to produce one million gallons of biobutanol per year by retrofitting an existing ethanol plant. The process can utilise much of the existing ethanol production system, but uses cellulosic yeast strains engineered to produce butanol instead of ethanol. In 2009, Gevo entered a licensing agreement with Cargill granting the company exclusive rights to use Cargill's host organisms in Gevo Integrated Fermentation Technology. Total has also reportedly invested in Gevo.
This built upon research by James Liao at the University of California, who developed E.Coli strains with genes coding for 2 enzymes that converted keto acides into aldehydes, and aldehydes into 1-butanol. When further manipulated, the microbes were able to produce butanol at much higher efficiencies, suitable for industrial production. In 2008, Gevo acquired an exclusive license to commercialize Liao's technology
In June 2006, DuPont and BP formed a partnership to develop new biobutanol production technology using lignocellulosic feedstocks. In July 2009 the partnership was cleared to take over the US company Biobutanol LLC. In 2009, BP and DuPont formed Butamax™ Advanced Biofuels, Wilmington.
Butamax’s business model is to offer current ethanol producers proprietary biobutanol technology to permit improved biofuels growth and plant profitability. In December 2011 Butamax™ Advanced Biofuels announced agreement on commercialization principles with Highwater Ethanol, the first entrant to the Butamax Early Adopters Group [Source: Butamax™ website].
In April 2012, Butamax entered into collaboration with leading biofuels engineering and construction company Fagen Inc. for commercial-scale biobutanol production (via retrofit of ethanol plants) using Butamax technology.
Butamax Advanced Biofuels Fact Sheet (700 Kb)
In November 2009, BP and DuPont announced the formation of Kingston Research Ltd and the establishment of a £25 million advanced biofuels research centre in Hull for demonstration of biobutanol technology (scheduled to become operational in 2010). The first commercial-scale biobutanol facility is expected to begin operating in 2014.
On 25 September 2009, BP and Mazda announced an Ethanol Biobutanol blend would be used in the Petit Le Man Race, US.
In the UK, Green Biologics has also developed butanol-producing GM microbial strains and will integrate these into a novel fermentation process. This technology advance should result in a step change in the economic viability of the fermentation and enable the large scale production of Green Biologics' Butafuel™ product.
In January 2012, Green Biologics Limited announced a merger with butylfuel™ Inc., US. The new company will operate under the Green Biologics name with headquarters in the UK, but with a strong operational presence and commercial focus in the US contributed by Green Biologics, Inc. [Source: Green Biologics].
In September 2008, Green Biologics signed an agreement with Laxmi Organic Industries to build a commercial biobutanol plant in India. The company is also working with a new generation of biobutanol producers in China.
In February 2012 it was announced that The U.S. Coast Guard was collaborating with Oak Ridge National Laboratory (US DoE) to test butanol blends in marine craft.
In March 2012 it was announced that Albermale would manufacture biojet fuel from butanol, provided by Cobalt, using NAWCWD's alcohol to jet technology.
Cobalt and Rhodia have formed a partnership to develop a demonstration plant in Brazil to convert sugarcane bagasse and other non-food feedstocks into biobutanol.
Butalco GmBH, Switzerland is developing new production processes for biobutanol based on genetically optimised yeasts together with partners in downstream processing technologies.
Older 'research notes' on biobutanol production
State corporation, Russian Technologies, will begin construction of a biobutanol factory in the Irkutsk region in spring 2011. The factory will use wood chips and other timber byproducts [Source: Moscow Times].
In the 1980s, hydrolyzates of lignocellulosic material were used to produce butanol on an industrial scale in Russia, and the processes developed have also attracted renewed interest from butanol researchers (the technology pathway for the new biobutanol factory was not mentioned in the news release).
In November 2009, researchers at UCLA announced that modified strains of Synechococcus elongatus could produce isobutyraldehyde and isobutanol directly from carbon dioxide [Source: Nature Biotechnology 27].
Research is also being carried out into the production of 2,3 butanediol (a potential biofuel) from agricultural residues (e.g. hydrolysis of hemicellulose-rich fractions by Trichoderma harzianum followed by fermentations using Klebsiella pneumoniae). Improved fermentation efficiency is one of the focuses of the FP7 SUPRABIO project.
Various biobutanol researchers are working with GM Colstridium strains.
Hydrolysis of cellulosic raw materials prior to butanol conversion potentially offers greatly increased yields. In research published by the USDA in 2007, wheat straw was hydrolyzed to lignocellulosic component sugars (glucose, xylose, arabinose, galactose, and mannose) prior to their conversion to butanol, by Clostridium beijerinckii P260. The rate of production of wheat straw hydrolysate to butanol was 214% over that from glucose.
Ongoing genetic research is focusing on 'gene knock-out' systems in Clostridium strains, whereby the enzymes that catalyse competing reactions (which produce Acetone, Ethanol, etc) are 'removed'.
Research into the ABE fermentation process has addressed issues of end-product inhibition and control of phage infection.