Biobutanol biorefineries

Publication date: 08/02/2016

Last update: 18/12/2017

General description ^{1,2,3,4,5,6,7}

Butanol is a four-carbon alcohol with chemical formula C₄H₁₀O. There are four possible isomers for this molecule: n-butanol, isobutanol, tert-butanol and sec-butanol. Their different structures have a straight impact on their physical and chemical properties.

Figure 1. Isomers of butanol

Biobutanol is commonly used to refer to the butanol produced from biomass. n-Butanol is the major natural product formed in ABE fermentation. Isobutanol can be produced in alcoholic fermentation. sec-Butanol cannot be directly obtained by fermentation although it can be generated via 2,3-butanediol from fermentative processes. tert-Butanol is not produced by any known biological route. For the purposes of this post, biobutanol will stand for n-butanol, isobutanol or both of them, depending on the case.

Butanol formation through anaerobic bacteria fermentation was already observed by Pasteur in 1861 and, during the first decades of the past century, ABE fermentative process was widely utilized to obtain it. However, it began to experience a decline by the 1960´s and, since that time, most butanol is produced commercially from fossil fuels. Cost issues, relatively low-yield and infections, among other causes, meant that fermentation could not compete on a commercial scale.

Currently, there is increasing interest in the biobased processes to generate this platform molecule. On the one hand, it represents an attractive alternative to current biofuels. In fact, cellulosic biobutanol is considered as the advanced biofuel of the future for oil industrial experts. On the other hand, it is a versatile chemical building block with a plenty of applications in different markets.

Process technologies and feedstocks ^{1,2,8,9,10,11,12,13,14}

As it was mentioned before, biobutanol was traditionally obtained by the ABE process that produces acetone, n-butanol and ethanol from carbohydrates such as starch and glucose using strains of bacteria from the class Clostridia. At present, several players involved in the biobutanol production are developing modifications of the original ABE process. For instance, working with non-GMO Clostridium strains that naturally favor the production of n-butanol without acetone or ethanol (Optinol), focusing on metabolic engineering of the Clostridium strains to optimize the yield of n-butanol (Green Biologics) or even using quorum sensing peptides to control n-butanol production (Butrolix).

Other companies have created their own proprietary yeasts to convert fermentable sugars into isobutanol through synthetic biology. Gevo’s proprietary integrated fermentation technology platform (GIFT®) uses genetically modified Escherichia coli and Butamax technology is based on engineered Pseudomonas.

Other production processes under development to obtain biobutanol:

• Photobiological production from carbon dioxide and water employing cyanobacteria. Phytonix owns a worldwide license and sublicensing rights for this technology.
• Catalytic condensation of bioethanol to produce biobutanol through the Guerbet reaction. Abengoa has developed and patented a catalyst that enables the manufacture of biobutanol by this method.

Biobutanol can be produced from sugar/starch feedstocks (corn, sugar cane, sugar beet,…). However, lignocellulosic feedstocks are now catching the eye of many research institutes and companies as an alternative feedstock for biobutanol production owing to the benefits it possesses. In this sense, the partnership of ButaNexT project (EU Horizon 2020 Research and Innovation Programme under grant agreement n° 640462) is working on maximising the biobutanol conversion yields from selected lignocellulosic feedstocks such as wheat straw, miscanthus and the organic fraction of MSW.

Applications ^2,3,5,7,14

Advanced biofuel

Conventional bioethanol exhibits a number of limitations relating to their sustainability, high production costs, performance properties and incompatibility with existing infrastructures. Biobutanol, based on sustainable feedstocks and highly efficient production processes, owns the potential to overcome these limitations. The following are some significant advantages of biobutanol over bioethanol:

• Ability of being used directly in the current design of internal combustion engines without any modifications.
• Can be mixed with conventional gasoline in a higher proportion than bioethanol.
• Can be transported in the existing pipeline infrastructure.
• Energy content more similar to that of the gasoline.

Moreover, if biobutanol is produced from sustainable feedstocks, GHG emissions can be reduced without adversely affecting the environment or the alimentary chain. The conversion of sustainable feedstock into fuel remains technologically challenging. Current fermentation techniques suffer from low butanol yields and the subsequent distillation required is the most energy intensive step in the entire production process. Despite these barriers, biobutanol have the potential to replace gasoline and diesel.

Biobased chemical building block

Even though the properties of butanol isomers are different, the applications are similar in some aspects. Below, a summary of the main uses of n-butanol and isobutanol.

n-butanol

• Chemical intermediate for jet fuel and bio-lube oil.
• Chemical intermediate in the production of monomers, polymeric emulsions, esters, plasticizers, glycol ethers and amines.
• Solvent for paints, coatings and varnishes.
• Extractant for antibiotics, hormones and vitamins.
• Perfume and cosmetics ingredient.
• Degreasers and cleaning solutions.

Isobutanol

• Chemical intermediate in the production of jet fuel.
• Key component in polymer intermediates.
• Solvent for surface coatings and adhesives.
• Ink ingredient.
• Flotation agent.
• Polish and paint cleaner additive.

Figure 2. Block diagram of a biorefinery concept with isobutanol as platform developed for Rotterdam by the IBPR (extracted from Reference 14)

Biorefineries at commercial scale and pilot plants ^{15,16,17,18,19,20,21,22,23,24,25,26,27}

According to the sources consulted and the information available online, several companies have been working in biobutanol production (at different levels) in the last few years but most of them have been taken over (Butylfuel acquired by Green Biologics, Butalco acquired by Lesaffre, Coskata acquired by Elekeiroz, Tetravitae Biosciences acquired by Eastman Chemicals), abandoned their activities related to this molecule (Cathay Industrial Biotech, METabolic Explorer, W2 Energy, ZeaChem) or even disappeared (Cobalt Technologies, Planktonix, Syntec Biofuel).

Below, a summary of the main characteristics of the facilities at commercial scale and pilot plants that are operating or under construction at the time of writing.

Commercial-scale facilities - Operating
Owner	Location	Feedstocks	Technology	Capacity	Status
Gevo	Luverne (MN, USA)	Corn	Addition of isobutanol production capacity to an existing bioethanol site with Gevo’s integrated fermentation technology platform (GIFT®). Microorganism: Genetically modified Escherichia coli.	750,000 to 1 million gallons of isobutanol in 2016. Simultaneously producing approximately 15-17 million gallons of ethanol.	Gevo acquired the facility in September 2010 and subsequently retrofitted it with Gevo’s GIFT® technology.
Green Biologics	Little Falls (MN, USA)	Corn	ABE fermentation: Clostridium microbial biocatalysts. Bioethanol plant full retrofitted to n-butanol production with Green Biologics Technology.	-	The existing manufacturing site (an ethanol plant) was acquired by GBL in December 2014 and re-named as Central MN Renewables (CMR). The 21 million gallon-per-year ethanol plant has been retrofitted with Green Biologics’proprietary advanced fermentation technology to produce biobutanol and acetone. The facility is running and the production is expected to ramp up to full capacity over the next twelve to eighteen months (December 2016, see post).

Commercial-scale facilities - Under construction
Owner	Location	Feedstocks	Technology	Capacity	Status
Highwater Ethanol	Lamberton (MN, USA)	Corn	Bioethanol plant retrofitted to isobutanol production with Butamax technology.	-	Butamax announced in August 2014 that the construction of Phase 1 of the retrofit of Highwater Ethanol’s plant in Lamberton was completed. Phase 1 includes the implementation of a proprietary Butamax technology to removes corn oil and prepare corn mash for fermentation. Expected start-up date is unknown. Currently, the facility is running in full ethanol production mode.
Porta	Argentina (specific locations unknown)	Corn	Gevo Integrated Fermentation Technology (GIFT®). Microorganism: Genetically modified Escherichia coli.	Up to 5 million gallons of isobutanol per year	Gevo announced in February 2016 that it had entered into a license agreement and a joint development agreement with Porta to construct multiple isobutanol plants in Argentina. The first plant is anticipated to begin producing isobutanol in 2017.
Butamax	Scandia (Kansas, USA)	Corn	Bioethanol plant retrofitted to isobutanol production with Butamax technology.	-	Butamax announced in April 2017 the acquisition of Nesika Energy LLC and its ethanol facility. The company intends to add isobutanol capacity to this plant and start immediately the detailed engineering. The facility will continue producing ethanol before and after adding this capacity. See post.

Demo plants
Owner	Location	Capacity	Status
Butamax	Hull (UK)	-	Demonstration plant. Operational since 2010.
GS Caltex	Yeosu industrial complex in South Cholla Province	400 ton/y	Demonstration plant. Construction works began on September 2016. The facility is scheduled for completion during the second half of 2017.
Celtic Renewables	Grangemouth (UK)	-	Demonstration plant. Biobutanol from whisky industry by-products (draff and pot ale). The construction is due to begin in early 2018.
ButaNexT project (Horizon 2020). Partnership: Green Biologics (leader), Técnicas Reunidas, CENER, Zabala Innovation Consulting, Universidad de Castilla-La Mancha, Dyadic Nederland BV, C-TECH Innovation Limited, E4tech, VITO and Greenovate! Europe.	-	-	Pilot plant. Biobutanol from lignocellulosic biomass (wheat straw, miscanthus and organic fibre from MSW). Expected start-up: unknown.

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REFERENCES

1 European Biofuels Technology Platform – Biobutanol. Available online: www.biofuelstp.eu/butanol.html (accessed on 29th January 2016).

2 A. Morone, R.A. Pandey: “Lignocellulosic biobutanol production: Gridlocks and potential remedies”. Renewable and Sustainable Energy Reviews, 37 (2014), 21–35.

3 F. Lameiras: “Butanol production in Lactic acid bacteria”. Master of Science Thesis in Biotechnology, Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg (Sweden), 2012.

4 Biobased Butanol Info – Butanol isomers. Available online: www.biobutanol.com/Butanol-Isomers-isobutanol,-n-butanol,-tert-butanol.html (accessed on 29th January 2016).

5 C. Machado: “Technical characteristics and current status of butanol production and use as biofuel”. V Seminario Latinoamericano y del Caribe de Biocombustibles, Santiago (Chile), August 17 – 18, 2010. Available online: www.olade.org/wp-content/uploads/2015/11/S5-B2010_C_Machado_Embrapa_Brasil.pdf (accessed on 5th February 2016). 

6 Biobased Butanol Info – History. Available online: www.biobutanol.com/Biobutanol-History.html (accessed on 29th January 2016).

7 Gevo – Isobutanol white paper. Available online: www.biofuelstp.eu/downloads/wp-isob-gevo.pdf (accessed on 29th January 2016).

8 Optinol – Technology. Available online: www.optinol.com/technology.php (accessed on 3rd February 2016).

9 Green Biologics - Clostridium microbial biocatalysts. Available online: www.greenbiologics.com/clostridium.php (accessed on 29th January 2016).

10 Butrolix – Technology. Available online: butrolix.com/ (accessed on 4th February 2016).

11 Gevo – Technology. Available online: www.gevo.com/about/company-overview/technology/ (accessed on 29th January 2016).

12 Phytonix - Sustainable Chemistry Powered by the Sun™. Available online: phytonix.com/ (accessed on 4th February 2016).

13 Abengoa Research – Bulletin February 2013. Available online: www.abengoa.es/htmlsites/boletines/en/febrero2013/tecnologia/ (accessed on 29th January 2016).

14 J.A. Posada Duque, H. Zirkzee, E.W. van Hellemond, A. Lopez-Contreras, J.W. van Hal, A.J.J. Straathof: "A Biorefinery in Rotterdam with Isobutanol as Platform?". May 2014, ECN-V—14-004.

15 K.S. Lokare: “To Be, or Not to Be…Butanol and The Case of a Global Sustainable Society”. Available online: www.biofuelsdigest.com/bdigest/2015/10/14/to-be-or-not-to-bebutanol-and-the-case-of-a-global-sustainable-society/ (accessed on 2nd February 2016).

16 S. Nejame, J. Evangelow: RIP Cobalt Technologies or…How Commercializing Butanol Technology is Like Riding the Tour de France. Available online: www.biofuelsdigest.com/bdigest/2015/06/24/rip-cobalt-technologies-orhow-commercializing-butanol-technology-is-like-riding-the-tour-de-france/ (accessed on 2nd February 2016).

17 Biobased Butanol Info – The players. Available online: www.biobutanol.com/Biobutanol-Producers-Gevo,-Butamax,-Cobalt,.html (accessed on 1st February 2016).

18 Gevo – Isobutanol Plant: Luverne, Minn. Available online: www.gevo.com/about/company-overview/isobutanol-plant-luverne-minn/ (accessed on 30th January 2016).

19 Green Biologics Press Release: Green Biologics Starts Construction in Little Falls, MN. Available online: www.greenbiologics.com/pdfs/pr-02122015.pdf (accessed on 31th January 2016).

20 Butamax Press release - Butamax and Highwater Ethanol Complete Phase 1 of Biobutanol Retrofit Project Including Installation of Novel Corn Oil Separation Technology. Available online: www.butamax.com/Portals/0/pdf/2_ButamaxandHighwaterEthanolCompletePhase1ofBiobutanolRetrofitProject.pdf (accessed on 31th January 2016).

21 Butamax - Butamax™ Demonstration Facility. Available online: www.butamax.com/biofuel-technology.aspx (accessed on 31th January 2016).

22 GS Caltex Gets Ready to Produce Biobutanol from Early Next Year. Available online: www.newsworld.co.kr/detail.htm?no=2168 (accessed on 4th February 2016).
23 Celtic Renewables Press Release – Celtic Renewables to build whisky residue biofuel plant at Grangemouth. Available online: http://www.celtic-renewables.com/news/latest-news/celtic-renewables-to-build-whisky-residue-biofuel-plant-at-grangemouth (accessed on 18th December 2017).

24 ButaNexT – Project. Available online: butanext.eu/en/project (accessed on 4th February 2016).

25 Gevo Press Release – Gevo Signs Licensing and Joint Development Agreements With Porta. Available online: ir.gevo.com/phoenix.zhtml?c=238618&p=RssLanding&cat=news&id=2134773  (accessed on 5th February 2016).

26 Butamax Press Release – BP and DuPont Joint Venture, Butamax®, Announces Next Step inCommercialization of Bio-Isobutanol with Acquisition of Ethanol Facility in Kansas (accesed on 11th April 2017).

27 News - GS Caltex to Produce World’s First Biomass Based Bio-butanol. Business Korea (accesed on 11th April 2017).