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Breaking down barriers to growth

Since the 1970s when biofuel production began, pre-treatment methods – and the powerful substances such as yeasts and enzymes used in these methods – have come a long way.


June 3, 2014
By Treena Hein

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Since the 1970s when biofuel production began, pre-treatment methods – and the powerful substances such as yeasts and enzymes used in these methods – have come a long way.

research group  
Dr. Anthony J. Clarke (centre back) with his University of Guelph research group taken in October 2013


 

“They have made an enormous difference in achievable yield of ethanol,” says Canadian Renewable Fuel Association President W. Scott Thurlow. “Research and development has been in perpetual state of innovation. Pretreatment using substances such as yeasts and enzymes allow us to derive more and more fuel from the same volume of feedstock material. This also allows us as a society to get more food and more fuel from the same amount of land.”

The efficiencies gained so far through pre-treatment processes have also made biofuel production greener. For example, water required in biofuel production has decreased consistently over the last decade, and this is partly due to the contribution of enzymes, Thurlow notes.

Technological developments in pre-treatments have also led to better safety. New enzyme and yeast products are more pH-tolerant than those used in the past, and are being used to replace (much more dangerous) ammonia in front-end processing of ethanol.

Pre-treatment 101
The main purpose of the pre-treatment is to increase the reactivity of the cellulose and hemicellulose feedstock material (corn, silage, woody biomass, straw) to the subsequent hydrolysis steps, to decrease the crystallinity of the cellulose and to increase its porosity. Only after pre-treatment are the sugar-containing materials accessible for hydrolysis, where lignin-free cellulosic material is split into sugars which are in turn fermented
into biofuel.

In a 2013 update of an international report called ‘Status of Advanced Biofuels Demonstration Facilities,’ scientists Dina Bacovsky, Nikolaus Ludwiczek, Monica Ognissanto and Manfred Wörgetter classify pre-treatment methods into three groups: chemical, physical and biological. “Well-known chemical pre-treatments involve concentrated and diluted acids,” the group explains. “They provide reduced corrosion problems and environmental issues but lower yields. Still other chemical pre-treatments being used and under investigation use ammonia, lye, organosolvents and ionic liquids.”

In terms of physical pre-treatment, Bacovsky and her colleagues note that steam explosion has been frequently applied in different parts of the world and delivers high yields of ethanol. They also note that ammonia fibre explosion requires less energy input, but raises environmental issues. It requires that liquid ammonia be added to the biomass in question under moderate pressure (100 to 400 psi) and temperature (70 to 200°C) and then the pressure is rapidly released.

They list physical pre-treatment methods under development as liquid hot water and CO2-explosion, which promise fewer side-products or low environmental impact respectively. The authors state that biological pre-treatment processes based on conversion by fungi and bacteria are not yet well-known or in
much use.

The scientists created the report for an international group called ‘IEA Bioenergy Task 39 – Commercializing Liquid Biofuels.’ IEA Bioenergy was set up in 1978 by the International Energy Agency (IEA) to improve cooperation between countries that have national programmes in bioenergy research, development and deployment. Task 39 is a group of international experts working to commercialize sustainable transportation biofuels.

Dr. Jack Saddler is a Task 39 ‘Leader,’ as well as a professor in ‘Forest Products Biotechnology and Bioenergy’ and Dean Emeritus in the Faculty of Forestry at the University of British Columbia in Vancouver. Saddler is also a member of Montreal-based BioFuelNet Canada, a biofuels research network that is aggressively addressing the challenges impeding the growth of an advanced biofuels industry, while focusing on non-food biomass
feedstocks. It is based at McGill University.  

Saddler agrees with Bacovsky and her colleagues about there being many ‘variations on a theme’ available in the cellulosic ethanol pretreatment arena – plenty of options are available in terms of which feedstock to use, how to pre-treat it and how to convert it. Of the three biofuel pretreatment methods (chemical, physical and biological) available, the scientists state that hydrotreatment (variations on steam explosion or dilute acid hydrolysis), as pursued by companies like Abengoa, Inbicon and Mascoma, currently accounts for most of the front-end commercial pre-treatments being pursued by the biofuel industry worldwide.

The interactive world map in the report references several cellulosic ethanol demonstration or pilot plants in Canada that use different processing methods. Tembec Chemical Group’s Temiscaming, Quebec demonstration plant uses thermochemical conversion of ligno-cellulosics into ethanol. Enerkem is building several commercial plants that use municipal solid waste (including woody biomass from construction debris and other sources), and they have a pilot plant in Sherbrooke, Quebec, and a demo facility in Westbury, Quebec (see the March/April issue of Canadian Biomass for details). Both use thermochemical conversion. Iogen Corporation has a demo plant in Ottawa that uses biochemical conversion of lignocellulosics into ethanol (see page 25 for details).

Regulatory harmony
If the industry was asked to choose one aspect of biofuel pre-treatment in this country that needs attention, it might well choose the quest to allow the same enzymes and yeasts that are legal to use in other markets to be legally permitted for use here. “There are new products that are approved in Europe and the United States, but not yet approved in Canada,” Thurlow explains. “Regulatory barriers and inconsistencies like this are giving biofuels producers in the global marketplace a distinct competitive advantage over our producers here.” This disparity creates a situation where foreign biofuel producers can produce higher volumes, with more fuel to export, and potentially have the ability to undercut Canadian producers.

Furthermore, the fruits of some of the enzyme research and development occurring here in Canada are approved for use in other markets (helping to boost yields there), but these same domestic products are not yet allowed for domestic biofuel production.

The problem is being addressed, but it’s anyone’s guess as to when it will be solved. The main mechanism for harmonizing and streamlining industrial and commercial regulations in the U.S. and Canada is the joint governmental ‘Regulatory Co-operation Council.’ “Prime Minister Harper and President Obama and other representatives of both nations attend Council meetings regularly, but dialogue is constant,” Thurlow explains.

He says the Canadian Renewable Fuels Association provides information on regulatory disparities to the Canadian government for addressing within the ‘Regulatory Co-operation Council’ framework, but also works on the same issues with the Canadian Food Inspection Agency, Environment Canada and Health Canada.

“The development of new pre-treatments is limitless,” notes Thurlow, “but regulatory harmony is critical. Canada has a natural biomass advantage in terms of the volume of agricultural and forestry-related feedstocks we have available and the harvesting infrastructure we have in place, but we cannot turn that into a competitive advantage until we have a level playing field. We must have that for the industry to prosper as it should.”

But regulatory harmony is only one of many important recommendations that the CRFA outlines in its new vision and action plan entitled ‘Evolution and Growth: From Biofuels To Bioeconomy,’ released April 8th. In it, the association recognizes how far the industry has come already and is positive about the future: “A thriving and fully realized domestic renewable fuels industry is more than possible – it is viable and working in Canada. Now is the time to build off this successful platform and do more.”

Enzymes in action
“Enzymes produced by fungi and bacteria degrade cellulose naturally – without added heat, force, acids and so on – and if we better understand this powerful process, we can discover if there is something we might be able to apply in industrial cellulose production,” explains Dr. Anthony Clarke.

Clarke, a professor of Molecular & Cellular Biology at the University of Guelph, started researching the enzymatic breakdown of cellulose about eight years ago with Dr. Jacek Lipkowski and Dr. John Dutcher (Canada Research Chairs in Electrochemistry and Soft Matter & Biological Physics respectively), both also at U of G.

The scientists are studying three types of bacterial enzymes that work together to attack different regions of the cellulose polymer. “Most of the work so far has been to establish methodology to view the process as it’s occurring in real time,” Clarke explains. “That has been a big accomplishment that enables understanding to occur.”

It may be that in the future, the best course will be to genetically engineer bacteria to produce super-enzymes more powerful than those that exist now, or those that can withstand and work faster at higher temperatures and in acidic conditions, all of which will make the production of cellulosic ethanol more efficient. 

For an interactive map of global biofuel projects visit: demoplants.bioenergy2020.eu/projects/mapindex .

A global report on biofuel facilities can be found online at: task39.org/files/2013/12/2013_Bacovsky_Status-of-Advanced-Biofuels-Demonstration-Facilities-in-2012.pdf .

The new CRFA vision and action plan is also online at: www.evolutionandgrowth.ca .


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