Final Report Summary - CANEBIOFUEL (Conversion of sugar cane biomass into ethanol)
The CANEBIOFUEL project has advanced the current state-of-the-art by creating new fundamental knowledge on the components in sugar cane bagasse and straw. The treatability of both raw materials has been evaluated and it was found that straw was easier to hydrolyse and ferment compared to bagasse. This is directly related to the different chemical composition and morphology of the two. Despite of the large chemical and structural differences found in the two materials, the optimum pre-treatment conditions are found to be similar for both straw and bagasse during acid catalysed pre-treatment, which allows for co-feeding of the two substrates. The dynamic interface between pre-treatment chemistry and enzyme biochemistry is extremely complex. However, the project has gained an understanding of the relationships between pre-treatment and enzyme hydrolysis.
The cost modelling showed that, as could be expected, it is difficult to match the ethanol cost in first generation (sugarcane) w/o subsidies. However, it was found that for the integrated case the average ethanol production cost is at the same level as corn based ethanol and production cost of second generation ethanol is comparable to European Union (EU) starch based ethanol, which is primarily due to the low cost of first-generation from sugar cane.
The optimum process scenario for second-generation ethanol production is found when heat and streams are integrated with first-generation and sugar cane leaves and tops are utilised. It was found that 1 tonne of sugarcane produces 144 kg of straw. In other words, a typical sugarcane harvest in Brazil will generate at least 90 million tonnes of straw. Approximately 50 % of all this 'waste' has massive fuel potential and thus utilising the straw from the sugar cane ethanol fuel production could significantly increase the ethanol production without using more land.
Project context and objectives:
Second-generation biofuels may hold one of the keys to unlock Europe's objective of becoming more energy and resource efficient by 2020. But today a number of hurdles prevent second-generation biofuels from being commercialised and fully exploited. Second-generation biofuels are made from lignocellulosic biomass. Sugarcane bagasse, the fibrous material by-product of crushed stalk, as well as sugarcane tops and leaves (in the following called straw or trash) are examples of lignocellulosic biomass. Other examples of lignocellulosic biomass include tree bark, corn stover and wood chips. Despite the promises of second-generation biofuels and the availability of the technology, no one has successfully scaled up the process to convert lignocellulosic biomass waste into a commercially viable fuel. Several EU-funded research projects are currently working to change this. One of those is the CANEBIOFUEL project that studied the conversion of sugarcane biomass into ethanol.
The CANEBIOFUEL project is studying the structural components of sugarcane biomass. What was once discarded as waste or used for cogeneration should one day produce clean and inexpensive ethanol fuel. CANEBIOFUEL is one of the first to explore sugarcane straw as a lignocellulose source. The consortium, which built on an already established partnership, involved leading industry and academic partners within the relevant fields from Europe and Latin America.
The overall objective of CANEBIOFUEL was to create a scientific and technological platform for the development of a commercially viable process for converting sugar cane bagasse and trash (i.e. sugar cane biomass) into fermentable sugars. Furthermore, the aim was to integrate such a process with existing production of 1st generation ethanol based on sugar cane. In order to develop such a process, a deeper knowledge about the structural components of sugar cane biomass has been provided with the aim of capturing the easier fraction of the cellulose sugars. Furthermore, the project has aimed to achieve a better understanding of the dynamic impact between pre-treatment and enzymatic hydrolysis in order to specifically design the process and enzymes for cost-effective cellulose conversion. The main technical barriers in the project related to the application of an integrated approach, achieving economically attractive production of second generation ethanol based on sugar cane biomass as opposed to converting biomass into energy or other alternative use. Moreover, challenges were related to achieving process compatibility with existing plants and the accomplishment of a simple and cheap process.
In order to realise the potential of sugar cane biomass, a number of technological challenges related to different process stages have to be fulfilled for successfully implementing conversion technologies for sugar cane biomass and achieve the overall objectives of the CANEBIOFUEL project.
The CANEBIOFUEL project, through collaboration between world leading EU and Latin American (LA) researchers and industrial partners within the biomass and disciplines treated, have addressed these issues through an integrated work plan to achieve project objectives. Thereby, the project aimed to fill the remaining important gaps of knowledge related to the dynamics between pre-treating and hydrolysing lignocellulosic biomass originating from sugar cane processing, thus paving the way for the introduction of fully commercially viable second generation technology.
As such, besides the isolated commercial potential in sugar cane biomass itself, also from a scientific and technical viewpoint there is a need for the CANEBIOFUEL project as a collaborative endeavour of an EU-LA consortium, for which the Framework Programme SICA actions represent an ideal vehicle.
The CANEBIOFUEL project aimed to contribute to the scientific foundation of establishing an integrated process technology for fuel ethanol production from sugar cane biomass with special focus on the interrelated disciplines of lignocellulose pre-treatment chemistry, enzyme hydrolysis biochemistry, as well as process integration and cost simulation. The process must be cost-effective and significantly improve the energy balance of sugar cane production as well as overall environmental sustainability. It was not the intention to verify the final production cost at a pilot or demonstration scale within project-life, but rather to develop a platform that can form the basis for such a technology.
Project results:
In accordance with the CANEBIOFUEL concept and the science and technology (S&T) challenges addressed, a number of specific objectives of the project are defined in the following. The scientific objectives of CANEBIOFUEL was to advance the current state-of-the-art by creating new fundamental knowledge on:
- structural components of sugar cane bagasse and trash components;
- the treatability of various cane biomass fractions;
- chemical changes occurring during cane biomass pre-treatment;
- the dynamic interface between pre-treatment chemistry and enzyme biochemistry;
- enzymatic cellulose convertibility of pre-treated cane biomass;
- factors in pre-treated cane biomass that impact enzyme hydrolysis;
- the technical implications of integrating first and second generation processes;
- process simulation and cost modelling of processing steps for cane biomass conversion;
- process simulation and cost modelling of the whole integrated first and second generation ethanol production with heat and power production.
The technological objectives of CANEBIOFUEL were:
- identification of the best suitable fraction(s) of sugar cane biomass for an enzymatic conversion process;
- development of detailed characterisation of structural components in sugar cane bagasse and trash;
- development of enzymes for improved cellulose conversion of pre-treated cane biomass;
- reduction of ethanol production costs for conversion of cane biomass to a level comparable to current corn-based ethanol of approximately EUR 235/m3 by improvements in the pre-treatment and enzymatic hydrolysis and by process integration;
- development of a process outline for a conversion technology for cane biomass into fuel ethanol;
- increase of the fuel production capacity of existing sugar cane mills by at least 50 % by utilising cane biomass;
- demonstration of an improved energy balance when using sugar cane biomass for fuel ethanol production as compared to its alternative use, i.e. primarily as energy source in sugar mills;
- improved sustainability in sugar cane processing by both reducing carbon dioxide (CO2) emission and avoiding air pollution from trash and bagasse burning in fields and partially at sugar mills.
In order to develop the CANEBIOFUEL process, deeper knowledge about the structural components of the biomass was required with the aim of capturing the most convertible fraction of the cellulose sugars.
Knowledge gaps remained in understanding the dynamics between pre-treating and hydrolysing lignocellulosic biomass. Pre-treating involves opening the lignocellulosic fibre structure. It exposes the cellulose and hemi-cellulose in bagasse and the sugarcane straw for enzymatic hydrolysis. Hydrolysis, on the other hand, introduces an enzyme catalyst that releases the fermentable sugars from the more complex carbohydrates. But for second-generation biofuels to become a reality, the CANEBIOFUEL project first had to identify which part of sugarcane biomass is the most susceptible for an enzyme-based conversion technology to produce the fuel. They also evaluated the best pre-treatment conditions to help reduce the final cost to the consumer. Thus, the project aimed to build a detailed understanding of the dynamic impact between pre-treatment and enzymatic hydrolysis in order to specifically design the process and enzymes for cost-effective cellulose conversion from the selected sugar cane biomass fractions, and integrate this with existing sugar cane processing facilities.
The CANEBIOFUEL project has focused on the following research and technological development (RTD) activities:
- Detailed characterisation of structural components in sugar cane bagasse and trash;
- Understanding the treatability of various fractions;
- Pre-treatment of biomass with focus on integration with existing technology;
- Enzyme development for improved cellulose hydrolysis;
- Process simulation and cost estimation.
In order to evaluate which fraction of the sugar cane biomass is most adequate for an enzyme based conversion technology to produce fuel ethanol, the CANEBIOFUEL project participants had to collect sugar cane samples. In April 2009, 40 people from the Sao Martinho mill in Brazil mechanically harvested approximately 200 ton of sugarcane. Additionally, 150 kg of cane straw was collected from the field. Part of the harvested sugarcane was then separated by the researchers into its individual parts and its moisture content and impurities was measured. The bagasse samples were subsequently vacuum packed, conditioned and shipped on truck to Novozymes Latin America and UFPR installations located in Curitiba (400 km distance from the mill), where the samples were properly stored. The biomass fractions were analysed in relation to their chemical compositions using chromatographic and spectrometric methods. Both the freshly harvested straw and the bagasse collected inside the mill were evaluated. The chemical and morphological characterisation done by the Department of Chemistry at UFPR in collaboration with CTC evidenced significant differences in the chemical and structural composition of bagasse and straw. The treatability of both raw materials has been evaluated and it was found that straw was easier to hydrolyse and ferment compared to bagasse. This is directly related to the different chemical composition and morphology of the two. Despite of the large chemical and structural differences in the two materials, the optimum pre-treatment conditions are found to be similar for both straw and bagasse during acid catalysed pre-treatment which could allow for co-feeding of the two substrates.
Water-washed, steam-treated fractions of cane biomass were characterised and enzyme accessibility of steam-treated cane biomass evaluated. The use of cellulolytic enzymes to convert these materials to ethanol is not a new concept. However, high performance enzymes are a key point for cost-effective production of fermentable sugars from residues. CANEBIOFUEL has been able to narrow down the best-performing enzyme cocktails. When pre-treating bagasse and cane straw using steam explosions, under catalysed and auto-hydrolysis conditions, the project has identified a high-performing combination of enzymes and pre-treatment conditions. Novozymes demonstrated the latest enzyme technology from Novozymes CellicTM CTec and HTec are the first enzymes that live up to these criteria, indicating that the enzyme solution under development at Novozymes is on the right track.
CTC has showed that fermentation of hydrolysates generated under the selected pre-treatment conditions performed similar to the industry standards considering both batch and fed batch feeding strategies.
A flow sheeting model of each individual first and second generation ethanol plant has been implemented and the current autonomous distillery has been simulated as a reference. Separately, a model for estimation of the production cost of ethanol from a combined sugarcane juice and bagasse facility has been developed and all cost data been defined. The cost modelling efforts done by the Department for Chemical Engineering at Lund University showed that by combining the first and second generation based technologies it is possible to reach cost levels similar to starch based ethanol produced in EU.
The CANEBIOFUEL project has advanced the current state-of-the-art by creating new fundamental knowledge on the components in sugar cane bagasse and straw / trash. The treatability of both raw materials has been evaluated and it was found that straw / trash has been shown to be easier to hydrolyse and ferment compared to bagasse. This is directly related to the different chemical composition and morphology of the two. Despite of the large chemical and structural differences in the two materials the optimum pre-treatment conditions were found to be similar for both straw / trash and bagasse during acid catalysed pre-treatment, which allows for co-feeding of the two substrates.
In general, lower severity during pre-treatment, with lower temperatures and shorter times, result in better glucose yield than the opposite. Primarily based on ease of enzyme hydrolysis it was also found that H3PO4 is superior to H2SO4 for the acid catalysed pre-treatment.
The dynamic interface between pre-treatment chemistry and enzyme biochemistry is extremely complex. However, the project has gained an understanding of the relationships between pre-treatment and enzyme hydrolysis. A negative correlation between the concentration of HMF and enzyme hydrolysis on bagasse has been demonstrated, and furthermore a correlation was also found for enzyme hydrolysis with increasing lignin concentration based on straw. In general, fed-batch results in higher fermentation yields compared to batch fermentation and the Monod model provided a very good fit of the experimental fermentation data.
From a boilers point of view, residuals are very similar to sugarcane bagasse / straw and can be used in standard sugar mill boilers when mixed to the bagasse / straw (moisture content should be below 52 % for existing boilers).
The cost modelling showed that, as could be expected, it is difficult to match the ethanol cost in first generation (sugarcane) w/o subsidies. However, it was found that for the integrated case the average ethanol production cost is at the same level as corn based ethanol and production cost of second generation ethanol is comparable to EU starch based ethanol, which is primarily due to the low cost of first generation from sugar cane.
The optimum process scenario for second-generation ethanol production is found when heat and streams are integrated with first-generation and sugar cane leaves and tops are utilised. It was found that 1 tonne of sugarcane produces 144 kg of straw. In other words, a typical sugarcane harvest in Brazil will generate at least 90 million tonnes of straw. Approximately 50 % of all this 'waste' has massive fuel potential and thus utilising the straw from the sugar cane ethanol fuel production could significantly increase the ethanol production without using more land.
Potential impact:
Finding alternative sources of energy is vital for Europe. Whether it is for transport or heating the home, second-generation biofuels are a promising alternative to fossil fuels. And should CANEBIOFUEL project contribute to paving the way for the world's first cost-effective and commercially viable process for converting sugarcane biomass into fermentable sugars, then Europe's goal of becoming a more energy and resource efficient 2020 will become all the more attainable. Already, Europe imported some 10 Mhl of ethanol in 2009, up from 3 Mhl in 2004. It is hoped that, by 2020, at least 10 % of all fuel used in Europe will come from renewable sources, including ethanol. And according to the European Commission (EC), biofuel must emit at least 35 % less greenhouse gases than the fuel they replace. Within that formula is a carbon footprint that must be taken into consideration.
Considering the estimated production of sugar cane in the harvest of 2009 - 2010 according to CONAB and that 1 ton of sugarcane generates 270 kg bagasse and 144 kg trash/straw, the harvest will generate at least 168 million tons of bagasse and 90 million tons of trash/straw. An amount of 1 ton of dry bagasse would allow production of 180 litres of anhydrous ethanol considering 95 % cellulose recovery during pre-treatment, showing a vast potential for boosting the current ethanol production from sugar cane without occupying more arable land in Brazil.
At the commercial level, a working and commercially viable process for the conversion of sugar cane biomass will mean the establishment of a strong value chain consisting of LA sugar cane industry with a globally leading European bio-innovation company (Novozymes A/S), exploiting a very promising business opportunity to the benefit of both regions and their citizens. The market potential of ethanol production based on sugar cane biomass is substantial. The potential ethanol yield in Brazil alone, based on 2006 figures and only considering bagasse, represents a market value of between EUR 26 and EUR 36 Bn. This potential, moreover, will be growing in the coming years due to the gradual accession of new land for sugar cane production. A website was established for the project (please see http://www.CANEBIOFUEL.org online) in order to provide public access to general information on the project. The website is also used as one of the means for disseminating the publications and presentations of the project and the public deliverable reports have also been made available on this site.
All the partners have been actively involved dissemination of project results. During the secon year of the project, results have been presented at several international conferences in Brazil, Europe and North America. Furthermore, some of the project results have been disseminated in 'International Innovation', the leading global dissemination resource for the wider scientific, technology and research communities within the areas: energy, climate, environment, food and agriculture, healthcare, nanotechnology and United States (US) research with around 30 000 readers across the whole of Europe, Africa, LA and the International Cooperation (INCO) countries. Besides what has already been disseminated, the project members still expect to publish several scientific papers concerning the latest project results.
The project has advanced the field of second-generation bio-ethanol from sugarcane to a better understanding of the integration and interaction between pre-treatment and enzyme hydrolysis and provided a better understanding of a Brazilian second-generation bio-ethanol scenario.
List of eebsites: A website was established for the project at: http://www.CANEBIOFUEL.org/
For additional information concerning the project please contact the coordinator, Nina Eriksen from Novozymes A/S, e-mail: Nie@novozymes.com
The cost modelling showed that, as could be expected, it is difficult to match the ethanol cost in first generation (sugarcane) w/o subsidies. However, it was found that for the integrated case the average ethanol production cost is at the same level as corn based ethanol and production cost of second generation ethanol is comparable to European Union (EU) starch based ethanol, which is primarily due to the low cost of first-generation from sugar cane.
The optimum process scenario for second-generation ethanol production is found when heat and streams are integrated with first-generation and sugar cane leaves and tops are utilised. It was found that 1 tonne of sugarcane produces 144 kg of straw. In other words, a typical sugarcane harvest in Brazil will generate at least 90 million tonnes of straw. Approximately 50 % of all this 'waste' has massive fuel potential and thus utilising the straw from the sugar cane ethanol fuel production could significantly increase the ethanol production without using more land.
Project context and objectives:
Second-generation biofuels may hold one of the keys to unlock Europe's objective of becoming more energy and resource efficient by 2020. But today a number of hurdles prevent second-generation biofuels from being commercialised and fully exploited. Second-generation biofuels are made from lignocellulosic biomass. Sugarcane bagasse, the fibrous material by-product of crushed stalk, as well as sugarcane tops and leaves (in the following called straw or trash) are examples of lignocellulosic biomass. Other examples of lignocellulosic biomass include tree bark, corn stover and wood chips. Despite the promises of second-generation biofuels and the availability of the technology, no one has successfully scaled up the process to convert lignocellulosic biomass waste into a commercially viable fuel. Several EU-funded research projects are currently working to change this. One of those is the CANEBIOFUEL project that studied the conversion of sugarcane biomass into ethanol.
The CANEBIOFUEL project is studying the structural components of sugarcane biomass. What was once discarded as waste or used for cogeneration should one day produce clean and inexpensive ethanol fuel. CANEBIOFUEL is one of the first to explore sugarcane straw as a lignocellulose source. The consortium, which built on an already established partnership, involved leading industry and academic partners within the relevant fields from Europe and Latin America.
The overall objective of CANEBIOFUEL was to create a scientific and technological platform for the development of a commercially viable process for converting sugar cane bagasse and trash (i.e. sugar cane biomass) into fermentable sugars. Furthermore, the aim was to integrate such a process with existing production of 1st generation ethanol based on sugar cane. In order to develop such a process, a deeper knowledge about the structural components of sugar cane biomass has been provided with the aim of capturing the easier fraction of the cellulose sugars. Furthermore, the project has aimed to achieve a better understanding of the dynamic impact between pre-treatment and enzymatic hydrolysis in order to specifically design the process and enzymes for cost-effective cellulose conversion. The main technical barriers in the project related to the application of an integrated approach, achieving economically attractive production of second generation ethanol based on sugar cane biomass as opposed to converting biomass into energy or other alternative use. Moreover, challenges were related to achieving process compatibility with existing plants and the accomplishment of a simple and cheap process.
In order to realise the potential of sugar cane biomass, a number of technological challenges related to different process stages have to be fulfilled for successfully implementing conversion technologies for sugar cane biomass and achieve the overall objectives of the CANEBIOFUEL project.
The CANEBIOFUEL project, through collaboration between world leading EU and Latin American (LA) researchers and industrial partners within the biomass and disciplines treated, have addressed these issues through an integrated work plan to achieve project objectives. Thereby, the project aimed to fill the remaining important gaps of knowledge related to the dynamics between pre-treating and hydrolysing lignocellulosic biomass originating from sugar cane processing, thus paving the way for the introduction of fully commercially viable second generation technology.
As such, besides the isolated commercial potential in sugar cane biomass itself, also from a scientific and technical viewpoint there is a need for the CANEBIOFUEL project as a collaborative endeavour of an EU-LA consortium, for which the Framework Programme SICA actions represent an ideal vehicle.
The CANEBIOFUEL project aimed to contribute to the scientific foundation of establishing an integrated process technology for fuel ethanol production from sugar cane biomass with special focus on the interrelated disciplines of lignocellulose pre-treatment chemistry, enzyme hydrolysis biochemistry, as well as process integration and cost simulation. The process must be cost-effective and significantly improve the energy balance of sugar cane production as well as overall environmental sustainability. It was not the intention to verify the final production cost at a pilot or demonstration scale within project-life, but rather to develop a platform that can form the basis for such a technology.
Project results:
In accordance with the CANEBIOFUEL concept and the science and technology (S&T) challenges addressed, a number of specific objectives of the project are defined in the following. The scientific objectives of CANEBIOFUEL was to advance the current state-of-the-art by creating new fundamental knowledge on:
- structural components of sugar cane bagasse and trash components;
- the treatability of various cane biomass fractions;
- chemical changes occurring during cane biomass pre-treatment;
- the dynamic interface between pre-treatment chemistry and enzyme biochemistry;
- enzymatic cellulose convertibility of pre-treated cane biomass;
- factors in pre-treated cane biomass that impact enzyme hydrolysis;
- the technical implications of integrating first and second generation processes;
- process simulation and cost modelling of processing steps for cane biomass conversion;
- process simulation and cost modelling of the whole integrated first and second generation ethanol production with heat and power production.
The technological objectives of CANEBIOFUEL were:
- identification of the best suitable fraction(s) of sugar cane biomass for an enzymatic conversion process;
- development of detailed characterisation of structural components in sugar cane bagasse and trash;
- development of enzymes for improved cellulose conversion of pre-treated cane biomass;
- reduction of ethanol production costs for conversion of cane biomass to a level comparable to current corn-based ethanol of approximately EUR 235/m3 by improvements in the pre-treatment and enzymatic hydrolysis and by process integration;
- development of a process outline for a conversion technology for cane biomass into fuel ethanol;
- increase of the fuel production capacity of existing sugar cane mills by at least 50 % by utilising cane biomass;
- demonstration of an improved energy balance when using sugar cane biomass for fuel ethanol production as compared to its alternative use, i.e. primarily as energy source in sugar mills;
- improved sustainability in sugar cane processing by both reducing carbon dioxide (CO2) emission and avoiding air pollution from trash and bagasse burning in fields and partially at sugar mills.
In order to develop the CANEBIOFUEL process, deeper knowledge about the structural components of the biomass was required with the aim of capturing the most convertible fraction of the cellulose sugars.
Knowledge gaps remained in understanding the dynamics between pre-treating and hydrolysing lignocellulosic biomass. Pre-treating involves opening the lignocellulosic fibre structure. It exposes the cellulose and hemi-cellulose in bagasse and the sugarcane straw for enzymatic hydrolysis. Hydrolysis, on the other hand, introduces an enzyme catalyst that releases the fermentable sugars from the more complex carbohydrates. But for second-generation biofuels to become a reality, the CANEBIOFUEL project first had to identify which part of sugarcane biomass is the most susceptible for an enzyme-based conversion technology to produce the fuel. They also evaluated the best pre-treatment conditions to help reduce the final cost to the consumer. Thus, the project aimed to build a detailed understanding of the dynamic impact between pre-treatment and enzymatic hydrolysis in order to specifically design the process and enzymes for cost-effective cellulose conversion from the selected sugar cane biomass fractions, and integrate this with existing sugar cane processing facilities.
The CANEBIOFUEL project has focused on the following research and technological development (RTD) activities:
- Detailed characterisation of structural components in sugar cane bagasse and trash;
- Understanding the treatability of various fractions;
- Pre-treatment of biomass with focus on integration with existing technology;
- Enzyme development for improved cellulose hydrolysis;
- Process simulation and cost estimation.
In order to evaluate which fraction of the sugar cane biomass is most adequate for an enzyme based conversion technology to produce fuel ethanol, the CANEBIOFUEL project participants had to collect sugar cane samples. In April 2009, 40 people from the Sao Martinho mill in Brazil mechanically harvested approximately 200 ton of sugarcane. Additionally, 150 kg of cane straw was collected from the field. Part of the harvested sugarcane was then separated by the researchers into its individual parts and its moisture content and impurities was measured. The bagasse samples were subsequently vacuum packed, conditioned and shipped on truck to Novozymes Latin America and UFPR installations located in Curitiba (400 km distance from the mill), where the samples were properly stored. The biomass fractions were analysed in relation to their chemical compositions using chromatographic and spectrometric methods. Both the freshly harvested straw and the bagasse collected inside the mill were evaluated. The chemical and morphological characterisation done by the Department of Chemistry at UFPR in collaboration with CTC evidenced significant differences in the chemical and structural composition of bagasse and straw. The treatability of both raw materials has been evaluated and it was found that straw was easier to hydrolyse and ferment compared to bagasse. This is directly related to the different chemical composition and morphology of the two. Despite of the large chemical and structural differences in the two materials, the optimum pre-treatment conditions are found to be similar for both straw and bagasse during acid catalysed pre-treatment which could allow for co-feeding of the two substrates.
Water-washed, steam-treated fractions of cane biomass were characterised and enzyme accessibility of steam-treated cane biomass evaluated. The use of cellulolytic enzymes to convert these materials to ethanol is not a new concept. However, high performance enzymes are a key point for cost-effective production of fermentable sugars from residues. CANEBIOFUEL has been able to narrow down the best-performing enzyme cocktails. When pre-treating bagasse and cane straw using steam explosions, under catalysed and auto-hydrolysis conditions, the project has identified a high-performing combination of enzymes and pre-treatment conditions. Novozymes demonstrated the latest enzyme technology from Novozymes CellicTM CTec and HTec are the first enzymes that live up to these criteria, indicating that the enzyme solution under development at Novozymes is on the right track.
CTC has showed that fermentation of hydrolysates generated under the selected pre-treatment conditions performed similar to the industry standards considering both batch and fed batch feeding strategies.
A flow sheeting model of each individual first and second generation ethanol plant has been implemented and the current autonomous distillery has been simulated as a reference. Separately, a model for estimation of the production cost of ethanol from a combined sugarcane juice and bagasse facility has been developed and all cost data been defined. The cost modelling efforts done by the Department for Chemical Engineering at Lund University showed that by combining the first and second generation based technologies it is possible to reach cost levels similar to starch based ethanol produced in EU.
The CANEBIOFUEL project has advanced the current state-of-the-art by creating new fundamental knowledge on the components in sugar cane bagasse and straw / trash. The treatability of both raw materials has been evaluated and it was found that straw / trash has been shown to be easier to hydrolyse and ferment compared to bagasse. This is directly related to the different chemical composition and morphology of the two. Despite of the large chemical and structural differences in the two materials the optimum pre-treatment conditions were found to be similar for both straw / trash and bagasse during acid catalysed pre-treatment, which allows for co-feeding of the two substrates.
In general, lower severity during pre-treatment, with lower temperatures and shorter times, result in better glucose yield than the opposite. Primarily based on ease of enzyme hydrolysis it was also found that H3PO4 is superior to H2SO4 for the acid catalysed pre-treatment.
The dynamic interface between pre-treatment chemistry and enzyme biochemistry is extremely complex. However, the project has gained an understanding of the relationships between pre-treatment and enzyme hydrolysis. A negative correlation between the concentration of HMF and enzyme hydrolysis on bagasse has been demonstrated, and furthermore a correlation was also found for enzyme hydrolysis with increasing lignin concentration based on straw. In general, fed-batch results in higher fermentation yields compared to batch fermentation and the Monod model provided a very good fit of the experimental fermentation data.
From a boilers point of view, residuals are very similar to sugarcane bagasse / straw and can be used in standard sugar mill boilers when mixed to the bagasse / straw (moisture content should be below 52 % for existing boilers).
The cost modelling showed that, as could be expected, it is difficult to match the ethanol cost in first generation (sugarcane) w/o subsidies. However, it was found that for the integrated case the average ethanol production cost is at the same level as corn based ethanol and production cost of second generation ethanol is comparable to EU starch based ethanol, which is primarily due to the low cost of first generation from sugar cane.
The optimum process scenario for second-generation ethanol production is found when heat and streams are integrated with first-generation and sugar cane leaves and tops are utilised. It was found that 1 tonne of sugarcane produces 144 kg of straw. In other words, a typical sugarcane harvest in Brazil will generate at least 90 million tonnes of straw. Approximately 50 % of all this 'waste' has massive fuel potential and thus utilising the straw from the sugar cane ethanol fuel production could significantly increase the ethanol production without using more land.
Potential impact:
Finding alternative sources of energy is vital for Europe. Whether it is for transport or heating the home, second-generation biofuels are a promising alternative to fossil fuels. And should CANEBIOFUEL project contribute to paving the way for the world's first cost-effective and commercially viable process for converting sugarcane biomass into fermentable sugars, then Europe's goal of becoming a more energy and resource efficient 2020 will become all the more attainable. Already, Europe imported some 10 Mhl of ethanol in 2009, up from 3 Mhl in 2004. It is hoped that, by 2020, at least 10 % of all fuel used in Europe will come from renewable sources, including ethanol. And according to the European Commission (EC), biofuel must emit at least 35 % less greenhouse gases than the fuel they replace. Within that formula is a carbon footprint that must be taken into consideration.
Considering the estimated production of sugar cane in the harvest of 2009 - 2010 according to CONAB and that 1 ton of sugarcane generates 270 kg bagasse and 144 kg trash/straw, the harvest will generate at least 168 million tons of bagasse and 90 million tons of trash/straw. An amount of 1 ton of dry bagasse would allow production of 180 litres of anhydrous ethanol considering 95 % cellulose recovery during pre-treatment, showing a vast potential for boosting the current ethanol production from sugar cane without occupying more arable land in Brazil.
At the commercial level, a working and commercially viable process for the conversion of sugar cane biomass will mean the establishment of a strong value chain consisting of LA sugar cane industry with a globally leading European bio-innovation company (Novozymes A/S), exploiting a very promising business opportunity to the benefit of both regions and their citizens. The market potential of ethanol production based on sugar cane biomass is substantial. The potential ethanol yield in Brazil alone, based on 2006 figures and only considering bagasse, represents a market value of between EUR 26 and EUR 36 Bn. This potential, moreover, will be growing in the coming years due to the gradual accession of new land for sugar cane production. A website was established for the project (please see http://www.CANEBIOFUEL.org online) in order to provide public access to general information on the project. The website is also used as one of the means for disseminating the publications and presentations of the project and the public deliverable reports have also been made available on this site.
All the partners have been actively involved dissemination of project results. During the secon year of the project, results have been presented at several international conferences in Brazil, Europe and North America. Furthermore, some of the project results have been disseminated in 'International Innovation', the leading global dissemination resource for the wider scientific, technology and research communities within the areas: energy, climate, environment, food and agriculture, healthcare, nanotechnology and United States (US) research with around 30 000 readers across the whole of Europe, Africa, LA and the International Cooperation (INCO) countries. Besides what has already been disseminated, the project members still expect to publish several scientific papers concerning the latest project results.
The project has advanced the field of second-generation bio-ethanol from sugarcane to a better understanding of the integration and interaction between pre-treatment and enzyme hydrolysis and provided a better understanding of a Brazilian second-generation bio-ethanol scenario.
List of eebsites: A website was established for the project at: http://www.CANEBIOFUEL.org/
For additional information concerning the project please contact the coordinator, Nina Eriksen from Novozymes A/S, e-mail: Nie@novozymes.com