Conversion of high sugar grasses to alcohol based transport fuel (GRASSOHOL)

Lead Research Organisation: Aberystwyth University
Department Name: IBERS

Abstract

Under the terms of the Renewable Transport Fuel Obligation (RTFO), the UK is committed to substituting 5.75% of its gasoline consumption with bio-derived fuels by December 2010. This demand is predicted to increase in the future, particularly in response to concerns about climate change and fuel security. Current, biofuel generation in the UK is negligible and demands are met by bioethanol imports from countries such as Brazil. Bioethanol is mainly produced from 'first generation' crops (e.g. maize, wheat, sugar beet and sugar cane) which are characterised by a high non-structural carbohydrate content. The technology involved is straightforward and production has become more price competitive. The feasibility of producing biofuel from such crops in the UK is limited because of the requirement for arable land which is primarily used for food production and the high energy input involved. Production of biofuel from 'second generation' lignocellulosic crops such as grasses offers a potential alternative. Grasslands comprise up to 70% of UK agricultural land greatly exceeding the area used for food crops. Perennial ryegrass achieves similar biomass yields to other lignocellulosic crops used for biofuel production. This crop has a number of traits which are desirable in a fermentable feedstock including a readily available high water-soluble sugar content, high fibre digestibility and a low lignin content in comparison with other candidate lignocellulosic crops. Perennial grasses have low annual input requirements and contribute to the rural landscape, maintaining biodiversity and environmentally sensitive landscapes which have major attractants for the tourist industry. UK farmers have the necessary expertise involved in management of these grasses which can be harvested over a long season and stored over winter. We propose that perennial ryegrass can provide an environmentally and economically viable feedstock for the production of bioethanol and that existing biological material and technologies can be readily adapted to achieve this. The main challenges for development of a sustainable, low input process, for conversion of grasses to bioethanol will be addressed in this programme. This will include reducing the major operating costs, maximising yield and carbon cost efficiency. IGER's large selection of ryegrass germplasm will be exploited to select for appropriate varieties, in particular, high sugar perennial grasses with high digestibility (low lignin). The legume, white clover, will be included in grass swards to provide nitrogen and minimise green house gas emissions associated with artificial fertilizer. This programme will test the feasiblility of juicing on-farm to generate two separate feedstocks; a water soluble carbohdyrate (fructan) rich liquid fraction and a high dry-matter stable lignocellulosic fraction. Procedures for handling, preserving/stabilising and transporting these feedstocks will be assessed. A major aim is to maximise utilisation of the full range of sugars in perennial ryegrass for fermentation to ethanol. This will be achieved by using an appropriate combination of pre-treatments, enzymes, yeast and an ethanol producing thermophilic micro-organsim, taking advantage of TMO Renewables groundbreaking method for producing ethanol from almost any type of biomass. Fermentation conditions will be optimised to maximise ethanol production from ryegrass feedstock both at laboratory and pilot scale. The carbon and energy balance as well as the economic viability of these processes will be evaluated. Data generated by this programme will provide valuable information for accurate comparisons with other crops used in bioethanol production.

Technical Summary

Current biofuel generation in the UK will not meet the UK's Renewable Transport Fuel Obligation. The production of bioethanol from 'first generation' crops (e.g. maize, wheat, etc.) in the UK is limited by the requirement for arable land (primarily used for food production) and high energy inputs. Grasses, which comprise up to 70% of UK agricultural land, offer a potential alternative. Perennial ryegrass, which can achieve similar biomass yields to other lignocellulosic biofuel crops, contains high quantities of readily available water-soluble sugars, has high fibre digestibility, low lignin content, low annual input requirements while contributing to the rural landscape, maintaining biodiversity and environmentally sensitive landscapes. Our objective is to provide an environmentally and economically viable feedstock for the production of bioethanol using IBER's large collection of ryegrass germplasm. The legume, white clover, will be included in grass swards to provide nitrogen and minimize green house gas emissions associated with artificial fertilizer. From the grass, two separate feedstocks will be produced; a water soluble carbohydrate rich liquid fraction and a high dry-matter stable lignocellulosic fraction. Procedures for handling, preserving/stabilizing and transporting these feedstocks will be assessed. The utilization of the full range of sugars for fermentation to ethanol will be achieved by using an appropriate combination of pre-treatments, enzymes, yeast and an ethanol producing thermophilic micro-organism which can ferment a wide range of C5 and C6 sugars. Fermentation conditions will be optimized to maximize ethanol production both at laboratory and pilot scale. The carbon and energy balance as well as the economic viability of these processes will be evaluated. Data generated by this programme will provide information for accurate comparisons with other crops used in bioethanol production.

Publications

10 25 50
 
Description In this project, perennial ryegrass was assessed as a feedstock for the production of bioethanol. A series of plots were set up using a range of different grasses with differing water soluble sugar content. The grasses were grown with different applications of nitrogen and also as mixed clover swards. Yield and sugar content was monitored over the growing season. A high sugar grass mixture (HSGII) supplied by Germinal Ltd. showed consistently higher yields and sugar content over the growing season and a direct correlation was also observed between nitrogen levels applied to the soil and grass yield.
Following harvesting, the grass was processed through a screw press to produce both a rich juice containing high levels of water soluble sugars and a highly digestible fibre. The juice was transferred to a holding tank at 4oC, acidified and heated to pasteurise. This resulted in coagulation of the soluble proteins, which were recovered by centrifugation, and the conversion of the complex water-soluble sugars to simple, fermentable sugars. Alternative processing methods that included conversion of the complex soluble sugars to simple sugars using enzymes was shown not to be cost effective.
The pasteurised juice represented a rich fermentation media with a high sugar content. Following a series of optimisation experiments, assessing different nitrogen sources, additives and buffering systems, an optimised process was developed for the conversion of the soluble sugars to bioethanol using commercially available yeast.
The fibre component, resulting from the pressing of the grass, was subjected to a range of thermo-chemical and enzymic pre-treatments to maximise the release of fermentable sugars, while reducing the amount of fermentation inhibitors. An optimised process was developed that included the use of stream-explosion followed by cellulose and xylanase digestion. The resulting sugars were converted to bioethanol using a thermophilic bacterium capable of using both C5 and C6 sugars. The fermentation process was optimised by altering temperature, additives and buffering systems. Using the optimised processing and fermentation system, it was demonstrated that fibre from grass harvested early in the growing season produced more ethanol per kg that material harvested later in the season.
A model for the production of bioethanol was developed that included agronomy, storage, transport and processing components. Economic analysis demonstrated that bioethanol production was commercially viable using grass juice if the protein in the juice and the remaining fibre were used as animal feed. Production of ethanol from the fibre fraction was not economical, however, this may change with the development of cheaper enzymes and more efficient fermenting organisms.
Exploitation Route These finding have been taken forward in the assessment of grass as a potential feedstock for biorefining. This work has led to additional funding in the area of grass biorefining. A patent application has been filed.
Sectors Agriculture

Food and Drink

Chemicals

Environment

Manufacturing

including Industrial Biotechology

Retail

 
Description Since this research was completed, two companies from Ireland have been in contact regarding the financial possibilities of building a grass biorefinery in Ireland and the UK. Additionally, a biomass probe sold for monitoring yeast growth in fermentations was demonstrated as part of this project to be able to monitor lignocellulosic biomass breakdown in the presence of hydrolytic enzymes, continuously and in real-time. This has opened up new markets for the company.
Sector Chemicals,Energy,Manufacturing, including Industrial Biotechology
Impact Types Economic

 
Description 2012 International Partnering Award US-UK Biorefining Collaboration
Amount £30,290 (GBP)
Funding ID BB/K021427/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 06/2013 
End 07/2015
 
Description Academia for Business (A4B)-STARS
Amount £800,000 (GBP)
Organisation Government of Wales 
Department Welsh European Funding Office
Sector Public
Country United Kingdom
Start 01/2013 
End 12/2014
 
Description Accelerating Synthetic Biology Approaches to Renewable Chemicals and Fuels
Amount £51,020 (GBP)
Funding ID BB/M027740/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 03/2015 
End 03/2019
 
Description BEACON + Biorefining Center
Amount £8,000,000 (GBP)
Organisation European Commission 
Department European Regional Development Fund (ERDF)
Sector Public
Country Belgium
Start 06/2015 
End 12/2019
 
Description BEACON Biorefining Center
Amount £12,000,000 (GBP)
Organisation European Commission 
Department European Regional Development Fund (ERDF)
Sector Public
Country Belgium
Start 06/2011 
End 06/2015
 
Description Integrated Biorefining Research and Technology Club
Amount £800,000 (GBP)
Funding ID BB/I005390/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 09/2012 
End 09/2016
 
Description Sparking Impact
Amount £16,682 (GBP)
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 08/2013 
End 03/2014
 
Description TRansnational Industial Biotechnology: UTilization of Extremophiles through academic-industry Partnership (TRIBUTE)
Amount £30,082 (GBP)
Funding ID BB/L027097/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 04/2014 
End 05/2017
 
Description Technology Strategy Board - Chitin and lactic acid production crab shell waste
Amount £160,000 (GBP)
Funding ID TS/L006790/1 
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 03/2014 
End 12/2014
 
Title Grassohol Model 
Description Using data from research with input from industrial partners, we have developed a model to predict the environmental and economic potential of setting up a grass based biorefinery primary based on the production of bio-ethanol 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact We have used aspects of this model in other projects in the area of grass biorefining to determine viability of different scenarios 
 
Title NREL BioLUC model 
Description The model was developed by NREL to look at environmental and economic impact of utilising crops and residues for the production of biofuels and platform chemicals. 
Type Of Material Computer model/algorithm 
Year Produced 2015 
Provided To Others? Yes  
Impact This model will be used by academia, industry and government, particularly in the united states to determine policy and research direction. 
URL https://github.com/NREL/bioluc
 
Title Bioethanol from Grass 
Description Process for the conversion of grass juice to bioethanol and platform chemicals 
IP Reference GB1502174.4 
Protection Patent granted
Year Protection Granted 2017
Licensed No
Impact To early, not yet granted
 
Description ADAS visit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact Presentation and discussion with representatives from ADAS as well as people from own institute on using grass as a feedstock for biorefining as well as for animal feed. Through these discussions, it is hoped that information will be conveyed to the farming community and industry.
Year(s) Of Engagement Activity 2018
 
Description AIEC opening 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Opening of AU new Biorefining centre. Presentations were made on current biorefining projects along with equipment available to academics and industry.
Year(s) Of Engagement Activity 2019
 
Description Barroness Eluned Morgan Welsh Assembly Member discussion on bio-economy policy and research 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Policymakers/politicians
Results and Impact Presentation on work on biorefining projects and discussion on our contribution to driving the rural strategy for Wales.
Year(s) Of Engagement Activity 2017
 
Description Beer and cider special interest group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Presentation on capability and research projects
Year(s) Of Engagement Activity 2018
 
Description Ben Lake MP visit 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Presentation on our biorefining research
Year(s) Of Engagement Activity 2018
 
Description Brazil Workshop (Minton) 2016 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Third sector organisations
Results and Impact Workshop in the area of biorefining and Biofuels.
Year(s) Of Engagement Activity 2016
 
Description Chief Scientific Officer for Wales Julie Williams 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Policymakers/politicians
Results and Impact Presentation of research in biorefining and discussions regarding future direction of science in Wales
Year(s) Of Engagement Activity 2016
 
Description Coleg Cambria visit 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Undergraduate students
Results and Impact Presentation and discussion on aspects of biorefining and implications for the future farming community.
Year(s) Of Engagement Activity 2017
 
Description Crab industry 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Presentation and disicussion on the possibility and practicalities of utilisation crab shells for biorefining.
Year(s) Of Engagement Activity 2015
 
Description Farming Group - Diversification 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Presentation and discussion with Farmers on new opportunities to diversity into new crops or look for new markets for existing crops in the context of biorefining.
Year(s) Of Engagement Activity 2017
 
Description National Farmers Union Wales 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Third sector organisations
Results and Impact Discussion to help direct delivery of NFU policy towards zero carbon including biorefining solutions
Year(s) Of Engagement Activity 2020
 
Description Newton visit Brazil (Huws) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Third sector organisations
Results and Impact Discussion with researchers and industry in Brazil regarding areas of overlap/interest to develop new funding applications in the areas. Presentation of specific projects.
Year(s) Of Engagement Activity 2016
 
Description Presentation to farmers group 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Presentation to a farming group on the potential use of grasslands for the production of energy, biofuels and platform chemicals including potential existing and developing supply chains.
Year(s) Of Engagement Activity 2015
 
Description Regional Stakeholder Partnership for Land-based Goods 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Presentation of production of platform chemicals/fuels/fine chemicals and potential health care products as well as integrated biorefining from a range of land-based feedstock.
Year(s) Of Engagement Activity 2018
 
Description Visit by Jane Hutt to Beacon 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Visit by Jane Hutt (Wales Finance Minister) to the Beacon facility to view the work being done in the area of Industrial Biotechnology and its contribution to the Welsh Economy.

Improved ministerial awareness of the role of the bioeconomy in Wales.
Year(s) Of Engagement Activity 2014
 
Description Visit of Fulbright scholars to Beacon 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Discussions of similarities and differences between US and Wales bioeconomy practices.

We are expecting PhD enquiries to result.
Year(s) Of Engagement Activity 2014
 
Description Wales Festival of Innovation 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Presentation on biorefining capability and discussion of relevant projects undertaken by our research group with members of the public, students and farming community to inform on potential opportunities.
Year(s) Of Engagement Activity 2017
 
Description Welsh Gov. innovation team 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Policymakers/politicians
Results and Impact Presentation and discussion with Welsh Government Innovation Team, current projects, research strategy and future directions in the area of Industrial Biotechnology. This included our strategy for interacting with the business community, both in Wales and beyond.
Year(s) Of Engagement Activity 2017
 
Description Welshpool Earth Science group visit 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Presentation and discussions on future farming and the potential of biorefining, creating new markets for agricultural outputs.
Year(s) Of Engagement Activity 2017