Isolation fractionation and modification of fructans from rye-grass to produce novel biosurfactants and polymers as part of a rye-grass biorefinery

Lead Research Organisation: Glyndwr University
Department Name: Science Research Centre


There are a large number of biorefinery initiatives in Europe based on a range of different feedstocks including grass, cereals, legumes and sugar beet. Grass-based biorefinery initiatives are located in Ireland, Belgium, Austria, Poland, Germany, and the Netherlands. High-sugar perennial rye-grass has the potential to provide an ideal biorefinery feedstock for the production of bio-ethanol and bulk chemicals such as succinates and lactic acid, with other co-product streams such as biocomposite materials and animal feeds manufactured from the fibre fraction. This grass is high yielding (ca.15 tonne dry wt./hectare/year) and is ideally suited to the climatic and soil conditions experienced in the UK. It can grow on marginal land that will not support the growth of cereal crops and hence will not jeopardise future food supplies. It requires low annual inputs, especially when grown with clover as a source of nitrogen, and does not require investment in new equipment for sowing and harvesting. This feedstock is available now and is abundant throughout the UK. From a biorefining perspective, it is highly digestible (4-6% lignin) and has a high water soluble sugar content (up to 40%). It also has the benefit of storing its carbohydrate reserves in the form of the water-soluble sugar, fructan, rather than starch. Unlike starch, which requires treatments with heat, acids and a series of enzymes, for conversion to a fermentable sugar, fructan can be converted through the use of a single enzyme. A grass biorefinery based on ethanol and bulk chemicals as well as biocomposites production alone, however, is unlikely to be economically viable and it is necessary to produce additional high value chemicals from the fructan molecules isolated. This project involves a multidisciplinary team of scientists with complementary skills ranging from plant biology to biochemistry, chemistry and surface and colloid science. It sets out to utilise the diverse range of fructan molecules found in perrential ryegrass, as well as novel molecules created by the action of fructan hydrolysing enzymes on these fructans to produce novel high value chemicals. It will initially identify the optimum rye-grass feedstock for a biorefinery by screening a range of perennial ryegrasses developed at Aberystwyth University that will produce high yields of fructans with specific size and molecular architecture. Novel ultrasound technologies will be investigated to maximise the release of plant sugars from the rye-grass through mechanical rupture of cell walls and to assist in the removal of coloured impurities. The fructans will be separated into different classes according to their molecular size and will then be chemically modified to produce a range of high-value sugar-based polymer and surfactant molecules that can be used in the formulation of a broad range of commercial products including, pharmaceuticals, cosmetics, personal care, coatings, etc.. Their role in these products is to aid the dispersion of particles, the emulsification of oils and in the control the rheological behaviour. The global demand for surfactants in 2000 was 19.2 million tonnes with carbohydrate based products accounting for 2.9 million tonnes. The demand for biosurfactants produced from renewable sources is likely to expand rapidly, with increasing pressure to reduce the reliance on petroleum derived products. The contribution of the value of the speciality chemicals produced during the course of the project will be assessed with regards to the economics of a total grass grass biorefinery.

Technical Summary

This proposal is concerned with the establishment of a sustainable biorefinery based on rye-grass and brings together a team of academics with complementary expertise ranging from plant biology, to biochemistry, chemistry and colloid science. The project exploits perennial ryegrass which produces a diverse range of fructan molecules (branched/linear) varying in composition from 3-90 fructose units with different bond types (beta 2,1 and beta 2,6) that will be chemically modified to produce novel polymers and surfactants. These molecules will be produced either directly or through the action of fructan hydrolysing enzymes (endo and exo). Isolation will include the use of novel ultrasound technologies to aid the release of plant sugars from the rye-grass and removal of coloured impurities. Membrane filtration technologies will be used to fractionate the fructans according to their molecular size. The fructans will then be modified to produce a range of polymers and surfactants that can be used in the formulation of a broad range of products including cosmetics, personal care products, pharmaceuticals, surface coatings etc. Chemical modification will be achieved by reacting the fructans with alkenyl succinic anhydrides and alkyl acyl chlorides under relatively mild aqueous conditions. Maillard -type complexes will be produced with a series of proteins and protein hydrolysates using the enzyme treated-fructans. By choosing fructans of varying chain length it will be possible to produce materials which can perform as wetting agents, emulsifiers and rheological modifiers. The performance of the surfactants will be assessed by measurement of the contact angle and dynamic surface tension while the performance of the polymers will be investigated by measurement of the steady shear viscosity.

Planned Impact

The Integrated Biorefining Research and Technology (IBTI) Club was set up to promote the development of sustainable biorefineries based on biomass and its Steering Group has members from both Academia and Industry. This proposal is in response to the IBTI Club Second call and addresses all three of the science themes set out namely a) 'optimisation of feedstock composition' by screening for plants with altered fructan chemistry, b) 'integrative bio-processing'by creating new sets of molecules using existing technologies and c) 'enhanced product value' by creating high value chemicals from water soluble sugars. This application represents an integration of academic expertise from plant biology and chemistry disciplines to work on an area of science relevant to industry. It will have major social and economic impact since it involves establishing biorefinery technologies which will lead to the creation of both revenue and jobs in the agricultural sector while supplying a broad range of industries with a new set of unique molecules that are currently produced from oil without jeopardising future food supplies. The resulting discoveries and their commercialisation will have an impact by reducing the dependence on oil and hence reducing greenhouse gas emissions without jeopardising food supplies and also by increasing employment in the 'green supply chain'. The main beneficiaries of this research will be: (1)the members of the IBTI Club through the establishment of a sustainable biorefinery based on rye-grass and the creation of a new set of polymers and surfactants based on biodegradable fructans that can be commercially exploited. (2)the academics involved in the project through the development new knowledge and subsequent dissemination in the scientific and/or patent literature. (3)the staff directly employed on the project through specialist training and acquisition of project management, communication and high-level technical skills. (4)the UK agricultural sector through the development of a sustainable crop leading to an increase in revenue and the creation of new jobs (5)the UK Government through the development of processes which reduce the impact of industrialisation on the environment and increase opportunities for the development of the low carbon economy. (6) the UK as a whole by increasing employment in the 'green supply chain' and reducing the dependence on oil and lowering 'green house' emissions. (7)future generations through the mitigation of climate change. AU and BU have existing collaborative interactions in the area of biorefining and are therefore aware of the development of collaborative agreements that includes project management and sharing of IP and BU and GU are currently collaborating on a technology transfer project funded through the Welsh Assembly Government. Once the proposal is approved an appropriate agreement will be put in place between the three Universities and an exploitation plan developed. The primary route to realising the economic impact will be through the IBTI Club industrial partners in recognition of their support for this initiative. The Principal Investigators will be responsible for ensuring that all of the results of the work are published in peer reviewed scientific journals and/or patents and also as popular articles for the wider community. An overview of the project will be included on the websites of the three collaborating Universities and will be regularly updated to include new developments. A Workshop will be organised to apprise the the academic and industrial communities of the project and of the biorefinery initiative in general. The Principal Investigators have a strong publication record and considerable experience of technology transfer activities and commercialisation of IP. They have secured funding through EPSRC, BBSRC, DEFRA-Renewable Materials Link, EU, TSB and KTP programmes.
Description The work was concerned with the synthesis, characterization and properties of a series of alkylated fructans with a view to developing a sustainable biorefinery based on fructans derived from rye-grass. The project led to the production of a range of bio-based surfactants that have potential application for the encapsulation and delivery of active hydrophobic compounds as well as for application as emulsifying and foaming agents in personal care and home care products.
Exploitation Route The surfactants developed have potential application as emulsifiers and foaming agents and discussions have been on-going with relevant industrial companies
Sectors Chemicals,Environment,Healthcare,Pharmaceuticals and Medical Biotechnology