*EPSRC* Harnessing ‘waste’ biomass to make modified cellulose with valuable novel properties

Rationale. This project targets the EPSRC’s growing Research Area of Chemical Biology and Biological Chemistry. It comprises novel research that is both of fundamental interest and has industrial applicability in creating new materials from Nature — specifically from ‘waste’ pulp biomass. By developing new, non-polluting procedures, the aim is to generate high-value materials with sought-after physical properties, especially a controllable viscosity. Starting with cheap, cellulose-rich materials available downstream of agri-food industries (e.g. pulp from sugar-beet and carrots after extraction of the sugar- and vitamin-rich juices), the aim is to make valuable non-natural materials — an example of synthetic biology applied to a novel and exciting physicochemical science research programme for the benefit of agricultural technologies.

Preliminary data from the applicants’ laboratories. In a preliminary project in Prof. Fry’s laboratory, the applicants have partially characterised pulp-based materials with desirably high viscosities that have potential as industrial ingredients. We have discovered how to subject pulps to a combination of chemical (appropriate doses of non-polluting oxidants) and physical conditions (stirring, temperature, time) to yield high-viscosity materials. A high proportion of the pulps’ pectic and hemicellulosic polysaccharides are degraded and largely removed during the treatment, but most of the cellulose remains — albeit in an interestingly modified form. Currently, there is a degree of variability in the products’ viscosity, but our unpublished data have pinpointed certain physico-chemical features of the most successful batches. Specifically, the results indicate that in ‘good’ preps the cellulose undergoes novel oxidation reactions that gelatinise it. These changes appear to correlate with the generation of an end-product with the desired viscosity (rheology).

Student’s role: initially working under close guidance. The student will explore the specific chemical changes occurring in pulp cellulose during the oxidation treatments. The student will hydrolyse the oxidised cellulose (with acids and/or enzymes) and isolate the modified sugar ‘building-blocks’ present. Initially, this exploration will be by chromatography and electrophoresis, with detailed practical advice and guidance from the supervisors. Training will be provided in polysaccharide analysis, including monosaccharide composition, linkage analysis, molecular weight and charge determination; presentation of seminars, posters, reports and manuscripts; and experience of undergraduate teaching (practicals).

Student’s role: subsequent opportunities for independent exploration. Later, depending on initial findings and the student’s interests, the student will have the opportunity to devise the best ways forward to fully characterise the modified sugars. This may involve 1H- and 13C-nuclear magnetic resonance spectroscopy in collaboration with colleagues at the EastChem School of Chemistry (Drs Ian Sadler and Dušan Uhrín), and mass spectrometry in collaboration with SynthSys (Dr Hannah Florance) — both in neighbouring laboratories.

Industrial liaison. When the student has elucidated the chemistry of the beneficial modified sugars formed during pulp treatment, he/she will be encouraged to devise and test ways of enhancing their yield. This will involve periods of work at the CelluComp laboratories, where new methods of industrially relevant pulp handling can be realistically tested. These periods of industrial liaison will give the student some insight into the opportunities and practicalities of novel engineering processes, including handling industrial materials and reactors.

The student will be mainly based in the Edinburgh Cell Wall Group (ECWG); for background on the Group’s current interests, see: http://fry.bio.ed.ac.uk//

Currently the ECWG comprises Professor S.C. Fry (Principal Investigator), 3 BBSRC-funded postdocs, 6 PhD students (all within years 1–4; funded by various sources, including self-funding, University of Edinburgh/CelluComp co-funding, a Commonwealth Scholarship, the Omani Ministry of Manpower, Mars Chocolate Ltd, and Aberdeen University), 1 visiting 6-month PhD student (funded by HEC, Pakistan), and 1 BBSRC-funded technician. Their research projects focus on plant cell wall chemistry and biophysics and are thus at the border between biological and physicochemical science.

The student will also spend some time at CelluComp, Burntisland, Fife, supervised by the industrial collaborator (Dr Eric Whale).