Photocatalytic bioethanol Production

Lead Research Organisation: The Robert Gordon University
Department Name: Env Eng and Sustainable Energy

Abstract

One of the greatest challenges in the 21st century is to meet the global energy demand. Dwindling supplies of fossil fuel, combined with detrimental release of green house gases (GHG) have lead to the quest for renewable sources of fuel/energy with EU targets of 10% energy from renewable by 2020. Wind, solar, tidal and biofuel from crops (sugar cane and corn) are rapidly being introduced as alternative energy supplies. However, use of food crops has been widely criticised due to escalating population, food prices and deforestation for cultivation of energy crops hence there is an urgent need to develop more sustainable alternatives that do not impact global food production. One approach is the exploitation of significant quantities of available fibrous waste, which consist largely of cellulose. This waste, generated by agriculture, forestry and industry (e.g. paper manufacturing) can be exploited for biofuel production. It has been estimated that in the UK alone, annual excess straw exceeds 5.7 million Tonnes. This abundant waste resource, coupled to the fact that they are geographically evenly distributed across the country, could offer localised, low energy solutions for production of biofuel.
As a carbohydrate cellulose consists of sugar molecules which can be fermented to provide ethanol but unlike starch the structure of cellulose prevents simple release of bound sugars. Previous attempts to harness cellulosic waste have used extreme treatment conditions to release the usable sugars. In existing pre-treatment procedures, enzymes, acid and alkali explosion, wet oxidation, steam explosion may be combined with high pressure and temperature. These procedures are expensive, energy demanding and generate hazardous waste.
In this project, we propose a cost effective, low environmental impact approach to produce bioethanol from cellulosic waste by photocatalysis combined with fermentation in a single reactor. Photocatalysis is a process which uses a catalyst to accelerate a photoreaction by generating free radicals, and is commonly exploited in a range of applications (waste water treatment, antifouling paints, self-cleaning glass). Photocatalysis will be used to release sugars from the cellulose which will pass through a semi-permeable membrane where they will be fermented by yeast (or other selected microbes) to yield bioethanol. This approach has multiple advantages; catalyst is low cost, non-toxic, self cleaning, recoverable and activated by harvested natural light (augmented by low energy LED's where required). This integrated work programme is led by the experts in microbiology (Professor Linda Lawton - RGU), engineering (Professor Peter Robertson-RGU) and chemistry (Professor John Irvine - St Andrews) all of whom have a proven track record in application driven research.
Key components of the work programme include; substrate targeted design and synthesis of novel catalysts, which will be screened for maximum liberation of fermentable sugars, screening of microbes for maximum production of bioethanol, design, fabrication, testing and optimisation of the parallel bench scale reactor. A key features of the reactor is the use of selective membranes to separate the liberated sugars from the catalyst. Under typical conditions the photocatalytic reaction would completely degrade compounds in contact with the catalyst hence liberated sugars will pass through the membrane where they will be available for microbial degradation. This novel reactor will be simple and scale-able facilitating implementation at local or municipal scale. For maximum versatility, the reactor will be optimised to produce bioethanol from an array of waste feed stocks from agriculture and industry.
This multidisciplinary project will address the challenge of renewable energy with the development of a sustainable, cost effective, low environmental impact process for conversion of low value fibrous waste into high value bioethanol.

Planned Impact

Current trends on world's energy are unsustainable. Rapid depletion of fossil fuels coupled with increased global population, industrialisation and climate change, necessitate radical changes in strategy. Development of practical, renewable energy solutions is essential to secure a sustainable global energy supply.

To address this challenge, the project aims to develop and optimise a scale-able parallel reactor for the conversion of waste biomass from plants into bioethanol. The process will be cost effective with low environmental impact, exploiting the photocatalytic conversion of waste to produce sugars followed by fermentation into bioethanol. The potential of the proposed concept has been clearly demonstrated in a preliminary study at RGU by the photocatalytic release of fermentable sugars from cellulose using a photocatalyst (TiO2). The outcome of this 4-year project has been expected drive into potential socio-economic and environmental impacts for sustainable human life and environment, for both developed and developing countries. To meet this challenge, we have assembled a multidisciplinary team, of application driven researchers and developed a programme that reflects a clear pathway to impact in research, society and the environment.

Development of this novel approach for bioethanol production has multiple direct beneficiaries; industry (re-use of waste reducing carbon footprint), environmental organisations (reduction in pollutants from waste and current processes), governments (positive economical value, fuel and food security), communities (employment, rural income, infrastructure development).In addition to contributing to future renewables, the technology involved in the parallel reactor will have enormous potential for low cost/energy bio-processing applications with clear global benefit. The success of this reactor would provide a world leading technology with clear export value globally as the reactor design would be suitable for application in most countries.

This project provides opportunities for public communication and engagement; local and national media, podcasts, web pages, schools (projects for pupils, exhibitions and science festivals), covering areas on use of low value waste for biofuel production, harnessing natural light and smart bio-processing. The multidisciplinary nature of the work would make it particularly relevant to developing interest in SET subjects with school pupils encouraging students to pursue these topics to a higher level.

Close collaboration of PIs, co-Is and PDRAs is pivotal to success in this project and will clearly benefit development of the PDRAs by means of knowledge transfer, interdisciplinary training and exchange visits. Development of innovative young scientists is essential for a sustainable research and development capability.

Significant impact of this project is that it will involve high quality research at the forefront of science and technology. It is expected to lead to high impact publications, multiple technology patents and extensive public/industrial engagement activities. The ultimate impact is to deliver a sustainable, technological solution to meet the future energy challenges and demonstrate the UK's commitment to this important agenda.

Publications

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Hui J (2017) Promoting photocatalytic H evolution by tuning cation deficiency in La and Cr co-doped SrTiO. in Chemical communications (Cambridge, England)

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Nagarajan S (2017) Comparative assessment of visible light and UV active photocatalysts by hydroxyl radical quantification in Journal of Photochemistry and Photobiology A: Chemistry

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Nagarajan S (2017) Cellulose II as bioethanol feedstock and its advantages over native cellulose in Renewable and Sustainable Energy Reviews

 
Description We have discovered methods to photocatalytically degrade cellulose releasing sugars. We have demonstrated how hydrogen fuel can also be produced during this process.

We have now shown that a range of sugars can be produced by this process and that the products change during the reaction. Reaction conditions such as pH have also been found to influence the product range and yield of the different sugars.

We have also demonstrated that the products of the photocatalysis (i.e. the sugars) can be fermented to yield ethanol as a potential biofuel.
Exploitation Route The findings provide an alternative/controlled way to release chemicals from waste cellulose which could be exploited in many chemical processes.

The developments here provide a way to yield platform chemicals and produce biofuels.

A range of cellulose sources (barley strew, paper waste pulp and sawdust) have been all shown to produce sugars during photocatalysis.
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Chemicals,Energy,Environment,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Transport

 
Description Internal (RGU) fully funded studentship award
Amount £75,000 (GBP)
Organisation Robert Gordon University 
Sector Academic/University
Country United Kingdom
Start 02/2014 
End 02/2017
 
Description BBC Countryfile Live (Oxford) - Bioenergy tent/workshop in association with University of Southampton Roadshow, Aug 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Younger kids were fascinated by how much we can produce from 'waste' and the importance of recycling. I saw bigger impact with adults who again were surprised to hear how much bioenergy does and that there are options other than a wind turbine. A lot of people were interested in the comic and wanted to know more about what their local communities/councils were doing in terms of bioenergy - a few seemed very concerned that their local area wasn't doing enough.
Year(s) Of Engagement Activity 2017
 
Description Development of a bioenergy graphic novel 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Dr Nathan Skillen has been one of the team developing this outreach activity: The graphic novel is a public engagement project funded by the SuperGen Bioenergy Hub. The project consists of 10 PDRA's from across the UK and 5 artists who have worked together to develop a novel that describes what bioenergy actually is. The novel addresses the need for bioenergy, where it comes from, types of bioenergy and technologies, controversies and future scenarios. As far as we know this will be one of the first times a project like this has been done.
Year(s) Of Engagement Activity 2017
 
Description North East Big Bang Festival (Liverpool) - Bioenergy stall promoting the Bioenergy Graphic Novel, July 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Teachers very interested to have the comic as a teaching aid. In terms of students (secondary pupils), they were more interested to learn about the novel work we do as the had already learnt about the basics of bioenergy in school. A number of them also had projects coming up at school and were interested to do something on bioenergy so they were very engaging and liked to ask a lot of questions. We also meet a number of students who were designing furniture from sustainable materials as part of their project at the big bang festival so they were keen to speak to us about biomass and the sources of materials we can use.
Year(s) Of Engagement Activity 2017
 
Description Press release highlighting the research project 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Email dialog, web posts, industrial discussions

Increased base of interested industries
Year(s) Of Engagement Activity 2014
URL https://www.energyvoice.com/otherenergy/50025/universities-land-1-1m-biofuel-research/?utm_source=tw...
 
Description Regular distrubution of Bioenergy Graphic Novel during Opend days and school visits 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact During outreach visits we offer free copied of the Bioenergy Graphic Novel which has been distributed through the University reception area to visitors and staff, to those attending open days and at school science visits throughout Scotland
Year(s) Of Engagement Activity 2017
 
Description School visit (Lairhillock, Aberdeenshire) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Around 75 older years primary school pupils, supporting science block that they were undertaking. Each pupil received the Biofuels graphic novel which was very well received
Year(s) Of Engagement Activity 2018
 
Description • All Energy - Bioenergy workshop at Glasgow Science Museum, May 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Workshop on Bioenergy and distributing the Bioenergy graphic Novel. We spoke to about 50-75 people on that day and it was a mix of school children (mainly primary age), teachers and general members of the public.
o Impact: The biggest impact I saw for this one was with teachers who were very keen on something (the comic) that was freely available and could be used as a teaching aid. They all said that bioenergy was beginning to be included in the syllabus more so they were happy to find material that was more engaging for them and their students. With general members of the public, it was more surprise to learn how big a role bioenergy does and can play in the UK energy sector. For a lot of people, they see wind turbines and they know what that is and that it provides electricity. They were surprised to know that its actually bioenergy that typically contributes the most to UK renewable energy and were interested to hear about the different types of biomass and how we can convert them (even with photocatalysis!)
Year(s) Of Engagement Activity 2017