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Waldron, Paul (2017) The generation of dual purpose wheat that is high yielding, adapted to climate change and provides straw that is specifically adapted for bio-refining. PhD thesis, University of Nottingham.

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Abstract

The planet we live on is for all intents and purposes a closed environment with finite resources, which over the last few hundred years humans have managed to deplete at an alarming rate. As they take millions of years to form they will eventual run out, and because of this there is a clear need for a sustainable replacement for liquid fossil fuels. Wheat straw is an agricultural waste product that has the potential to produce 70 gallons of ethanol per ton of biomass. The aim of this work was to firstly identify variation in wheat straw tissue and growing conditions with regard to recalcitrance and sugar availability for bio-fuel production; this was carried out using the commercial wheat variety Xi19. Xi19 was fractionated into leaf, peduncle- both upper (stem above 10cm) and lower (stem below 10cm) fractions, and samples of “whole” un-fractionated straw. It was found that the only differences seen with regard to tissue type was between the leaf samples and all other fractions (p < 0.05). Xi19, Cordiale and Grafton grown in field conditions under differing plant growth regulator (PGR) and nitrogen applications were then analysed using leaf, stem and “whole” un-fractionated straw and it was shown that neither treatment had any significant impact on recalcitrance and sugar availability (p > 0.05).

Wheat is a member of the grass family that has been domesticated over thousands of years. This has caused erosion of the gene pool and, with this in mind, crosses have been created using ancient wild type plants with an aim of increasing genetic diversity. The second aim of this study was to analyse the first progeny of these potential new wheat lines for traits such as enhanced sugar composition or reduced recalcitrance that improve the straws suitability for bio-refining. Results suggest that the genetic variation within this new population had increased dramatically and showed an impact on morphology, recalcitrance, and sugar availability following enzyme digestion (% available glucose recovered ranging from a low of 15% to a high of 34%). Thus the wild type relatives do appear to be providing traits that would be beneficial for the use of straw in a bio-refining process.

Water consumption for bio-fuel can vary from 2–10 gallons of fresh water for each gallon of bio-fuel produced depending upon the method used. The third aim of this work was to determine if sea water can be substituted for fresh water for each production step. This work showed that acid pre-treatments performed the same in both fresh and sea water, and that the use of sea water for the pre-treatment stage does not appear to effect subsequent enzyme hydrolysis (p > 0.05); Enzyme hydrolysis performed in sea water showed a significant reduction to that in fresh water (p < 0.05). The effects of salinity on metabolic growth of yeast showed no differences with or without the addition of 6% glucose (p > 0.05), and that during fermentation ethanol production was unaffected.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Tucker, G.A. King, I. King, J.
Subjects:	S Agriculture > SB Plant culture
Faculties/Schools:	UK Campuses > Faculty of Science > School of Biosciences
Item ID:	43005
Depositing User:	Waldron, Paul
Date Deposited:	10 Nov 2017 13:44
Last Modified:	07 May 2020 12:45
URI:	https://eprints.nottingham.ac.uk/id/eprint/43005

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