An evolution-led genomic study into E. coli styrene tolerance.
Lead Research Organisation:
University of Nottingham
Department Name: Faculty of Engineering
Abstract
Styrene is an important chemical across multiple industries, most notably as a monomer in production of plastics and rubbers. There has been demonstrated efforts to produce styrene using an E. coli platform, however the toxicity of this molecule significantly reduces productivity. My research aims to apply experimental evolutionary techniques to an E. colistrain to create mutant variants that display desirable styrene tolerance behaviour. These variants will then be subjected to the 'omics' studies to determine the genetic, proteomic and the lipodomic basis of adaptation to exogenous styrene stress.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M008770/1 | 01/10/2015 | 31/10/2024 | |||
| 1647874 | Studentship | BB/M008770/1 | 01/10/2015 | 30/09/2019 |
| Description | The aim of this research project is to improve the styrene tolerance of type strain E. coli BW25113 and demonstrate improved styrene production titres using the strain in a bioprocess, This will be achieved via three main targeted objectives: 1. Isolate styrene resistant E. coli mutants using random mutagenesis 2. Characterisation of the mutants using an 'omics' approach. 3. Use bioinformatics tools to identify gene(s) that confer resistance to styrene. 4. Use gene knock ins and outs to analyse and confirm gene contributions to phenotype. 5. Test the mutant strain for styrene production. Styrene is a mono-aromatic platform chemical commonly used as a monomer in many types of high performance plastics and composites, most notably polystyrene ((SIRC)., 2011). Styrene is also used in the production of several copolymers such as acrylonitrile-butadiene styrene, styrene acrylonitrile and styrene butadiene rubber. The versatility of styrene and its multiple uses in industry has seen global demand generally increase over time. As of 2013, the global styrene demand was in total around 27 million tons. Styrene has a market value of just $1300 per metric ton and it is clear that the demand from both consumer and industry is what upholds the value of the chemical. Research commissioned in 2004 by the US styrene industries reported on how vast the benefits of styrene were to both the consumer and the economy. Their study sought to quantify the socioeconomic value of styrene by assessment of the costs to the consumer if they were to switch to a substitute product and also how the manufacture of styrene effects the US economic welfare. Findings from this study can be transferable to other global economy regions perhaps with even greater impact as emerging markets based in the Middle east and Africa have had the fastest forecasted growth. However despite the very evident benefits of styrene, the bulk process for its production is unsustainable. The conventional commercial preparation of styrene involves (i) the reaction of benzene and ethylene to ethylbenzene (ii) dehydrogenation to styrene. This process requires temperatures in excess of 600°C. In addition to this, the source of lower olefins such as ethylene used in the conventional styrene production processes comes primarily from depleted raw materials such as natural gas and crude oil. These facts and findings has driven research into more sustainable processes to produce styrene. The criteria of such a process should be: (i) it must be produced from a renewable feedstock (ii) it must be an energy efficient route to styrene production. Micro-organisms have the potential to produce various industrial chemicals from metabolic pathways which can be constructed and/or modified. There is currently interest in using microbial bioprocesses to produce platform chemicals rather than petrochemical driven processes. The adoption of using microbial bioprocesses to produce renewable bio-monomers has been slow, as attention was mostly paid to the production of subsidised transport fuels and high value pharmaceuticals. The rationale in looking for a styrene bioprocess comes from its aforementioned high socioeconomic value. The last decade has seen accelerated research efforts into styrenic monomer bioprocesses. McKenna and Nielsen 2011 was the first study to report on microbial styrene production from a glucose feedstock. However the main hindrance to this bioprocess is the issue of product toxicity which ultimately hinders production titres. The aim of this study is to evolve an Escherichia coli strain to be styrene resistant at an industrially relevant concentration. |
| Sector | Manufacturing, including Industrial Biotechology |