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Characterization of microorganisms for conversion of aromatic substrates

Skyvell, Martin (2018) MOBN03 20172
Degree Projects in Molecular Biology
Popular Abstract
Lignin as a feedstock for chemicals – a step towards a greener world

The world and its inhabitants are standing in front of a great challenge if the Earth should continue to be liveable. There is a pressure both on ourselves and the industries to turn into a more renewable lifestyle instead of the one based on fossil fuels which is dominating nowadays. To do this, an abundantly available starting material that can be turned into a broad spectrum of products is required. Lignin, which is one of three substantial components of trees but also other plants such as grasses, seems to be a good candidate for this purpose. Lignin is already transported from the forest to the paper and pulp industries where it is separated from the two other... (More)
Lignin as a feedstock for chemicals – a step towards a greener world

The world and its inhabitants are standing in front of a great challenge if the Earth should continue to be liveable. There is a pressure both on ourselves and the industries to turn into a more renewable lifestyle instead of the one based on fossil fuels which is dominating nowadays. To do this, an abundantly available starting material that can be turned into a broad spectrum of products is required. Lignin, which is one of three substantial components of trees but also other plants such as grasses, seems to be a good candidate for this purpose. Lignin is already transported from the forest to the paper and pulp industries where it is separated from the two other components. This means that the questions regarding how to transport lignin from the source of origin and how to get it in pure form are already solved.

The purpose of this project was to find bacteria that can grow on different building blocks of lignin. If the organism takes up a certain building block into its cell, it may be converted to another compound and excreted out of the cell. These excreted compounds may in turn be useful chemicals in the way that they can be used for fuels or joined together to form materials such as more environmentally friendly plastics.

Bacteria were grown in shake flasks and samples were collected to determine growth through light absorption by the organism. The liquid fraction of the samples were analysed by different chromatography techniques to see if interesting compounds had been excreted by the organism. Chromatography is a technique in which one specific compound can be determined out of a complex mixture of many different compounds. This is because different compounds attach with different strength onto a specific packing material within a metal tube. These compounds are then detached from the packing material by changing the composition of a solution that is rinsed through the metal tube. Depending on the compound, it is detached more or less easily from the packing material. The time of attachment to the packing material is specific for a certain compound and can be used to determine the different compounds in a mixture.

Promising results were obtained in this project. Especially one microorganism was found to grow on different building blocks, and importantly on one of them. Interestingly, it did not only grow on this building block but also excreted compounds that was determined through chromatography. These results support the idea that environmentally friendly methods, such as bacterial conversion, may be used to generate chemical products of interest. The work conducted in this project, is however only a first step towards such a process. More experimental work is needed to gain more knowledge. It would for example be interesting to see if the exchange of excreted compounds could be improved. It would also be a milestone to determine the genes responsible for growth on the most interesting building block, and possibly inserting them into a more efficient organism for the purpose of chemical production.

Master’s Degree Project in Molecular Biology 60 credits 2017-2018
Department of Biology, Lund University
Advisor: Professor Gunnar Lidén and Krithika Ravi
Department of Chemical Engineering, Lund University (Less)
Please use this url to cite or link to this publication:
author
Skyvell, Martin
supervisor
organization
course
MOBN03 20172
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8946932
date added to LUP
2018-06-08 11:30:05
date last changed
2018-06-08 11:30:05
@misc{8946932,
  author       = {Skyvell, Martin},
  language     = {eng},
  note         = {Student Paper},
  title        = {Characterization of microorganisms for conversion of aromatic substrates},
  year         = {2018},
}