No Cover Image

E-Thesis 265 views 77 downloads

Development of an amyloid protein-based composite biomaterial for coating applications / CRAIG ALLAN

Swansea University Author: CRAIG ALLAN

DOI (Published version): 10.23889/SUthesis.63533

Abstract

Streptomyces bacteria are highly versatile micro-organisms, which have been recognised as potent biochemical, soil and biomaterials engineers. In particular, functional non-pathogenic amyloid proteins can be formed from the expression of β-sheet proteins. These β-sheet proteins known as chaplins, wh...

Full description

Published: Swansea, Wales, UK 2023
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: van Keulen, Geertje. and Penney, David.
URI: https://cronfa.swan.ac.uk/Record/cronfa63533
Tags: Add Tag
No Tags, Be the first to tag this record!
Abstract: Streptomyces bacteria are highly versatile micro-organisms, which have been recognised as potent biochemical, soil and biomaterials engineers. In particular, functional non-pathogenic amyloid proteins can be formed from the expression of β-sheet proteins. These β-sheet proteins known as chaplins, which aggregate to form a fibrillar morphology, has been shown to protect against desiccation in hydrophobic environments. These robust Chaplin proteins have served here as a source of inspiration for materials development, based on the chaplins’ ability to modulate the properties of its own surface and that of its natural environment.This study has developed more economical and environmentally friendlier methods for chaplin protein production by replacing the existing TES buffer for a potassium bicarbonate buffer and by modifying the downstream processing to assist in the removal of trifluoroacetic acid. Combinations of different media and buffers were tested for alternative fermentations that support Streptomyces morphological differentiation in liquid media, in which a potassium bicarbonate buffer system proved as efficient as well as more economical when compared to conventional fermentations with expensive organic buffer systems that support differentiation. Downstream processing of amyloid proteins was furthermore improved by adopting synthetic peptide procedures resulting in an environmentally friendlier amyloid purification method. This modified medium was also demonstrated within a bioreactor at 1.7 L scale which further enhances the economic benefit which could be implemented for production of other secondary metabolites.The resulting chaplin proteins were then applied with β-glucans to form a biocomposite for different industrial applications. Material properties and anti-corrosion were determined by goniometry and high-resolution imaging, and by qualitative and quantitative electrochemistry. Our protein-based corrosion resistant nano-coating has great potential for the manufacturing, defence and other industries, including healthcare and biomaterials manufacturing.
Keywords: Streptomyces, biomaterials, corrosion, fermentation
College: Faculty of Medicine, Health and Life Sciences