July 2021 Webinar: Synthetic Biology in the Industrial Biotechnology Application Domain
This webinar was presented in July 2021 as part of the Synthetic Biology Future Science Platform (SynBio FSP) Seminar Series. This webinar covers work in the Industrial Biotechnology Application Domain.
Regular webinars offer information about the latest work from SynBio FSP including funded projects, the work of CSIRO-University Fellows and SynBioFSP PhD students.
Dr Charlotte Williams, Application Domain Leader, Industrial Biotechnology, welcomed participants, acknowledged the Traditional Owners and introduced the speakers:
Joel Lee, PhD student at the University of Adelaide and Fellow at CSIRO’s Synthetic Biology Future Science Platform spoke about Enzymes and Bleach: Engineering Cytochrome P450 Peroxygenases for Fine Chemical Synthesis.
James Heffernan, PhD student at UQ’s Institute of Biotechnology and Nanoengineering and Fellow at CSIRO’s Synthetic Biology Future Science Platform spoke about developing a heterologous system for uncovering transcriptional architecture in Clostridium autoethanogenum and progressing CO2 fermentation.
Full biographies and abstracts
Joel Lee, PhD student, University of Adelaide and CSIRO Synthetic Biology Future Science Platform
Joel Lee is a PhD candidate from A/Prof Stephen Bell’s group in the University of Adelaide. He currently holds a Master of Philosophy in Chemical Sciences from the same lab and is a recipient of a Synthetic Biology Future Science Platform PhD Scholarship and expects to submit his thesis at the end of 2022.
Cytochrome P450 peroxygenases are a niche subclass of heme enzymes that can functionalise C-H bonds in fatty acids using hydrogen peroxide (H2O2). Recently, it has been demonstrated that the more abundant cytochrome P450 monooxygenase enzymes, can be engineered to function as peroxygenases. This would enable the selective oxidation of numerous substrates without the addition of expensive cofactors or electron transfer partner proteins. However, too much H2O2 can inactivate these enzymes by reacting with the heme. The development of methods of in situ H2O2 formation in the presence of both natural and engineered P450 peroxygenases, to increase the efficiency of H2O2-driven catalytic activity will be described. This includes the use of light-activated flavin systems and chemical oxygen surrogates that supply H2O2 as well as strains of Escherichia coli that can build up higher levels of H2O2. Preliminary studies on the addition of tags to these peroxygenases to allow their immobilisation onto solid surfaces, such as silica, for applications in flow chemistry will be presented. Crystallographic studies on these peroxygenase P450s to investigate in crystallo ¬H2O2-driven reactions have also been performed. Ultimately, the goal is to be able to apply these different approaches for larger scale oxidative reactions.
James Heffernan, PhD student, Australian Institute of Bioengineering and Nanotechnology, The University of Queensland and CSIRO Synthetic Biology Future Science Fellow
During a final year project on recycling waste-gas from anaerobic digesters James Heffernan discovered the field of gas fermentation, then the Marcellin Lab, and was keen to get involved in their research. Shortly after completing a B.E.(Hons) in Chemical and Process Engineering (minor in Bioprocess Engineering) at the University of Canterbury (NZ), he moved to Brisbane to join the UQ-based group. His PhD research has focussed on the development of CO2 fermentation and how best to harness redox from CO and H2 to improve CO2 uptake. Upon receiving a CSIRO SynBio FSP Top-Up Scholarship he also began development of a heterologous system capable of investigation and rational engineering of acetogenic transcriptional regulation.
Acetogens are a broad set of ancient microbes that now represent robust platforms for production of fuels and commodity chemicals from C1 feedstocks. The first industrial scale gas fermentation process was recently implemented by LanzaTech, with Clostridium autoethanogenum converting waste steel mill off-gas to fuel ethanol. With the recent and ongoing development of a genetic toolbox for acetogens there are numerous opportunities to develop this platform for use of variable C1 containing waste gases and production of various compounds. Recently, the Marcellin group identified a novel promoter motif and identified an interacting sigma factor (TetR family protein, CAETHG_RS0459) which is involved in regulation of the Wood-Ljungdahl Pathway (WLP) and other core autotrophic genes of acetogens. Transcriptional regulation represents a knowledge gap for acetogens, and modification of a transcriptional regulator has not been attempted in acetogens before. Further, only in vitro high-throughput methods are accessible for acetogens at this stage, limiting certain aspects of metabolic engineering. Development of a heterologous system enables HTP methods while retaining some benefits of traditional engineering. Therefore, we are developing a heterologous tool for simple investigation and rational engineering of novel regulatory factors, which can then be mined to modify C. autoethanogenum.