“It’s very important that START researchers can continue to access to synchrotrons, cryo-Electron Microscopy, and nuclear magnetic resonance facilities.”
Dr Phillip Venter, Watchmaker Genomics
The Problem
People interact with surfactants daily by using detergents, lubricants, or emulsion agents in applications like cleaning, applying make-up or eating fatty emulsified food. Surfactants are surface-active agents that lower the surface tension between two phases, such as liquid-liquid phases or liquid-solid phases. They make it easier to mobilise and combine materials – such as water, oils, fats, and solvents – that otherwise would not mix due to their incompatible molecular properties1.
Most chemical surfactants are currently synthesized from petroleum, produced in very large quantities, and used on a very large scale2. These surfactants are not easily biodegradable and are environmentally toxic3. This poses a serious problem in countries such as South Africa, where wastewater finds its way into rivers and oceans, affecting rural communities and aquatic biodiversity. An alternative is the use of biosurfactants, which are made from biological sources, and are non-toxic, and biodegradable.
The challenge
Biosurfactants are a special class of surfactants produced by microorganisms such as bacteria, fungi, and yeast. These microorganisms produce diverse biosurfactants, each with its unique properties and possible applications. Once a surfactant is identified and characterised the challenge is to identify the synthetic pathway and devise a method of scaling up the production to industrial quantities at reasonable cost. For this, a detailed understanding of the enzymology behind the synthesis is necessary, including the structures of the enzymes involved. This requires access to synchrotrons and nuclear magnetic resonance (NMR) instruments not available on the African continent.
The Solution
Biosurfactants were produced from an enzyme discovered by co-supervisor Marla Trindade and collaborators, Lonnie van Zyl and Wesley Williams at the Institute for Microbial Biotechnology and Metagenomics (IMBM) at the University of the Western Cape (UWC)4 in South Africa. The structure and chemistry were investigated by Phillip Venter from the University of Cape Town (UCT), supervised by Trevor Sewell and Marla Trindade. The enzyme – Ornithine acyl-ACP N-acyltransferase (OlsB) –produces promising and novel biosurfactants (lyso-ornithine lipids), that can potentially be produced at low cost and high yield.
Phillip studied the enzymatic reaction of OlsB and produced an E. coli expression system that doubled the yield of the biosurfactant. Structural studies using X-ray crystallography and nuclear magnetic resonance elucidated the structure of OlsB’s active site and interface of interaction with its helper protein, the acyl carrier protein (AcpP). The research was performed using the protein production, purification, and crystallisation facilities at UCT. The enzyme was also manipulated to make specific types of the biosurfactant to tailor them to specific applications, and new forms of the biosurfactant were discovered.
Funding from GCRF START and Instruct Eric’s iNEXT Discovery enabled Phillip to access the UK’s national synchrotron – Diamond Light Source (Diamond) and the nuclear magnetic resonance instruments at Universiteit Utrecht (collaborator Dr Hugo van Ingen). This funding also covered staff, expertise, and training on protein NMR and synchrotron techniques. The GCRF START grant provided access to the facilities at UCT as well as consumables and shipping. The South African National Research Foundation (NRF) gave access to local purification facilities, reagents, and laboratory supplies at UWC’s IMBM.
Impact
The structural studies will allow further evaluation of OlsB to produce biosurfactants and will improve its viability by understanding the mechanisms surrounding its enzymatic reaction. The new expression system addresses the problem of lower yields achieved with general biosurfactant production and is currently being patented.
Future commercial production and use of this biosurfactant offers the potential for cleaner wastewater in rivers and oceans, which will benefit rural communities and aquatic biodiversity across South Africa and globally. The research addresses the UN Sustainable Development Goals, including building resilient infrastructure, promoting inclusive and sustainable industrialisation, and fostering innovation (SDG 9), sustainable consumption and production patterns (SDG 12), improving life below water (SDG 14) and on land (SDG 15), health and wellbeing (SDG 3).
Capacity building
Phillip started his career at the North-West University (NWU) under the supervision of Rencia van der Sluis in Biochemistry. START member Albie van Dijk at the NWU introduced him to structural biology and encouraged his study toward a PhD under Trevor Sewell. The study exposed him to international facilities and cutting-edge structural biology techniques, enabling him to expand his skills and networks. This enabled Phillip to complete his PhD and unlock exciting employment opportunities, launching his career as a commercial biotechnology scientist at Watchmaker Genomics at their facility in Cape Town.
The funding enabled Phillip to attend training courses led by experts, including the EMBO Practical course in High-throughput Protein Production and Crystallisation in the UK, the GCRF START Biophysics & Structural Biology at Synchrotrons course, the CCP4 Crystallographic School in South Africa, and the START: Health & Bio Science Legacy of START conference, amongst others.
“The discovery of the biosurfactant expression system and the subsequent patent application was a unique milestone for me. It was also life-changing career-wise. The novel OlsB enzyme was discovered in a lake close to where I grew up and gave me hope that research is possible in South Africa, by South Africans, for the benefit of South Africa and beyond. It’s very important that START researchers can continue to access to synchrotrons, cryo-Electron Microscopy, and nuclear magnetic resonance facilities. We are completely dependent on this access to perform our work.”
Dr Phillip Venter, Watchmaker Genomics
References
1 See https://www.cesio.eu/index.php/about-surfactants/what-are-surfactants accessed 9.3.2023
2 Surfactants are used on such a large scale that it is the synthetic chemical that is produced in the greatest quantities in production volume (see https://europepmc.org/article/med/22006024) In 2017 the production volume of this synthetic chemical was estimated at 17 million tonnes (Edser, C. 2018. SIZING UP THE SURFACTANTS MARKET. Focus on Surfactants. 2018(1):1-2. DOI: https://doi.org/10.1016/j.fos.2018.01.001).
3 See https://www.sciencedirect.com/science/article/abs/pii/S1359511312001675; and https://link.springer.com/article/10.1007/s00253-007-0988-7
4 Williams, W., Kunorozva, L., Klaiber, I. et al. Novel metagenome-derived ornithine lipids identified by functional screening for biosurfactants. Appl Microbiol Biotechnol 103, 4429–4441 (2019). https://doi.org/10.1007/s00253-019-09768-1