Optimizing the production of biosurfactants from marine bacteria for applications in personal care sector

New programme as from May2022:

Biosurfactants are amphiphilic chemicals used in almost every sector of modern industry. However, they are mainly produced by chemical synthesis using fossil fuel-based precursors, and as such these chemicals are often characterized as eco-toxic and non-biodegradable. Biosurfactant-producing microorganisms offer a much more sustainable, non-toxic, and eco-friendly source for these chemicals. This project will focus on biosurfactants produced by marine bacteria, with a focus on rhamnolipids, which are a class of glycolipids consisting of one or two rhamnose sugar groups attached to one or two fatty acid chains. Rhamnolipid production has been well characterized in Pseudomonas aeruginosa, but a major limitation in getting these compounds to market is often associated with the pathogenicity of the producing organism - i.e. Pseudomonas aeruginosa which is the main source of rhamnolipids, but this organism is pathogenic. Other non-Pseudomonas organisms have been found to produce rhamnolipids, but they too are pathogenic or can become so under certain conditions. As such, there have been numerous studies on identifying microorganisms with the potential to synthesize rhamnolipids that are non-pathogenic. This project will explore the synthesis of biosurfactants, including rhamnolipids, in non-pathogenic strains of marine bacteria, and attempt to enhance the production of these compounds using synthetic biology approaches and further optimization by manipulation of fermentation conditions in order to produce sufficient quantities for industrially use.
Original programme:
Recover, Recycle, Reengineer: A microbial and biotechnological solution to tackle the waste tyre problem
Used rubber tyres, particularly when disposed to landfill, have been recognised to fast becoming one of the foremost environmental waste problems in the world. The recycling of rubber is a very challenging task and to date there is no solution to this increasingly important problem. The industrial partner Recircle Ltd has developed a novel sustainable technology to devulcanise and reuse rubber waste for reprocessing into high value rubber products using microorganisms. The devulcanisation/desulfurisation of rubber relies on the work of enzymes which are not fully identified yet.
This PhD project will investigate the key processes involved in biodesulfurisation of rubber. The PhD student will be trained in cutting-edge techniques to analyse and identify all genes and enzymes that are responsible for biodesulfurisation in order to get a better understanding and further improve the devulcanisation process. This project will also aim to enrich and isolate new desulfurising bacteria from tyre dump sites and mine for novel genes in the degradation of organosulfur compounds. In addition, the student will utilise site-directed mutagenesis to create mutant strains of the bacteria that constitutively express these desulfurisation enzymes.