Manipulating microalgal-to-microbial carbon transfer for sustainable bioenergy and bioproducts

Microorganisms have significant potential as sources of chemicals and metabolites to be used for industrial applications such as the production of high-value chemicals, food products or biofuels. Many species of bacteria and yeast are very efficient at producing biofuels via fermentation and are extremely amenable to genetic engineering but are dependent on the supply of organic carbon substrates, thus reducing the sustainability and potential carbon neutrality of chemicals from these organisms. In contrast, photosynthetic organisms such as microalgae can make use of freely available carbon dioxide and sunlight, but currently have limitations as viable industrial biotechnology platform strains. This project aims to combine the properties and potential of microalgae with the proven biotechnological characteristics of certain bacterial and yeast strains to drive towards the carbon neutral production of chemicals and biofuels. We will evaluate the utilisation of sugars derived from microalgae to sustain cultivation and fermentation of strains such Saccharomyces cerevisiae and Clostridium acetobutylicum. One set of experiments will investigate the breakdown of microalgal biomass to release sugars for use for fermentation and will screen for optimal microalgal saccharification and yeast fermentation conditions. A second experimental approach will genetically engineer the model eukaryotic microalga Chlamydomonas reinhardtii to allow sugar efflux. Computational modelling will be used to optimise the cultivation and metabolic conditions of the autotrophic microalga and the heterotrophic yeast or bacterium, using previously developed approaches. The goal will be to develop a combined system that will harness the photosynthetic properties of the microalga to provide carbon to microorganisms to drive industrial chemical production. Furthermore, the microorganism biomass will be evaluated as a 'biorefinery' in order to evaluate by-products for additional applications and so to make full use of the cultivated biomass. The project will provide training in a variety of experimental techniques and disciplines including molecular biology, genetic engineering, and metabolic modelling.