Saving the planet through carbon recycling: engineering bacterial capture of gasified waste for bioplastics production

Wider context

Climate change caused by the release of greenhouse gases from fossil fuels and through change of land use threatens life on our planet. Drastically lowering these emissions, remains a major challenge for humanity.

One way this might be achieved is through gas fermentation, a process where bacteria grow on the carbon dioxide (CO₂) and carbon monoxide (CO) contained within certain industrial waste gases and in syngas, the latter being obtained through the gasification of otherwise recalcitrant lignocellulosic and municipal waste. These gases are promising feedstocks for the microbial production of chemical commodities, fuels and bioplastics (Arenas-López et al., 2019).

CO is by far the most abundant in syngas, but due to its high toxicity it can only be utilised by a limited number of species. Previous attempts to equip the autotrophic bioplastic-producing bacterium Cuprivavidus necator with the enzymatic machinery needed to utilise CO as an additional source of carbon and energy have been met with limited success (Heinrich et al., 2017).

Aims & objectives

The overall aim of this studentship is to engineer C. necator to efficiently grow on CO-containing waste gases and convert these into desirable chemicals and biopolymers such as polyhydroxybutyrate (PHB). This will be achieved through the following objectives:

(i) Introduction of CO-utilisation gene clusters from other species

(ii) Identification of essential and so far unrecognised accessory factors encoded within these clusters and outside

(iii) Optimisation of expression of all relevant genes involved, as identified under (i) and (ii)

(iv) In vitro evolution of CO-resistant and CO-utilising strains and their genomic and physiological characterisation.

Training

This project builds on a previous study in which C. necator strains displaying considerably increased CO resistance were successfully obtained. It offers training in microbiology, continuous fermentation systems, gas/liquid chromatography, advanced microbial genetics, next generation sequencing, adaptive laboratory evolution and synthetic biology/metabolic engineering.

Research environment

You will join the BBSRC/EPSRC Synthetic Biology Research Centre Nottingham (https://sbrc-nottingham.ac.uk/ ) equipped with state of art facilities including laboratory suites dedicated to multiplexed gas fermentation, high-throughput robotics and analytics (HPLC, GC, GC-MS, LC-MS-MS). We have strong links to key groups in the Biotech sector in Europe, the US, China and India, providing ample opportunity for knowledge exchange, training and collaboration.