Microbial bioprocess scale-up for the production of molecular energy vectors is currently facing major challenges to reach competitive productivity levels, resulting in poor cost and sustainability performances despite encouraging results at laboratory scale. Microalgae bioprocesses for instance is limited at larger scale by light availability and gaseous substrates delivery. In parallel, the chemical industry, likewise aiming to increase performance and sustainability, has embarked in a green revolution leading to the process intensification conceptual framework. An important achievement from process intensification research has been the development of continuous microreactors enabling major performance improvements in terms of gas transfer, heat transfer, and mixing performance. In addition, the modularity of microreactors provides an opportunity for rapid scale-up from prototypes in stark contrast to the scale-up of classical discontinuous batch reactors.
We propose for this project to build on results from process intensification research, and take advantage of the skillset of the project coordinator in microalgae processes, to develop a microphotobioreactor for the intensified cultivation of microalgae. The microphotobioreactor will be designed and tested for the optimisation of gas transfer and light distribution with the help of the research team PROMETHEE in M2P2 specialised in process intensification at microscale. Having validated the microreactor design, initial cultivation tests will be performed with a strain of Chlorella vulgaris for which lipid productivity was previously characterized and modelled in a previous study by the project coordinator. This work will provide a first verification of the microreactor intensification potential. Finally, our set-up will be tested for microalgal phototrophic dihydrogen production by maintaining anoxic conditions under light illumination which we hypothesise will be permitted by the intensified gas stripping performance of the newly designed microreactor.
The proposed project will be a stepping stone for the M2P2 laboratories in the development of 1) microalgal cultivation skillset and 2) opening a new research line on bioprocess intensification which we aim to extend to other metabolisms in the future.