Immobilizing photosynthetic microbes is a promising technique to create efficient cell factories for sustainable chemicals production. For this purpose, it is essential that the immobilization matrix structure has not only biological compatibility with the cells, but also high mechanical performance in the challenging submerged production conditions. We entrapped cyanobacteria within never-dried hydrogel films of TEMPO-oxidized cellulose nanofibers (TCNF) cross-linked with polyvinyl alcohol (PVA) to create a novel matrix architecture for biocatalytic ethylene production. Here, we demonstrate how the self-standing matrix outperforms conventional alginate-based solutions. Based on rheological investigations, the rigid nature of the colloidal nanofiber network and the strong cross-linking with PVA enables much stronger hydrogel formation compared with polymeric alginate cross-linked with reversible ionic bonds. The porous and hygroscopic nanofiber network is also able to protect the cells from environmental stress, resulting in faster cell recovery and improved long-term cell fitness. Finally, cell immobilization within the novel TCNF matrix allows efficient ethylene production in challenging submerged conditions with NaHCO3 supplement. In contrast, alginate-based matrices rapidly disintegrate in these conditions with severe cell leakage, rendering them completely unsuitable for submerged ethylene production. All in all, the results showcase the versatility and potential of cell immobilization with the never-dried colloidal TCNF matrix, paving the way towards novel biotechnological pathways using solid-state cell factories designed for efficient and sustainable production of many valuable chemicals, such as monomers and fuels.

Mechanically stable nanocellulose-based immobilization matrix for enhanced ethylene production with photosynthetic cell factories

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.