Green algae are photosynthetic organisms that can easily be cultivated on large scale. Some members have evolved as a valuable food source due to high content of essential fatty acids. The development of biotechnological tools to modify these organisms is currently of great interest. In this project, we will engineer the surface of the green alga Chlamydomonas reinhardtii (C. reinhardtii) to transform the organism into a carrier for the specific delivery of active compounds. Already existing cell-surface engineering has found a broad range of applications. For human and animal health, cell-surface engineering is used for vaccine development, and more recently, for drug delivery. As enzymes can be immobilized on the surface, it has also found numerous applications within the food industry, energy production and others. Additionally, cell-surface engineering has aided basic research with unveiling the mechanism of cell wall formation. The overall aim of the ‘Green Surfing’ project is to establish a platform for drug delivery application by transforming the alga C. reinhardtii with cell-surface engineering. We propose to modify the photosynthetic organism into a carrier of therapeutically active compounds by expressing specific anchor at its surface. We developed in the first year a new surface engineering strategy for C. reinhardtii. This method represents the first example of expression of designed anchor at the cell-wall of this complex organism. More specifically the objectives are to identify and characterize functional anchoring domains; to evaluate displayed proteins accessibility to external molecules and particles; to evaluate modified C. reinhardtii strains as a drug delivery system.
What is special about the project?
The alga, C. reinhardtii, is a model organism possessing a photosynthetic system, is generally recognized as safe (GRAS) by the FDA and thereof is a potential food source. However, up to date, it is not possible to display protein at its surface using a recombinant surface. The ‘Green Surfing’ project tackle this unmet need by applying a systematic set of experiments to generate functional anchoring domains in the algal system. This key technology unlocks several biotechnological applications, by either algae biological or economical traits both required for the translation of the academic knowledge to the society. For instance, the GRAS status of C. reinhardtii renders it applicable for human and animal health, as well as for food-processing technologies, drug delivery and whole-cell biocatalyst. The photosynthetic capacity of C. reinhardtii combined with its aquatic nature are attractive characteristics for tackling environmental problems. This modified organism could be used for cleaning polluted bodies of water bodies contaminated by compounds with poor membrane permeability such as glyphosate. The low production cost and possibility of surface engineering is attractive for biocatalytic processes, such as lipase-produced biofuels. Finally, the autotrophic-engineered organism combined with a controlled drug-release strategy could be used to treat chronic and traumatic wounds in over 400 million people worldwide.
During the project, we developed a unique strategy to functionalize the surface of C. reinhardtii. Our results led to the identification of two proteins to target the cytoplasmic membrane and the cell wall. As a proof of principle, we labeled both proteins with the fluorescent protein mVenus and could observe a label around C. reinhardtii cells. To render our system more applicable, two conditions were evaluated, and our results indicated the release of the fluorescently labeled anchor. This methodology has a direct impact on the field of protein expression, purification, and biocatalysis. Additionally, one of the anchors could be functionalized with two fluorophores, which shows the potential of our strategy to be used in a high throughput setup.
Molino JVD, Carpine R., Gademann K., Mayfield S., Sieber S. Development of a Cell Surface Display System in Chlamydomonas reinhardtii
. bioRxiv 2021. doi:10.1101/2021.05.06.442888«;
Shchelik IS, Molino JVD, Gademann K. Biohybrid Microswimmers Against Bacterial Infections
. 2021. bioRxiv 2021.05.10.443410;
Carpine, R. Sieber, S. Antibacterial and antiviral metabolites from cyanobacteria: Their application and their impact on human health
. CRBIOT 2021. 3: 65–81. doi:10.1016/j.crbiot.2021.03.001;
Molino JVD, de Carvalho JCM, Mayfield S. Evaluation of secretion reporters to microalgae biotechnology: blue to red fluorescent proteins
. Algal Res. 2018. 31: 252–261;
Molino JVD et al. Comparison of secretory signal peptides for heterologous protein expression in microalgae: Expanding the secretion portfolio for Chlamydomonas reinhardtii
. PLoS ONE. 2018. 13(2): e0192433;
Chávez MN, Schenck TL, Hopfner U, Centeno-Cerdas C, Somlai-Schweiger I, Schwarz C, et al. Towards autotrophic tissue engineering: Photosynthetic gene therapy for regeneration
. Biomaterials. 2016;75(October):25–36.
Persons involved in the project
Last update to this project presentation 23.06.2021