Systematic analyses and rational engineering of fast CO2 fixation pathways in living cells

Descripción del proyecto

El aumento de la eficacia de la fijación del CO2

La fijación biológica del CO2 es fundamental para la producción de biomasa y alimentos, pero la vía dominante del ciclo de Calvin para conseguirlo es ineficiente, incurre en elevados costes energéticos y tiene una cinética enzimática lenta. En este sentido, el proyecto FASTFIX, financiado por el Consejo Europeo de Investigación, pretende mejorar el proceso explorando vías sintéticas de fijación del CO2 más eficientes. Un desafío clave reside en los limitados datos cinéticos disponibles para las enzimas relevantes, que pueden no reflejar su rendimiento en células vivas. Para ello, el equipo de FASTFIX desarrollará un método novedoso para cuantificar la cinética enzimática directamente en «Escherichia coli» modificada. Al vincular las tasas de crecimiento a los niveles de enzimas, el equipo del proyecto pretende analizar y seleccionar sistemáticamente las vías sintéticas óptimas, allanando el camino para una fijación del CO2 eficiente desde el punto de vista energético y una mejora de los rendimientos agrícolas.

Objetivo

Biological CO2 fixation is the primary process responsible for biomass and food production and a key player in the atmospheric CO2 balance. Almost all biological CO2 fixation is caried out by a single pathway: the Calvin cycle. Despite the dominance of this pathway in nature it seems relatively inefficient due to high energy costs and poor enzyme kinetics. An exciting option to improve this efficiency, is the exploration of potentially more efficient synthetic CO2 pathways. However, a key challenge to identify promising synthetic CO2 fixation pathways is the limited availability of kinetic data on relevant enzymes. In addition, kinetic data are usually measured in vitro and hence not always representative for the performance in living cells.
In FASTFIX, I will develop and use a novel method to quantify kinetics of enzymes within living cells. I will do this by making the growth rate of engineered Escherichia coli cells directly dependent on the kinetics and levels of the enzymes of interest. By measuring the growth rates and enzyme levels by absolute quantitative proteomics, the in vivo kinetics of the enzymes can be determined.
This approach will be used to generate a complete overview of the kinetics of enzymes involved in promising synthetic CO2 fixation pathways. This will enable an unprecedented systematic analysis of the kinetics of synthetic CO2 fixation pathways.
Based on this analysis I will select the most promising pathway design. Enabled by the in vivo kinetics data I will then employ a novel forward-engineering method to effectively engineer and demonstrate the performance of the full pathway in E. coli.
The realization of a fast, energy-efficient synthetic CO2 fixation pathway in living cells will be a major milestone. The anticipated results will be promising for efficient CO2-based biotechnological production, and in the longer-term may increase agricultural yields and help to more efficiently mitigate humanity’s CO2 footprint.