Toxic effects of high O2 in microalgae and cyanobacteria
Why does O2 inhibit photosynthesis and what can we do about it?
Project type:
BSc, MSc, PUK
Keywords:
Microbiology; Biochemistry; Biology; Biotechnology
Project description:
Anywhere photosynthetic microbes occur in high abundance and with high activity, a paradoxical challenge occurs – the very process of photosynthesis that enables the organisms to grow also generates high concentrations of O2 that severely inhibits these organisms.
This is a problem both in natural environments and in photobioreactors where the microbes are cultivated for practical applications. In fact, high O2 caused by photosynthesis is one of the biggest biological challenges for upscaled cultivation of photosynthetic microbes. The main physiological causes of growth inhibition are probably a combination of photorespiration (due to RuBisCO oxygenase activity) and oxidative stress.
In this project, we aim to (1) determine the physiological factors responsible for growth inhibition under high O2 conditions and (2) to identify strategies to mitigate its impact. The long-term goal is to provide biological solutions that can effectively counter O2 inhibition, especially in large-scale commercial microalgae and cyanobacteria cultivation.
We will perform experiments to address one or more of these critical questions:
- What is the abundance and physiological impact of reactive oxygen species (ROS) at high O2?
- What is the most important factor causing inhibition by high O2 – photorespiration or oxidative damage?
- Can the detrimental effects of photorespiration be alleviated by increased CO2 concentrations?
We use various model organisms of cyanobacteria and microalgae and our methodologies include highly specialized equipment for measurements of ROS and custom-made cultivation setups where the composition of the gas phase and the liquid phase can be manipulated.
Contact:
Niels-Ulrik Frigaard (nuf@bio.ku.dk). The project will be carried out at the Section for Marine Biology in Helsingør.