Project Results

This experiment has provided us with valuable insight into the effect of additive profiles on the flocculation rate of the microalgae species Spirulina and Chlorella vulgaris. Our four weeks of study of the effect of whey protein and iron filings have shown that whey protein powder led to an average increase in biomass density production of 7.2%. 

The experiment was carried out using a base growth cycle as our constant which contained Spirulina (10g dry weight), 2l distilled water and 5g f/2 growth enhancer, and a comparison growth cycle containing Spirulina (10g dry weight), 2l distilled water and 5g f/2 growth enhancer, 5g dry weight whey powder.

Both were kept under the same growth conditions at 22 degrees C (with some minor variation), illuminated by LED light strips with a 16 hours illumination, 8 hour dark phase and bubble cycle using natural air, to simulate natural day and night periods within acrylic bioreactors. pH was variable due to the effects of the additives, but was generally between 6-8.7. 

They were monitored daily Monday to Thursday for a period of four weeks and lux was recorded each day using a luxometer which was used to calculate flocculation rate. The ambient lab temperature, internal temperature of the growth vessels, and pH of the growth medium was also recorded, along with any other remarks on changes to the system.

About This Project

To stop the negative effects of climate change we need carbon capture technology to be developed and deployed worldwide as soon as possible. Nellie is a direct air carbon capture system that is able to help solve this global problem using microalgae. We have a working prototype and now need to test certain additives which will increase the efficiency of our system and accelerate the at-scale removal of Carbon Dioxide from the atmosphere and mitigate the effects of climate change.

Ask the Scientists

What is the context of this research?

Carbon Dioxide Removal (CDR) is vital to stopping climate change, as stated in the IPCC’s 6th AR and the European Green Deal. There are many types of CDR but direct air capture by microalgae is a promising, low-cost high-efficiency technology that can immediately remove and permanently store atmospheric CO2 (Erans et al., 2022). Algae convert CO2 to O2 and biomass by photosynthesis, at a higher efficiency that terrestrial plants, and the biomass product is permanently stored or processed into bioenergy, fertiliser, etc. The CDR sector is in its infancy, so there are not yet accessible technologies that offer scalable carbon capture that can be deployed in the necessary locations and environmental conditions.

What is the significance of this project?

Our feasibility studies and technoeconomic analysis predict a capture rate of about 50,000 tonnes CO2 per acre per annum. It is envisaged that an additive profile exists that should increase this rate 5%, hence the need to test several additives. Algal carbon capture rate varies in different substrates, so finding the materials that help it photosynthesise as efficiently as possible will let us design the best CDR system we can and prepare it for use so we can start solving the global issue of CO2 emissions and global warming. This project also has the potential to kickstart new questions around how to improve our carbon capture technologies and measure their effectiveness, generating new scientific knowledge which can be shared in efforts to improve carbon capture globally.

What are the goals of the project?

These funds will be used to acquire additives that will be added to test bioreactors in different quantities to find which profile of additives will increase photosynthetic rate the most, i.e., which additive profile will help our systems capture the most CO2. We will build several small reactors with different additive profiles and monitor biomass and biogas production for four weeks using a remote sensor stack. We will then analyse the data to determine which additives cause the most productivity. Testing will take place at AberInnovation in mid Wales over a period of four weeks starting in early January 2023. A full report on the project's outputs will be prepared and disseminated publicly.