Bioinspired hydrogels for improved cultivation of microalgal biomass

Lead Research Organisation: University of Cambridge
Department Name: Chemistry

Abstract

Theme: Agriculture and Food Security

Summary: Microalgae are an essential contributor to the biosphere, producing ~75% of the global oxygen demand as well as playing an invaluable role in the food chain among many other ecological functions. As well as their ecological significance, they are also important in many industries, such as biofuels and human nutrition. However, despite their industrial potential, current cultivation methods prevent microalgal biotechnology from being economically and environmentally sustainable, mainly due to the prevalence of suspended cultivation approaches, such as raceway ponds. By converting to an immobilised cultivation technique, higher productivity can be achieved with lower energy and water demands, also in a smaller space footprint. Here agarose hydrogels are used as a scaffold to grow Chlorella vulgaris as a biofilm. Biofilms are naturally more productive than suspended cultivation, have lower water and energy demands, while also being easier to harvest. Despite the advantages of immobilised cultivation there are still many efficiency improvements required to make algal based technology sustainable. Here the focus is optimising the photosynthetic rate of the culture. Through the addition of scattering particles, such as cellulose nanocrystals, light attenuation is increased throughout the culture, creating more even illumination and reducing cell self-shading, which in turn improves the photosynthetic rate. If the current cultivation issues, such as poor productivity, can be overcome, microalgae can be exploited to achieve their biotechnological potential in a cost-effective and scalable manner.

Additional to this a machine learning approach is being taken to understand the correlation between the optical response of a single cell and its physiology. Measuring biomass quantity and quality is an important procedure both in industry and research, such as lipid content or growth stage. Quantifying the biochemical compound content of the biomass, for example pigment or lipid content, at present is mainly done by chemical extraction which is an invasive process and destroys the sample. By using machine learning, a non-invasive optical based assessment method to evaluate biomass qualities from pigment content to cell size distribution and culture age can be developed. Once this has been understood at a single cell level, it will be expanded to bulk culture optical measurements to act as an in-situ, non-invasive measurement tool for characterising a culture's physiological properties.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M011194/1 30/09/2015 31/03/2024
1804914 Studentship BB/M011194/1 30/09/2016 30/05/2021 Alyssa Smith
 
Description Bionic Algae 
Organisation University of Cambridge
Department Cambridge Graphene Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution Provision of algae materials, equipment and plant biology expertise
Collaborator Contribution Provision of materials (graphene, cellulose nanocrystals (CNC) and hydroxypropyl cellulose(HPC)), equipment and chemistry expertise.
Impact The project encompasses areas of both biology and chemistry. The major outcome has been successful long-term suspension of Chlorella vulgaris cells in liquid culture, which is in contrast to the usual sedimentation of cells within 24 hours. Additionally, it has been shown that CNC, HPC and graphene are not problematically toxic to the cells.
Start Year 2018
 
Description Bionic Algae 
Organisation University of Cambridge
Department Department of Biochemistry
Country United Kingdom 
Sector Academic/University 
PI Contribution Provision of algae materials, equipment and plant biology expertise
Collaborator Contribution Provision of materials (graphene, cellulose nanocrystals (CNC) and hydroxypropyl cellulose(HPC)), equipment and chemistry expertise.
Impact The project encompasses areas of both biology and chemistry. The major outcome has been successful long-term suspension of Chlorella vulgaris cells in liquid culture, which is in contrast to the usual sedimentation of cells within 24 hours. Additionally, it has been shown that CNC, HPC and graphene are not problematically toxic to the cells.
Start Year 2018
 
Description Bionic Algae 
Organisation University of Cambridge
Department Melville Laboratory of Polymer Synthesis
Country United Kingdom 
Sector Academic/University 
PI Contribution Provision of algae materials, equipment and plant biology expertise
Collaborator Contribution Provision of materials (graphene, cellulose nanocrystals (CNC) and hydroxypropyl cellulose(HPC)), equipment and chemistry expertise.
Impact The project encompasses areas of both biology and chemistry. The major outcome has been successful long-term suspension of Chlorella vulgaris cells in liquid culture, which is in contrast to the usual sedimentation of cells within 24 hours. Additionally, it has been shown that CNC, HPC and graphene are not problematically toxic to the cells.
Start Year 2018
 
Description Guest Encapsulation within Surface-Adsorbed Self-Assembled Cages 
Organisation University of Cambridge
Department Department of Chemistry
Country United Kingdom 
Sector Academic/University 
PI Contribution Measurements on integrating sphere to assess colour change in samples
Collaborator Contribution Creation and further characterisation of samples
Impact Paper in preparation
Start Year 2019
 
Description Photonic properties of cyanobacterial cells 
Organisation Queen Mary University of London
Department School of Biological and Chemical Science QMUL
Country United Kingdom 
Sector Academic/University 
PI Contribution Single cell transmission and reflection measurements of cyanobacteria cells on a microscope
Collaborator Contribution Provision of material and other characterisations of photonic properties of cells
Impact Paper in preparation
Start Year 2019