Microalgae are grown in mass cultures to produce biomass that contain a number of high-value products. Phototrophic growth is often slow due to light and other limitations. Some microalgae can also grow heterotrophically (using organic carbon sources) that is a fast process, but the content of some bioactive compounds (e.g. pigments) in biomass is low.Some species are able to undergo trophic conversions from heterotrophic to phototrophic growth mode as to produce high density cell cultures in the 1st stage and then, in the 2nd stage is transferred to a phototrophic regime (photoinduction) to enhance target products such as intracellular proteins, pigments and lipids. Physiological changes behind trophic conversions have to be elucidated in order to manipulate this biotechnological process. Using a trophic conversion strategy high biomass productivity and quality can be achieved, indicating that this strategy provides a promising way to boost economic benefit and considerably reduce production costs.
This two-stage process is a promising strategy as to provide a more efficient way for large scale production of microalgae biomass containing valuable compounds.
Leading co-ordinator: Félix Lopez Figueroa (University of Málaga, Spain)
Local co-ordinator: Jiří Masojídek (Centre Algatech, Třeboň, Czech Republic)
Local team leader: Karolína Ranglová (Centre Algatech, Třeboň, Czech Republic)
Number of participants: 10-15
Field experiments: None
Lab experiments: Centre Algatech, Institute of Microbiology in Třeboň
Data management: Centre Algatech, Institute of Microbiology in Třeboň
Microalgae cultures will be grown firstly in flasks or fermenters in heterotrophic mode (dark, organic substrate). Then, the cells are harvested, washed and transferred to inorganic medium. We intend to combine physiological methods (variable fluorescence - ETR, oxygen evolution) with biochemical analysis of cell composition (pigments, lipids, proteins and carbohydrates) and quantitative genomics and proteomics to understand the processes of trophic conversion.
In a series of laboratory and diurnal field trials, heterotrophically-grown microalgae cultures will be exposed to light and cultured phototrophically. Key physiological variables and biomass quality (e.g. pigments, lipid, proteins and carbohydratecontent) will be monitored to study the influence of growth conditions on the process of trophic conversions. We will set-up several experimental ‘nests’ focusing on various techniques (physiological and biochemical analyses, oxygen measurement, fluorescence, advanced biomass analyses, etc.). Diel sampling will be done every 2-4 hours during trials. Various outdoor and laboratory cultivation units (photobioreactors) will be compared.
Alternatively we can employ other techniques according to participant suggestions, skills and their equipment delivered.