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Dynamic photobioreactor management
for automated microalgae production

Philipp Norf

The efficient conversion of light energy and other available ressources to algae biomass requires a high degree of optimization and the development of effective photobioreactor (PBR) systems plays an important role in making large scale algae biomass production economically viable. This doctoral research project takes place within the scope of an Russian-German bioeconomy cooperation emphasising on the development and characterisation of hydrogel-based photobioreactor concepts and the development of a dynamic control and management module aiming for mostly automated microalgae production.
The Russian side of the project provides a hydrogel-based photobioreactor system. The hydrogel is a water-soaked matrix of polyvinyl alcohol and -carrageenan crosslinked by repeated freeze-thawing cycles. Light dispersing pigments (TiO2) embedded within the hydrogel enhance the scattering of light into the culture providing a more evenly illumination. This setup of a hydrogel-based photobioreactor then will be compared to conventional photobioreactor designs and own prototypes. Automatisation of control and management processes are already widely used in large scale chemical applications yet remain rare in the up-scaling of biotechnological processes. The vast amount of interacting factors prevents the direct port of available solutions known from chemical engineering and limits the current state of the arts in (photo-)bioreactor automatisation. Available systems remain limited to short running lab scale PBR systems or rely on expert handlers to hardcode control parameters. This dependency on expert handlers is obstrusive to wide-spread use and will also result in a general lower acceptance of such systems by the general public. One of the main objectives of this doctoral research project is the development of the dynamic control module required for the automatisation of biomass production, thus eliminating the requirement for an expert handler and have the control module take over the system, optimising the performance of the system towards a biological target function (e. g. CO2 sequestration). Finally the connection of build prototypes and developed control modules provides an algae biomass cultivation system with sufficient self-adjusting capabilities able to keep working autonomously, only requiring human intervention in extreme error cases like culture crash, severe contamination, leakage or lack of resources.