On-Line Monitoring and Real-Time Data processing of microalgae production

This project focusses on the development of new monitoring strategies for reliable estimation of microalgal growth and secondary metabolite productions at short-time scales through On-Line elemental mass balancing and Softsensor implementation.


Monitoring of microalgal processes is a key discipline for experimental research and industrial production. To improve these processes and obtain higher productivities detailed knowledge and adequate process control is required. Proper process control can only be achieved with sufficient information of the current process state. This information therefore has to be acquired as accurately and fast as possible.

The monitoring and control of microalgal based processes can be challenging due to multiple reasons:

  • Microalgae are able to adapt to their environment by subsequently adjusting their metabolism and the concentrations of intracellular components such as pigments or storage compounds. However, many currently established methods of process analysis are based on the assumption of constant cellular properties. This can lead to less accurate parameter estimation with ongoing process time.
  • Microalgae species considered for large-scale production are derived from a high variety of environments, Cultivation processes consequently have to be performed under similar conditions. This causes high requirements for sensors regarding robustness and sensitivity to be applied in a wide range conditions such as pH, temperature, and salinity. Many sensors do not fulfill these requirements and are therefore unsuitable for consideration in standardized monitoring of microalgal processes.
  • Another drawback of many analysis methods is that they require time-consuming processing of reactor samples. Obtained Information are consequently not representing the current process state anymore and cannot be used for decision making and adequate process control.

The development of improved monitoring techniques which are applicable in a wide range of process conditions and reliably estimate changes of cellular properties is thereby necessary. On-Line elemental mass balancing is considered to be a promising strategy to resolve many of the shortcomings of conventional analytic methods.

On-Line elemental mass balancing comprises the determination of amount of elements converted in to biomass by monitoring their respective consumption and productions over the reactor system while the process is running (On-Line).

Project description

This project aims for the development of strategies for On-Line elemental mass balancing for reliable process monitoring at  real time. Our mayor objective is to develop a model approach to be applicable for various algal strains and reactor types. The techniques to be developed should result in reliable estimates of microalgal growth and respective contents of secondary metabolites such as lipids and carbohydrates. Within this project we therefore test various process control strategies and combination of in- and on-Line measurements. Moreover, we investigate data treatment strategies to be used for correction of timely increasing signal alteration known as sensor drifts to further increase measurement reliability. Strategies of on-Line monitoring to be proposed will be developed and tested at lab-scale and at pilot plant level.