Microalgae have recently received specific attention as the most potential biofuel feedstock due to their unique characteristics such as rapid growth rate, high lipid content and no requirement of high quality agriculture land. The growth of microalgae as well as the accumulation of cell components including protein, lipid, carbohydrate is tightly related with the environmental conditions, whereas little information is available on the dynamic change of intracellular carbon and energy flux of microalgae according to growth conditions.

Recently, the research team led by Prof. CONG Wei at Institute of Process engineering (IPE) of the Chinese academy of Sciences, set up a photobioreactor system to monitor and control microalgae culture on-line to explore the method of dynamic monitoring of intracellular carbon and energy flux of microalgae.

The system could implement the control and monitoring of the common parameters as traditional fermentation system, besides that, it could correlate the parameters to get more useful information, such as CUR, OER and PQ, and attain the state of carbon and energy flux in microalgae, further. This system was applied to the culture of Nannochloropsis sp., and the cell composition and intracellular ATPs partition in the nitrogen-replete culture and nitrogen-limit culture were monitored on-line and compared. These results provided a reference for on-line control of culture of Nannochloropsis sp..

This study indicated an advanced the photobioreactor culture system and parameter calculation methods to gain some dynamic information on microalgae metabolism. The results have been published on Bioresource Technology, 2014, 164, 86-92.

Figure (a) Design of hardware construction of the system; (b) Picture of the system; (c) On-line parameter monitoring; (d) Intracellular ATP consumption; (e) PQ, carbon flux and component contents.