Effective Light Penetration Explains the High Photosynthetic Efficiency of Microalgae in Attached Cultivation Technique

An "attached" cultivation technique for microalgae production has shown better biomass production and photosynthetic efficiency over conventional open-pond suspended cultures. Tianzhong Liu of the Chinese Academy of Sciences now aims to study how light is transferred and distributed in the attached cultivation technique.

The growth of microalgal cells in both open-pond and attached cultivation were studied to test the effective light penetration during cultivation. In a conventional outdoor 2-cm deep open-pond, all algal cells were fully-illuminated in the first 3 days of cultivation. As biomass concentration increased, light penetration gradually decreased until biomass density reached its peak. In the attached cultivation system, almost 100% of the immobilized algal cells inside the biofilm were effectively illuminated from day 0 through 10 even when the biomass density increased.

The higher light penetration efficiency could be the reason why photosynthetic efficiency of algae was higher using attached cultivation than those for conventional open-pond suspended cultures.