A novel suspended-solid phase photobioreactor to improve biomass production and separation of microalgae

• Solid carriers were added and kept suspended by aeration in this ssPBR.
• Microalgae could attach and grow on the carriers.
• By catching carriers, microalgae could easily be separated from liquid phase.
• Biomass production in ssPBR was increased by adding solid carriers.

A novel suspended-solid phase photobioreactor (ssPBR) was proposed in this paper to solve the problem of microalgal expensive and complex harvest system for biomass/biofuel production. In this ssPBR, solid carriers were added and kept suspended by aeration. Part of microalgae could attach and grow on the carriers. By catching carriers, microalgae could easily be separated from liquid phase. Three kinds of Carriers A, B, C made of cotton, mohair and linen, respectively, were used in this study. Compared with the reactor without carriers, the biomass production in each ssPBR was increased by adding these three kinds of carriers at a dosage of 2 g/L, and the maximum increments of biomass were 2.2 × 105 (10.3%), 7.8 × 104 (3.9%) and 4.4 × 105 (20.5%) cells/mL, respectively. By increasing the dosage of Carriers-C to 4 g/L, the maximum increment of microalgal biomass could reach up to about 30% in the ssPBR compared with control group.