Attached cultivation of microalgae in biofilm is potential cultivation method of microalgae which has variety of advantages including high biomass productivity, less medium consumption, economical harvesting and ease to scale-up. We have proposed and constructed this attached cultivation technology and has demonstrated its feasibility of efficient cultivation for variety of microalgae species. Systematic investigations on the cultivation conditions including inoculum density, attached substratum, medium composition, CO2 concentration and medium addition method have been carried out. The principle of attached cultivation photobioreactor design based on the dilution of solar light intensity has been proposed to boost the utilization efficiency of solar light and then produce dramatic high biomass of around 40~100gm-2d-1. A pilot cultivation photobioreactor of curtain structure in array with 200m2 scale has been constructed, and continuous cultivations lasting more than one month for both oleaginous specie of Tribonema minus and Spirulina sp. have been finished. More than 10% of solar photosynthesis efficiency (to optical spectrum), or maximum 40gm-2d-1 biomass productivity has been approached.
Fig.1 Attached mass cultivation of oleaginous Tribonema minus in 200m2 pilot scale