A photobioreactor comprising a vertical framework, which supports reactiontroughs, thereby creating a column of easily accessible reaction troughs. Inone embodiment, the reaction troughs are constructed from vacuum moldedstiff plastic. Each reaction trough is operatively associated with anillumination system that is attached to the reaction trough immediately aboveit. The photobioreactor includes harvesting system, comprising scraper wandsthat move the biomass towards the funnel positioned at the end of eachreaction trough. Each trough has media, gas and nutrient supplies that areoperatively associated with it. The bioreactor can be used to grow single-celled micro-organisms and other small multi-cellular organisms.
