Continuous or semi-continuous flow photobioreactor and method of use

A photobioreactor for continuous or semi-continuous flow culturing photosynthesizing biomass, the photobioreactor including a housing (2) defining an interior chamber (58) comprising a culture chamber portion (8) and a gas feeding chamber portion (60), a temperature regulation system (9), a flow-regulating system (3) comprising a culture mixing and concentrating entity (23) comprising a biomass-directing flow propulsion device (47) and a lighting system (5), the culture chamber portion comprising a culture concentrating zone (18) and a culture harvesting zone (19) which is below the culture concentration zone, the temperature regulation system, the flow-regulating system being within the culture chamber portion, the lighting system being within the culture concentrating zone and the biomass-directing flow propulsion device causing an at least partially vertical flow of culture medium contained in the housing such that the biomass is concentrated in the culture concentrating zone and wherein the culture harvesting zone is located near the bottom end of the culture chamber (8) and further comprising a feed-back control unit (6) comprising a sample collection unit (31) and wherein feed-back control unit (6) further comprises a sample reinjection line (36) in fluid communication with an upper feeding line (24) of a feeding device (4) through the opening of a multiport valve (35) for re-injecting the sample collected in the sample collection unit (31) into the culture chamber portion (8).