A helical tubular photobioreactor producing Spirulina in a semicontinuous mode

A 21 l bench-top, helical tubular photobioreactor was operated, under steady-state conditions, for Spirulina sp. production as a semicontinuous reactor using different dilutions from 1 : 20 to 1 : 4. A maximum value of 5.82 gdryweightl−1 was obtained for a dilution rate (D) of 0.0078 h−1. The maximum productivity value obtained was 0.40 gl−1 d−1 (8.52 greactor−1 d−1 or 6.45 gm−2 d−1) using a dilution of 1 : 5 and 0.0078 h−1 of dilution rate. The reactor was operated for 984 h. The determination of a satisfactory condition for the use of this type of photobioreactor in tropical climates and the study of its performance under various dilutions were the main objectives of this work.