author(s)
Nadim Hammoud, Hamed Mayhoub, Tarek Allaan

abstract
In order to optimize Cosmarium subtumidum algae growth isolated from local from various geographic regions, this study was conducted at different concentrations of soil extract and under threernlight intensities as follows 1500, 2000, 2500 Lux with a photoperiod of 16 hours light : 8 hours dark. The maximum growth rate was 3.38, at the lowest doubling time of 2.14 and under light intensity of 2500 Lux. On the 35^th day of Cosmarium subtumidum cultivation. Thus, the higher soil extract concentration and light intensity, the higher growth rate occurred. As for protein content, the highest record was 14.88% at a concentration of 8ml/50 of soil extract and under a light intensity of 1500 Lux. Thus, the higher soil extract concentration and the lower light intensity, the higher protein content was.