CONTINUOUS CULTURES OF SPIRULINA-PLATENSIS UNDER PHOTOAUTOTROPHIC CONDITIONS WITH CHANGE IN LIGHT-INTENSITY

In continuous cultures of Spirulina platensis under photoautotrophic c onditions, the operation mode to maintain constant cell concentration is examined using culture apparatuses with light path lengths of 0.02 and 0.156 m. The values of dilution rates in the continuous cultures a re determined by employing specific growth rates of the cells correspo nding to light intensity distribution in liquid medium. When incident light intensity is fixed at 25, 50 or 400 W m(-2), it is found that th e cell concentration in the continuous culture is kept almost constant , and agrees fairly well with the prescribed value of the cell concent ration in the range of 0.09 to 2.43 kg m(-3). It is also demonstrated that the operation mode is valid to obtain stable cell concentrations in the continuous cultures associated with the change in incident ligh t intensity ranging from 25 to 400 W m(-2) during the cultures.