Studies on the Growth of Chlorella by Continuous Cultivation

Part I

Abstract

In the preliminary experiment, it has been found that only the normal cells which con-tain about 50%, protein are produced, when the nutrients are sufficiently supplied. Then, only the normal cells being treated, the growth characteristics of Chlorella ellipsoidea were investigated. The cell growth was not affected by the agitation of the rotor speed up to 780 r.p.m. with the gas supply at the rate of 300ml./I-min. Upon this, the algal suspension was constantly agitated only by bubbling of gas supply.
In the conditions favourable for cell growth, the restricting factors are light intensity and cell concentration. And the growth rate related to these factors was investigated in the continuous culture process, in which the growth rate is equivalent to the flow rate in the limited range as shown in Equation 7.
In the exponential phase the growth rate is constant having no relation to the cell concentration, and the functional relation to the light intensity is shown by Equation 6a. In the linear phase, the increase of cells per unit area and time is constant at a fixed light intensity as shown by Equation 8a, and therefore, the growth rate or flow rate is in inverse proportion to the cell concentration as cited in Equation 9. The yield obtained by the continuous culture was the same as that by the batch culture.