Calculation of the specific growth rate of microalgae

The work focuses on techniques of quantifying the specific growth rate of microalgae in both batch and continuous culture. It is shown, that to prove that the specific growth rate is a constant value, both the ratio of two chemical biomass characteristics and dimensional structure of cell population must be constant. Critical analysis of the correctness of using the logarithmic formula for estimating the specific growth rate (μ) of microalgae in the exponential phase of growth of batch culture is held: μ = (lnB2 – lnB1) / (t2 – t1), where B1 and B2 are densities (concentrations) of the culture at a moment of time t1 and t2, respectively. This formula is widely used by most microalgae researchers without proving exponential growth character. Availability of such proofs makes the applying of the logarithmic formula meaningless. Examples of quantitative description of the experimental data obtained for two types of marine microalgae in the exponential and linear phases of culture growth are given.