M Mohammad Mirzaei - Department of Polymer and Chemical Engineering, school of engineering, Yazd University
M Baradaran - Department of Polymer and Chemical Engineering, school of engineering, Yazd University

Chlorella vulgaris was grown in mixotrophic cultivation using cheap substrates of molasses and corn steep liquor. Mathematical modeling of growth rate was carried out in optimum conditions of the most significant variables namely light intensity and carbohydrate concentration. Multiplication of Haldane I equation times Haldane S equation led to the present model fitted with the experimental results very well. In the growth process, microalgae first consumed the organic carbon source in the heterotrophic mode and then, CO2 in the autotrophic mode. Maximum specific growth rate was obtained in CO2 consumption, followed by a decrement due to a light limitation. The present model indicated that the mixotrophic growth of microalgae was not a simple combination of growth in heterotrophic and autotrophic metabolism. Mathematical models were also developed in this research work for growth-associated lipid production and substrate consumption. All introduced models predicted the experimental data very well.

Chlorella vulgaris; mathematical models; growth rate; cheap substrates; mixotrophic cultivation