Effect of Light Intensity and Thickness of Culture Solution on Oxygen Production by Algae

Abstract : Data from a small cylindrical culture unit with variable annular culture chambers indicate that: (a) the rate of oxygen evolution by an algal culture in the linear phase of growth is a logarithmic function of light intensity, and (b) the rate of oxygen evolution per unit volume of suspension is linearly related to the reciprocal of culture thickness. These two relationships have been combined in an empirical equation, which gives the expected variation of the oxygen production rate with light intensity, culture thickness, and suspension volume. The applicability of this equation has been tested on a larger, multi-light culture unit in this laboratory. The agreement between the experimental and calculated oxygen production rates was very satisfactory, suggesting that the equation is not limited to a particular culture unit but may have wide applicability. The efficiency of the culture unit from the viewpoint of electrical power utilization has been calculated, and it was found that the maximum conversion of electrical energy to chemical energy based on oxygen evolution was only 0.51 percent. The maximum efficiency in converting light energy to chemical energy was approximately 12 percent. An extrapolation of the experimental results suggests that approximately 2 cubic feet and 30 kilowatts would be required to provide for the oxygen needs of one man. (Author)