Determining the best specific light uptake rates for the lumostatic cultures in bubble column photobioreactors

Lumostatic cultures of Haematococcus pluvialis were performed and compared using three different types of specific light uptake rate, qe: cell concentration, cell projection area, and fresh weight. These three parameter are representing one, two, and three-dimensional characteristic values of the biomass, respectively. The qe value using cell concentration for optimal lumostatic operation was 3.5 × 10−8 μE cell−1 s−1 and the maximal cell concentration was increased over 160% compared to that of the control. The optimum qe values using projection area and fresh weight were determined as 35 and 3.5 μE m−2 s−1, respectively, and the maximal cell concentrations of the lumostatic cultures were 140% and 150% higher than that of the control, respectively. When the three optimal lumostatic operations were compared to determine the best parameter for lumostatic cultures of H. pluvialis, the lumostatic cultures using qe based on cell concentration attained the highest final cell concentration as well as astaxanthin concentration for H. pluvialis cultures. The lumostatic operation of bubble column photobioreactors are always more efficient than the standard operation no matter which parameter is used to calculate the specific light uptake rate and are more important at higher cell concentrations.