Statistical optimization of medium for biomass production of a local Iranian microalgae Picochlorum sp. RCC486 by response surface methodology

Microalgae biomass production and optimization is necessary to overcome food security problems and address environmental topics as well as high-value compounds production. In this investigation the influence of three culture media (BBM, BG-11 and Guillard f/2) on the growth and biomass production of Picochlorum sp. RCC486 microalgae was evaluated. One-way ANOVA with Tukey’s HSD and Fisher’s LSD tests were used to test the ef-fect of different culture media on optical density. Then maximum optical density and biomass production by Picochlorum sp. RCC486 was evaluated using response surface methodology. Lastly, Historical data design (HDD) of response surface methodology was used to find the optimum response, which yielded the highest biomass production. It was found that microalgal growth in Guillard f/2 medium reached its highest cell count in the considered time period, and the microalgae presented the highest biomass production in comparison with the other two culture media (BBM and BG-11). Additionally, biomass productivity (58 mg L-1d-1 ), specific growth rate (0.681d-1), dry weight (1.516 g L-1), and cell density(52.9 ×106 cells mL-1) were also the highest in comparison with the other two culture media. Using the HDD, the predicted optical density and biomass production were found to be close to their experimental values of 1.50313 and 1.976gL-1, respectively, while the nitrogen source and phosphorus source were achieved in concentrations of 1345.55 mg L−1 and 6.983 mg L−1, respectively. Under the optimum condition, the biomass yield was 1.961 gL-1, which is 0.76% less than the predicted value. Also, the study reported that the biomass production of Picochlorum sp. RCC486 improved from 1.516 g L-1 in the defined Guillard f/2 medium to 1.961 g L-1 in the modified Guillard f/2 medium resulting in a 22.69% increase. Thus, the Picochlorum sp. RCC486 biomass content can be enhanced by optimizing nitrogen and phosphorus concentrations.