Astaxanthin accumulation in the green microalga : Effect of initial phosphate concentration and stepwise/continuous light stress.

Nutrient composition and light stress significantly affect the productivity of astaxanthin in . Hence, the present study aimed to investigate the effect of initial phosphate concentration and two distinct light regimes on astaxanthin accumulation in In the green stage, microalgae were cultivated in different initial phosphate concentrations under 2000 lx and a 12:12 h photoperiod. To initiate astaxanthin accumulation, an increased light intensity of 5000 lx was provided using two methods; (i) stepwise light stress, where a 12:12 h photoperiod was provided for 14 days, followed by 14 days of continuous illumination, and (ii) continuous illumination for 28 days.

Development of an artificial neural network model to simulate the growth of microalga Chlorella vulgaris incorporating the effect of micronutrients.

Artificial neural network (ANN) models can be trained to simulate the dynamic behavior of biological systems. In the present study, an ANN model was developed upon multilayer perceptron neural network architecture with 23-20-1 configuration to predict the cell concentration of microalga Chlorella vulgaris at a given time. Irradiance level, photoperiod, temperature, air flow rate, CO percentage of the air stream, initial cell concentration, cultivation time and the nutrient concentrations of the media were considered as the input variables of the model.