Process optimization and modeling for the cultivation of Nannochloropsis sp. and Tetraselmis striata via response surface methodology

Abstract

The aim of this study was to determine the optimal physical process conditions for the cultivation of locally isolated strains of Nannochloropsis sp. and Tetraselmis striata to achieve maximum growth rate. It was essential to evaluate biomass production at different agitation rates, light intensities, and temperature levels. Central composite design and response surface methodology were applied to design the experiments and optimize the cultivation process for Nannochloropsis sp. and T. striata. The specific growth rate of 0.250 d(-1) was obtained for Nannochloropsis sp. cells under the light intensity of 54 μmol photons · m(-2) · s(-1) , at the agitation rate of 151 rpm in 24.5°C. The optimal physical process conditions for T. striata were obtained under the light intensity of 56 μmol photons · m(-2) · s(-1) in 25.5°C at the agitation rate of 151 rpm in 25.5°C, resulting in a specific growth rate of 0.226 d(-1) . The predicted values were justified by the verification tests. Good agreement between the predicted values and the experimental values confirmed the validity of the models for the cultivation of microalgal strains. In this article, the noteworthy result was that temperature was a dominant factor in obtaining high chl-a content for Nannochloropsis sp., whereas the growth of T. striata strongly depended on light exposure.

Evaluation of the effect of agitation speed on the growth and high‐value LC‐PUFA formation of Porphyridium cruentum based on basic rheological analysis

“…The agitation speeds of 150 and 300 rpm were generally optimal for P. cruentum culture, which was consistent with the findings of Imamoglu et al, 19,39 who reported that an agitation speed of 151 rpm was optimal for the growth of Nannochloropsis sp. and Tetraselmis striata, and 148.73 rpm optimal for Dunaliella salina.…”

“…In summary, the relevance of the rheological characterization of microalgal suspensions is an active area of research geared toward improving the overall microalgal production process. 19 As a key rheological parameter, agitation speed can markedly influence microalgae growth. Previous studies demonstrated that agitation was associated with damage to microalgal cells and indicated that hydrodynamic effects require a careful evaluation for the design of microalgae bioreactors.…”

Optimization of Cryopreservation Process Using Response Surface Methodology for Chlorella saccharophila and Chlorella zofingiensis

“…The cryoprotectant agent as DMSO is used for the treatment of microalgae because it easily permeates cell membranes and its low hydrophilicity [13]. In order to obtain optimum cell viability after cryopreservation, it is necessary to optimize of three factors (cryoprotectant concentrations, incubation time and cryopreservation time) by using response surface methodology (RSM) in analytical optimization [14].…”

Long-term storage of microalgae: determination of optimum cryopreservation conditions

“…In order to obtain optimum cell viability, it is necessary to optimize these factors using multivariate statistical techniques (Bezerra et al ., 2008). Among others, response surface methodology (RSM) is generally preferred to determine and evaluate the interactions statistically among the parameters affecting the process (Imamoglu et al ., 2015). In this study, optimization of cryopreservation conditions was performed by central composite design (CCD) using response surface methodology with parameters of cryoprotectant concentration (0–25%), pretreatment duration (1–15 min) and the duration of cryopreservation (7–180 days) for C. vulgaris and N. texensis .…”