Evaluation of different scale-up strategies for Haematococcus pluvialis cultivation in airlift photobioreactor

Abstract

Large scale algal biomass production can be very challenging due to the potential issues of sustain-ability, environmental ethics, and economic concerns. A strategic approach to the transition from the laboratory to the industrial scale allows the prediction of process characteristics, design and analysis of large scale systems, and reduction of extra costs. In this study, a scale-up procedure that consid-ered different approaches was carried out by selecting the Haematococcus pluvialis as a model or-ganism. Three scale-up parameters (constant mixing time (tm), volumetric power consumption rate (P/V), and oxygen mass transfer coefficient (kLa)) were tested for biomass production in a 2-L airlift photobioreactor and they were compared with those obtained from a 1-L aerated cultivation bottle. Among three strategies, the maximum cell concentration, 4.60±0.20×105 cells/mL, was obtained in a constantvolumetricpowerconsumptionrateexperiment.Also,totalcarotenoidamountshowedsimilarchangeswiththecellconcentrationandreachedthemaximumconcentrationof2.02±0.11mg/L under constant P/V experiment. However, the cultivation bottle presented the highest biomass amount of 0.62 g/L and specific growth rate of 0.38 day-1 of all of the photobioreactors. This result might be attributed to the low aeration rates or improper configuration of the system, which created a non-homogenous culture medium and led to ineffective mass transfer.

Keywords

• haematococcus pluvialis
• scale-up
• airlift photobioreactor
• biomass production
• carotenoid