Production of astaxanthin by Haematococcus pluvialis: Taking the one‐step system outdoors

Abstract

The feasibility of a one‐step method for the continuous production of astaxanthin by the microalga Haematococcus pluvialis has been verified outdoors. To this end, influence of dilution rate, nitrate concentration in the feed medium, and irradiance on the performance of continuous cultures of H. pluvialis was firstly analyzed indoors in bubble column reactors under daylight cycles, and then outdoors, using a tubular photobioreactor. At the laboratory scale, the behavior of the cultures agreed with that previously recorded in continuous illumination experiences, and attested that the major factors determining biomass and astaxanthin productivity were average irradiance and specific nitrate supply. The rate of astaxanthin accumulation was proportional to the average irradiance inside the culture, provided that a nitrate limiting situation had been established. The accumulation of astaxanthin under daylight cycles was maximal for a specific nitrate input of 0.5 mmol/g day. The recorded performance has been modeled on the basis of previously developed equations, and the validity of the model checked under outdoor conditions. Productivity values for biomass and astaxanthin of 0.7 g/L day and 8.0 mg/L day respectively, were obtained in a pilot scale tubular photobioreactor operating under continuous conditions outdoors. The magnitude of the experimental values, which matched those simulated from the obtained model, demonstrate that astaxanthin can be efficiently produced outdoors in continuous mode through a precise dosage of the specific nitrate input, taking also into consideration the average irradiance inside the culture. Biotechnol. Bioeng. 2009;102: 651–657. © 2008 Wiley Periodicals, Inc.

An applicable nitrogen supply strategy for attached cultivation of Aucutodesmus obliquus

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Photoautotrophic Production of Astaxanthin by the Microalga Haematococcus pluvialis

“…However, most of the studies performed have been focused on the induction phase of pigment accumulation [10,13]. Recently, García-Malea et al set and modeled optimal conditions for enhancing growth in the "green stage" [43,44]. Continuous culture with a simulated solar cycle has been performed in bubble-column reactors operated indoors.…”

Astaxanthin in microalgae: pathways, functions and biotechnological implications

“…Besides the two-stage culture mode, a single-stage cultivation mode has also been tested to produce astaxanthin in flagellates of some H. pluvialis strains in a chemostat system (Del Río et al 2005, 2008, García-Malea et al 2009). Under optimal light irradiance, nutrient concentration and dilution rate, algal biomass productivities of 0.7-1.9 g L -1 d -1 were obtained, corresponding to an astaxanthin productivity of 5.6-21 mg L -1 d -1…”