Microalgae Secondary Metabolites

*Microalgae - From Physiology to Application*

pressure. Plant Molecular Biology.

and Photobiology, B: Biology.

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2001;**45**:691-703

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**190**

Chapter 11

Abstract

and biofuels.

1. Introduction

193

Microalgae Cultivation for

Facundo J. Márquez-Rocha, Diana Palma-Ramírez,

Pedro García-Alamilla, Jenny F. López-Hernández,

Ivonne S. Santiago-Morales and Abelardo I. Flores-Vela

Keywords: microalgae metabolism, mixotrophy, continuous cultivation,

cultivation of microalgae in photobioreactors and produce fine chemicals:

Industrial reactors for microalgae cultivation have been generally constructed using channels with movement and adapted for a better gas exchange. One of the biggest problems in this culture system is the low density of microalgae cells; they are constructed between 15 and 30 cm deep along the canal, limiting therefore the available light in addition to increasing the potential for contamination. A system proposed to solve the problem of low density and pollution has been found in closed polyethylene pipe systems, having the geometric design of the reactor as its main objective. Some strategies addressing three aspects have been developed to improve

secondary metabolites, fine chemicals, biofuels, pigments

Microalgae including cyanobacteria have been recognized as an excellent source of fine chemicals, renewable fuels, vitamins, and proteins and usually are found in health food stores around the world. However, the accumulation of these compounds generally occurs at end of the exponential growth phase; furthermore, biomass density in cultivation commonly is low. Open cultures have been used for pigment, biofuels, and biomass production, but these types of culture system are not a good choice for the production of fine chemicals, due to contamination problems and the expensive production costs. Closed photobioreactors can be operated in a continuous cultivation providing an increase on biomass density and contamination-free condition and generally working at a maximum growth rate under specific conditions; besides, these systems can recycle the consumed culture medium at least three times before a new enriched medium is supplied, generating a more cost-effective production system. In addition, microalgae metabolism can be manipulated to provoke a specific secondary metabolite accumulation by the addition of organic carbon source or changing light intensity or both. In other words, photobioreactors can operate in continuous mode, with efficient light supply and the supplementation of organic carbon source to produce fine biochemicals such as anticancer, antibacterial, antioxidant, lectins, antiviral compounds,

Secondary Metabolite Production
