High‐density photoautotrophic algal cultures: Design, construction, and operation of a novel photobioreactor system

Abstract

A photobioreactor system has been designed, constructed and implemented to achieve high photosynthetic rates in high-density photoautotrophic algal cell suspensions. This unit is designed for efficient oxygen and biomass production rates, and it also can be used for the production of secreted products. A fiber-optic based optical transmission system that is coupled to an internal light distribution system illuminates the culture volume uniformly, at light intensities of 1.7 mW/cm(2) over a specific surface area of 3.2 cm(2)/cm(3). Uniform light distribution is achieved throughout the reactor without interfering with the flow pattern required to keep the cells in suspension. An on-line ultrafiltration unit exchanges spent with fresh medium, and its use results in very high cell densities, up to 10(9) cells/mL [3% (w/v)] for eukaryotic green alga chlorella vulgaris. DNA histograms obtained form flow cytometric analysis reveal that on-line ultrafiltration influences the growth pattern. Prior to ultrafiltration the cells seem to have at a particular point in the cell cycle where they contain multiple chromosomal equivalents. Following ultrafiltration, these cells divide, and the new cells are committed to division so that cell growth resumes. The Prototype photobioreactor system was operated both in batch and in continuous mode for over 2 months. The measured oxygen production rate of 4-6 mmol/L culture h under continuous operation is consistent with the predicted performance of the unit for the provided light intensity.

Microalgae and Wastewater Treatment

“…Currently significant interest is developed in some advanced world nations such as Australia, USA, Thailand, Taiwan and Mexico (Borowitzka andBorowitzka, 1988, 1989a,b;Moreno et al, 1990;Wong and Chan, 1990;Renaud et al, 1994). These are due to the understanding of the biologists in these nations for the biology and ecology of largescale algal cultures, as well as in the engineering of large-scale culture systems and algal harvesting methods, all of which are important to the design and operation of high rate algal cultures to produce high-value products, such as Pharmaceuticals and genetically engineered products (Javanmardian and Palsson, 1991). These include antibacterial, antiviral, antitumers/anticancer, antihistamine and many other biologically valuable products (Starr et al, 1962;Borowitzka, 1991;Ibraheem, 1995;Haroun et al, 1995).…”

Diseño de un fotobiorreactor Airlift a escala banco

“…Se observa que la cantidad de intensidad empleada genera 14,496 fotones, cantidad coherente con lo referenciado en la literatura [13] donde se dice que son necesarios cerca de "16 pares de fotones para suplir las necesidades de luz o requerimiento cuántico que facilitan la reducción de las moléculas de CO 2 ." También, se analizaron los fotones y los luxes totales producidos por todo el sistema de iluminación (cuatro tiras de led), el cual genera 1993,47 lux/m 2 , valor aproximado a los 2000 lux/m 2 , intensidad de luz requerida por la microalga.…”

Biotechnology of algal biomass production: a review of systems for outdoor mass culture

“…Such systems could have controllable illumination for up to 24 hours a day rather than variable duration sunlight exposure. They can utilize artificial light only (Pohl et al, 1988;Javanmardian & palsson, 1991;Wohlgeschaffen et al, 1992), or combined sunlight and artificial light (Mori, 1985), or light source enriched in specific wavelengths (Junter et al, 1990). Several companies are now selling such equipment: e.g.…”