Microalgae systems

The microalgae are cultured in bioreactors under solar or artiflcial light in the presence of carbon dioxide and salts. The bioreactors may be closed systems made of polyethylene sleeves rather than open pools. Optimal conditions for pigment production are low to medium light intensity and medium temperatures (20 to 30°C). Pigment extraction is achieved by cell breakage, extraction into water or buffered solution, and centrifugation to separate out the filtrate. The filtrate may then be partly purified and sterilized by microfiltration and spray dried or lyophilized. 

The current production of microalgae is mainly focused around a few species, such as Spirulim, Chlorella, Dunaliella or Haematococcus for nutritional purposes (for humans) and animal feed (especially aquaculture). Other sectors, such as cosmetics, effluent treatment and bioenergy, have shown interest, incorporating these or other species of microalgae and cyanobacteria into commercial products. Currently, 95% of the production of microalgae is based on open systems... 

Figure 17. Microalgae culture in open system (raceway) and close photobioreactor (Almeria University and Palmerillas Research Center).

The book is divided into 3 sections. Section I.Cellular Model Systems, includes 3 chapters (Allelopathy and plant cell diagnostics, Cellular models as biosensors and microalgae for determining the effects of allelochemicals). Section II. New Methods of Microscopy has 5 chapters (Microscopic methods to study morpho-cytological events during the seed germination,... 

Sakaguchi, T., A. Nakajima, and T. Horikoshi. 1981. Studies on the accumulation of heavy metal elements in biological systems. Accumulation of molybdenum by green microalgae. European Jour. Appl. Microbiol. Biotechnol. 12 84-89. 

Fig. 2.31. Chromatogram of crude lutein from the microalga Chlorella vulgaris by HPLC analysis, A = lutein. Conditions column reversed-phase C18 column (250 X 4.6 mm i.d., 5 pm) mobile phase methanol-dichloromethane-acetonitrile-water (67.5 22.5 9.5 0.5, v/v) flow rate l.Oml/min detection at 450 nm (a). Chromatogram of crude lutein from the microalga Chlorella vulgaris by preparative HSCCC separation, A = lutein. Conditions column multilayer coil of 1.6mm i.d. PTFE tube with a total capacity of 230ml rotary speed 800rpm solvent system ra-hexane-ethanol-water (4 3 1, v/v) mobile phase lower phase (ethanol-water) flow rate lml/min detection at 254 nm sample size 200 mg retention of the stationary phase 58 per cent (b). Reprinted with permission from H.-B. Li el al. [70].

In spite of yielding a lower CL intensity, the oxidation of luminol (124) by H2O2, catalyzed with Cr(II) ions in a FIA system is claimed to be a viable alternative to HPR catalysis, as it avoids the enzyme instability and high price. LOD is 40 nM. The method was tested for determination of H2O2 produced in vitro by various microalgae species (Chlamydomonas reinhardtii, Chlorella fusca and Monoraphidium brauniif. ... 

Benemann, J.R. and Weissman, J.C. 1984. Chemicals from microalgae. In Bioconvers ion Systems (Ed. D.L. Wise). (CRC Press, Boca Raton, Florida), pp. 59-70. 

Marxen, K., Vanselow, K.H., Lippemeier, S., Hintze, R., Ruser, A., Hansen, U-P. (2005). A photobioreactor system for computer controlled cultivation of microalgae. J. Appl. Phycol. 17 535-49. 

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