Influences of different stress media and high light intensities on accumulation of astaxanthin in the green alga Haematococcus pluvialis.
ABSTRACT Haematococcus pluvialis Flotow is used in the aquaculture, pharmaceutical and cosmetic industries. The aim of this study was to compare the effect of various stress media and high light intensities on astaxanthin accumulation. The experimental design was achieved by four different stress media and two different light intensities for 14 days of induction period. The astaxanthin concentrations of 29.62 mg g(-1) and 30.07 mg g(-1) were obtained in distilled water with CO(2) and N-free medium, respectively, with no significant difference between them at 546 micromol photons m(-2)s(-1). Because of the morphological changes of H. pluvialis, microscopic observation was considered during the induction period to facilitate the selection of stress medium. It was clear that the rate of astaxanthin accumulation was much faster in distilled water with the addition of CO(2). The main point is that, this medium is more economical than others, especially for the large-scale productions.
Article: Effects of Salinity on Growth and Total Lipid Content of the Biofuel Potential Microalga Ankistrodesmus falcatus (Corda) Ralfs[show abstract] [hide abstract]
ABSTRACT: Growth responses and total lipid content of a native strain of the biofuel potential freshwater oleaginous microalgae A.falcatus was studied owing to its inherently high lipid content for potential utilization as renewable biomass feedstock of biofuels. Influences of salinity in increasing order from 40 mM to 320 mM of NaCl in BG11 medium on growth (µ), total lipid (TL) content and calorific value (CV) were studied in triplicate batch mode culture at light intensity 35 µmol/m 2 /s, temperature 25 ± 2 0 C and 16:8 hrs light and dark diurnal cycles. Enhanced growth and total lipid contents were observed with increasing salinity up to 160 mM NaCl. The highest specific growth (µ=0.313 d -1) and least doubling time (T2=2.21 days) with maximum increase in cell numbers (2.9 x 105 ml -1) were recorded in medium supplemented with 160 mM of NaCl compared to control medium (µ=0.209 d -1 , T2=3.32 days and 1.52 x 105 ml -1 respectively). Improved total lipid (55.3%), carbohydrate (14.5%), and protein (4.8%) contents were also determined compared to control medium (lipid 38.3%, carbohydrate 12.6%, and protein 3.1%, respectively). With maximum energy value of 27.9 ± 0.15 kJg -1 , a close correlation (R 2 = 0.955) between lipid content and calorific value was observed. With the support from present research findings, the native strain of freshwater oleaginous microalga A. falcatus could be a potent candidate for production of renewable biomass feedstock of biofuels. The present research findings will be supportive towards further culture optimization for increased biomass yield with c oncomitant lipid content and improved of fatty acid profile in mass cultivation.International Journal of Scientific & Engineering Research. 07/2012; 3(7):1-7.
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ABSTRACT: Microalgae have found commercial applications as natural sources of valuable macromolecules, including carotenoids, long-chain polyunsaturated fatty acids, and phycocolloids. As photoautotrophs, their simple growth requirements make them attractive for bioprocesses aimed at producing high added-value compounds that are in large demand by the pharmaceutical market. A few compounds synthesized by microalgae have indeed proven to possess anti-inflammatory, antiviral, antimicrobial, and antitumoral features; astaxanthin, a known antioxidant produced by Haematococcus pluvialis, is an illustrative example with important anti-inflammatory and antitumoral roles. From a chemical standpoint, several such compounds are polysaccharides or long chain fatty acids, where the latter can be either saturated or unsaturated. Additionally, their chemical structures are often atypical, whereas their concentrations can exceed those found in many other natural sources. The productivity and biochemical composition of microalgae depend strongly on the mode of cultivation, medium composition, and nutrient profile. Consequently, numerous efforts aimed at elucidating the practical impacts of the aforementioned parameters have been developed. This review accordingly covers the knowledge produced in the last two decades on the uses of microalgae to obtain physiologically active compounds, and on the optimization of the underlying production and purification processes. It also identifies major gaps and opportunities in this field that should be addressed or exploited in the near future.Biotechnology Progress 01/2011; 27(3):597-613. · 2.34 Impact Factor