Comprehensive Analysis of Lutein and Loroxanthin in Scenedesmus obliquus: From Quantification to Isolation.

Carotenoids are hydrophobic pigments produced exclusively by plants, fungi, and specific microbes. Microalgae are well suited for the production of valuable carotenoids due to their rapid growth, efficient isoprenoid production pathway, and ability to store these compounds within their cells. The possible markets for bio-products range from feed additives in aquaculture and agriculture to pharmaceutical uses. The production of carotenoids in microalgae is affected by several environmental conditions, which can be utilized to enhance productivity. The current study focused on optimizing the extraction parameters (time, temperature, and extraction number) to maximize the yield of carotenoids. Additionally, the impact of various nitrogen sources (ammonia, nitrate, nitrite, and urea) on the production of lutein and loroxanthin in Scenedesmus obliquus was examined. To isolate the carotenoids, 0.20 g of biomass was added to 0.20 g of CaCO3 and 10.0 mL of ethanol solution containing 0.01% (w/v) pyrogallol. Subsequently, the extraction was performed using an ultrasonic bath for a duration of 10 min at a temperature of 30 °C. This was followed by a four-hour saponification process using a 10% methanolic KOH solution. The concentration of lutein and loroxanthin was measured using HPLC-DAD at 446 nm, with a flow rate of 1.0 mL/min using a Waters YMC C30 Carotenoid column (4.6 × 250 mm, 5 µm). The confirmation of carotenoids after their isolation using preparative chromatography was achieved using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an atmospheric pressure chemical ionization (APCI) probe and UV-vis spectroscopy. In summary, S. obliquus shows significant promise for the large-scale extraction of lutein and loroxanthin. The findings of this study provide strong support for the application of this technology to other species.

Manipulation in Culture Conditions of Nanofrustulum shiloi for Enhanced Fucoxanthin Production and Isolation by Preparative Chromatography.

Microalgae produce a variety of high-value chemicals including carotenoids. Fucoxanthin is also a carotenoid that has many physiological functions and biological properties. For this reason, the cost-effective production of fucoxanthin at an industrial scale has gained significant attention. In the proposed study, fucoxanthin production was aimed to be increased by altering the culture conditions of N. shiloi. The effect of light intensity aeration rate, different nitrogen sources, and oxidative stress on the biomass and fucoxanthin productivity have been discussed. Based on these results, the fucoxanthin increased to 97.45 ± 2.64 mg/g by adjusting the light intensity to 50 µmol/m2s, and aeration rate at 5 L/min using oxidative stress through the addition of 0.1 mM H2O2 and 0.1 mM NaOCl to the culture medium. Fucoxanthin was then purified with preparative HPLC using C30 carotenoid column (10 mm × 250 mm, 5 µm). After the purification procedure, Liquid chromatography tandem mass spectrometry (LC-MS/MS) and UV-vis spectroscopy were employed for the confirmation of fucoxanthin. This study presented a protocol for obtaining and purifying considerable amounts of biomass and fucoxanthin from diatom by manipulating culture conditions. With the developed methodology, N. shiloi could be evaluated as a promising source of fucoxanthin at the industrial scale for food, feed, cosmetic, and pharmaceutical industries.

Induction of lutein production in Scenedesmus obliquus under different culture conditions prior to its semipreparative isolation.

Microalgae with their improved growth rates and accumulation of high-value-added products make their commercial production attractive. Among them, lutein, which is a carotenoid, plays a very important role due to its various applications in the food and pharmaceutical industry. Induction of its biosynthesis can be triggered by various stress conditions like light. In this study, three different light intensities (50,150 and 300 µmol photons/m2s) and aeration rates (1, 3, and 5 L/min) were utilized to induce the lutein biosynthesis and biomass productivity in Scenedesmus obliquus. Lutein was isolated by preparative chromatography using a semiprep C30 column (10 × 250 mm, 5µm) and its confirmation was made by LC-MS/MS. According to the results, Scenedesmus obliquus synthesized the maximum lutein (8.01 ± 0.1 mg/g) with biomass productivity of 1.698 g/L at 150 µmol photons/m2s light intensity using 3 L/min as aeration rate. To the best of the authors' knowledge, this was the first study that the lutein was isolated by preparative chromatography using semiprep C30 carotenoid column with a simple and rapid separation, which can be used as a reference methodology for the isolation of other carotenoids. Scenedesmus obliquus can be an important alternative source for commercial production of lutein, as it is indicated from the results of this study.

Enhancement of biomass and phycocyanin content of Spirulina platensis.

Response surface methodology (RSM) based on the 23 factorial central composite design (CCD) was employed to evaluate optimum culture conditions (temperature, light irradiance and agitation) to enhance biomass and phycocyanin content of Spirulina platensis. The predicted maximum biomass and phycocyanin content by RSM was 1.06 g L-1 and 107 mg L-1, respectively, whereas maximum biomass and phycocyanin content of 1.32 g L-1 and 127 mg L-1 was obtained in the validation experiments under optimized conditions after 10 days of cultivation. Further, influence of optimized conditions (temperature 33±2 ºC, light irradiance 44 µmol photons m-2 s-1 and a flow rate of 2.5 L min-1) on growth and phycocyanin content of S. platensis in 7L Panel photobioreactor (PPBR) cultivation was investigated. A 15 days production was carried out and it was observed that a maximum biomass yield of 2.42 g L-1 with a specific growth rate 0.202 day-1 and phycocyanin content of 228 mg L-1 was obtained in the PPBR. The optimum culture conditions obtained through response surface methodology were successfully determined to maximize the biomass and phycocyanin.

Process optimization and modeling for the cultivation of Nannochloropsis sp. and Tetraselmis striata via response surface methodology.

The aim of this study was to determine the optimal physical process conditions for the cultivation of locally isolated strains of Nannochloropsis sp. and Tetraselmis striata to achieve maximum growth rate. It was essential to evaluate biomass production at different agitation rates, light intensities, and temperature levels. Central composite design and response surface methodology were applied to design the experiments and optimize the cultivation process for Nannochloropsis sp. and T. striata. The specific growth rate of 0.250 d(-1) was obtained for Nannochloropsis sp. cells under the light intensity of 54 µmol photons · m(-2) · s(-1) , at the agitation rate of 151 rpm in 24.5°C. The optimal physical process conditions for T. striata were obtained under the light intensity of 56 µmol photons · m(-2) · s(-1) in 25.5°C at the agitation rate of 151 rpm in 25.5°C, resulting in a specific growth rate of 0.226 d(-1) . The predicted values were justified by the verification tests. Good agreement between the predicted values and the experimental values confirmed the validity of the models for the cultivation of microalgal strains. In this article, the noteworthy result was that temperature was a dominant factor in obtaining high chl-a content for Nannochloropsis sp., whereas the growth of T. striata strongly depended on light exposure.

Carotenoid and fatty acid compositions of an indigenous Ettlia texensis isolate (Chlorophyceae) under phototrophic and mixotrophic conditions.

Ettlia oleoabundance (formerly known as Neochloris oleoabundance) is an attractive candidate for biodiesel production because of its high lipid accumulation, and it's taking the majority of the attention among the strains of Ettlia genus; however, potential of the other genus members is unknown. An indigenous strain from Salda Lake (South West Turkey) identified by 18S rDNA sequencing as Ettlia texensis (GenBank accession no: JQ038221), and its fatty acid and carotenoid compositions under phototrophic and mixotrophic conditions was investigated to evaluate the potential of the strain for commercial uses. A threefold increase was observed in total lipid content (total fatty acids; from 13% to 37%) in mixotrophic culture respect to the phototrophic growth conditions. The oleic acid (C18:1) and alpha-linolenic acid (18:3) were the major unsaturated fatty acids accounting for 40% and 13.2% of total fatty acids in mixotrophic culture, respectively. Carotenoid analyses of the mixotrophic culture revealed the metabolite canthaxanthin, a commercially valuable carotenoid used mainly for food coloring, was the major constituent among other pigments. The possible use of E. texensis in biotechnological applications is discussed.

The effects of spirulina on allergic rhinitis.

The prevalence of allergic rhinitis is increasing globally due to various causes. It affects the quality life of a large group of people in all around the world. Allergic rhinitis still remains inadequately controlled with present medical means. The need of continuous medical therapy makes individuals anxious about the side effects of the drugs. So there is a need for an alternative strategy. Effects of spirulina, tinospora cordifolia and butterbur were investigated recently on allergic rhinitis in just very few investigations. Spirulina represents a blue-green alga that is produced and commercialized as a dietary supplement for modulating immune functions, as well as ameliorating a variety of diseases. This double blind, placebo controlled study, evaluated the effectiveness and tolerability of spirulina for treating patients with allergic rhinitis. Spirulina consumption significantly improved the symptoms and physical findings compared with placebo (P < 0.001***) including nasal discharge, sneezing, nasal congestion and itching. Spirulina is clinically effective on allergic rhinitis when compared with placebo. Further studies should be performed in order to clarify the mechanism of this effect.