Zarrouk Medium Research Articles

Research technology of cultivation of spirulina algae with the use of CO2 hidden from the smoke of rice husk boiler

This paper presents an investigation of Spirulina algae cultivation by the CO2 gas emitted from the combustion of rice husk. The gas emitted from the rice husk combustion containing CO2 but no toxic gas of SOx. The CO2 molecules are absorbed into the micro-algae cultivation medium and then converted into the HCO3 by the assimilation of Spirulina. At the same time, the pH values are controlled to be from 8.5 to 9.5, which is suitable for Spirulina algae. At the first seven days of cultivation in Zarrouk medium the values of Spirulina algae biomass and pH increase from 0.05 g/l and 8.5 to 1.0 g/l and 10.2, respectively. On the 8th day, when the amount of 7,6 % CO2 v/v under 35–40 ºC and 1 atm is introduced into the above medium, the decrease of pH from 10.2 to 8.6 is observed. This pH value, which is maintained over the following days, is optimal for the growth yield of the Spirulina. As a result, the biomass concentration increases from 1.0 to 1.4 g/l. The obtained results are compared with those of the control sample from Zarrouk medium without gas introduction. For the latter case, the biomass reaches the maximum and then decreases. On the basis of the obtained results, the cultivation of Spirulina algae by using the CO2 molecules emitted from the combustion of rice husk can be applied practically.

Chromium bioremediation from river Yamuna using cyanobacteria at white and red illumination wavelengths

Industrial waste from thermal power plants and tanneries discharged into natural water bodies contaminate water and limit its usage for drinking and irrigation purposes. Heavy metals present in the water are detrimental to health. Removal of such heavy metals is a necessity due to their non-biodegradability in the environment. Chromium (Cr) imparts high toxicity to water in two valence states - Cr (III) and Cr (VI). Microalgae possess a mechanism for uptake of both trivalent and hexavalent Cr and deposit them in the polymeric form of trivalent Cr. This work emphasizes on the process of bio enrichment of Cr (III) in microalgae Spirulina sp. NCIM5143. The first stage involves acclimatizing the strain to high concentrations of Cr (up to 80 mg/L) in the Yamuna River water and Zarrouk's medium used as cultivation media. This was achieved by a serial increase of Cr in the increment of 20 mg/L in each batch. A Cr (III) removal of 88.1% in the Yamuna medium and 87% in the Zarrouk's medium was obtained, whereas a Cr (VI) removal of 74% in the Yamuna medium and 83.1% in the Zarrouk's medium was obtained. A complete removal of 100% was observed when red LED was used along with the production of pigments chlorophyll and phycocyanin. Hence, Spirulina sp. proved to be an excellent scavenger of Cr (III) and Cr (VI) ions and for the production of value-added pigments. Also, Spirulina sp. assisted Cr (III) and Cr (VI) bio sequestration has no detrimental effects on environment.

Exploratory analysis of Spirulina platensis LB 2340 growth in varied concentrations of anaerobically digested pig effluent (ADPE)

There is a significant interest in novel waste management solutions to treat wastewater from swine operations. Anaerobic digestion is a rising and prominent solution, but this technology still generates highly concentrated effluent that requires further remediation. Therefore, the aim of this study was to explore the feasibility of cultivating the cyanobacterium Spirulina platensis in swine effluent for future applications in biological waste treatment and value-added fermentation. To accomplish this goal, growth of S. platensis was characterized in varying proportions of ideal, synthetic Zarrouk medium and anaerobically digested pig effluent (ADPE) to obtain growth rate models. Results yielded a positive correlation between S. platensis growth rate and Zarrouk medium proportion, with the highest growth rate in 100% Zarrouk media but comparable growth in the 50/50% Zarrouk/ADPE mixture. This study demonstrates the potential for S. platensis to further improve the treatment efficacy of anaerobic digestion systems, and the exploratory analysis also highlights that further testing is required to investigate possible carbon availability, chemical inhibition, and overall nutrient reduction in ADPE. This research contributes important data toward the feasibility of producing value-added cyanobacterial biomass while simultaneously consuming excess nutrients to aid in agricultural wastewater management efforts and generate cost-effective products in a more sustainable manner.

Phytohormone production and morphology of Spirulina platensis grown in dairy wastewaters

Microalgae cultivation in dairy wastewaters is of major interest for nutrient removal and sustainable microalgal biomass production. This biomass is a profitable raw material to produce biofertilizers and biocompounds for use in agriculture and food and pharmaceutical industries. This study aimed to compare biomass production, morphology, and phytohormone levels in Spirulina platensis (UTEX LB1926) grown on dairy wastewaters, in comparison to Zarrouk medium. An extraction method from lyophilized biomass was developed to detect and quantify the endogenous phytohormones Indole-3-acetic acid (IAA), Phenylacetic acid (PAA), Salicylic acid (SA), Jasmonic acid (JA), Abscisic acid (ABA), Gibberellin A1 (GA1), Gibberellin A4 (GA4), Indole-3-butyric acid (IBA), 1-Aminocyclopropane-1-carboxylic acid (ACC), 6-Benzylaminopurine (BAP), and Kinetin (KA) in S. platensis, cultivated in dairy wastewater and cheese whey, from a local dairy industry. Phytohormones were generally higher in S. platensis cultivated in dairy wastewaters than in a synthetic medium. The concentrations of phytohormones widely varied with the culture medium and the lighting conditions. Low light intensity significantly promoted the filaments of S. platensis to grow longer and thicker in wastewater, especially in cheese whey, enhancing biomass harvest. The cultivation of S. platensis in dairy wastewaters allows the production of both biomass and phytohormones, at low cost, while treating these waters.

Scaling-up production of Spirulina sp. LEB18 grown in aquaculture wastewater

This study evaluated the nutrient-removal efficiency, production, and biochemical composition of Spirulina sp. LEB18 biomass produced in aquaculture wastewater supplemented with 25% Zarrouk medium (T25) in triplicated outdoor 240 L raceway reactor systems. Nutrient removal efficiencies for nitrate (86.6%), phosphate (91.2%), chlorides (93.7%), and sodium (66.4%) were achieved by Spirulina sp. LEB18 in the T25 treatment group. The T25 biomass production (1.23 g L−1) was higher than the control (1.10 g L−1) and yielded 32.3% proteins, 47.4% carbohydrates, 8.1% ash, and 12.2% lipids. The fatty acid profile was mainly composed of 40.8% C16:0, 26.1% (C18:2n6t), and 12.9% (C18:2n6c). Bioactive substances, such as chlorophyll-a (2.48 μg mL-1) and chlorophyll-b (2.46 μg mL−1), total carotenoids (8.07 μg mL−1), and phycocyanin (2.66 mg mL−1), were also detected. This study demonstrated that the T25 treatment can be utilized for large-volume reactors and outdoor systems, achieving high phytoremediation efficiency, Spirulina sp. LEB18 biomass production, high biomolecule content, and bioactive substances.

Chemical characterization and nutritional value of Spirulina platensis cultivated in natural conditions of Chichaoua region (Morocco)

The aim of the current study was to characterize the phytochemical, phytopigments, and nutritional value of Spirulina platensis produced in Chichoua region of Morocco. A natural medium based on well water-wood ash is used instead of an artificial Zarrouk medium. Several analyses including phytochemical screening and antioxidant activity (DPPH and ABTS) were performed in extracts (methanol, ethanol and acetone) of S. platensis. The phytopigments were analyzed by measuring chlorophylls a and b, carotenoids, and phycobiliproteins. The nutritional composition was evaluated through dry matter, lipids, carbohydrates, crude protein, acidic detergent lignin, neutral detergent fiber, acidic detergent fiber, minerals, and vitamins. The methanolic extract showed the highest phenolic contents (7.00±0.07 mg GAEs/g), flavonoids (1.00±0.011 mg QEs/g), and ABTS•+ free radical scavenging activity (38.35±1.68%). Spirulina platensis produced in the well water-wood ash medium is rich in crude proteins (53.29%), c-phycocyanins (18.25±1.81%), and minerals. It also contains a high vitamin concentrations such as pantothenic acid (B5), niacin (B3), riboflavin (B2), and folic acid (B9). The results confirmed that the cultivation of S. platensis under natural conditions, using well water-wood ash medium increases the amounts of some minerals, c-phycocyanin, and water-soluble vitamins. Furthermore, this medium can be profitable for large-scale mass production of S. platensis with yields similar to that obtained from Zarrouk medium.

A new record of Spirulina subsalsa (Oersted Ex Gomont, 1892) with molecular profile isolated in Vellar Estuary, Portonovo, South East Coast, Tamil Nadu (India)

Spirulina is a filamentous, multi-cellular and autotrophic cyanobacterium having distinct features of helical shape filaments ( i.e. trichomes). An investigation is to isolate a marine, Spirulina subsalsa from Vellar estuary, South East Coast zone of India. The isolated strain sub-cultured in Zarrouk medium with optimum conditions for sustaining growth. Pure cultures were examined in a research microscope for morphometric studies through 16S rRNA sequencing and the sequence was submitted to NCBI-GENBANK, the accession number is MW037197 which displays the maximum similarity as 100% with a diverse sequence in databank i.e. LC 215280. The investigation is the first record for the existence of Spirulina subsalsa in Vellar Estuary, South East Coast, Tamil Nadu (India) as affirmed by a molecular nucleotide sequence.

Alternative culture media and cold-drying for obtaining high biological value Arthrospira platensis (Cyanobacteria)

ABSTRACT Arthrospira platensis is a source of proteins, polysaccharides, polyunsaturated fatty acids (in tiny amounts) and phenolic components that give it different biological properties. The type of nutrients present in the culture medium can influence the microalga metabolism and, consequently, the growth, composition and content of nutrients, bioactive compounds and biological properties. In this work, A. platensis was cultivated in the laboratory using six culture media (Zarrouk as a standard medium, and Media 1–5), containing different nitrogen sources, and subsequently harvested and dried by freeze-drying or cold-drying. Medium 4, with KNO3 as nitrogen source, proved to optimize the productivity of A. platensis (with a maximum yield of 1.34 ± 0.08 g l–1, better than the Zarrouk medium), to maximize protein synthesis (up to 70% w/w) and to increase the antioxidant activity. Conversely, Medium 3, containing KNO3 and NH4NO3, was the best to optimize carbohydrates and lipids (up to 30% w/w and 2% w/w, respectively). Both Media 3 and 4 were able to increase chlorophyll-a and carotenoid synthesis compared to the other tested media. Cold-drying has proved to be an excellent alternative to the more expensive lyophilization: the content of carotenoids and antioxidant components was better preserved. This research has shown that low-cost media and cold-drying can be a promising strategy for obtaining a high biological value product, usable in both the pharmaceutical and food sectors, reducing production times and costs.

Microalgae Consortia for Post-treating Effluent of Anaerobic Digestion of Cattle Waste and Evaluation of Biochemical Composition of Biomass

The aim of this study is to cultivate Spirulina platensis and Scenedesmus obliquus microalgae in consortia using effluents of cattle waste anaerobic treatment in order to give possibilities to the production of microalgae biomass to biorefineries uses. The biomasses obtained were characterized to evaluate the potential for the production of biofuels and other bioproducts. The effluent was used in sterile and non-sterile conditions to better understand the influence of other microorganisms in N and P removal. The biomass obtained with the addition of 10% of sterile effluent in Zarrouk media (20%) presented 44.12 and 34.62% of carbohydrates, using Spirulina platensis in monoculture or the 50%/50% consortia of Spirulina and Scenedesmus, respectively, this biomass presenting the potential to be used to bioethanol production. Nitrogen and phosphorous removal were higher in non-sterile conditions and reached 92.7 and 49.66% of nitrogen and phosphorous removal, respectively, using the consortia and with the addition of 30% effluent in the media. The cultivation of microalgae in a consortium may be used to assist the treatment of water concurrently with the production of biomass to different applications.

Polyhydroxyalkanoates and pigments coproduction by Arthrospira (Spirulina) platensis cultivated in crude glycerol

Valorization of industrial waste as an alternative carbon source for microalgae mixotrophic cultivation and co-production of high-value compounds are strategies to enhance the bioprocess revenue and make large-scale production of microalgae polyhydroxyalkanoates (PHAs) feasible, with these biopolymers as potential substitutes to conventional polymers, such as polypropylene (PP) and high-density polyethylene (HDPE). In this sense, the use of crude glycerol, a main byproduct of the biodiesel industry, is an alternative to reduce cultivation costs and, at the same time, to provide a biotechnological solution for the excess of this byproduct produced, approximately 10 wt% per biodiesel batch. Thus, this work evaluated the effect of pure and crude glycerol supplementation and nutrient depletion (N and P) on growth, total carotenoids, phycocyanin and PHAs content in Arthrospira platensis xenic cultures. The highest final biomass concentrations, 1.68 and 1.40 g L-1, and PHAs contents, 1.1 and 0.5 % were achieved by supplying a Zarrouk medium with 6.14 g L-1 of pure or crude glycerol, respectively. In spite of having its content reduced at 6.14 g L-1 of pure glycerol, phycocyanin still presents a reasonable content (4.2 %) in this condition and in crude glycerol at 3.07 g.L-1 attained the highest content (10.8 %). On the other hand, glycerol mixotrophic cultivations with simultaneous nutrient depletion (nitrogen or phosphorus) did not improve the accumulation of PHAs.

Potential utilization of fish waste for the sustainable production of microalgae rich in renewable protein and phycocyanin-Arthrospira platensis/Spirulina

The fish processing industry generates the solid biological waste (head, trimmings, skin, viscera, scale, bone etc) based on the processing methods, which poses a serious effect on the environment. Fish waste is valorized by various treatment methods which are costly and generate the effluents with high organic load. The objective of the present study was to utilize the fish waste in the form of fish protein hydrolysate (FPH) as an organic nitrogen source for the cultivation of Spirulina instead of inorganic nitrogen. Since the inorganic nitrogen in the algal cultivation accounts for high costs and energy, in addition to the continuous discharge of unspent inorganic nitrogen causing severe environmental problems. The proposed organic nutrient could be a sustainable and environment friendly solution from both the perspective of fish waste valorization and Spirulina cultivation. The proximate and amino acid composition of FPH derived from fish waste were characterized. Inorganic nitrogen (sodium nitrate) in the conventional medium was replaced with different concentrations of FPH varying from 0.1 to 1% (v/v). The effect of various concentrations of FPH on the growth, biomass productivity, biochemical composition and pigments of Spirulina were investigated. FPH concentration of 0.5% enhanced dry cell weight (DCW), biomass productivity (Pb), protein, and phycocyanin content by 34%, 39% and 15% and 98% respectively, compared to the conventional Zarrouk medium (control). Increase in the FPH concentration decreased the in vitro digestibility of the protein. The carbohydrate content and theoretical ethanol production were 5 times higher in the 0.1% FPH concentration than that of control. Results showed that the fish waste in the form of FPH could be a potential organic nitrogen for the cultivation of Spirulina with high quality pigment. Finally, a preliminary sustainability assessment has been made to analyze the bioeconomy of the process.

Potential Applications of Native Cyanobacterium Isolate (Arthrospira platensis NIOF17/003) for Biodiesel Production and Utilization of Its Byproduct in Marine Rotifer (Brachionus plicatilis) Production

To achieve strong, successful and commercial aqua-biotechnological microalgae applications, screening, isolation, molecular identification, and physiological characterizations are needed. In the current study, a native cyanobacteria strain Arthrospira platensis NIOF17/003 was isolated from the surface water of El-Khadra Lake, a saline-alkaline lake located in Wadi El-Natrun, Egypt. The cyanobacterium was phylogenetically identified by 16S rRNA molecular marker and deposited in the GenBank database (accession number MW396472). The late exponential phase of A. platensis NIOF17/003 was reached at the 8th day of growth using Zarrouk medium, with a recorded dry weight (DW) of 0.845 g L−1. The isolated strain showed 52% of protein, 14% of carbohydrate, biomass productivity of 143.83 mg L−1 day−1, 8.5% of lipid, and lipid productivity of 14.37 mg L−1 day−1. In general, the values of cetane number, iodine value, cold filter plugging point (52.9, 85.5 g I2/100 g oil, and −2.2 °C, respectively) of the isolated fatty acid methyl esters are in accordance with those suggested by international standards. Besides, applying algal-free lipid (FL) as biodiesel byproduct in the production of rotifer (Brachionus plicatilis) revealed that a 0.6 g L−1 FL significantly increased the rotifer population females carrying eggs, confirming that FL can be used efficiently for B. plicatilis production. The current study concluded that the new isolate A. platensis NIOF17/003 is a promising strain for double sustainable use in biodiesel production and aquaculture feed.

Anaerobic digestate abattoir effluent (ADAE), a suitable source of nutrients for Arthrospira platensis cultivation

Untreated as well as partially treated anaerobic digestate abattoir effluent (ADAE) were used for the cultivation of Arthrospira platensis in this study. The effect of CO2 addition on the biomass productivity, nutrient removal efficiency and biochemical composition were also investigated. Arthrospira platensis exhibited significant improved growth in raw ADAE when alkalinity of the medium was adjusted to 6.3 g L−1 using NaHCO3. Addition of CO2 resulted in 20% increase in biomass productivity and higher ammoniacal nitrogen removal rate (99.0%) when compared to the cultures with no CO2 supplementation. No significant differences were found in protein (50.2%) and phycocyanin (12.0%) content of A. platensis cultivated in raw ADAE supplemented with HCO3− and that grown in synthetic Zarrouk medium. This study demonstrated that raw ADAE can be successfully used as culture media for A. platensis when its alkalinity is adjusted using bicarbonate. Such an approach would reduce the need of freshwater and external synthetic nutrients for A. platensis cultivation if the aim is to produce reclaimable water as well as biomass rich in protein content and phycocyanin for potential use as an animal and aquaculture feed.

Research on key technology and equipment for cultivation of Spirulina platensis from the CO2 capture from exhaust smoke

This paper presents the results of experimental research on key technology and equipment for cultivation of Spirulina platensis from the CO2 capture from the smoke of rice husk boiler with the climate conditions in Viet Nam. The experimental cultivation of Spirulina platensis in the Zarrouk medium were conducted in the 1 litter of volume’s photobioreactor which has stirred with aeration pump. Experimental results show that the temperature changes every day in a fairly wide range from 25 to 40 oC and get over the optimal temperature for growth of Spirulina platensis 30 to 38 oC but not much at noon time; when blowing from the smoke of steam boiler with the suitable temperature and stirring simultaneous by the circulating pump; at the same time the CO2 absorption process into water was occurred and converting it into HCO3-, as a suitable substrate for Spirulina platensis is easy to assimilate; the biomass concentration of Spirulina increases from 0.1 to 1.81 g/l and the pH of suspension increases from 8.5 to 10.2 after the stage’s first time of 7 days of cultivation with Zarrouk medium and since the eight days to 16th day of the cultivation is steaming stage from boiler with period of 30 minute into the above medium that containing 7.76 % CO2 for maintaining the pH of solution from 8.5 to 9.5. The smoke of steam boiler that has CO2 in which blow to supply the carbon nutrient source in the formation of HCO3-, to maintain the pH value in the range of 8.5 ¸ 9.7 and increase biomass productivity to 2.53 g/l simultaneously. The photosynthetic rate of algae biomass was compared with the cultivation of Spirulina platensis under the same conditions like that using the pure CO2 and non-using the pure CO2 and the results in two of the above conditions are equivalent. This research is basis for constructing equipment and building a technology process in which utilizing CO2 from exhaust gas for Spirulina platensis cyanobacteria’s cultivation with the aim of reducing green-house gas CO2 in industry.

Comparación de parámetros proximales entre aislados comerciales y Arthrospira platensis Gomont, especie cultivada en condiciones controladas en Paraguay

At present, microalgae have become the object of great interest, since they are a source of important natural substances and produce biomaterials that present various industrial applications. The proximal parameters of three isolated species of the genus Arthrospira of different geographical origins were analyzed, out of which two were of Chilean and Argentine origin; the third isolate was obtained from the cultivation under controlled conditions of the Arthrospira platensis native of Paraguay, in a batch-type photobioreactor with Zarrouk medium under 24-hour light conditions, 0.45 vvm and luminous Intensity of 12,500 lm for 75 days, which generated a yield of 5.82 grams of biomass per liter of culture. Determinations made to evaluate the proximal composition of the three isolated were moisture, ash, proteins and total fats. For the strain of Arthrospira platensis native to Paraguay, the value of the percentage of protein obtained was about 67.40%, total fats 5.69%, humidity 20.02% and ash 9.11%. These results of the parameters analyzed suggests that this microalga could be used as a nutritional supplement.

Extracellular neutral protease from Arthrospira platensis: Production, optimization and partial characterization

Proteases are industrially important catalysts. They belong to a complex family of enzymes that perform highly focused proteolysis functions. Given their potential use, there has been renewed interest in the discovery of proteases with novel properties and a constant thrust to optimize the enzyme production. In the present study, a novel extracellular neutral protease produced from Arthrospira platensis was detected and characterized. Its proteolytic activity was strongly activated by β-mercaptoethanol, 5,5-dithio-bis-(2-nitrobenzoic acid) and highly inhibited by Hg2+ and Zn2+ metal ions which support the fact that the studied protease belongs to the cysteine protease family. Using statistical modelling methodology, the logistic model has been selected to predict A. platensis growth-kinetic values. The optimal culture conditions for neutral protease production were found using Box-Behnken Design. The maximum experimental protease activities (159.79 U/mL) was achieved after 13 days of culture in an optimized Zarrouk medium containing 0.625 g/L NaCl, 0.625 g/L K2HPO4 and set on 9.5 initial pH.The extracellular protease of A. platensis can easily be used in the food industry for its important activity at neutral pH and its low production cost since it is a valuation of the residual culture medium after biomass recovery.

Characterization of selenium-containing polysaccharide from Spirulina platensis and its protective role against Cd-induced toxicity

Herein, selenium-containing polysaccharide from Spirulina platensis (Se-SPP) was prepared and its structural characteristics and protective role against Cd-induced toxicity in vivo and in vitro were investigated. Se-SPP was alkali-extracted from selenium-containing Spirulina platensis which was cultured in Zarrouk medium supplemented with Na2SeO3. The contents of carbohydrate, protein, uronic acid, sulfate and elements (including Se, C, H, O, N, and S) as well as the monosaccharide composition, molecular weight, surface morphology and FT-IR spectra of Se-SPP was compared to that of selenium-free polysaccharide (SPP). The results revealed that SPP and Se-SPP were both high-molecular-weight heteropolysaccharide with similar molecular weight and monosaccharide composition but significantly different selenium content, indicating that the covalently-bonding of a small amount of selenium did not destroy the original structure of polysaccharide. Furthermore, CdCl2 was utilized to build Cd-intoxicated cells model in vitro and rats model in vivo respectively. Then, the protective effect of Se-SPP against cadmium-induced toxicity was assessed. The results demonstrated that Se-SPP treatment provided significant protection against Cd-induced toxicity, which was superior compared to that of SPP or Na2SeO3 alone. The enhancement of protective role may be affected by the covalently-bonding of selenium to polysaccharide.

Cellular Stress Conditions as a Strategy to Increase Carbohydrate Productivity in Spirulina platensis

Spirulina platensis, when grown under stress, may alter its metabolic pathways, leading to carbohydrate accumulation. Research on the combined effects of stress factors such as UV radiation, photoperiod, and light, and the influence of micronutrients (Ca, Fe, and Mg) on microalgae carbohydrate composition is scarce. The aim of the present study was to evaluate the effects of combined cell stress factors on the microalgal growth and biochemical composition of S. platensis, to apply the biomass in the context of biorefineries. Assays were performed at two cultivation stages: in the first stage, Zarrouk medium (50%) was used until the end of the exponential growth phase (18 days) and, in the second stage, the cells obtained in the first stage were centrifuged and recultivated in 20% Zarrouk’s medium under physical (UV, photoperiod/light, NaCl) and nutritional stress (limitation of Ca, Fe, and Mg concentrations in 20% Zarrouk). The highest carbohydrate yields (27.84 mg L−1 day−1) were obtained in the photoperiod/light intensity-stressed cultures in the medium with nutrient limitation. The study outcomes showed the methods to increase carbohydrate synthesis in cultures under optimized conditions. Our results showed that nutrient limitation by 20% Zarrouk combined with higher light intensity (67.5 μmol photons m−2 s−1) and photoperiod (18-h/6-h light/dark cycles) is an efficient strategy to achieve higher intracellular concentrations (59.71%) and carbohydrate yields (55.85 mg L−1 day−1) in a discontinuous culture method.

Optimization Growth of Spirulina (Arthrospira) Platensis in Photobioreactor Under Varied Nitrogen Concentration for Maximized Biomass, Carotenoids and Lipid Contents.

Spirulina (Arthrospira) platensis (SP) microalgae were cultured in Zarrouk Medium (ZM), containing three nitrogen concentrations (N-limited, N-optimal and Nrich medium) in ten liter-photo-bioreactor (10 L PBR) for 15-days, in order to study changes in lipid compounds (total carotenoids and total lipids and their effect on fatty acid profile). Based on US patent, the yield of bioactive compounds (such as gamma-linolenic acid GLA, C18:3) extracted from microalgae biomass, mainly depends on the extraction processes (1). GLA has much attention with respect to its therapeutic properties such as its ability to decrease blood cholesterol levels. The impact of the addition of N in cultures of S. platensis in terms of growth, biomasses and induced lipid compounds (total carotenoids and total lipid contents and its fatty acid profile), as well as the Sonication (SON) and Microwave (MIC) process as aiding techniques for lipid extraction compared with a Cold Condition (COL), was examined. GC/MS method was used to determine the fatty acid profile of lipid extract of SP cultures. In all S. platensis tested culture, the SP was growing successfully, with varying degrees. In N-rich media, the highest cell growth rate and biomass yield were obtained compared with that recorded in other cultures. Under an N-limited condition, SP had higher Total Carotenoids (TCAR, 45.54 mg/g dw) and total lipid contents (TL, 29.51%± 1.92 g/100g dw) compared with that recorded either in N-rich (11.2 mg/g dw) or in N-optimal (6.23 mg/g dw) cultures. Thus, SP copes with the N -stress by altering the metabolic pathways towards inducing lipid biosynthesis. To maximize the TL and TCAR extraction yields, from N-limited cultures, a set of operating process was applied including the Sonication (SON) and Microwave (MIC), which were used as aiding techniques for lipid extraction compared with the Cold Condition (COL) techniques. The results showed that the extraction efficiency of the S. platensis TL increased in the following order: MIC (29.51%± 1.92) > SON (25.46% ± 1.65> COL (20.43% ±1.43). In a comparative study for its fatty acid profiles (FAPs) among all SP cultures, lipids were analyzed by GC/MS. The predominant fatty acids (>10%, of total FA) were found to be myristic acid (C14:0, MA), palmitic acid (C16:0, PA) and oleic acid (C18:1). The study concluded that the N-limited condition was found to have a strong influence on biomass dry weight and lipid contents and total carotenoids in SP cells compared to either Nrich or N-optimal conditions. The use of sonication and the microwave techniques lead to a great increase in the extraction of lipid contents and in high amount Polyunsaturated Fatty Acids (PUFAs) in N-limited cultures, in particular, the omega-6 (ω 6) and omega-3 (ω 3) of the essential C18 fatty acids. It seems that the SP rich in lipid content with a high amount of GLC produced under nitrogen limitation in PBR conditions can be used as a food additive or as a nutritional supplement.

Minimising the Cost of Spirulina platensis Culture Medium using Vinh Hao Natural Mineral Water

This paper describes the use of a linear programming method to construct a formula for preparing culture medium for Spirulina platensis (S. platensis) algae using Vinh Hao natural mineral water (Binh Thuan Province, Vietnam) with a low cost. The results show that the cost of preparing the culture medium using Vinh Hao mineral water is less than 252.49 VND/L, which is approximately 13.05 % less than the cost of Zarrouk medium. To verify the optimised medium composition, S. platensis algae was cultured in the two media under the same conditions (25 to 40 C; pH 8.5 to 10.2). The algae biomass concentration reached 1.0 g/L after 7 d of culturing. The experimental growth rates of S. platensis algae in Vinh Hao culture medium and Zarrouk medium had an average difference of 1.49 %. This study provides a basis for implementing S. platensis algae production on an industrial scale using media formed from Vinh Hao natural mineral water from Binh Thuan Province, Vietnam.