Bold Basal Medium Research Articles

Diversity of algal species present in waste stabilisation ponds and different factors affecting its enrichment and phototaxis

ABSTRACT Several algal species were found in the samples collected from a wastewater treatment plant located in Uttarakhand, India. Several media and their modifications were employed to understand the role of these elements and compounds in the species composition and proliferation. Euglena, Chlamydomonas-reinhardtii, Chlorella-sorokiniana, Chlorococcum, several diatoms and cyanobacteria were found in the wastewater samples. In stagnant and flowing municipal wastewater, Euglena, Chlorococcum, cyanobacteria and Volvox were predominant. In a bold basal medium, Scenedesmus and several diatom species were observed along with Chlorococcum. In the presence of acetate Selenastrum species were abundant. Metagenomic analysis of wastewater collected during winter revealed that Tetradesmus wisconsinensis (21.23%) and Actinastrum hantzchii (11.48%) were the dominant species. Some cyanobacterial species accumulated near the high-intensity light region. Hence, subsequent phototaxis experiments were performed. Under the white light, most species showed positive phototaxis. However, under the blue and red light, all the algal species present in the sample showed negative phototaxis. Under the green light, Chlorococcum and Chlamydomonas showed positive phototaxis and Euglena showed negative phototaxis. However, under the pink light, neither negative nor positive phototaxis was observed. Hence, the obtained results provided new insights into the effects of the studied parameters on the species’ diversity and proliferation.

Performance Characteristics of Ankistrodesmus falcatus in Different Culture Media and Concentration.

This study determined the effect of growth media and culture concentration on the growth, proximate, and microelement composition of Ankistrodesmus falcatus. The culture of A. falcatus was done using three media, namely Modified COMBO Medium (COMBO), Bold’s Basal Medium (BBM), and Bristol, at two concentrations (50% and 100%). The results obtained show that the cell density (>3.5 × 107 cells/mL), optical density (>0.24), and specific growth rate (>0.429%/day) were significantly higher (p ≤ 0.05) in BBM and COMBO than in Bristol (<3.1 × 107 cells/mL; <0.23; <0.416%/day, respectively) at both concentrations. However, biomass was higher in BBM (>2.20 g/L) than in COMBO (1.87–2.13 g/L), while Bristol had the lowest value observed (1.70–1.73 g/L). Biochemical and microelement composition showed variations between media and at the different concentrations, with higher values observed in BBM and COMBO. Based on the growth parameters and nutritional composition, it was concluded that BBM and COMBO were better media for the propagation of A. falcatus growth than Bristol. The study also demonstrated that the microalgae can be cultured using half of the media’s concentration to lower production costs.

Pemanfaatan Hidrolisat Talas (Colocasia esculenta L.) pada Kultur Miksotrofik Mikroalga Tetraselmis chui: Pengamatan Pertumbuhan dan Kadar Lipida

This study aims to observe the potential use of taro hydrolysate (Colocasia esculenta L.) as a source of complex organic carbon to produce optimum cell density, biomass, lipid and chlorophyll content from T. chui microalgae under myxotrophic conditions. The culture was carried out in a vial containing 400 mL of bold basal medium. Taro hydrolysate is given in five concentrations, namely: 0, 5, 10, 15 and 20 g/L. The results showed that T. chui microalgae could grow in myxotrophic conditions with the addition of taro hydrolysate in the concentration range of 5 to 20 g/L. The maximum cell density and dry weight in the addition of 10 g/L taro hydrolysate were 4.23 x 105 cells/ml and 0.57 g/L, respectively. Meanwhile, the maximum fresh weight and lipid content were achieved at the addition of 15 g/L taro hydrolysate, namely 4.85 g/L and 67.4%. Chlorophyll content decreased with increasing concentration of taro hydrolysate. In conclusion, the use of taro hydrolysate can increase cell density, fresh weight and dry weight, lipid content and decrease the chlorophyll content of T.chui microalgae in myxotrophic culture.&#x0D; Keywords: Taro Hydrolysate, Lipid, Mixotrophic, Growth, Tetraselmis chui

Municipal Wastewater: A Sustainable Source for the Green Microalgae Chlorella vulgaris Biomass Production

The need to reduce the costs associated with microalgae cultivation encouraged scientific research into coupling this process with wastewater treatment. Thus, the aim of this work was to assess the growth of Chlorella vulgaris (Chlorophyta) in different effluents from a municipal wastewater treatment plant (WWTP), namely secondary effluent (SE) and sludge run-off (SR). Assays were performed, under the same conditions, in triplicate with 4 dilution ratios of the wastewaters (25%, 50%, 75% and 100%) with the standard culture medium bold basal medium double nitrated (BBM2N) as a control. The capability of C. vulgaris for biomass production, chlorophyll synthesis and nutrients removal in the SE and SR was evaluated. The 25% SE and 25% SR showed increased specific growth rates (0.47 and 0.55 day−1, respectively) and higher biomass yields (8.64 × 107 and 1.95 × 107 cells/mL, respectively). Regarding the chlorophyll content, the 100% SR promoted the highest concentration of this pigment (2378 µg/L). This green microalga was also able to remove 94.8% of total phosphorus of SE, while in 50% SR, 31.2% was removed. Removal of 73.9% and 65.9% of total nitrogen in 50% and 100% SR, respectively, was also observed. C. vulgaris growth can, therefore, be maximized with the addition of municipal effluents, to optimize biomass production, while cleansing the effluents.

EXTRACTION AND QUANTIFICATION OF INTRACELLULAR LIPID AS POTENTIAL BIOFUEL FROM ALGAL BIOMASS

Purpose: Fossil fuels occuring as ancient algae deposit is the major source of energy that we energise our engines today. It is a limited non-renewable resource that will eventually run out. Algae have been reported to generate renewable fuels known as biofuel. It is in this regards that this work was carried out to determine, extract and quantify intracellular lipid in algal biomass for subsequent use as biofuel.&#x0D; Methodology: Four average sized ponds within Federal University Dutse Campus, Nigeria (11.00̊ N to 13.00̊ N and longitude 8.00̊ E to 10.15̊ E and altitude 465.5m). were randomly selected and 20ml pond water were collected from top, middle and bottom of each pond. 60ml pond water was taken to laboratory and were processed by first preparing the media. 3ml NPK gel fertilizer was mixed with distilled water and autoclave at 121°C for 15 min. Bold's Basal Medium (BBM) consisting stock solution and BBM consisting of trace elements were separately mixed with distilled water. 10 ml of the stock solution and 1.0 ml of the trace elements were autoclave at 121°C for 15 min. The media (BBM and fertilizer) were cooled at room temperature, antibiotics (penicillin G, di-hydro-streptomycin sulfate and gentamycin sulfate) were added and pH adjusted to 7.5 and the media were kept ready for used. Isolations of species were carried out by serial dilution using BBM and under microscope sterile syringe and needles were used to isolate some target cells from the samples. Thus, four different algal species; Euglena, Spirogyra, Selenastrum and Chlorella were isolated and identified. Culturing of the microalgae isolates was carried out by transferring into 50 ml growth chamber containing BBM and NPK fertilizer media separately and cultured using sunlight for 10 days under controlled pH. Two successfully grown species; Spirogyra and Selenastrum were transferred aseptically into four constructed photobioreactors containing 400 ml liquid media; two containing BBM and the other fertilizer media. Nile Red was used to stain the algal wet biomass and observed under microscope and subsequently photographed. Microalgal cultures were dewatered by repeated centrifugations at 4000 rpm and the supernatants were discarded and the micoralgal biomass rinsed with deionised water to remove the residual salt and later dried using thermostatic drying oven and subsequently grinded. Growths were determined through dry weight determination and growth percentage was obtained as: dried biomass of a species from each medium/total dried biomass of the species x 100. The dried algal biomass was extracted and evaporated and extracts were heated using vacuum rotary evaporator to separate the solvent (chlorofoam) from the extracts. Transesterification was carried out and first prepared solution was poured into a conical flask containing 5.2 g lipid of Selenastrum species and the second solution was poured into a conical flask containing 2 g lipid of Spirogyra spp. Both flasks were heated over constant temperature magnetic stirrer with condenser attached maintained at 60°C.m Phase separation was carried out along with purification in which soap and other impurities were removed and resulting solution remained flammable biodiesel.&#x0D; Findings: While Euglena and Chlorella failed to grow in the initial media, both Spirogyra, and Selenastrum produced significant amount of biodiesel with Selenastrum species producing higher quantity than that obtained from Spirogyra, hence a potential source of the fuel.

Sustainable biorefinery associated with wastewater treatment of Cr (III) using a native microalgae consortium

Microalgae have emerged as renewable and sustainable candidates for biorefineries since they can generate bioproducts and bioenergy through the removal of contaminants contained in wastewater. In the present study, a native microalgae consortium (NMC) is isolated from a wastewater treatment plant, and used to remove 100 mgL−1 Cr(III). The native microalgae consortium is enriched in a photobioreactor with the following conditions: Bold’s Basal Medium (BBM), pH 8, room temperature and 20 µmolm−2s−1 light intensity. The molecular characterization reveals the presence of the following species: Tetradesmus sp., Scenedesmus sp and Ascomycota sp. The development of microalgae is evaluated through the production of biomass, pH, protein, lipid and carbohydrate, while the consortium presents the potential to obtain biofuels. The ability of the consortium to absorb two different sources of Cr (III) was determined using real tannery wastewater and synthetic water prepared with Cr2(SO4)3. The adsorption efficiency of the microalgae is analyzed using adsorption isotherms of Langmuir model, indicating 99% adsorption efficiency of 100 mgL−1 Cr(III). FT-IR and SEM analyses enable to identify the presence of Cr(III) in the native microalgae consortium. The promising features of this NMC underpin the idea of establishing a sustainable biorefinery to generate different bioproducts, in order to achieve a resource-efficient biomass use for a circular bioeconomy.

Tertiary treatment of dairy industry wastewater with production of Chlorella vulgaris biomass: evaluation of effluent dilution

Secondary wastewaters from the dairy industry may cause eutrophication of water bodies when not properly treated, mainly because they contain nutrients such as phosphorus and nitrogen. Tertiary treatment using microalgae could be an adequate solution for Minas Gerais State, the largest Brazilian milk producer, contributing to the reduction of environmental impacts, as well as providing biomass for oil extraction, and obtaining active compounds and inputs (including proteins) for animal feeding. In this work, dilutions (with distilled water) of the secondary wastewater from the dairy industry were evaluated to cultivate Chlorella vulgaris in a bench-scale tubular photobioreactor. The results indicate the feasibility of using wastewater from the dairy industry, after secondary treatment, to cultivate microalgae, showing cell growth like that obtained in control cultures (Bold basal medium). The secondary wastewater without dilution (100% wastewater) provided the best condition for biomass production. The biomass obtained in wastewater showed no differences from the biomass obtained in the Bold basal medium (control) in terms of protein, lipid content, or fatty acid profile.

Aquatic Toxicity of Photocatalyst Nanoparticles to Green Microalgae Chlorella vulgaris

In the last years, nanoparticles such as TiO2, ZnO, NiO, CuO and Fe2O3 were mainly used in wastewater applications. In addition to the positive aspects concerning using nanoparticles in the advanced oxidation process of wastewater containing pollutants, the impact of these nanoparticles on the environment must also be investigated. The toxicity of nanoparticles is generally investigated by the nanomaterials’ effect on green algae, especially on Chlorella vulgaris. In this review, several aspects are reviewed: the Chlorella vulgaris culture monitoring and growth parameters, the effect of different nanoparticles on Chlorella vulgaris, the toxicity of photocatalyst nanoparticles, and the mechanism of photocatalyst during oxidative stress on the photosynthetic mechanism of Chlorella vulgaris. The Bold basal medium (BBM) is generally recognized as an excellent standard cultivation medium for Chlorella vulgaris in the known environmental conditions such as temperature in the range 20–30 °C and light intensity of around 150 μE·m2·s−1 under a 16/8 h light/dark cycle. The nanoparticles synthesis methods influence the particle size, morphology, density, surface area to generate growth inhibition and further algal deaths at the nanoparticle-dependent concentration. Moreover, the results revealed that nanoparticles caused a more potent inhibitory effect on microalgal growth and severely disrupted algal cells’ membranes.

The effect of culture medium on the oil yield and fatty acid methyl ester of freshwater microalgae Chlorella vulgaris

Microalgae are commonly used in the biodiesel industry to produce lipids. The selection of media is one of the vital factors to culture the microalgae. The Chlorella vulgaris used in this study as a microalgae was cultured in three different culture media, namely the Modified Bold’s Basal medium (BBM), Blue-Green medium (BG11) and Jaworski’s medium (JM) using the immobilization method. Through this method, all the cultured microalgae were cultivated for 11 days to evaluate the oil yield. Then, the extracted oil was transesterified to produce fatty acid methyl ester (FAME). It was found that the BBM medium showed the highest oil yield (71.43%), followed by JM (67.50%) and BG11 (53.14%). In addition, BBM also is the best composition to produce FAME as it contains high nitrogen.

Assessment of Antioxidant Contents and Free Radical-Scavenging Capacity of Chlorella vulgaris Cultivated in Low Cost Media

The current study assessed antioxidants contents (total phenolics and total flavanoids, β-carotene and lycopene) present in Chlorella vulgaris (C. vulgaris) cultivated in low cost media and their free radical scavenging activities. Microalgae was cultured using Bold basal medium (BBM) as a control, 5% banana stem compost (BCM) and aquaculture wastewater supplemented with 1.0 g/L NPK (ANM). The free radical scavenging ability was analysed using 1,1-diphenyl -2-picrylhydrazyl assay. Cells grown on BCM resulted in higher (13.73 ± 0.121%) extraction yield than in other media. The phenolic (8.53 ± 0.10 mg/g GAE) and lycopene (0.29 ± 0.008 mg/g) content were highest in cells grown on BCM and BBM, respectively. Microalgae cultured in ANM displayed higher (547.023 ± 34.703 mg/g RE) flavanoid and β-carotene (2.887 ± 0.121 mg/g) content than in other media. Furthermore, cells cultivated in BCM showed highest (97.87 ± 0.088%) scavenging activity than in BBM. These results indicated that the BCM and ANM can be used as alternative to expensive synthetic media for antioxidant production in C. vulgaris.

Development of Cost-Effective Fertilizer-Based Media for the Microalgae Cultivation Aimed at Effective Biomass Production

In the diversification of the world's energy portfolio, microalgae biofuels have gained particular attention as a means of providing carbon-neutral hydrocarbon-based fuels. The progress on this front has been hindered because of expensive and unreliable microalgae cultivation systems, where the preparation of synthetic culture media poses a monetary strain. This study aims to investigate a new microalgae growth media that is readily available and cost-effective. The new microalgae fertilizerbased media (FBM) were designed and compared with Bold Basal media (BBM) in terms of growth parameters, production of lipid and value-added algal by-products (carotenoid and phycobiliprotein). The growth parameters such as cell count and specific growth rate were investigated for FBM and BBM. FBM showed a significant growth rate of 7 million/mL-per day as compared to 2 million/ml per day. A similar growth trend was observed for chlorophyll (a), (b) and carotenes which increased to the values of 5microgram/gram formula weight (µg/gfw), 3 µg/gfw and 2 µg/gfw for FBM. On the other hand, lipid and phycobiliprotein showed a decrease of 18.75 % and 16.66 %, respectively, compared to BBM. Even though some growth parameters are negatively affected by fertilizer-based media, the cost reduction is substantial to allow this drawback to be overlooked. The medium's cost is reduced by a factor of 7 and provides ground for the use of the FBM in the large-scale cultivation of algae for biomass production.

Adjustments of the photosynthetic unit and compensation mechanisms of tolerance to high ammonia concentration in Chlorella sp. grown in food waste digestate

Anaerobically digested food waste (ADF) is a waste effluent produced from anaerobic digestion of food wastes. It is difficult to treat but also holds high potential for valorization. Microalgae cultivation is a promising path for its treatment and valorization. However, ADF is very turbid and has toxic concentration of ammonia nitrogen (NH3-N) (up to 5000 mg L−1 NH3-N). Here we looked at the physiological responses and acclimation patterns of Chlorella sp., Mur 269 to toxicity and turbidity in ADF, compared to bolds basal medium (BBM), under different irradiances. Indicators obtained via pulse amplitude modulation (PAM) fluorometry such as electron transport rate (ETR), fv′/fm′ and alpha (α), alongside oxygenesis as an indicator of photosynthesis, were used to study the state of the photosystem of the organism. Pigment (chlorophylls and carotenoids) ratios were studied as indicators of adjustments in the photosynthetic unit and growth rates and productivities were used to monitor cell growth. μmax and biomass productivities were 63 and 47% higher in ADF than in BBM. μmax and biomass productivity of Chlorella sp., Mur 269, remained close to their optimal values at 0.681 ± 0.03 d−1 and 165 ± 8 mg L−1 d−1 even at high irradiance intensities of 1500 μmol m−2 s−1, indicating applicability of this species in outdoor cultures at high irradiance. On the other hand, the results showed that in comparison with BBM, the efficiency of Chlorella sp., Mur 269 photosystem II at optimum irradiance, as reflected in Fv′/Fm′ values, was reduced by 16% in ADF. A critical look at the photosynthesis of the species by PAM fluorometry revealed that the adaptive methods of this microalgae to toxicity involves adjustment of the photosynthetic unit to maximize absorption of light and compensation mechanisms for reductions in PSII activity including switching to mixotrophic growth mode.

Cultivation of Chlorella vulgaris in anaerobically digested gelatin industry wastewater

Abstract This work aimed to study the effect of using anaerobically digested gelatin industry wastewater as a culture medium for the cultivation of Chlorella vulgaris microalgae in bubble column photobioreactors (PBRs). Batch experiments were carried out to determine the growth kinetics by inoculating microalgae in wastewater prepared with different dilutions and supplemented with Bold's Basal Medium (BBM). From the values of the saturation constants (KS = 50.25 mgN-NH4+·L−1) and substrate inhibition (KI = 28.12 mgN-NH4+·L−1) obtained in the adjustment to the Andrews kinetic model (R2 = 0.817), the PBRs achieved specific maximum growth rates (μmax) of 0.343 d−1, biomass productivity of 0.141 g·L−1·d−1, lipid content of 12.45%, lipid productivity of 17.63 mg·L−1·d−1 and instantaneous ammoniacal nitrogen consumption rates of 20.06 and 14.22 mg·L−1·d−1. The addition of wastewater to the culture medium provided an increase in biomass productivity of 57.45% in relation to the negative control. The results obtained demonstrate the high efficiency of C. vulgaris in the removal of nitrogenous compounds and the potential of using anaerobically digested gelatin industry wastewater in the production of microalgae biomass.

Evaluating Cost-Effective Culture Media for Nutraceutics Production from Microalgae Using Computer-Aided Large Scale Predictions

The purpose of this research consist of microalgae biomass productivity prediction in a large scale plant from Chlorella vulgaris using SuperPro Designer software. Two culture media were evaluated to identify their potential use in large-scale processes: (a) the Bold Basal medium enriched with sodium acetate and (b) a growth medium for high cell density cultures proposed from references. Results found in this research suggest that simulated plant should reach a capacity to generate 1.4 kg/h of biomass at a cost of 1.44 USD/g using Bold Basal medium. In contrast, a productivity of 28 kg/h at a cost of 0.14 USD/g was found using a medium proliferation of highly dense microalgae cultures. These findings suggest that Bold Basal medium could negatively impact operating costs, limiting its use in large-scale processes regarding nutraceutics production. Results found here demonstrate the potential usage of simulators for estimating costs and production which allows predicting the bioprocess feasibility.

Evaluation of preliminary plant design for Chlorella vulgaris microalgae production focused on cosmetics purposes

Although there are currently different large-scale microalgae production systems, its performance is subject to high production cost problems. That is why the main goal of this research is analyzing the feasibility of obtaining the Chlorella vulgaris microalgae from a proposed preliminary industrial plant design, considering its use in the cosmeceutical industry as skin care. Parameters used in the SuperPro Designer simulations were programmed based on experimental data reported from bibliography. For biomass and cell extract production, a Bold Basal enriched medium at 1% with soy flour was used. It is found that mass flow significantly affects production costs since a product value of 8.58 USD/ml was estimated operating the plant with 20 kg/h of mass flow. Interestingly 84 % unit reduction cost was improved by operating the proposed plant at 140 kg/h mass flow since 1.34 USD/ml of cosmetic product was determined. These findings show the potentiality of Chlorella vulgaris to be positioned in the world market. The latter, by considering its dependence on a successfully large scale plant. The above, in order to identify potential improvements focused on maximizing productivity and profits at the lowest operating cost.

Nitrogen supplementation for the production of Chlorella vulgaris biomass in secondary effluent from dairy industry

• Secondary effluent from dairy industry was used for Chlorella vulgaris cultivation. • Nitrogen was supplemented for achieving N:P = 1.72:1. • Biomass productivity with effluent was the same as that with standard medium. In this study, secondary effluent from dairy industry was employed for the cultivation of Chlorella vulgaris in a bench-scale tubular photobioreactor. We sought to evaluate the biomass production, the consumption of nitrogen in the medium, and the final biomass composition. Considering the need of nitrogen supplementation, we evaluated the nitrogen:phosphorus ratio: the same proportion found in Bold basal medium (N:P = 1.71:1) and Redfield ratio (N:P = 16:1), comparing with no nitrogen supplementation and Bold Basal Medium. The results showed that nitrogen supplementation improves biomass growth (up to 2824.93 mg.L −1 ), also granting efficient nutrients consumption (up to 98 % of nitrogen removal). Nitrogen supplementation following the Bold medium ratio was the most suitable protocol, since it requires less nitrogen addition without impairment in biomass productivity (Px =259.90 mg.L −1 .d −1 ), in comparison with cultures with supplementation following Redfield ratio (Px =296.73 mg.L −1 .d −1 ) or control culture (Px =221.02 mg.L −1 .d −1 ). In addition, the final biomass showed satisfactory amounts of proteins (up to 21.92 %) and lipids (up to 35.75 %), besides presenting a profile with high concentrations of saturated (C16:0) and monounsaturated fatty acids (C18:1).

Microalga Scenedesmus bijugus: Biomass, lipid profile, and carotenoids production in vitro

Manipulating specific nutrients in growth media to boost production of lipids or carotenoids in microalgae is a widespread practice; however, it decreases overall biomass productivity, an important consideration for viable production of biofuels. In the present study, maximum productivity of lipids (117.01 mg/L/d) and biomass (249.60 mg/L/d) was obtained on day 13 in Bold's basal medium (BBM) modified by adding 25 mM NaCl and 20 μM phosphate. Lutein and astaxanthin productivity was, however, only slightly different from that in the standard medium, namely blue-green-11 (BG-11). The lipids profile was dominated by C16:0 and C 18:1 fatty acids ranging from 26.69 to 39.32% and 10.8–35.31% (palmitic and oleic acids) in all the five variants of the culture medium. These results indicate that the highest proportion of saturated fatty acids (SFA; 61.02%) was obtained in BG-11 whereas that of monounsaturated fatty acids (MUFA; 37.34%) was obtained in BBM supplemented with NaCl (50 mM) and phosphate (20 μM). All the five variants led to lipids suitable for biodiesel production, marked by a lipid profile dominated by the two fatty acids. It is concluded that making the culture medium more saline and enriching it with phosphates increased lipid and biomass productivity and the synthesis of fatty acids methyl esters (FAME).

Effect of type of nutrient media on the biomass and fatty acid profiles of microalgae (Chlorella spp.)

Locally available nutrient materials (Cow dung, Soybean extracts and Diammonium Phosphate (DAP)/UREA) were used to prepare culture media for growing Chlorella spp. and compared to the commonly constituted Bold’s Basal Medium (BBM) as a control. Algae was cultured in 25L rectangular glass tanks with 24 hour illumination and aeration. Ammonia, pH and counts of algae cells/ml were recorded daily for 24 days. Chlorella spp. production rate, effect of intrinsic ammonia and pH on culture performance, duration of culture cycle and the di fferences in resultant fatty acid composition of the algae were tested. Results indicated a significant effect of culture media on the growth performance of Chlorella spp. (F = 3.42, P 40% of Total Fatty Acids) were predominant in all media. Monounsaturated fatty acids (MUFAs) were recorded low (

Effect of &lt;i&gt;Ascophyllum nodosum&lt;/i&gt; extracts on the growth, yield and antioxidant capacity of &lt;i&gt;Haematococcus pluvialis&lt;/i&gt; carotenoids

Recent research has shown that the use of biological extracts, which contain a wide variety of nutrients and phytohormones are potentially useful in the production of plants of agricultural importance. Seaweed extracts are particularly rich in minerals and micronutrients necessary for the growth of microalgae. The effect of three commercial extracts of Ascophyllum nodosum as plant growth inducers (Stimplex®, Acadian Soils® and Liquid Seaweed Concentrate®), provided by Acadian Sea Plants Ltd., were evaluated in relation to the growth and production of biomass and carotenoids in Haematococcus pluvialis. The results were evaluated by one-way ANOVA and post-hoc analysis utilizing Tukey's test with a significance level of 95% (α= 0.05). The reference medium used was the Bold basal medium, to which 250 ppm of each extract was added. The Stimplex® extract had an increase of 22.79% in cell density and 17% in dry matter, higher than the control culture. The content of carotenoids and antioxidant capacity, respectively, with Stimplex® was 30.05% and 141.76% higher than the control culture.

Comparison of Sensitivity of Tropical Freshwater Microalgae to Environmentally Relevant Concentrations of Cadmium and Hexavalent Chromium in Three Types of Growth Media.

Sensitivity of tropical freshwater microalgae (Mesotaenium sp., Chlorococcum sp. and Scenedesmus sp.) to environmentally relevant concentrations of hexavalent chromium (Cr6+) and cadmium (Cd2+) was compared individually in three growth media viz. Bold's Basal Medium (BBM), Test Medium 1 (TM1) and Test Medium 2 (TM2) based on fluorescence reduction. Free metal content of growth media was determined by Visual MINTEQ (version 3.1). After 24h, relative fluorescence of microalgae in the three media decreased with increased metal concentration showing a concentration dependent graded toxicity response. All microalgae were more sensitive to the metals when grown in TM1, when compared, more sensitive to Cr6+ than Cd2+. Metal speciation indicated that TM1 and TM2 media have higher percentage of bioavailable Cd2+ than BBM, and chromium was present mainly as CrO42- and HCrO4-. The results suggest that the TM1 medium is more suitable under short term exposure of microalgae to metals in environmental monitoring.