Chlorella Vulgaris Beijerinck Research Articles

Terrestrial algae: pioneer organisms of carbonate rock solutional weathering in South China karst.

The formation of soil in karst ecosystem has always been a scientific problem of great concern to human beings. Algae can grow on the exposed and non-nutrition carbonate surface, inducing and accelerating weathering of rock substrates, thus promoting soil formation. Yet the actual contribution of algae to solutional weathering intensity remains unclear. In this study, we performed weathering simulation experiment on two algae species (Klebsormidium dissectum (F.Gay) H.Ettl & G.Gärtner and Chlorella vulgaris Beijerinck), which were screened from carbonated rock surfaces from a typical karst region in South China. The results showed: (1) both algae have solutional weathering effect on carbonate rock, (2) there is no difference of solutional intensity observed, yet the solutional modes are different, suggesting different ecological adaptative strategies, (3) algae on carbonate rocks have higher carbonic anhydrase activity (CAA) and secrete more extracellular polysaccharide (EPS), accelerating rock weathering. (4) The absolute dissolution amount of carbonate rock with algae participation is 3 times of that of without algae. These results indicate the significant impact of terrestrial algae on carbonate rock solutional weathering and provides quantitative evidence that terrestrial algae are pioneer species. It also contributes to our further understanding of soil formation in karst ecosystems in South China.

Phytohormonal impacts on fatty acid profiles in Chlorella vulgaris Beijerinck: endogenous identification and exogenous application of cytokinins and abscisic acid

Phytohormonal impacts on fatty acid profiles in Chlorella vulgaris Beijerinck: endogenous identification and exogenous application of cytokinins and abscisic acid

Application of Chlorella vulgaris Beijerinck as a Biostimulant for Growing Cucumber Seedlings in Hydroponics.

Hydroponics is a promising method for growing agricultural plants and is especially relevant in the context of global climate change. Microscopic algae, including Chlorella vulgaris, has great potential for use in hydroponic systems as natural growth stimulators. The effect of the suspension of an authentic strain of Chlorella vulgaris Beijerinck on the length of cucumber shoots and roots, as well as its dry biomass, was studied. During cultivation in a Knop medium with the addition of Chlorella suspension, the length of the shoots was shortened from 11.30 to 8.15 cm, while the length of the roots also decreased from 16.41 to 10.59 cm. At the same time, the biomass of the roots increased from 0.04 to 0.05 g. The data obtained indicate the positive effect of the suspension of the Chlorella vulgaris authentic strain on the dry biomass of cucumber plants in hydroponic conditions and make it possible to recommend this strain for use when growing plants in hydroponic systems.

Exogenous Indole-3-Acetic Acid Production and Phosphate Solubilization by Chlorella vulgaris Beijerinck in Heterotrophic Conditions

The role of soil-borne microalgae in the edaphic ecosystem is barely known, especially concerning their plant-growth-promoting traits, although they are used as biofertilizers. In this study, a microalgal strain isolated from soil cultivated with maize was evaluated as an exogenous producer of indole-3-acetic acid (IAA) in potato dextrose broth—PD—and sugarcane molasses, with or without tryptophan, and phosphate solubilizer (in ‘National Botanical Research Institute’s phosphate’—NBRIP—medium with tricalcium phosphate)with plant-growth-promoting traits, under heterotrophic conditions. The species of microalga was identified, by sequencing the ITS region in the rDNA and the morphological characteristics, as Chlorella vulgaris. Its growth was significantly higher in the PD medium, with slower growth in molasses. The addition of tryptophan did not influence the growth of C. vulgaris in either medium, but it increased the production of IAA, mainly in the PD medium, to 265 µg mL−1. The microalga grew in the medium with insoluble phosphate, releasing phosphorus into the medium (30 mg L−1 after 72 h). This is the first study on the application of C. vulgaris as a phosphate solubilizer. More studies should be performed on C. vulgaris as a prospective plant-growth-promoting microorganism, besides its ability to produce exogenous IAA, and further investigations should be conducted on developing inexpensive culture media.

Evaluation of Roundup® effects on Chlorella vulgaris through spectral changes in photosynthetic pigments in fresh and marine water

• Roundup® caused spectral changes in photosynthetic pigments of Chlorella vulgaris . • Absorption spectra and peak areas were used to monitor toxic effects. • Cells were stimulated from 10 to 5,000 µg L −1 in freshwater and inhibited otherwise. • C. vulgaris adapted to seawater was more tolerant above 1 mg L −1 of glyphosate. • The dose-response relationship depended on salinity. Glyphosate is a broad-spectrum herbicide whose use is now restricted because of its potential toxicity to human and environmental health. Its presence is observed even in aquatic ecosystems where this emerging contaminant affects primary producers such as phytoplankton. This study focuses on the cosmopolitan green microalga, Chlorella vulgaris Beijerinck, 1890. The ecotoxicological effects of the commercial herbicide, Roundup®, were evaluated in freshwater (FW) and seawater (SW) using ultraviolet/visible spectroscopy over a five-day experiment. A dose-response relationship was investigated on a wide range of concentrations (0.1 to 25,000 µg L −1 ). The population of FW- Chlorella was stimulated when exposed to concentrations from 10 to 5,000 µg L −1 and inhibited otherwise. Chlorophylls and carotenoids exhibited their highest peak area values after four days, before their signal was depleted by day 5, regardless of Roundup® concentration. Conversely, cells of SW- Chlorella were stimulated at the highest concentrations (> 1 mg L −1 ), as if glyphosate was acting as a source of phosphorous nutrient. The peak areas of chlorophylls and carotenoids increased in the presence of the contaminant, especially on day 3. The defense mechanisms activated during its adaptation to marine salinity ( e.g. , decrease in the chlorophyll/carotenoid peak area ratio) could have favored its resilience. Exposure to Roundup® caused a shift in the wavelength at maximum absorbance, which could introduce a bias when measuring peak heights at a single wavelength. The analysis of absorption spectra and the use of peak areas appear to be a promising approach for monitoring changes in photosynthetic pigments.

Fatty acids and their derivatives from Chlorella vulgaris extracts exhibit in vitro antimicrobial activity against the honey bee pathogen Paenibacillus larvae

The green microalga Chlorella vulgaris Beijerinck (Chlorellaceae) is widely used as a food supplement for humans and animals. In beekeeping practice, Chlorella vulgaris has potential as a pollen supplement. We studied whether Chlorella extracts display antimicrobial properties against Paenibacillus larvae, the causative agent of the honey bee bacterial disease American foulbrood. We identified components responsible for antimicrobial activity and evaluated the added values of Chlorella as a food supplement for honey bees. Different extracts (water, acetone, methanol) were prepared from Chlorella biomass (phototrophically and heterotrophically cultivated) and screened for antimicrobial activity against ERIC I and ERIC II genotypes of P. larvae. Active acetone extracts of phototrophically cultivated Chlorella vulgaris biomass were fractioned via preparative reverse-phase chromatography. Antimicrobial activity was detected for 9 of the resulting 33 fractions. Further analysis revealed the chemical composition of the active fractions. C. vulgaris extracts showed a significant antimicrobial effect against vegetative cells and spores of P. larvae strains of ERIC I and ERIC II genotypes. The lowest MIC of the most active acetone extract was 6.3 µg/mL for both tested genotypes. In the majority of the active fractions, monolinolenin, fatty acid linoleic acid, and methyl esters of linoleic and/or palmitic acid were identified via high-performance liquid chromatography coupled with high-resolution mass spectrometry analysis. Based on our results, we concluded that algal C. vulgaris food supplements not only contain nutritional but also potential prophylactic properties for honey bee health.

Microalgae (Chlorella vulgaris Beijerinck) alleviates drought stress of broccoli plants by improving nutrient uptake, secondary metabolites, and antioxidative defense system

Microalgae, such as Chlorella vulgaris Beijerinck (green algae), are beneficial microscopic organisms that may help plants to improve nutrient uptake, growth, and abiotic tolerance to stressors. The current study was performed to investigate the effectiveness of algae (Chlorella vulgaris Beijerinck) foliar applications [1%, 3%, or 5% (v/v)] on mitigation of drought stress in broccoli plants subjected to water deficit at 25% of field capacity. The results showed that the broccoli plants grown under drought stress alone exhibited severe disturbance in growth with considerable reductions in the shoot length, and fresh and dry weights, leaf area, relative water content, leaf water potential, and photosynthetic pigment contents and elevated levels of the lipid peroxidation product malondialdehyde in the leaves. Additionally, the foliar application of microalgae mitigated the detrimental effects of drought, leading to better growth performance (increase of 9%–132%) when compared with the drought-stressed plants that had not received an application of microalgae. Microalgae-mediated beneficial effects were particularly evident in the enhancement of the photosynthetic pigment contents, including chlorophyll-a (6%–60%), chlorophyll-b (19%–55%), and total carotenoids (26%–114%). Exogenous microalgae also contributed to the reduction of membrane damage, as proven by significantly decreased levels of malondialdehyde (10%–39%) in the leaves of the broccoli plants exposed to drought stress. The application of microalgae increased the total flavonoid and phenolic contents, and nutrition uptake. Furthermore, the activities of enzymatic antioxidants like ascorbate peroxidase, catalase, glutathione reductase, and superoxide dismutase increased in response to mediation, resulting in significant alleviation of drought-induced oxidative damage. The most effective application concentration of microalgae was determined as 5%. Overall investigations revealed that the foliar application of microalgae could be recommended as a sustainable strategy to improve the defense system of drought-stressed broccoli plants.

Integration of bioelectricity generation from algal biophotovoltaic (BPV) devices with remediation of palm oil mill effluent (POME) as substrate for algal growth

The exploitation of renewable energy sources for delivering carbon neutral or carbon negative solutions has to be achieved through strategies involving the removal of CO2 from the atmosphere. Agro-industries like palm oil processing are important sources of energy but are also generators of large volumes of wastewater, causing pollution problems. Bioremediation of these effluents utilizing microalgae has shown promising results. In the present study, we developed an algal-biophotovoltaic device to generate direct bioelectricity from photosynthesis while using palm oil mill effluent (POME) as substrate for microalgal growth. Nine microalgal strains from the University of Malaya Algae Culture Collection (UMACC) were cultured using POME in four different concentrations (50%, 25%, 10%, and 5%) for 12 days. Chlorella vulgaris Beijerinck UMACC 051 showed the highest specific growth rate (1.32 d−1) and Chlorella UMACC 301 showed high photosynthetic performance (Alpha = 0.88) when grown in 5% POME–BBM medium. Three selected microalgal strains were grown in the control medium (Bold’s Basal Medium) and 5% POME–BBM medium in an annular biophotovoltaic device. The maximum power density (0.45 mW m−2) obtained from Chlorella UMACC 313 in the POME–BBM medium, was 15% higher than the power density generated when the microalgal cells were grown in the control medium (0.38 mW m−2). When Chlorella UMACC 313 was cultured in a 4L round integrated fuel cell-photobioreactor prototype device, the maximum power density obtained was 0.28 mW m−2. The reductions in NO3-N, o-PO43−, NH3-N and COD were 54.92%, 29.41%, 80.75 and 60.09% respectively. A final biomass of 810 mg L−1 was obtained after 12 days’ growth and the CO2 fixation rate was 76.82 mgCO2 L−1 d−1. This BPV system represents a multi-functional system that generates low power density while providing wastewater bioremediation and carbon removal. This has potential as a sustainable environment-friendly carbon-neutral or carbon-reducing energy generation system.

Removal of Heavy Metal Contaminants from Wastewater by Using Chlorella vulgaris Beijerinck: A Review

Removal of heavy metals is very important in wastewater treatment process, due to their abundant hazardous effects. There are various chemical and physical methods including ion exchange, reverse osmosis, electrodialysis, and ultrafiltration for removing heavy metals from wastewater, but biological treatment has attracted researchers for years as it is cheap and efficient. Microalgae have a significant capability of absorbing and eliminating heavy metals from wastewater. One of the most attractive microalgae species for this application is the Chlorella vulgaris Beijerinck. The current study takes a literature review of using microalgae species, especially C. vulgaris, with the aim of wastewater heavy metal treatment. In this regard firstly, various methods of eliminating heavy metals using microalgae were investigated, and then the application of C. vulgaris in the process of eliminating heavy metals from wastewater is fully presented. It became obvious that the use of C. vulgaris application is more helpful in the case of Copper, Lead, Zinc, Cadmium, and Nickel. Moreover, the main factor affecting heavy metal treatment using C. vulgaris is the pH of media, and the second effective parameter is temperature that is often considered about 25°C. The appropriate time period for the treatment was 5-7 days. Generally, C. vulgaris presented a very favorable efficiency in eliminating various heavy metals and is capable of removing heavy metals from wastewater to more than 90% on average.

Вміст пігментів та фотосинтетична активність Chlorella vulgaris Beijerinck (Chlorophyta) за дії натрію Селеніту, Цинку Сульфату і Хрому хлориду

Вміст пігментів та фотосинтетична активність Chlorella vulgaris Beijerinck (Chlorophyta) за дії натрію Селеніту, Цинку Сульфату і Хрому хлориду

A simple method for the cultivation of algae Chlorella vulgaris Bejerinck

Chlorella vulgaris Beijerinck stimulates the growth of agricultural plants and suppress the development of pathogenic microorganisms. Original data about on development of culture medium and selection of optimal cultivation conditions for the alga Chlorella vulgaris are presented. The most favorable conditions for algae growth were daylight, temperature 25° C and rotation at the speed 100 rpm. The most effective culture medium was of the Bold basal medium with the addition of vitamins thiamine, cyanocobalamin and soil extract. This method may used for creation the biopesticide and growth stimulators on the basis Chlorella biomass.

The effects of barley straw extract on the microalgae growth

One of the most common environmental problems of recent decades is the eutrophication of surface water and the associated algal bloom. As one of the approaches to eliminate this phenomenon, the use of biological methods, in particular biological preparations from barley straw, is considered. In this work presents the results of laboratory modeling of the effect of 1 and 2% (v/v) of barley straw (Hordeum vulgare L.) extract on the development of unicellular algae (Chlorella vulgaris Beijerinck). The alhistatic effect was evaluated by the parameters of algae growth, which were measured using the spectrophotometric and fluorescent methods. The parameters were measured at 0, 7, 14 and 21 days. The addition of barley straw extract reduced algae growth, both with the addition of 1% and 2% concentration. A two-day toxicity test using Daphnia magna Straus showed no toxic effect of barley straw extract for both 1% and 2% concentration.

Chlorella vulgaris integrates photoperiod and chloroplast redox signals in response to growth at high light.

Photoacclimation to variable light and photoperiod regimes in C. vulgaris represents a complex interplay between "biogenic" phytochrome-mediated sensing and "operational" redox sensing signaling pathways. Chlorella vulgaris Beijerinck UTEX 265 exhibits a yellow-green phenotype when grown under high light (HL) in contrast to a dark green phenotype when grown at low light (LL). The redox state of the photosynthetic electron transport chain (PETC) as estimated by excitation pressure has been proposed to govern this phenotypic response. We hypothesized that if the redox state of the PETC was the sole regulator of the HL phenotype, C. vulgaris should photoacclimate in response to the steady-state excitation pressure during the light period regardless of the length of the photoperiod. As expected, LL-grown cells exhibited a dark green phenotype, low excitation pressure (1 - qP = 0.22 ± 0.02), high chlorophyll (Chl) content (375 ± 77fg Chl/cell), low Chl a/b ratio (2.97 ± 0.18) as well as high photosynthetic efficiency and photosynthetic capacity regardless of the photoperiod. In contrast, C. vulgaris grown under continuous HL developed a yellow-green phenotype characterized by high excitation pressure (1 - qP = 0.68 ± 0.01), a relatively low Chl content (180 ± 53fg Chl/cell), high Chl a/b ratio (6.36 ± 0.54) with concomitantly reduced light-harvesting polypeptide abundance, as well as low photosynthetic capacity and efficiency measured on a per cell basis. Although cells grown under HL and an 18h photoperiod developed a typical yellow-green phenotype, cells grown at HL but a 12h photoperiod exhibited a dark green phenotype comparable to LL-grown cells despite exhibiting growth under high excitation pressure (1 - qP = 0.80 ± 0.04). The apparent uncoupling of excitation pressure and phenotype in HL-grown cells and a 12h photoperiod indicates that chloroplast redox status cannot be the sole regulator of photoacclimation in C. vulgaris. We conclude that photoacclimation in C. vulgaris to HL is dependent upon growth history and reflects a complex interaction of endogenous systems that sense changes in photoperiod as well as photosynthetic redox balance.

English

Conventional identification of three coccoid green algae isolates was attempted to characterize the studied algae morphologically under compound microscope, which demonstrated confusional phenomenal convergence; all were classified microscopically as the green alga Chlorella vulgaris Beijerinck, 1890. Phylogenetic studies were conducted to settle the argument about the phenotype by studying the genotype. Genotype the promising field in advance classification by using 18S rRNA and compared to GenBank database using to search the related sequences. The determined sequences showed high a similarity to the strains registered in GenBank. Phylogenetic tree of ITS within 18S RNA were analyzed: the phylogram separated into two clusters, the first cluster included C1-ITS-Iraq and C2-ITS-Iraq and put with Coelastrella Chodat, 1922 which was well supported in bootstrap tests (86-100%), while the second cluster included C3-ITS-Iraq and put with C. sorokiniana Shihira and Krauss, 1965, which have bootstrap value 100% with the mentioned species. however, in this study, the green alga Colestrella was identified as new record genus in Iraqi freshwater belonged to the order Sphaeropleales.

Impact of tropho-metabolic activity of earthworms (Lumbricidae) on distribution of soil algae within Acer platanoides L. plantation in recultivated territories of Western Donbass (Ukraine)

Rational use of natural resources in conditions of modern environmental management is an ongoing challenge to maintain sufficient level of wellbeing – natural resources and healthy environment in the contest of biodiversity preservation, formation of soil fertility, esthetic properties of landscapes and other ecologically important services. One way to optimize technogenic landscapes is forest recultivation – creation of stable forest ecosystems on disturbed territories, which can be powerful environmentcreation tool. The pertinent activity of animals – ecological engineers has great importance for improvement of ecological state of forest ecosystems on the recultivated territories. Soil engineers, such as earthworms, are the key organisms in functioning of soil – most important component of terrestrial ecosystem. They participate in various ecological processes and play key role in numerous ecosystem services: biogeochemical cycles support, forming of sustainable hydrological regime of territory and soil productivity, protection from the erosion. Additional natural soil biotic factor, multiplying these effects – algae, which reflect biogenic grade of soil and their naturalization in conditions of forest recultivation. Although, soil algae and earthworms are important components, supporting soil fertility, biogenic relationship of these groups of organisms, especially in the conditions of forest recultivation, remains largely unstudied The aim of the research is to evaluate the impact of pedotrubation and tropho-metabolic activity of earthworms ( Oligochaeta : Lumbricidae ) on resettlement of soil algaflora representatives within maple ( Acer platanoides L.) plantation on the soil recultivation plot in Western Donbass in the Steppe zone of Ukraine. In fresh coprolites of earthworms Aporrectodea caliginosa on the studied plot, five species of soil algae ( Chlorella vulgaris Beijerinck , Botrydiopsis eriensis Snow, Phormidium retzii (Agardn) Gomont, Bracteococcus sp ., Chlorococcum pulchrum Archibald et Bold) were found. They belong to divisions Chlorophyta , C уа nophyta , Xantophyta and represented by Ch - and P -living forms, which can dwell in artificial forest ecosystem with severehydrothermal conditions. Such representatives as Phormidium retzii , Chlorococcum pulchrum , Botrydiopsis eriensis were present only in soil and coprolites on the soil surface. This indicates their rise to the soil surface in result of tropho-metabolic and pedotrubation activity of worms. This allows considering that, earthworms in the studied plot of soil recultivation contribute to redistributions and resettlement of soil algae, their exploration to new territories, and ultimately – naturalization of artificial edaphotopes of forest plantations in recultivated lands.

Bioaccessibility of phenolic compounds, lutein, and bioelements of preparations containing Chlorella vulgaris in artificial digestive juices

Chlorella vulgaris Beijerinck is a spherical, green alga belonging to the genus Chlorella and family Chlorellaceae. It has high nutritional value and shows multiple biological effects. Dietary supplements that contain extracts of C. vulgaris are sold in the form of tablets, capsules, powders, and aqueous solutions. To the best of our knowledge, this is the first study to determine the content of bioelements (zinc, iron, and magnesium), phenolic compounds, and lutein before and after incubation with artificial digestive juices from preparations containing C. vulgaris. In this study, we used commercial preparations in the form of powder and tablets. The samples were incubated in artificial gastric juice and then in artificial intestinal juice for 30 and 90 min. The contents of bioelements were determined by using the flame atomic absorption spectrometric method. Lutein and phenolic compounds were analyzed by high-pressure liquid chromatography. We also aimed to evaluate the quality of chlorella-containing formulations by using the methods described in the European Pharmacopoeia 8th edition. According to the results, the preparations containing C. vulgaris demonstrated the presence of phenolic compounds and lutein. Therefore, daily supplementation of preparations containing C. vulgaris substantiates its usefulness for humans. The qualitative composition of the examined organic substances and bioelements was found to be in accordance with the manufacturer’s declarations on the packaging containing C. vulgaris compared with the control samples; however, the contents of bioelements were found to be negligible after incubation with artificial digestive juices. This shows that the examined preparations containing C. vulgaris are not good sources of bioelements such as zinc, iron, or magnesium.

Effects of Chicken Manure Extract on the Population Growth, Mixis Induction and Body Size of the Freshwater Rotifer Brachionus angularis Gosse 1851

This study investigated the effects of chicken manure extract (CME) on the population growth, mixis induction and body size of the freshwater rotifer Brachionus angularis Gosse 1851. Four concentrations of CME (i.e.0.5, 1.0, 2.0 and 3.0 ml . L -1 ), each in triplicate, were used in glass jars containing 20 mL of sterilised pond water. Thirty clones (24 h old) of B. angularis were placed in each jar and the specified concentrations of CME were added except in the control jars. Chlorella vulgaris Beijerinck 1890 (2.5x10 6 cells . mL -1 ) was supplied daily in all jars. The treatments were incubated at 25 o C in darkness for 7 days without exchanging water. CME significantly (P 0.05) affect the unfertilised mictic females. The specific population growth rate was significantly (P<0.05) highest at 2.0 mL . L -1 of CME. The resting egg production decreased with increasing concentrations of CME. The lorica length increased at 3.0 mL . L -1 of CME but the lorica width was unaffected by CME. These results suggest that addition of 2.0 mL . L -1 of CME enhances the population growth and regulates lorica size; hence can be applied in the freshwater larviculture initiatives.

A quick and effective estimation of algal density by turbidimetry developed with Chlorella vulgaris cultures

A quick and effective estimation of algal density by turbidimetry developed with Chlorella vulgaris cultures The use of Chlorella vulgaris Beijerinck as a food source for zooplanktonrequires the optimizationof algal-cultureconditions for prolonged growth maintenance. In this study, we developed a method that relates algal density to culture turbidity to estimate culturebiomass. Thismethodwasimprovedby applyingdigital analysisfor algalcounting,whichpromotesaccuracy, low culture disturbance, easy repetition and the rapid acquisition of results. Two 3-L cultures of C. vulgaris, maintained for two weeks with continuous lighting (eight light-emitting diodes at 50 µmol photons m -2 ·s -1 , at 660 nm) and aerators to prevent algal sedimentation, reached turbidities of 214 and 280 NTUs, respectively. Sample counting was performed using digital images obtained with an inverted microscope. Aliquot sedimentation was compared with or without previous homogenization through photographs taken in the central, middle, and peripheral sectors of the Utermohl settling chambers. For each procedure, we counted between 17 and 404 individuals image -1 , requiring, on average, one minute image -1 .A t low turbidity (<40 NTU), the data dispersion was similar between the two protocols (error range, 16 to 60%); at higher turbidity, the direct sedimentation alone gave a larger error (31-50%) than with prior homogenization (5-13%). Regression analysis at low data fit (67%) suggested that the sedimentation heterogeneity of non-homogenized samples corresponded to a pattern of settled algae having increasing density from the periphery to the centre of the chamber, but with homogenization, a better model fitting (99%) resulted, contributing to greater consistency with that procedure. We consider that this turbidometric protocol could be used successfully with cultures of algae that have geometrical shapes recognizable by the image software.

Мicroscopic investigations (LM, TEM and SEM) and identification of Chlorella isolate R-06/2 from extreme habitat in Bulgaria with a strong biological activity and resistance to environmental stress factors

An extremophilic Chlorella strain R-06/2, isolated from a geothermal spring (+42 °C) in the region of Rupite village (SW Bulgaria), was investigated for species identification. This was done by observation of the cell morphology, reproduction and ultrastructure by light microscopy, scanning electron microscopy and transmission electron microscopy, and by investigation of the cell-wall chemistry. The pyrenoid ultrastructure with a double-layered thylakoid traversing the matrix, the shape of the starch envelope, as well as the cell wall, composed of glucosamine and developed around young autospores, were the features that allowed us to classify the thermophilic strain Chlorella R-06/2 as Chlorella vulgaris Beijerinck 1890.

Fluoranthene induced changes in photosynthetic pigments, biochemical compounds and enzymatic activities in two microalgal species: Chlorella vulgaris Beijerinck and Desmodesmus subspicatus Chodat

The photosynthetic pigments, biochemical and enzymatic activities in two freshwater microalgal species, Chlorella vulgaris and Desmodesmus subspicatus at different fluoranthene concentrations were compared with the control conditions. During 16-days of incubation period when treated with fluoranthene, both microalgal species exhibited variable amount of photosynthetic pigment, biochemical compounds and enzymatic activities. The addition of fluoranthene at concentrations ranged from 1.5 mg l-1; to 10 mg l-1; to microalgal cultures led to changes in all different metabolites but the patterns varied from species to species. Among the two species tested, pigment, biochemical and enzymatic contents were remarkably declined from 7 % to 95% in C. vulgaris. Moreover, all metabolites in D. subspicatus also diminishing significantly by 3% to 88% of fluoranthene doses (10ppm). These results suggest that fluoranthene-induced changes of pigments, biochemical and enzymatic variations in test microalgae, D. subspicatus and C. vulgaris, might reveal its resistance and ability to metabolize PAHs. At the same time, the PAH impact changes on different metabolic activities were higher at 12 and 16 days than at 4 and 8 days in treated microalgae. DOI: http://dx.doi.org/10.3126/ije.v3i1.9941 International Journal of Environment Vol.3(1) 2014: 41-55