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1.
Pol J Microbiol ; 68(4): 527-539, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31880896

RESUMO

Ulleungdo and Dokdo are volcanic islands with an oceanic climate located off the eastern coast of South Korea. In the present study, we used barcoded Illumina MiSeq to analyze eukaryotic microalgal genera collected from Seonginbong, the highest peak on Ulleungdo, and from groundwater sites on Dongdo and Seodo Islands, which are part of Dokdo. Species richness was significantly greater in the Seonginbong samples than in the Dongdo and Seodo samples, with 834 operational taxonomic units (OTUs) identified from Seonginbong compared with 203 OTUs and 182 OTUs from Dongdo and Seodo, respectively. Taxonomic composition analysis was also used to identify the dominant microalgal phyla at each of the three sites, with Chlorophyta (green algae) the most abundant phyla on Seonginbong and Dongdo, and Bacillariophyta (diatoms) the most abundant on Seodo. These findings suggest that differences in the abundances of Chlorophyta and Bacillariophyta species in the Seonginbong, Dongdo, and Seodo samples are due to variations in species richness and freshwater resources at each sampling location. To the best of our knowledge, this is the first report to detail freshwater microalgal communities on Ulleungdo and Dokdo. As such, the number of species identified in the Seonginbong, Dongdo, and Seodo samples might be an indicator of the ecological differences among these sites and varying characteristics of their microbial communities. Information regarding the microalgal communities also provides a basis for understanding the ecological interactions between microalgae species and other eukaryotic microorganisms.Ulleungdo and Dokdo are volcanic islands with an oceanic climate located off the eastern coast of South Korea. In the present study, we used barcoded Illumina MiSeq to analyze eukaryotic microalgal genera collected from Seonginbong, the highest peak on Ulleungdo, and from groundwater sites on Dongdo and Seodo Islands, which are part of Dokdo. Species richness was significantly greater in the Seonginbong samples than in the Dongdo and Seodo samples, with 834 operational taxonomic units (OTUs) identified from Seonginbong compared with 203 OTUs and 182 OTUs from Dongdo and Seodo, respectively. Taxonomic composition analysis was also used to identify the dominant microalgal phyla at each of the three sites, with Chlorophyta (green algae) the most abundant phyla on Seonginbong and Dongdo, and Bacillariophyta (diatoms) the most abundant on Seodo. These findings suggest that differences in the abundances of Chlorophyta and Bacillariophyta species in the Seonginbong, Dongdo, and Seodo samples are due to variations in species richness and freshwater resources at each sampling location. To the best of our knowledge, this is the first report to detail freshwater microalgal communities on Ulleungdo and Dokdo. As such, the number of species identified in the Seonginbong, Dongdo, and Seodo samples might be an indicator of the ecological differences among these sites and varying characteristics of their microbial communities. Information regarding the microalgal communities also provides a basis for understanding the ecological interactions between microalgae species and other eukaryotic microorganisms.


Assuntos
Microalgas/isolamento & purificação , Clorófitas/classificação , Clorófitas/genética , Diatomáceas/classificação , Diatomáceas/genética , Diatomáceas/isolamento & purificação , Água Doce/análise , Ilhas , Microalgas/classificação , Microalgas/genética , Filogenia , Análise de Sequência de DNA
2.
Mar Pollut Bull ; 148: 1-2, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31422294

RESUMO

The article entitled "Non-indigenous species refined national baseline inventories: A synthesis in the context of the European Union's Marine Strategy Framework Directive" by Tsiamis et al. (2019, Mar. Pollut. Bull. 145, 429-435) reports a list of 52 non-indigenous microalgae in the European Seas. Comments on the validity of categorizing these species as non-indigenous are reported.


Assuntos
Espécies Introduzidas , Microalgas/isolamento & purificação , Europa (Continente) , Microalgas/classificação , Oceanos e Mares
3.
Colloids Surf B Biointerfaces ; 178: 329-336, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30889440

RESUMO

This paper investigates the flocculation of Chlorella sorokiniana suspensions with a novel cellulose derivative, namely hairy cationic nanocrystalline cellulose (CNCC). CNCC are a brand new family of nanocellulose characterized by having two positively charged amorphous ends joint through a common crystalline shaft. Flocculation was monitored through laser reflectance and its mechanism was studied by means of zeta potential, fractal dimension and turbidity removal. CNCC dosage and shear rate were varied and their effect on floc morphology and filterability were assessed. CNCC effectively flocculated the cultures at dosages well below and over the isoelectric point, being the flocculation mechanisms and floc strength highly dependent on the doses applied. The filtration propensity of flocculated suspensions proved highly sensitive to small differences in flocs' geometry. The aggregation process entailed two phases, a first one in which the CNCC adsorbed on the surface of microalgal cells according to a flat random deposition up to reaching a maximal cell coverage, and a second one in which the free spots left were progressively covered with orthogonally deposited CNCC, being this later configuration the main responsible for intercellular attachment. The present work demonstrates that CNCC is an effective flocculant of microalgal cell suspensions and constitutes an alternative worth exploring for the aggregation of other cells' suspensions.


Assuntos
Celulose/química , Microalgas/isolamento & purificação , Nanopartículas/química , Cátions/química , Floculação
4.
Biomed Pharmacother ; 111: 42-50, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30576933

RESUMO

Cancer is an everyday medical concern which requires an appropriate treatment strategy. The malfunction of cell cycle is a well-established cause for cancer induction. Chemotherapy and radiation are the standard available therapeutic approach for cancer treatment; however severe side effects were reported in association to such treatments, for instance, the efficacy of patients' immune system is adversely affected in apart by radiation. These side effects may be minimized by providing novel remedial preparations. Complementary and alternative medicinal compounds, which were obtained from fresh or marine flora particularly micro and macro algae, were reported to its anti-cancerous activities. Several types of bioactive molecules are also present in microalgae, such as carotenoids, various forms of polysaccharides, vitamins, sterol, fibres, minerals…ect; the great unused biomass of microalgae and their excellent diversity of chemical constituents may introduce a major step in developing of anti-malignant drugs. Previously, such characteristic of microalgal bio-diversity was commercially exploited to make food supplements and gelling substances. However, recently, several investigations were designed to study the potential anti-carcinogenic effect of microalgal extracts, where they mostly concluded their ability to induce apoptotic cancer cell death via caspase dependent or independent pathways. In this review paper, we reported the various species of microalgae that possessed anti-tumor activity, the tumor cell lines altered through using microalgal extracts along with the levels of such extracts that reported to its inhibitor effect against cell cycle and proliferation.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Biomassa , Microalgas , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Humanos , Microalgas/isolamento & purificação , Microalgas/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia
5.
Sci Total Environ ; 654: 1379-1388, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30527887

RESUMO

Machu Picchu Inca sanctuary (Cusco Region, Peru) was constructed on a granitic plateau, better known as Vilcabamba batholith. One of the most important carved granitic rocks from this archaeological site is the Sacred Rock, used by Inca citizens for religious rituals. Due to the location and climatic conditions, different rocks from this archaeological site are affected by biocolonizations. Concretely, the Sacred Rock shows flaking and delamination problems. In this work, a non-destructive multi analytical methodology has been applied to determine the possible role of the biodeteriogens, forming the biological patina on the Sacred Rock, in the previously mentioned conservation problems. Before characterizing the biological patina, a mineralogical characterization of the granitic substrate was conducted using X-ray Diffraction, Raman microscopy (RM) and micro energy dispersive X-ray fluorescence spectrometry. For the identification of the main biodeteriogens in the biofilm, Phase Contrast Microscopy was used. RM also allowed to determine the distribution (imaging) and the penetration (depth profiling) of the biogenic pigments present in the biopatina. Thanks to this study, it was possible to asses that some colonizers are growing on inner areas of the rock, reinforcing their possible assistance in the delamination. Moreover, the in-depth distribution of a wide variety of carotenoids in the patinas allowed to approach the penetration ability of the main biodeteriogens and the diffusion of these biogenic pigments to the inner areas of the rocky substrate.


Assuntos
Biofilmes/crescimento & desenvolvimento , Cianobactérias/fisiologia , Líquens/fisiologia , Microalgas/fisiologia , Arqueologia , Cianobactérias/isolamento & purificação , Líquens/isolamento & purificação , Microalgas/isolamento & purificação , Microscopia Óptica não Linear , Peru , Pigmentos Biológicos/classificação , Dióxido de Silício , Espectrometria por Raios X , Análise Espectral Raman , Difração de Raios X
6.
Electrophoresis ; 40(6): 969-978, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30221789

RESUMO

The composition of the ship's ballast water is complex and contains a large number of microalgae cells, bacteria, microplastics, and other microparticles. To increase the accuracy and efficiency of detection of the microalgae cells in ballast water, a new microfluidic chip for continuous separation of microalgae cells based on alternating current dielectrophoresis was proposed. In this microfluidic chip, one piece of 3-dimensional electrode is embedded on one side and eight discrete electrodes are arranged on the other side of the microchannel. An insulated triangular structure between electrodes is designed for increasing the inhomogeneity of the electric field distribution and enhancing the dielectrophoresis (DEP) force. A sheath flow is designed to focus the microparticles near the electrode, so as to increase the suffered DEP force and improve separation efficiency. To demonstrate the performance of the microfluidic separation chip, we developed two species of microalgae cells (Platymonas and Closterium) and a kind of microplastics to be used as test samples. Analyses of the related parameters and separation experiments by our designed microfluidic chip were then conducted. The results show that the presented method can separate the microalgae cells from the mixture efficiently, and this is the first time to separate two or more species of microalgae cells in a microfluidic chip by using negative and positive DEP force simultaneously, and moreover it has some advantages including simple operation, high efficiency, low cost, and small size and has great potential in on-site pretreatment of ballast water.


Assuntos
Eletroforese , Dispositivos Lab-On-A-Chip , Microalgas , Navios , Microbiologia da Água , Clorófitas/citologia , Closterium/citologia , Eletroforese/instrumentação , Eletroforese/métodos , Desenho de Equipamento , Microalgas/citologia , Microalgas/isolamento & purificação , Poliestirenos
7.
Mater Sci Eng C Mater Biol Appl ; 94: 56-64, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30423741

RESUMO

Drug delivery using synthetic mesoporous nanomaterials, including porous silicon, has been extensively used to ameliorate the constraints currently experienced with conventional chemotherapy. Owing to the amazing potential, the silica based nanomaterials have been used widely. Nevertheless, synthetic nanomaterial involves high cost, lack of scalability, and the use of toxic substances limits its utilization. These issues can be overcome by the use of nature generated nanoscale materials, such as diatoms would serve as a boon for pharmaceutical industries. In this study we investigate the use of a mesoporous, biodegradable nanomaterial obtained from the natural silica found in the diatom species Amphora subtropica (AMPS) for drug delivery applications. AMPS cultures cleaned and chemically treated to obtain Amphora frustules (exoskeleton) (AF), followed by surface functionalization with chitosan (Chi). Results of our experiments demonstrate high drug loading, strong luminescence, biodegradable and biocompatible nature of the doxorubicin tethered diatom. Further, toxicity studies employing immortalized lung cancer cell line (A549) indicates sustained drug delivery and less toxic compared to the free doxorubicin (DOX), suggesting AF could be an excellent substitute for synthetic nanomaterials used in drug delivery applications.


Assuntos
Antineoplásicos/farmacologia , Quitosana/química , Diatomáceas/química , Sistemas de Liberação de Medicamentos , Dióxido de Silício/química , Células A549 , Morte Celular/efeitos dos fármacos , Humanos , Teste de Materiais , Microalgas/isolamento & purificação , Filogenia , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Propriedades de Superfície
8.
Bioresour Technol ; 273: 177-184, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30445270

RESUMO

The present study investigated the feasibility of domestic sewage wastewater (DSW) as an alternate to fresh-water microalgae growth media towards high-value bioenergy feedstock production. Eight native microalgal strains were screened from DSW and the effect of raw DSW (RDSW), and autoclaved DSW (ADSW) on growth and bioremediation potential were evaluated and compared with control BG11 medium. The study confirmed RDSW as a potential growth medium while Monoraphidium sp. KMC4 showed superior biomass (1.47 ±â€¯0.08 g L-1) and lipid yield (436.01 ±â€¯0.06 mg L-1). The corresponding values for bioremediation of ammonia, nitrate, phosphate, as well as COD remained within 88-100%. CHNS, biochemical, TGA, FTIR, FAME analysis of KMC4 confirmed it's potential as bioenergy feedstock. Additionally, a comprehensive characterization of lipid-extracted microalgae biomass (LEMB) was carried out which suggested that LEMB can be used as a growth promoter as well as feedstock for biogas, bioethanol, and bio-oil production.


Assuntos
Biomassa , Microalgas/isolamento & purificação , Biodegradação Ambiental , Meios de Cultura , Lipídeos , Esgotos , Águas Residuárias
9.
Bioprocess Biosyst Eng ; 42(3): 425-433, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30465129

RESUMO

The isolated microalga Chlorella sorokiniana BENHA721_ABO4 was grown in Bold's basal medium (BBM) as a control, municipal wastewater (WW), and wastewater enriched with BBM elements (WW+). Cultivation in WW+ showed the highest cell number which represented 25.3 and 47.3% over that grown in WW and BBM, respectively. However, rapid growth in WW+ was accompanied by significant reduction in lipid content. Due to lipid accumulation in WW, it showed the maximum significant lipid productivity of 16.2 mg L-1 day-1. Microalgae cultivation in WW for 10 days showed 74.2, 83.3, and 78.0% removal efficiency for NO3-N, NH3-N and TP, respectively. In addition, growth in WW significantly reduced polyunsaturated fatty acids by 36.0% with respect to BBM in favor of monounsaturated fatty acids. The present results confirmed that C. sorokiniana isolate BENHA721_ABO4 grown in secondary effluent municipal wastewater offers real potential for future application in wastewater treatment and biodiesel production.


Assuntos
Biocombustíveis , Biomassa , Chlorella , Microalgas , Águas Residuárias/microbiologia , Microbiologia da Água , Purificação da Água , Chlorella/crescimento & desenvolvimento , Chlorella/isolamento & purificação , Microalgas/crescimento & desenvolvimento , Microalgas/isolamento & purificação
10.
Mol Cell Probes ; 43: 72-79, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30419277

RESUMO

Frequent outbreaks of toxic algal blooms devastate marine ecosystems, marine fisheries, and public health. Monitoring toxic algae is crucial to reduce losses caused by imminent algal blooms. However, traditional detection techniques relying on morphological examination are tedious and time-consuming. Therefore, the development of convenient strategies to detect toxin-producing microalgae is necessary. In this study, a novel method for the rapid, sensitive detection of Amphidinium carterae by loop-mediated isothermal amplification (LAMP) combined with a chromatographic lateral-flow dipstick (LFD) was established. The partial internal transcribed spacer gene was PCR amplified, cloned, and sequenced to design four LAMP primers and a detection probe for A. carterae detection. The LAMP detection conditions were optimized, and the optimum parameters were determined to be the following: dNTP concentration, 1.2 mM; betaine concentration, 1.2 M; magnesium ion concentration, 8 mM; ratio of inner primer to outer primer, 8:1; amplification temperature, 59 °C; and amplification time, 60 min. The specificity of LAMP-LFD was confirmed by cross-reactivity tests with other algal species. LAMP-LFD was 100 times more sensitive than regular PCR and similarly sensitive as LAMP and SYBR Green I. LAMP-LFD can be completed within 70 min and did not require special detection equipment. The convenience of the established LAMP-LFD assay was further validated by tests with simulated field-water samples. In conclusion, the developed LAMP-LFD assay can be used as a reliable and simple method of detecting A. carterae.


Assuntos
Cromatografia/métodos , Microalgas/genética , Microalgas/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/métodos , Reologia , Sequência de Bases , Sensibilidade e Especificidade
11.
Environ Pollut ; 244: 617-626, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30384067

RESUMO

Plastic debris carry fouling a variety of class-size organisms, among them harmful microorganisms that potentially play a role in the dispersal of allochthonous species and toxic compounds with ecological impacts on the marine environment and human health. We analyzed samples of marine plastics floating at the sea surface using a molecular qPCR assay to quantify the attached microalgal taxa, in particular, harmful species. Diatoms were the most abundant group of plastic colonizers with maximum abundance of 8.2 × 104 cells cm-2 of plastics, the maximum abundance of dinoflagellates amounted to 1.1 × 103 cells cm-2 of plastics. The most abundant harmful microalgal taxon was the diatom Pseudo-nitzschia spp., including at least 12 toxic species, and the dinoflagellate Ostreopsis cf. ovata with 6606 and 259 cells cm-2, respectively. The abundance of other harmful microalgal species including the toxic allochthonous dinoflagellate Alexandrium pacificum ranged from 1 to 73 cells cm-2. In the present study, a direct relationship between the abundance of harmful algal species colonizing the plastic substrates and their toxin production was found. The levels of potential toxins on plastic samples ranged from 101 to 102 ng cm-2, considering the various toxin families produced by the colonized harmful microalgal species. We also measured the rate of adhesion by several target microalgal species. It ranged from 1.8 to 0.3 day-1 demonstrating the capacity of plastic substrate colonizing rapidly by microalgae. The present study reports the first estimates of molecular quantification of microorganisms including toxin producing species that can colonize plastics. Such findings provide important insights for improving the monitoring practice of plastics and illustrate how the epi-plastic community can exacerbate the harmful effects of plastics by dispersal, acting as an alien and toxic species carrier and potentially being ingested through the marine trophic web.


Assuntos
Diatomáceas/crescimento & desenvolvimento , Dinoflagelados/crescimento & desenvolvimento , Monitoramento Ambiental , Toxinas Marinhas/análise , Microalgas/crescimento & desenvolvimento , Plásticos/química , Diatomáceas/isolamento & purificação , Dinoflagelados/isolamento & purificação , Humanos , Microalgas/isolamento & purificação , Resíduos/análise
12.
Molecules ; 23(9)2018 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-30158494

RESUMO

The evolution of regulations concerning biocidal products aimed towards an increased protection of the environment (e.g., EU Regulation No 528/2012) requires the development of new non-toxic anti-fouling (AF) systems. As the marine environment is an important source of inspiration, such AF systems inhibiting the adhesion of organisms without any toxicity could be based on molecules of natural origin. In this context, the antibiofilm potential of tropical microalgal extracts was investigated. The tropics are particularly interesting in terms of solar energy and temperatures which provide a wide marine diversity and a high production of microalgae. Twenty microalgal strains isolated from the Indian Ocean were studied. Their extracts were characterized in terms of global chemical composition by high resolution magic angle spinning (HR-MAS) and nuclear magnetic resonance (NMR) spectroscopy, toxicity against marine bacteria (viability and growth) and anti-adhesion effect. The different observations made by confocal laser scanning microscopy (CLSM) showed a significant activity of three extracts from Dinoflagellate strains against the settlement of selected marine bacteria without any toxicity at a concentration of 50 µg/mL. The Symbiodinium sp. (P-78) extract inhibited the adhesion of Bacillus sp. 4J6 (Atlantic Ocean), Shewanella sp. MVV1 (Indian Ocean) and Pseudoalteromonas lipolytica TC8 (Mediterranean Ocean) at 60, 76 and 52%, respectively. These results underlined the potential of using microalgal extracts to repel fouling organisms.


Assuntos
Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Metanol/farmacologia , Microalgas/química , Oceano Atlântico , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Oceano Índico , Mar Mediterrâneo , Microalgas/isolamento & purificação , Testes de Sensibilidade Microbiana , Microbiologia da Água
13.
Bioprocess Biosyst Eng ; 41(10): 1449-1459, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29946745

RESUMO

Microalgae could be of importance for future biodiesel production as an alternative for a third generation of biofuels. To select the most appropriate strain for biodiesel production, three microalgae species, namely Isochrysis sp., Nannochloropsis maritima and Tetraselmis sp., isolated from Tunisian coast, were biochemically characterized. Initially, gas chromatography analysis showed that Isochrysis sp. and N. maritima contained 5- and 10-fold total fatty acids, respectively, more than Tetraselmis sp. Then, the two microalgae Isochrysis sp. and N. maritima were subject to random mutagenesis using ultraviolet-C radiation. Subsequently, a total of 18 mutants were obtained from both species. The neutral lipid evaluation on said 18 mutants allowed the retention of only 7 to further fatty acid characterization. Finally, gas chromatography revealed that the mutant 5c Isochrysis sp. was characterized by a high level of saturated fatty acids (52.3%), higher amount of monounsaturated fatty acids (29.3%), lower level of polyunsaturated fatty acids (18.4%) and a significant 1.3-fold increase in its C16-C18 content compared to the wild-type strain, which would make it an interesting candidate for biofuel production.


Assuntos
Biocombustíveis , Haptófitas , Metabolismo dos Lipídeos , Lipídeos , Microalgas , Microbiologia da Água , Haptófitas/crescimento & desenvolvimento , Haptófitas/isolamento & purificação , Lipídeos/biossíntese , Lipídeos/química , Microalgas/crescimento & desenvolvimento , Microalgas/isolamento & purificação , Tunísia
14.
Harmful Algae ; 75: 105-117, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29778220

RESUMO

Blooms of ichthyotoxic microalgae pose a great challenge to the aquaculture industry world-wide, and there is a need for fast and specific methods for their detection and quantification in monitoring programs. In this study, quantitative real-time PCR (qPCR) assays for the detection and enumeration of three ichthyotoxic flagellates: the dinoflagellate Karenia mikimotoi (Miyake & Kominami ex Oda) Hansen & Moestrup and the two raphidophytes Heterosigma akashiwo (Hada) Hada ex Hara & Chihara and Fibrocapsa japonica Toriumi & Takano were developed. Further, a previously published qPCR assay for the dinoflagellate Karlodinium veneficum (Ballantine) Larsen was used. Monthly samples collected for three years (Aug 2009-Jun 2012) in outer Oslofjorden, Norway were analysed, and the results compared with light microscopy cell counts. The results indicate a higher sensitivity and a lower detection limit (down to 1 cell L-1) for both qPCR assays. Qualitative and semi-quantitative results were further compared with those obtained by environmental 454 high throughput sequencing (HTS, metabarcoding) and scanning electron microscopy (SEM) examination from the same samplings. All four species were detected by qPCR and HTS and/or SEM in outer Oslofjorden (Aug 2009-Jun 2012); Karlodinium veneficum was present year-round, whereas Karenia mikimotoi, Heterosigma akashiwo and Fibrocapsa japonica appeared mainly during the autumn in all three years. This is the first observation of Fibrocapsa japonica in Norwegian coastal waters. This species has previously been recorded off the Swedish west coast and German Bight, which may suggest a northward dispersal.


Assuntos
Dinoflagelados/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Estramenópilas/isolamento & purificação , Proliferação Nociva de Algas , Toxinas Marinhas/análise , Microalgas/isolamento & purificação , Noruega
15.
Harmful Algae ; 75: 94-104, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29778229

RESUMO

This paper presents a novel portable sample filtration/concentration system, designed for use on samples of microorganisms with very low cell concentrations and large volumes, such as water-borne parasites, pathogens associated with faecal matter, or toxic phytoplankton. The example application used for demonstration was the in-field collection and concentration of microalgae from seawater samples. This type of organism is responsible for Harmful Algal Blooms (HABs), an example of which is commonly referred to as "red tides", which are typically the result of rapid proliferation and high biomass accumulation of harmful microalgal species in the water column or at the sea surface. For instance, Karenia brevis red tides are the cause of aquatic organism mortality and persistent blooms may cause widespread die-offs of populations of other organisms including vertebrates. In order to respond to, and adequately manage HABs, monitoring of toxic microalgae is required and large-volume sample concentrators would be a useful tool for in situ monitoring of HABs. The filtering system presented in this work enables consistent sample collection and concentration from 1 L to 1 mL in five minutes, allowing for subsequent benchtop sample extraction and analysis using molecular methods such as NASBA and IC-NASBA. The microalga Tetraselmis suecica was successfully detected at concentrations ranging from 2 × 105 cells/L to 20 cells/L. Karenia brevis was also detected and quantified at concentrations between 10 cells/L and 106 cells/L. Further analysis showed that the filter system, which concentrates cells from very large volumes with consequently more reliable sampling, produced samples that were more consistent than the independent non-filtered samples (benchtop controls), with a logarithmic dependency on increasing cell numbers. This filtering system provides simple, rapid, and consistent sample collection and concentration for further analysis, and could be applied to a wide range of different samples and target organisms in situations lacking laboratories.


Assuntos
Monitoramento Ambiental/métodos , Filtração/métodos , Proliferação Nociva de Algas , Microalgas/isolamento & purificação , Replicação de Sequência Autossustentável/métodos , Filtração/instrumentação , Fitoplâncton/isolamento & purificação , Água do Mar/análise , Replicação de Sequência Autossustentável/instrumentação
16.
BMC Microbiol ; 18(1): 1, 2018 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-29433435

RESUMO

BACKGROUND: Renewable energy for sustainable development is a subject of a worldwide debate since continuous utilization of non-renewable energy sources has a drastic impact on the environment and economy; a search for alternative energy resources is indispensable. Microalgae are promising and potential alternate energy resources for biodiesel production. Thus, our efforts were focused on surveying the natural diversity of microalgae for the production of biodiesel. The present study aimed at identification, isolation, and characterization of oleaginous microalgae from shola forests of Nilgiri Biosphere Reserve (NBR), the biodiversity hot spot of India, where the microalgal diversity has not yet been systematically investigated. RESULTS: Overall the higher biomass yield, higher lipid accumulation and thermotolerance observed in the isolated microalgal strains have been found to be the desirable traits for the efficient biodiesel production. Species composition and diversity analysis yielded ten potential microalgal isolates belonging to Chlorophyceae and Cyanophyceae classes. The chlorophytes exhibited higher growth rate, maximum biomass yield, and higher lipid accumulation than Cyanophyceae. Among the chlorophytes, the best performing strains were identified and represented by Acutodesmus dissociatus (TGA1), Chlorella sp. (TGA2), Chlamydomonadales sp. (TGA3) and Hindakia tetrachotoma (PGA1). The Chlamydomonadales sp. recorded with the highest growth rate, lipid accumulation and biomass yield of 0.28 ± 0.03 day-1 (µexp), 29.7 ± 0.69% and 134.17 ± 16.87 mg L-1 day-1, respectively. It was also found to grow well at various temperatures, viz., 25 °C, 35 °C, and 45 °C, indicating its suitability for open pond cultivation. The fatty acid methyl ester (FAME) analysis of stationary phase cultures of selected four algal strains by tandem mass spectrograph showed C16:0, C18:1 and C18:3 as dominant fatty acids suitable for biodiesel production. All the three strains except for Hindakia tetrachotoma (PGA1) recorded higher carbohydrate content and were considered as potential feed stocks for biodiesel production through hydrothermal liquefaction technology (HTL). CONCLUSIONS: In conclusion, the present investigation is a first systematic study on the microalgal diversity of soil and water samples from selected sites of NBR. The study resulted in isolation and characterization of ten potent oleaginous microalgae and found four cultures as promising feed stocks for biodiesel production. Of the four microalgae, Chlamydomonadales sp. (TGA3) was found to be significantly thermo-tolerant and can be considered as promising feedstock for biodiesel production.


Assuntos
Biocombustíveis , Microalgas/crescimento & desenvolvimento , Microalgas/isolamento & purificação , Microalgas/metabolismo , Biodiversidade , Biomassa , Carboidratos/análise , Chlorella , Meios de Cultura , Ésteres/análise , Ácidos Graxos/análise , Florestas , Concentração de Íons de Hidrogênio , Índia , Lipídeos/análise , Microalgas/classificação , Filogenia , Proteínas/análise , RNA Ribossômico 18S/genética , Microbiologia do Solo , Temperatura Ambiente , Volvocida , Microbiologia da Água
17.
Bioprocess Biosyst Eng ; 41(4): 519-530, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29299676

RESUMO

Cultivation of microalgae in wastewater is a promising and cost-effective approach for both CO2 biofixation and wastewater remediation. In this study, a new strain of Coelastrum sp. was isolated from cattle manure leachate. The isolated microalgae were then cultivated in wastewater. Effects of different sCOD concentrations (600, 750, 900, 1050 mg L-1) and light intensities (1000, 2300, 4600, 6900 and 10000 Lux) on biomass production, CO2 consumption rate and nutrient removal from wastewater were investigated. The results showed that maximum cell growth and CO2 consumption rate were 2.71 g L-1 and 53.12 mg L-1 day-1, respectively, which were obtained in the wastewater with 750 mg L-1 sCOD and under the light intensity of 6900 Lux. The microalgae were able to completely consume all CO2 after incubation period of 4 days. The highest sCOD, total Kjeldahl nitrogen (TKN), nitrate and total phosphorous (TP) removal at such conditions were 53.45, 91.18, 87.51 and 100%, respectively. The lipid content of microalgal biomass was also measured under different light intensities; maximum amount of lipid was determined to be 50.77% under illumination of 2300 Lux. Finally, the CO2 consumption rate and biomass productivity of microalgae in semi-batch culture with continuous gas flow (CO2 6%:N2 94%) were investigated. The rate of CO2 consumption and biomass productivity were 0.528 and 0.281 g L-1 day-1, respectively. The TKN, nitrate, TP and sCOD removal rate of microalgae were 83.51, 80.91, 100, 41.4%, respectively.


Assuntos
Dióxido de Carbono/metabolismo , Clorófitas/crescimento & desenvolvimento , Lipídeos/biossíntese , Microalgas/crescimento & desenvolvimento , Águas Residuárias/microbiologia , Microbiologia da Água , Microalgas/isolamento & purificação , Purificação da Água/métodos
18.
ISME J ; 12(1): 300-303, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29053151

RESUMO

Physiological performance, disease and bleaching prevalence are often patchy within individual coral colonies. These responses are largely influenced by coral-associated microbes, but how the coral microbiome changes over small spatial scales has never been quantified before. We performed a high-resolution quantification of the spatial scale of microbial species turnover (ß-diversity) within skeletons of boulder-forming Porites corals. We found very strong prokaryotic species turnover across spatial scales ranging from 4 mm to 2 m within individual colonies, possibly resulting from dispersal limitation and microbial interactions. The microalgal community was more homogeneously distributed, which is likely due to these photosymbionts actively boring through limestone. Our findings highlight unprecedented levels of intra-colony heterogeneity in the skeletal microbiome, which has implications for the experimental design of coral microbiome studies and for our understanding of coral resilience.


Assuntos
Antozoários/microbiologia , Microbiota , Animais , Bactérias/isolamento & purificação , Microalgas/isolamento & purificação
19.
Biotechnol Prog ; 34(1): 160-174, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29086506

RESUMO

In this study, shear-induced flocculation modeling of Chlorella sp. microalgae was conducted by combination of population balance modeling and CFD. The inhomogeneous Multiple Size Group (MUSIG) and the Euler-Euler two fluid models were coupled via Ansys-CFX-15 software package to achieve both fluid and particle dynamics during the flocculation. For the first time, a detailed model was proposed to calculate the collision frequency and breakage rate during the microalgae flocculation by means of the response surface methodology as a tool for optimization. The particle size distribution resulted from the model was in good agreement with that of the jar test experiment. Furthermore, the subsequent sedimentation step was also examined by removing the shear rate in both simulations and experiments. Consequently, variation in the shear rate and its effects on the flocculation behavior, sedimentation rate and recovery efficiency were evaluated. Results indicate that flocculation of Chlorella sp. microalgae under shear rates of 37, 182, and 387 s-1 is a promising method of pre-concentration which guarantees the cost efficiency of the subsequent harvesting process by recovering more than 90% of the biomass. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:160-174, 2018.


Assuntos
Chlorella/química , Chlorella/isolamento & purificação , Microalgas/química , Microalgas/isolamento & purificação , Biomassa , Chlorella/genética , Floculação , Microalgas/crescimento & desenvolvimento , Resistência ao Cisalhamento , Software
20.
Trends Biotechnol ; 36(2): 216-227, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29132753

RESUMO

Although microalgae are a promising biobased feedstock, industrial scale production is still far off. To enhance the economic viability of large-scale microalgae processes, all biomass components need to be valorized, requiring a multi-product biorefinery. However, this concept is still too expensive. Typically, downstream processing of industrial biotechnological bulk products accounts for 20-40% of the total production costs, while for a microalgae multi-product biorefinery the costs are substantially higher (50-60%). These costs are high due to the lack of appropriate and mild technologies to access the different product fractions such as proteins, carbohydrates, and lipids. To reduce the costs, simplified processes need to be developed for the main unit operations including harvesting, cell disruption, extraction, and possibly fractionation.


Assuntos
Biotecnologia/economia , Filtração/métodos , Extração Líquido-Líquido/métodos , Microalgas/química , Proteínas de Algas/isolamento & purificação , Biocombustíveis/economia , Biomassa , Biotecnologia/métodos , Carboidratos/isolamento & purificação , Filtração/economia , Floculação , Humanos , Líquidos Iônicos/química , Lipídeos/isolamento & purificação , Extração Líquido-Líquido/economia , Microalgas/crescimento & desenvolvimento , Microalgas/isolamento & purificação , Micro-Ondas , Sonicação/economia , Sonicação/métodos
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