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Hyun Uk Cho, Young Mo Kim, Jong Moon Park
The goal of this study was to investigate the influences of gradually mixotrophic culture conditions on microalgal biomass and lipid production by a consortium of indigenous microalgae and bacteria present in raw municipal wastewater. Lab-scale photobioreactors containing the consortium were operated in repeated batch mode. Initial cultivation (phase I) was performed using only the municipal wastewater, then 10% and 25% of the reactor volumes were replaced with the effluent from a sewage sludge fermentation system producing volatile fatty acids (SSFV) at the beginnings of phase II and phase III, respectively...
December 25, 2016: Bioresource Technology
Ying Pan, Shi-Wei Yan, Ruo-Zhu Li, Yi-Wen Hu, Xue-Xiu Chang
Although the well-known antibiotic norfloxacin (NOR) is recognized as an important environmental pollutant, little is known about its impacts on ecological processes, particularly on species interactions. In this paper, we quantified Daphnia magna (Crustacea, Cladocera) responses in mortality rate at lethal NOR concentrations (0, 25, 50, 100, 200, 300 and 400 mg L(-1)), and in heartbeat rate, swimming behavior and feeding rate (on the green alga Chlorella pyrenoidosa) at sublethal NOR concentrations (0, 25, 50 and 100 mg L(-1)) to determine the effects of this antibiotic in plankton systems...
January 12, 2017: Scientific Reports
Jing Zhu, Uta Goebel
Congratulations to the winners of our cover competition. The first prize goes to the cover of the October issue, which was provided by the authors of the article "Chlorella species as hosts for genetic engineering and expression of heterologous proteins: Progress, challenge and perspective" by Bo Yang, Jin Liu, Yue Jiang and Feng Chen ( Very close by only very few votes followed the July issue cover showing a nice illustration of Aspergillus fungi, which was selected by BTJs Production manager Sigi Mehren and Technical editor Bernadette Gmeiner...
January 2017: Biotechnology Journal
Ekaterina Minaeva, Elena Ermilova
The unicellular green alga Chlorella variabilis NC64A is an endosymbiont of the ciliate Paramecium bursaria. The host's control, including the transfer of biochemical substrates from P. bursaria to C. variabilis, is involved in symbiotic relationships. C. variabilis NC64A that had been re-infected to P. bursaria for more than 1 year and isolated from the host showed higher chlorophyll levels compared to those in free-living cells. Unlike the host, the expression of C. variabilis NC64A heat shock 70 kDa protein was independent of establishment of endosymbiosis...
January 11, 2017: Protoplasma
João Serôdio, William Schmidt, Silja Frankenbach
This work introduces a new experimental method for the comprehensive description of the physiological responses to light of photosynthetic organisms. It allows the integration in a single experiment of the main established manipulative chlorophyll fluorescence-based protocols. It enables the integrated characterization of the photophysiology of samples regarding photoacclimation state (generating non-sequential light-response curves of effective PSII quantum yield, electron transport rate or non-photochemical quenching), photoprotection capacity (running light stress-recovery experiments, quantifying non-photochemical quenching components) and the operation of photoinactivation and photorepair processes (measuring rate constants of photoinactivation and repair for different light levels and the relative quantum yield of photoinactivation)...
January 9, 2017: Journal of Experimental Botany
Asma Ahmed, Nimmakayala Jyothi, Adithya Ramesh
A single step process is proposed for ammonium removal from nitrogenous industrial effluents, with a concomitant generation of algal biomass. A microalgal strain found in the effluent treatment plant of a fertilizer industry in Mumbai, India was systematically adapted to remove up to 700 ppm of ammoniacal nitrogen from industrial wastewater, which is nearly four times higher than the ammonium tolerance reported in the literature as well as other algal strains tested in our laboratory. 18S rRNA sequencing revealed the strain to be Chlorella pyrenoidosa...
January 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
C Venâncio, E Anselmo, A Soares, I Lopes
Within the context of global climate changes, it is expected that low-lying coastal freshwater ecosystems will face seawater intrusion with concomitant increase in salinity levels. Increased salinity may provoke disruption of competitive relationships among freshwater species. However, species may be capable of acclimating to salinity, which, in turn, may influence the resilience of ecosystems. Accordingly, this work aimed at assessing the effects of multigenerational exposure to low levels of salinity in the competitive outcome of two species of green microalgae: Raphidocelis subcapitata and Chlorella vulgaris...
January 7, 2017: Environmental Science and Pollution Research International
K Akhil, S Sudheer Khan
Zinc oxide nanoparticles are one of the most extensively used nanoparticles in various commercial products. Depending on the purpose, the particles are coated with various agents including poly vinyl pyrrolidone, poly vinyl alcohol, ethylene glycol etc. As the particles are heavily used, the chance of the particles to get run off into the environment is very high. The study explains the difference in toxicity of bare and capped zinc oxide nanoparticles under various environmental conditions including humic acid and visible light against bacterial, algal and crustacean system...
December 19, 2016: Journal of Photochemistry and Photobiology. B, Biology
Yoram Gerchman, Barak Vasker, Mordechai Tavasi, Yael Mishael, Yael Kinel-Tahan, Yaron Yehoshua
Microalgae harvesting is a major hurdle in the use of microalgae for oil production. Here we describe the use of a standard cationic polymer used for water treatment, Polydiallyldimethylammonium chloride (PDADMAC), for sedimentation of Chlorella vulgaris and comparison of its flocculation properties with two other polymers, chitosan and Superfloc®. We found PDADMAC to be the most effective flocculant with 90% of the algae flocculating at concentrations as low as 5mg/L within 60min, and good activity even at pH=10...
December 21, 2016: Bioresource Technology
Anna E M F M Oliveira, Jonatas L Duarte, Rodrigo A S Cruz, Raimundo N P Souto, Ricardo M A Ferreira, Taires Peniche, Edemilson C da Conceição, Leandra A R de Oliveira, Silvia M M Faustino, Alexandro C Florentino, José C T Carvalho, Caio P Fernandes
BACKGROUND: Preparation of nanoformulations using natural products as bioactive substances is considered very promising for innovative larvicidal agents. On this context, oil in water nanoemulsions develop a main role, since they satisfactorily disperse poor-water soluble substances, such as herbal oils, in aqueous media. Pterodon emarginatus, popularly known as sucupira, has a promising bioactive oleoresin. However, to our knowledge, no previous studies were carried out to evaluate its potential against Culex quinquefasciatus, the main vector of the tropical neglected disease called lymphatic filariasis or elephantiasis...
January 3, 2017: Journal of Nanobiotechnology
Alireza Moosavi Zenooz, Farzin Zokaee Ashtiani, Reza Ranjbar, Fatemeh Nikbakht, Oberon Bolouri
Biodiesel production from microalgae feedstock should be performed after growth and harvesting of the cells and the most feasible method for harvesting and dewatering of microalgae is flocculation. Flocculation modeling can be used for evaluation and prediction of its performance under different affective parameters. However, the modeling of flocculation in microalgae is not simple and has not performed yet, under all experimental conditions, mostly due to different behaviors of microalgae cells during the process under different flocculation conditions...
January 3, 2017: Preparative Biochemistry & Biotechnology
Patricio López Expósito, Angeles Blanco Suárez, Carlos Negro Álvarez
Fast and reliable methods to determine biomass concentration are necessary to facilitate the large scale production of microalgae. A method for the rapid estimation of Chlorella sorokiniana biomass concentration was developed. The method translates the suspension particle size spectrum gathered though laser reflectance into biomass concentration by means of two machine learning modelling techniques. In each case, the model hyper-parameters were selected applying a simulated annealing algorithm. The results show that dry biomass concentration can be estimated with a very good accuracy (R(2)=0...
December 29, 2016: Journal of Biotechnology
Lin Zhou, Dujia Cheng, Liang Wang, Juan Gao, Quanyu Zhao, Wei Wei, Yuhan Sun
The growth of microalgae is inhibited by high concentration phenol due to reactive oxygen species. An evolved strain tolerated to 500mg/L phenol, Chlorella sp. L5, was obtained in previous study. In this study, comparative transcriptomic analysis was performed for Chlorella sp. L5 and its original strain (Chlorella sp. L3). The tolerance mechanism of Chlorella sp. L5 for high concentration phenol was explored on genome scale. It was identified that the up-regulations of the related genes according to antioxidant enzymes (SOD, APX, CAT and GR) and carotenoids (astaxanthin, lutein and lycopene) biosynthesis had critical roles to tolerate high concentration phenol...
March 2017: Bioresource Technology
Jian Zhao, Xuesong Cao, Zhenyu Wang, Yanhui Dai, Baoshan Xing
We systematically investigated the toxicity mechanism of three graphene-family materials (GFMs), graphene oxide (GO), reduced graphene oxide (rGO) and multi-layer graphene (MG), to algae (Chlorella pyrenoidosa). GFMs exhibited much higher toxicity than other carbon materials (carbon nanotube and graphite), with the 96 h median effective concentration (EC50) values of 37.3 (GO), 34.0 (rGO), and 62.2 (MG) mg/L. Shading effect contributed approximately 16.4% of growth inhibition by GO due to its higher dispersibility and transformation while the other GFMs did not show any shading effect...
December 23, 2016: Water Research
Y K Wong, Y H Ho, H M Leung, K C Ho, Y H Yau, K K L Yung
This article explores the potential of using an electro-coagulation-flotation (ECF) harvester to allow flotation of microalgae cells for surface harvesting. A response surface methodology (RSM) model was used to optimize ECF harvesting by adjusting electrode plate material, electrode plate number, charge of the electrodes, electrolyte concentration, and pH value of the culture solution. The result revealed that three aluminum electrode plates (one anode and two cathodes), brine solution (8 g/L), and acidity (pH = 4) of culture solution (optimized ECF harvester) The highest flocculant concentration was measured at 2966 mg/L after 60 min and showed a 79...
December 30, 2016: Environmental Science and Pollution Research International
Jayaseelan Murugaiyan, Murat Eravci, Christoph Weise, Uwe Roesler
Microalgae of the genus Prototheca (P.) spp are associated with rare algal infections of invertebrates termed protothecosis. Among the seven generally accepted species, P. zopfii genotype 2 (GT2) is associated with a severe form of bovine mastitis while P. blaschkeae causes the mild and sub-clinical form of mastitis. The reason behind the infectious nature of P. zopfii GT2, while genotype 1 (GT1) remains non-infectious, is not known. Therefore, in the present study we investigated the protein expression level difference between the genotypes of P...
December 29, 2016: International Journal of Molecular Sciences
Prathana Ramsundar, Abhishek Guldhe, Poonam Singh, Faizal Bux
Wastewater utilization for microalgal biomass production is potentially the most economical route for its fuel and feed applications. In this study, suitability of various wastewater streams within a domestic wastewater treatment plant was evaluated for microalgal cultivation. Pre-treatment methods were evaluated to minimize bacterial load. Biomass, cell physiology, nutrient removal efficiencies and biochemical constituents of Chlorella sorokiniana were investigated in influent (INF) and anaerobic tank centrate (AC) under mixotrophic (Mixo) and heterotrophic (Hetero) cultivation...
March 2017: Bioresource Technology
Veronica da Silva Ferreira, Mateus Eugenio ConzFerreira, Luís Maurício T R Lima, Susana Frasés, Wanderley de Souza, Celso Sant'Anna
Silver nanoparticles are powerful antimicrobial agents. Here, the synthesis of silver chloride nanoparticles (AgCl-NPs) was consistently evidenced from a commercially valuable microalgae species, Chlorella vulgaris. Incubation of C. vulgaris conditioned medium with AgNO3 resulted in a medium color change to yellow/brown (with UV-vis absorbance at 415nm), indicative of silver nanoparticle formation. Energy-dispersive X-ray spectroscopy (EDS) of purified nanoparticles confirmed the presence of both silver and chlorine atoms, and X-ray diffraction (XRD) showed the typical pattern of cubic crystalline AgCl-NPs...
February 2017: Enzyme and Microbial Technology
Josh Baker, Dirk Wallschläger
A freshwater microalga, Chlorella vulgaris, was grown in the presence of varying phosphate concentrations (<10-500μg/L P) and environmentally realistic concentrations of arsenate (As(V)) (5-50μg/L As). Arsenic speciation in the culture medium and total cellular arsenic were measured using AEC-ICP-MS and ICP-DRC-MS, respectively, to determine arsenic biotransformation and uptake in the various phosphorus scenarios. At high phosphate concentration in the culture medium, >100μg/L P, the uptake and biotransformation of As(V) was minimal and dimethylarsonate (DMAs(V)) was the dominant metabolite excreted by C...
November 2016: Journal of Environmental Sciences (China)
Ramachandran Sivaramakrishnan, Aran Incharoensakdi
The efficiency of oil extraction from Chlorella sp. and Scenedesmus sp. using different cell disruption and solvent system was investigated. The ultrasound cell disruption method showed the maximum oil extraction in both algae. Oil extraction with hexane resulted in maximum oil yield for both algae. The kinetic parameters were studied and the extraction followed the first-order kinetics. The activation energy and thermodynamic activation parameters were calculated for both microalgae and the results suggested that the extraction was endothermic, irreversible and spontaneous...
December 19, 2016: Environmental Science and Pollution Research International
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