485 research outputs found
Study of up- and downstream processes in Microcystis aeruginosa cultivation - One approach, two distinct objectives
BioTech 2017 and 7th Czech-Swiss Symposium with Exhibition[Excerpt] The cyanobacterium Microcystis aeruginosa and the accumulation of its cyanotoxin microcystin (MC) have been responsible for several human/animal deaths and intoxication incidents. Therefore, the World Health Organization established recommendation values for MC in water, givingrisetoanincreasingdemandforMC’s analytical standards to be used as laboratory standards both in human and environmental risk assessment studies. These Cyanotoxinsarealsoconsideredpromising anticancer/antitumor drugs as well as antifungal, antialgal and insecticide agents. Despite the interest, commercial MC availability is still limited due to constraints found in production, which inflate the final price to values as high as 28000 e/mg. [...]info:eu-repo/semantics/publishedVersio
Optimization of Microcystis aeruginosa cell disruption to enhance microcystin extraction and purification processes
[Excerpt] Worldwide occurrence of cyanobacterium Microcystis aeruginosa and accumulation of its hepatotoxin microcystin (MC) have been responsible for several incidents, leading the World Health Organization to implement guideline values for this toxin in water thus boosting the demand for MC’s analytical standards. Furthermore, cyanotoxins are also considered promising anticancer/antitumor drugs as well as antifungal, antialgal and insecticide agents. Consequently, the U.S. Environmental Protection Agency has introduced cyanotoxins in its list of substances to be studied as a precursor to regulatory action between 2018 and 2020. [...]info:eu-repo/semantics/publishedVersio
Assessment of synergistic interactions between environmental factors on Microcystis aeruginosa growth and microcystin production
The combined effect of four abiotic factors on Microcystis aeruginosa growth and toxin production was assessed by culturing the cyanobacterium under different light intensities (10190 mol photons·m 2·s 1), CO2 concentrations (010% (v/v)), temperatures (1540 °C), and pH values (6.59.5). Results indicate a significant influence caused by the synergistic effect of environmental factors over growth-related parameters and cyanobacteria toxicity. The combined use of low to medium light intensities (50120 mol photons·m 2·s 1) and CO2 concentration (16% v/v) led to higher cell concentrations, while specific growth rate and biomass productivity were favoured by medium to high light intensities (110190 mol photons·m 2·s 1), CO2 concentrations (49.5% v/v) and temperatures (2939 °C). Regarding microcystin (MC) production, higher concentrations were obtained at low light intensities and low CO2 concentrations while approximately 2000-fold lower MC concentrations were achieved by simultaneous use of high values of light intensity, CO2 concentration and temperature.info:eu-repo/semantics/publishedVersio
Pathway for cyanotoxin valorization: microscystin as case study
Book of Abstracts of CEB Annual Meeting 2017info:eu-repo/semantics/publishedVersio
Comparison of harvesting methods for the cyanobacteria Microcystis aeruginosa
BioTech 2017 and 7th Czech-Swiss Symposium with ExhibitionMicrocystis aeruginosa is a wellknown
cyanobacterium that has been
spreading all over the world due to increased
temperatures and eutrophication of water
bodies caused by intensive anthropogenic
activities. This toxin-producing microorganism
is frequently responsible for diminishing
water quality and causing intoxication
of humans and animals. Due to
this, its intracellular cyanotoxin – microcystin
(MC) – is commonly used as tool
for molecular and cell biology studies
or as a standard in human and environmental
risk assessment assays. Moreover,
MC is a promising anticancer/antitumor
drug candidate and a possible antimicrobial,
antifungal, antialgal and insecticide
agent. Despite MC’s potential application
in several biotechnological fields, its high
production costs significantly contribute
for the prohibitive selling prices (28000
e/mg). Thus, improvements in process’
cost-effectiveness is needed, especially in
terms of downstream processing techniques
which are probably the major bottlenecks
of cyanobacteria production at large scale, commonly representing 20-30 % of
the total costs.
Bearing this in mind, this study aimed
at optimizing harvesting of M. aeruginosa
induced by pH change and compares the
optimal conditions obtained with the use
of three different flocculant agents: chitosan,
ferric chloride, and aluminium chloride.
Harvesting induced by pH was assessed
by testing pH values ranging between
2 and 14. Despite the fact that harvesting
efficiencies above 90 % were obtained
for most pH values, pH 2 was the one
where higher sedimentation rate was observed
and consequently the chosen method
to compare with the three flocculants. Aluminium
chloride addition was found to be
the most efficient method, reaching 93 %
of sedimentation efficiency within the first
2 h. These results are in agreement with
zeta potential measurements where cells
presented nearly neutral (approx. 0 mV)
charge, while positive or negative charges
where achieved using the other three methodologies.This research work was supported by the grant SFRH/BPD/98694/2013 (Bruno Fernandes) and SFRH/BD/52335/2013 (Pedro Geada) from Fundação para a Ciência e a Tecnologia (Portugal). Luís Loureiro is recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), Project UID/Multi/04423/2013, Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), FCT Strategic Project of UID/BIO/04469/2013 unit, by the project NOVELMAR (reference NORTE-01-0145-FEDER-000035), co-financed by the North Portugal Regional Operational Programme (Norte 2020) under the National Strategic Reference Framework (NSRF), through the ERDF, and by BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio
Valorization of toxic cyanobacteria biomass - disruption efficiency assessment and consequent bioproduct availability using different disruption techniques
The worldwide occurrence of hepatotoxic cyanobacterium Microcystis aeruginosa and
accumulation of its toxin microcystin-LR, have been responsible for several human deaths and
animal intoxication incidents. In recognition to its toxicity, the World Health Organization and
several national governments established guideline values for this toxin in water, which gave rise
to an increasing demand for microcystin′s analytical standards. These standards might be useful
either as laboratory standards to apply in human and environmental risk assessment or as tools
for molecular and cell biology studies. However, their availability is still limited due to
constraints found in production and purification processes, which inflate the final price to values
as high as 28000 €/mg. As an example of the increasing interest observed over the last years,
U.S. Environmental Protection Agency has recently announced that cyanotoxins became part of
its list of substances to be studied as a precursor to regulatory action between 2018 and 2020.
Consequently, the optimization of this cyanobacterium cultivation and toxin purification
techniques is needed to decrease the production cost of such high added-value product. In
biotechnological industrial scale processes, the costs associated with downstream processing
often represent more than 60 % of the overall expenses.
The aim of this work is therefore to provide an insight regarding the development of a costeffective
process for obtaining high-quality and affordable microcystin-LR by evaluating the
efficiency of three different methodologies (microwave, freeze-thaw cycles and bead mill) on the
disruption of M. aeruginosa and consequent availability of bioproducts. For that purpose, several
parameters including time, power, and temperature were tested. The best conditions determined
for each extraction method were the following: i) 1.5 minutes at 800 W (microwave), ii) three 12-
hour cycles at -20 ºC (freeze-thaw cycles), and iii) 7 minutes using 20 % (v/v) of glass beads (bead
mill). According to cell counting and intracellular organic matter release determining techniques,
freeze-thaw cycles have shown to be the best disruption method presenting an overall efficiency
around 97 %
Enhancing extraction of food-grade pigments from the microalgae Chlorella Vulgaris through application of ohmic heating
[Excerpt] Introduction: The use of ohmic heating (OH) with the associated non-thermal effects due to the presence of an electrical field and frequency, has been suggested for extraction of compounds from biological matrices. Microalgae are considered as a very valuable source of compounds of interest for food sector (i.e. pigments, lipids, carbohydrates, and proteins) and the selection of extraction technique to recover these compounds is very challenging due to the intrinsic nature of the microalgae cell walls, which limits the mass transfer through it. The main objective of this study is to investigate the effects of OH on the extraction of pigmented solutes from Chlorella vulgaris. [...
Assessment of cell disruption efficiency of Microcystis aeruginosa using different mechanical techniques
This research work was supported by the grant SFRH/BPD/98694/2013 (Bruno Fernandes) and
SFRH/BD/52335/2013 (Pedro Geada) from Fundação para a Ciência e a Tecnologia (Portugal). Luís Loureiro is
recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the
European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. This study
was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the
strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), Project
UID/Multi/04423/2013, Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), FCT Strategic
Project of UID/BIO/04469/2013 unit, by the project NOVELMAR (reference NORTE-01-0145-FEDER-000035),
co-financed by the North Portugal Regional Operational Programme (Norte 2020) under the National Strategic
Reference Framework (NSRF), through the ERDF, and by BioTecNorte operation (NORTE-01-0145-FEDER000004)
funded by the European Regional Development Fund under the scope of Norte2020 - Programa
Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio
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