Search results for "photobioreactor"
showing 10 items of 35 documents
Boosting Biomass Quantity and Quality by Improved Mixotrophic Culture of the Diatom Phaeodactylum tricornutum
2021
Diatoms are photoautotrophic unicellular algae and are among the most abundant, adaptable, and diverse marine phytoplankton. They are extremely interesting not only for their ecological role but also as potential feedstocks for sustainable biofuels and high-value commodities such as omega fatty acids, because of their capacity to accumulate lipids. However, the cultivation of microalgae on an industrial scale requires higher cell densities and lipid accumulation than those found in nature to make the process economically viable. One of the known ways to induce lipid accumulation in Phaeodactylum tricornutum is nitrogen deprivation, which comes at the expense of growth inhibition and lower c…
Parameter identification and state estimation of a microalgae dynamical model in sulphur deprived conditions: Global sensitivity analysis, optimizati…
2014
International audience; In this article, a dynamic model describing the growth of the green microalgae Chlamydomonas reinhardtii , under light attenuation and sulphur‐deprived conditions leading to hydrogen production in a photobioreactor is presented. The strong interactions between biological and physical phenomena require complex mathematical expressions with an important number of parameters. This article presents a global identification procedure in three steps using data from batch experiments. First, it includes the application of a sensitivity function analysis, which allows one to determine the parameters having the greatest influence on model outputs. Secondly, the most influentia…
Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella
2019
[EN] Two outdoor photobioreactors were operated to evaluate the effect of variable ambient temperature on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella. Four experiments were carried out in different seasons, maintaining the temperature-controlled PBR at around 25¿°C (by either heating or cooling), while the temperature in the non-temperature-controlled PBR was allowed to vary with the ambient conditions. Temperatures in the range of 15¿30¿°C had no significant effect on the microalgae cultivation performance. However, when the temperature rose to 30¿35¿°C microalgae viability was significantly reduced. Sudden temperature rises triggered AOB growth in the indig…
Novel, automated, semi-industrial modular photobioreactor system for cultivation of demanding microalgae that produce fine chemicals - The next story…
2021
Abstract Recently, there has been increased interest in the use of microorganisms in the production of pharmaceuticals, nutraceuticals and energy supply products, which is due to their rapid growth rate and ability to biosynthesize fine chemicals or biotransform specific xenobiotics. To achieve the desired scale of production and optimization of microbial cultures, it is necessary to design bioreactors that enable process automation, control of working parameters, reduction of microbial and chemical contaminations, and culture independence of climate conditions. In response to this need, an original, modular airlift-type photobioreactor system was designed and manufactured. This novel semit…
Highly effective, regiospecific reduction of chalcone by cyanobacteria leads to the formation of dihydrochalcone: two steps towards natural sweetness
2017
Abstract Background Chalcones are the biogenetic precursors of all known flavonoids, which play an essential role in various metabolic processes in photosynthesizing organisms. The use of whole cyanobacteria cells in a two-step, light-catalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone, is reported. The prokaryotic microalgae cyanobacteria are known to produce phenolic compounds, including flavonoids, as natural components of cells. It seems logical that organisms producing such compounds possess a suitable “enzymatic apparatus” to carry out their biotransformation. Therefore, determination of the ability of whole cells of select…
Preliminary data set to assess the performance of an outdoor membrane photobioreactor
2019
[EN] This data in brief (DIB) article is related to a Research article entitled 'Optimising an outdoor membrane photobioreactor for tertiary sewage treatment' [1]. Data related to the effect of substrate turbidity, the ammonium concentration at which the culture reaches nitrogen-deplete conditions and the microalgae growth rate under outdoor conditions is provided. Microalgae growth rates under different substrate turbidity were obtained to assess the reduction of the culture's light availability. Lab-scale experiments showed growth rates reductions of 22-44%. Respirometric tests were carried to know the limiting ammonium concentration in thismicroalgae-basedwastewater treatment system. Gro…
Mixed microalgae culture for ammonium removal in the absence of phosphorus: Effect of phosphorus supplementation and process modeling
2014
Microalgal growth and ammonium removal in a P-free medium have been studied in two batch photobioreactors seeded with a mixed microalgal culture and operated for 46 days. A significant amount of ammonium (106 mg NH4-Nl(-1)) was removed in a P-free medium, showing that microalgal growth and phosphorus uptake are independent processes. The ammonium removal rate decreased during the experiment, partly due to a decrease in the cellular phosphorus content. After a single phosphate addition in the medium of one of the reactors, intracellular phosphorus content of the corresponding microalgal culture rapidly increased, and so did the ammonium removal rate. These results show how the amount of phos…
Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent
2012
This study investigated the removal of nitrogen and phosphorus from the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) by means of a lab-scale photobioreactor in which algae biomass was cultured in a semi-continuous mode for a period of 42 days. Solids retention time was 2 days and a stable pH value in the system was maintained by adding CO2. Nitrogen and phosphorus concentrations in the SAnMBR effluent fluctuated according to the operating performance of the bioreactor and the properties of its actual wastewater load. Despite these variations, the anaerobic effluent proved to be a suitable growth medium for microalgae (mean biomass productivity was 234 mgl(-1) d(-1)), achie…
Modeling light and temperature influence on ammonium removal by Scenedesmus sp. under outdoor conditions.
2016
[EN] The ammonium removal rate of the microalga Scenedesmus sp. was studied under outdoor conditions. Microalgae were grown in a 500 L flat-plate photobioreactor and fed with the effluent of a submerged anaerobic membrane bioreactor. Temperature ranged between 9.5 WC and 32.5 WC and maximum light intensity was 1,860 μmol·m2·s1. A maximum specific ammonium removal rate of 3.71 mg NH4 þ-N·g TSS1·h1 was measured (at 22.6 WC and with a light intensity of 1,734 μmol·m2·s1). A mathematical model considering the influence of ammonium concentration, light and temperature was validated. The model successfully reproduced the observed values of ammonium removal rate obtained and it is thus p…
Global sensitivity and uncertainty analysis of a microalgae model for wastewater treatment.
2022
The results of a global sensitivity and uncertainty analysis of a microalgae model applied to a Membrane Photobioreactor (MPBR) pilot plant were assessed. The main goals of this study were: (I) to identify the sensitivity factors of the model through the Morris screening method, i.e. the most influential factors; (II) to calibrate the influential factors online or offline; and (III) to assess the model's uncertainty. Four experimental periods were evaluated, which encompassed a wide range of environmental and operational conditions. Eleven influential factors (e.g. maximum specific growth rate, light intensity and maximum temperature) were identified in the model from a set of 34 kinetic pa…