Search results for "Chlorella"
showing 9 items of 39 documents
Identifying a marine microalgae with high carbohydrate productivities under stress and potential for efficient flocculation
2018
Microalgal biomass represents a potential third generation feedstock that could be utilised as a source of carbohydrates for fermentative production of a range of platform biochemicals. Identifying microalgal strains with high biomass and carbohydrate productivities while also being amenable to downstream processes is key in improving the feasibility of these processes. Utilising marine microalgae capable of growing in seawater will decrease reliance on freshwater resources and improve the sustainability of production. This study screened several marine microalgae believed to accumulate carbohydrates to find new high performing strains. Four strains had high growth rates and accumulated car…
Cultivation and biochemical characterization of isolated Sicilian microalgal species in salt and temperature stress conditions
2021
Abstract In the last years, the possibility to exploit autochthone microalgae in regional applications has been explored. The regional-based microalgal industry may bring several benefits, as autochthone microalgae are already adapted to the biotic and abiotic stresses of their environment. In this work, this concept was applied to Sicily, in which three microalgal strains were collected from the coastline. Monoalgal strains were then isolated and molecular characterization was performed for the species determination. Three of them, two strains of Chlorella and one of Dunaliella, were cultivated in lab-scale in four different conditions: Low Temperature-Low Salt (LT-LS), High-Temperature-Lo…
Non-hydrolysable macromolecular constituents from outer walls of Chlorella fusca and Nanochlorum eucaryotum
1992
Abstract Many green microalgae possess a thin trilaminar outer wall (TLS) with a very high resistance to chemical degradation. TLS are known to play an important protective role in living cells. They are also selectively preserved during fossilization and thus provide a major contribution to the fossil organic matter of a number of sedimentary rocks. However, little information is available on TLS chemical structure. Examination of the TLS of Chlorella fusca (a lacustrine Chlorophycea) and of Nanochlorum eucaryotum (a recently discovered marine Chlorophycea) indicated that (i) they exhibit morphological features commonly observed in other green microalgae, (ii) their non-hydrolysable macrom…
Population Dynamic of Algae and Bacteria in an Oxidation Channel
2003
A study on algae and bacteria population changes, as a function of time, was carried out in a pilot scale oxidation channel bioreactor using a carrousel system. Total Coliforms, Pseudomonas aeruginosa, and Streptococcus faecalis, the most common bacteria found in sewage, Scenedesmus obliquus and Chlorella vulgaris were the microalgae considered in this work. Physicochemical parameters such as COD, BOD, Chlorophyll a, nitrogen, and phosphorous compounds were studied and determined during the experiments. It was demonstrated that the level of wastewater contamination could be predicted based on the bacterial and algae composition. The relationships between the algae and bacteria population, a…
Assessment of cross-flow filtration as microalgae harvesting technique prior to anaerobic digestion: Evaluation of biomass integrity and energy demand
2018
[EN] In the present study, the effect of cross-flow filtration (CFF) on the overall valorization of Chlorella spp. microalgae as biogas was assessed. The effect of CFF on microalgae cell integrity was quantified in terms of viability which was correlated with the anaerobic biodegradability. The viability dropped as the biomass concentration increased, whereas anaerobic biodegradability increased linearly with the viability reduction. It was hypothesized that a stress-induced release and further accumulation of organic polymers during CFF increased the flux resistance which promoted harsher shear-stress conditions. Furthermore, the volume reduction as the concentration increased entailed an …
Biodiesel via in situ wet microalgae biotransformation: Zwitter-type ionic liquid supported extraction and transesterification
2017
The production of biodiesel derived from microalgae is among the most forthcoming technologies that provide an ecologic alternative to fossil fuels. Herein, a method was developed that enables the direct extraction and conversion of algal oil to biodiesel without prior isolation. The reaction occurs in aqueous media catalyzed by immobilized Candida antarctica lipase B (Novozyme 435). Zwitter-type ionic liquids were used as cocatalyst to improve the selectivity and reactivity of the enzyme. In a model reaction with sunflower oil, 64% biodiesel was obtained. Applying this method to a slurry of whole-cell Chlorella zof ingiensis in water resulted in 74.8% of lipid extraction, with 27.7% biotra…
Antioxidant Potential of Extracts Obtained from Macro- (Ascophyllum nodosum, Fucus vesiculosus and Bifurcaria bifurcata) and Micro-Algae (Chlorella v…
2018
Background: Natural antioxidants, which can replace synthetic ones due to their potential implications for health problems in children, have gained significant popularity. Therefore, the antioxidant potential of extracts obtained from three brown macroalgae (Ascophyllum nodosum, Fucus vesiculosus and Bifurcaria bifurcata) and two microalgae (Chlorella vulgaris and Spirulina platensis) using ultrasound-extraction as an innovative and green approach was evaluated. Methods: Algal extracts were obtained by ultrasound-assisted extraction using water/ethanol (50:50, v:v) as the extraction solvent. The different extracts were compared based on their antioxidant potential, measuring the extraction …
Catalytic Conversion of Glucose and Chlorella sp. into Furans in the Presence of Niobium Oxide
2023
A series of Nb2O5 solid catalysts have been prepared to be used for the catalytic dehydration of glucose and sugars from algae Chlorella sp. into added value furans. The glucose transformation gave rise to 5-hydroxymethylfurfural (5-HMF). Chlorella sp. was used in the same catalytic conditions to be valorised to furans. By preliminary studies we concluded that the algae aqueous suspension needed a previous treatment in the presence of SiO2 pellets to liberate the carbohydrates that in the catalytic reaction in the presence of Nb2O5 materials gave rise 5-HMF and furfural. The best operative conditions and Nb2O5 catalysts were individuated. The most performant Nb2O5 catalyst also showed an ex…
Kinetic of the Sewage Treatment: The Consumption of Organic Carbon of The Microalga Chlorella sp
2023
As well known, microalgae are eukaryotic or procaryotic microorganisms able to photosynthesize, namely transforming inorganic substrates and sun light into organic compounds and chemical energy. They result very promising in treating civil wastewaters thanks to their ability to employ nitrates and phosphates as nutrients (Lima et al., 2019). Autotrophic microalgae are, anyway, not useful in decreasing the organic carbon content of wastewaters, and for this reason, they cooperate with heterotrophic bacteria. The usefulness of microalgaebacteria consortia in treating wastewaters and the ratio of their inoculum was investigated in a previous work (Lima, 2022a). Contrarily to autotrophic microa…