Biomedical subjects

Jorge Alberto Vieira Costa

Publications and source records attributed to Jorge Alberto Vieira Costa.

6 recordsLinked to original sources

PubMed2006

Production of biomass and nutraceutical compounds by Spirulina platensis under different temperature and nitrogen regimes.

The cyanobacterium Spirulina platensis has been used by humans because of its nutritional and possibly medicinal effects. Our study evaluated the influence of temperature and nitrogen concentration in the medium on the production of biomass by this cyanobacterium and the biomass composition in protein, lipid and phenolic compounds. We found that at 35 degrees C there was a negative effect on biomass production but a positive effect on the production of protein, lipids and phenolics, the highest levels of these compounds being obtained in Zarrouk's medium containing 1.875 or 2.500 g l(-1) sodium nitrate. Higher biomass densities and productivity were obtained at 30 degrees C than at 35 degrees C, but nitrogen concentration appeared to have no effect on the amount of protein, lipid or phenolics, indicating that at 30 degrees C the concentration of sodium nitrate in Zarrouk's medium (2.50 g l(-1)) can be reduced without loss of productivity, an important cost-saving factor in large-scale cultivation.

Acids, Carbocyclic↗

PubMed2004

Improving Spirulina platensis biomass yield using a fed-batch process.

Increasing interest is being shown in the cyanobacterium Spirulina platensis because of its nutritional properties when used as food supplement and possible therapeutic effects. One of the most important areas being studied is the development of alternative nutrient sources which can be used to decrease the production costs of commercially produced S. platensis and obtain high productivity. Water from Mangueira Lagoon (Rio Grande do Sul State, Brazil) has high levels of carbonates and a high pH and has the potential to be used as a culture medium for S. platensis, although some nutrient supplementation may be required. We tested the effect of unsupplemented Mangueira Lagoon water (MLW) or MLW supplemented with 1.125 or 2.250 mg/l of urea and/or 21 or 42 mg/l of sodium bicarbonate on the growth of S. platensis in fed-batch culture using a 3(2) factorial design and found that there the addition of 1.125 mg/l of urea resulted in a 2.67 fold increase times in the final biomass concentration of S. platensis.

Bacterial Proteins↗

PubMedDate not supplied

Spirulina platensis growth in open raceway ponds using fresh water supplemented with carbon, nitrogen and metal ions.

To investigate the feasibility of using fresh water from Mangueira Lagoon (Rio Grande do Sul, Brazil) for biomass production in open raceway ponds (0.7 m long, 0.18 m wide, 0.075 m deep) we studied the influence of nutrient addition (carbon as sodium bicarbonate, nitrogen as urea, phosphate, sulfate, ferric iron, magnesium and potassium) on the growth rate of the cyanobacteria Spirulina platensis using a 22 factorial design. In unsupplemented lagoon water production of S platensis was 0.78 +/- 0.01 g/l (dry weight basis) while the addition of 2.88 g/l of sodium bicarbonate (without added urea, phosphate, sulfate or metal ions) resulted in 0.82 +/- 0.01 g/l after 400 hours of culture. The further addition of phosphate and metal ions resulted in growth for up to 750 h and a final S. platensis biomass of 1.23 +/- 0.04 to 1.34 +/- 0.03 g/l.

Brazil↗

PubMedDate not supplied

Fatty acids profile of Spirulina platensis grown under different temperatures and nitrogen concentrations.

The influence of culture temperature and the concentration of sodium nitrate (NaNO3) on the gas-chromatographic profile of the fatty acids of the filamentous cyanobacterium Spirulina platensis was evaluated. We found that temperature was the most important factor and that the greatest amount of gamma-linolenic acid (GLA) was obtained at 30 degrees C, the fatty acid profile of the Spirulina cultivated showing that (in order of abundance) palmitic, linolenic and linoleic acids were most prevalent.

Analysis of Variance↗

PubMedDate not supplied

Simultaneous cultivation of Spirulina platensis and the toxigenic cyanobacteria Microcystis aeruginosa.

Mangueira Lagoon, located in the extreme south of Brazil, has water with physicochemical characteristics such as alkaline pH and carbonate levels propitious for the growth of the cyanobacterium Spirulina platensis. Previously published studies have shown that Mangueira Lagoon water supplemented with small quantities of carbon and nitrogen is suitable for S. platensis cultivation and can significantly reduce production costs. We studied mixed cultures of Spirulina platensis and the toxic cyanobacterium Microcystis aeruginosa using a 2(3) factorial design in which the three factors were the initial biomass concentration of S. platensis and M. aeruginosa and the type of culture medium (100% Zarrouk's medium or 80% Mangueira Lagoon water plus 20% Zarrouk's medium). The highest S. platensis maximum specific growth rate (mu(max)) occurred in the culture with the highest M. aeruginosa biomass concentration and when undiluted culture medium was used (micro(max) = 0.283 d(-1)). The highest M. aeruginosa specific death rate (k) was obtained in the presence of S. platensis (k = 0.555 d(-1)) and was independent of the initial M. aeruginosa biomass concentration and culture medium, demonstrating that S. platensis cultures are not susceptible to contamination by M. aeruginosa. The culture medium had no significant influence (p > 0.05) on S. platensis micro(max) values, indicating that production costs could be reduced by using a medium consisting of 80% Mangueira Lagoon water plus 20% Zarrouk's medium.

Biomass↗

PubMedDate not supplied

Solid state biosurfactant production in a fixed-bed column bioreactor.

Biosurfactants are surface active substances which reduce interfacial tension and are produced or excreted at the microbial cell surface. We evaluated the biosurfactant production by Aspergillus fumigatus and Phialemonium sp. in solid state processes using fixed-bed column reactors. We evaluated two media, rice husks alone (simple support) and rice husks plus defatted rice bran (complex support), both enriched with either soy oil or diesel oil. The highest water-in-oil emulsifying activity (EAw/o) obtained was 7.36 EU g(-1) produced by A. fumigatus growing on complex support enriched with soy oil and supplied with air at a rate of 60 mL g(-1) h(-1), while Phialemonium sp. had a maximum production of 6.11 EU g(-1) using the simple support with diesel oil and an aeration rate of 120 mL g(-1) h(-1). The highest oil-in-water emulsifying activity (EAo/w) was 12.21 EU g(-1) produced by Phialemonium sp. on the complex support enriched with diesel oil and at an aeration rate of 60 mL g(-1) h(-1), while A. fumigatus produced a maximum EAo/w of 10.98 EU g(-1) when growing on the complex support with no additional carbon source and an aeration rate of 60 mL g(-1) 1 h(-1).

Aspergillus fumigatus↗