Luciane Maria Colla

Modelling of Spirulina platensis growth in fresh water using response surface methodology

The influence of nutrient addition on the growth rate of Spirulina platensis in the Mangueira Lagoon water was studied in order to investigate the feasibility of using this water for biomass production. The addition of urea and sodium bicarbonate was studied through surface response methodology, over concentration ranges from 0.0 to 0.01170 M, and 0.0–19.70 gl−1 respectively. The growth of Spirulina platensis in Mangueira Lagoon water with no addition of nutrients was carried out and compared with the biomass growth after nutrient addition. The results indicated that the optimal level of nutrients was 0.00585 M urea and without the addition of sodium bicarbonate. The biomass concentration was 1.4 gl−1 in 780 h of cultivation and the doubling time (td) was 3.85 days. In 300 h, the biomass concentration in the medium without nutrient addition was 0.9 gl−1, with a doubling time of 3.80 days.

Simultaneous production of lipases and biosurfactants by submerged and solid-state bioprocesses.

Lipases and biosurfactants are compounds produced by microorganisms generally involved in the metabolization of oil substrates. However, the relationship between the production of lipases and biosurfactants has not been established yet. Therefore, this study aimed to evaluate the correlation between production of lipases and biosurfactants by submerged (SmgB) and solid-state bioprocess (SSB) using Aspergillus spp., which were isolated from a soil contaminated by diesel oil. SSB had the highest production of lipases, with lipolytic activities of 25.22U, while SmgB had 4.52U. The production of biosurfactants was not observed in the SSB. In the SmgB, correlation coefficients of 91% and 87% were obtained between lipolytic activity and oil in water and water in oil emulsifying activities, respectively. A correlation of 84% was obtained between lipolytic activity and reduction of surface tension in the culture medium. The surface tension decreased from 50 to 28mNm(-1) indicating that biosurfactants were produced in the culture medium.

Spirulina platensis effects on the levels of total cholesterol, HDL and triacylglycerols in rabbits fed with a hypercholesterolemic diet

ABSTRACT In this work, hypercholesterolemia was induced in rabbits by feeding them a high cholesterol diet (CD, 350 mg/d) and the effects of supplementing this diet with 0.5 g/d Spirulina platensis was evaluated by measuring the levels of serum total-cholesterol (TC), triacylglycerols (TAG) and high-density lipoprotein (HDL-cholesterol) at the start of the experiment and after 30 d and 60 d. It was found that the levels of serum cholesterol decreased from 1,054±101 mg.dL -1 in the rabbits fed a CD without S. platensis to 516±163 mg.dL -1 to those fed with a high cholesterol diet supplemented with S. platensis (significant at p <0.0001). The addition of Spirulina to the cholesterolemic diet did not cause significative decrease on the levels of triacylglycerols in the animals. The levels of serum high-density lipoprotein (HDL-cholesterol) was 73±31 mg.dL -1 for rabbits fed a CD without S. platensis as compared to 91.0±15.7 mg.dL -1 in those fed a CD supplemented with S. platensis (significant at p=0.1533) Key words: Spirulina platensis , cholesterol, rabbits

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

Cultivation of microalgae Spirulina platensis (Arthrospira platensis) from biological treatment of swine wastewater.

The microalgae biomass production from swine wastewater is a possible solution for the environmental impact generated by wastewater discharge into water sources. The biomass can be added to fish feed, which can be used in the formulation of meat products. This work addresses the adaptation of the microalgae Spirulina platensis (Arthrospira platensis) in swine wastewater and the study of the best dilution of the wastewater for maximum biomass production and for removal of Chemical Oxygen Demand (COD), ammonia and phosphorous to the microalgae. The cultivation of Spirulina platensis, strain Paracas presented maximum cellular concentrations and maximum specific growth rates in the wastewater concentration of 5.0 and 8.5%. The highest COD removals occurred with 26.5 and 30.0% of wastewater in the medium. The maximum removal of total phosphorous (41.6%), was with 8.5% of wastewater, which is related to the microalgae growth. The results of Spirulina culture in the swine wastewater demonstrated the possibility of using these microalgae for the COD and phosphorous removal and for biomass production.

Effect of microalga Spirulina platensis (Arthrospira platensis) on hippocampus lipoperoxidation and lipid profile in rats with induced hypercholesterolemia.

ABSTRACT Studies have been conducted on microalga Spirulina platensis ( Arthrospira platensis ) due to its therapeutic potential in several areas, including the capacity for preventing and decreasing the damages caused by hyperlipidemia and the antioxidant activity. The aim of the study was to evaluate the effect of microalga Spirulina platensis on hippocampus lipoperoxidation and lipid profile in rats with induced hypercholesterolemia during 60 days. The measurement of hippocampus lipoperoxidation did not demonstrate significant difference (p>0.05) when Spirulina platensis was added to hypercholesterolemic diet. The evaluation of lipid profile showed that the administration of the microalga in therapeutic and preventive ways led to a significant protective effect (p<0.05) from hypercholesterolemia. Key words: Spirulina , Arthrorspira , lipids, cholesterol, antioxidant * Author for correspondence: telma@upf.br INTRODUCTION The alteration of plasma cholesterol and triglycerides levels may result in dyslipidemias and lead to the occurrence of cardiovascular diseases, mainly atherosclerosis. The oxidation of LDL (low-density lipoprotein) is indicated as a cause of atherosclerosis. Factors capable of avoiding this oxidation and modifying the quantities of lipoproteins constitute a way of decreasing the formation of the atherosclerotic plaque (Peruguini et al., 2000). Epidemiological and clinical studies established an inverse relation between the intake of compounds with anti-oxidant effects and the incidence of chronic diseases, like the cardiovascular ones (Belay, 2002). The microalga Spirulina (Arthrospira ) has been studied extensively due to its therapeutic potential in several areas, including the capacity of preventing and decreasing the damages caused by hyperlipidemia and the antioxidant activity (Belay, 2002). S. platensis is a photoautotrophic filamentous cyanobacterium used mainly as food supplement (Henrikson, 1994) because it has proteins (55-70%), sugars (12-25%), essential fatty acids (18%), vitamins, and minerals in its chemical constitution (Sanchez et al ., 2003). Spirulina

Surface response methodology for the optimization of lipase production under submerged fermentation by filamentous fungi

A Plackett–Burman Factorial Design of 16 experiments was conducted to assess the influence of nine factors on the production of lipases by filamentous fungi. The factors investigated were bran type (used as the main carbon source), nitrogen source, nitrogen source concentration, inducer, inducer concentration, fungal strain (Aspergillus niger or Aspergillus flavus were selected as good lipase producers via submerged fermentation), pH and agitation. The concentration of the yeast extract and soybean oil and the pH had a significant effect (p < 0.05) on lipase production and were consecutively studied through a Full Factorial Design 23, with the concentration of yeast extract and pH being significant (p < 0.05). These variables were optimized using a central composite design, obtaining maximum lipolytic activities with the use of 45 g/L of yeast extract and pH 7.15. The statistical model showed a 94.12% correlation with the experimental data.

Isolamento e seleção de fungos para biorremediação a partir de solo contaminado com herbicidas triazínicos

Bioremediation is a technology that uses microrganism metabolism to quickly eliminate or reduce pollutants to acceptable levels into the environment. The triazine herbicides are intensively used to control harmful grass in the culture of maize. The aim of this work was to isolate filamentous fungi from soil contaminated with triazine herbicides and screening these fungi due to their ability of growth in a medium added by atrazine. The fungi were isolated, cultivated in potato-dextrose-agar plus 50 mg.Kg -1 of atrazine and incubated for 5 days at 25oC. The measure of the rays of the colonies was carried out daily and the radial growth rate (RGR) through linear regression of colonies rays using the equation: r(t) = a + RGR .t (r:ray; t: time; RGR: radial growth rate). The RGR results were analyzed through analysis of variance and Tukey test for comparison of averages. Fifteen filamentous fungi from genus Aspergillus, Penicillium and Trichoderma were isolated. The highest RGRs were obtained with the fungi Aspergillus and Penicillium, when isolated from contaminated soil with atrazine and atrazine + simazine, respectively, showing RGR of 1.57 mm.d 1 and 1.28 mm.d -1 . The growth of these fungi in atrazine contaminated meas indicates a possible of use of them in bioremediation experiments with contaminated soil containing triazine herbicides.A biorremediacao e uma tecnologia que utiliza o metabolismo de microrganismos para eliminacao ou reducao, a niveis aceitaveis, de poluentes presentes no ambiente. Os herbicidas triazinicos sao usados intensivamente no controle de ervas daninhas, principalmente na cultura de milho. Objetivou-se, neste trabalho, isolar fungos filamentosos de solos contaminados com herbicidas triazinicos (atrazine e simazine) e selecionar os microrganismos isolados quanto a capacidade de crescimento em meio adicionado de atrazine. Os microrganismos foram isolados, cultivados em meio Agar-Batata-Dextrose (BDA) acidificado com acido tartarico 10%, adicionado de 50 mg.Kg-1 de atrazine e incubados por 5 dias a 25oC. Foi realizada a medida diaria do crescimento fungico e calculada a velocidade de crescimento radial atraves de regressao linear dos raios das colonias utilizando-se a equacao r(t) = a + VCR .t (r:raio; t: tempo; VCR: velocidade de crescimento radial). Os resultados de VCR foram analisados atraves de Anova simples e do teste de Tukey, para comparacao de medias. Foram isolados 15 fungos, pertencentes aos generos Aspergillus, Penicillium e Trichoderma. As maiores VCRs foram obtidas com fungos Aspergillus (A1) e Penicillium (AS1), isolados de solo contaminado com atrazine e atrazine adicionado de simazine, respectivamente, que apresentaram VCRs de 1,57 mm.d-1 e 1,28 mm.d-1. O crescimento dos fungos em meio contaminado com a atrazine indica a possibilidade de utilizacao desses fungos em estudos de biorremediacao de solos contaminados com herbicidas triazinicos.

Production and Characterization of Lipases by Two New Isolates of Aspergillus through Solid-State and Submerged Fermentation

Due to the numerous applications of lipases in industry, there is a need to study their characteristics, because lipases obtained from different sources may present different properties. The aim of this work was to accomplish the partial characterization of lipases obtained through submerged fermentation and solid-state fermentation by two species of Aspergillus. Fungal strains were isolated from a diesel-contaminated soil and selected as good lipases producers. Lipases obtained through submerged fermentation presented optimal activities at 37°C and pH 7.2 and those obtained through solid-state fermentation at 35°C and pH 6.0. The enzymes produced by submerged fermentation were more temperature-stable than those obtained by solid-state fermentation, presenting 72% of residual activity after one hour of exposition at 90°C. Lipases obtained through submerged fermentation had 80% of stability in acidic pH and those obtained through solid-state fermentation had stability greater than 60% in alkaline pH.

Potential application of microalga Spirulina platensis as a protein source.

The high protein level of various microalgal species is one of the main reasons to consider them an unconventional source of this compound. Spirulina platensis stands out for being one of the richest protein sources of microbial origin (460-630 g kg-1 , dry matter basis), having similar protein levels when compared to meat and soybeans. The use of S. platensis in food can bring benefits to human health owing to its chemical composition, since it has high levels of vitamins, minerals, phenolics, essential fatty acids, amino acids and pigments. Furthermore, the development of new protein sources to supply the shortage of this nutrient is an urgent need, and protein from S. platensis plays an important role in this scenario. In this sense, extraction processes that allow maximum protein yield and total utilization of biomass is an urgent need, and ultrasonic waves have proven to be an effective extraction technique. The number of scientific papers related to protein fraction from S. platensis is still limited; thus further studies on its functional and technological properties are needed.