S. Sato

• University of São Paulo

BACKGROUND Ethanol may be an attractive carbon source for microorganism growth for the production of several biomolecules. Nonetheless, high amounts of ethanol may be harmful for microbial cells. This study evaluated the effect of adding ethanol to the cultivation of Scenedesmus obliquus, under batch and fed‐batch processes. RESULTS A single addit...

Arthrospira (Spirulina) platensis was cultivated in bench-scale open ponds on a modified Schlösser medium. The fed-batch exponential supply of ammonium sulfate at defined feeding time and pH allowed obtaining optimum results in terms of biomass growth and composition. The cultivation conditions established herein will constitute the main starting p...

Arthrospira platensis is a microorganism that is produced worldwide. Its industrial cultivation requires a large quantity of alkaline medium with high salinity that could pollute the environment if discharged with no further treatment. The combined effects of the physicochemical processes of flocculation and adsorption were applied to reuse the spe...

Arthrospira platensis is widely cultivated in open ponds for industrial purposes. However, high- protein A. platensis biomass produced in photobioreactors (PBR) is recommended for pharmaceutical and cosmetic formulations. A. platensis was cultivated in a 3.5-L tubular airlift PBR using both sodium nitrate and urea as nitrogen sources. Sodium nitrat...

NH4NO3 simultaneously provides a readily assimilable nitrogen source (ammonia) and a reserve of nitrogen (nitrate), allowing for an increase in Arthrospira platensis biomass production while reducing the cost of the cultivation medium. In this study, a 22 plus star central composite experimental design combined with response surface methodology was...

Reusing culture medium of Arthrospira platensis is quite important in large scale production because its inappropriate disposal could exacerbate problems of environmental pollution. This study evaluates the suitability of using different quantities of exhausted Schlösser medium after continuous treatment using granular activated carbon (GAC) with a...

Arthrospira platensis cultivation produces a saline spent medium that must be treated to allow its reuse, thus saving water and avoiding environmental pollution. This study evaluates the association of flocculation followed by adsorption to treat the spent medium by applying different concentrations of granular activated carbon (GAC) and ferric chl...

Background Cyanobacteriae and microalgae industries require large amounts of water for their cultivation. Reusing the Arthrospira platensis culture medium is scarcely evaluated in the literature. This work evaluates the coagulation and the adsorption as a simultaneous process to treat the A. platensis spent medium by applying different concentratio...

Arthrospira platensis has been photoautotrophically cultivated for the production of high quality biomass. It contains satisfactory contents of protein, pigments, and fatty acids. The use of organic compounds as a carbon source has been studied, aiming to improve the biomass productivity in a mixotrophic process. In this study, A. platensis was cul...

The importance of this study lies in the investigation of the simultaneous influence of feeding time and amount of added nitrogen source (urea) on the fed-batch growth and composition of Arthrospira (Spirulina) platensis. Cultivations were performed in 5-L minitanks at constant temperature (25 °C) and light intensity (42 μmol photons/m2s) using exp...

The ability of Arthrospira platensis to use ethanol as a carbon and energy source was investigated by batch process and fed-batch process. A. platensis was cultivated under the effect of a single addition (batch process) and a daily pulse feeding (fed-batch process) of pure ethanol, at different concentrations, to evaluate cell concentration (X) an...

Photobioreactor design and operation mode are essential steps to ensure a high overall microalgae yield and cell productivities, making viable the commercial production. For this reason, there are trends of research in the field of microalgae that encompass design and development of reactor systems towards maximum productivity with minimum operatio...

To reduce CO2 emissions from alcoholic fermentation, Arthrospira platensis was cultivated in tubular photobioreactor using either urea or nitrate as nitrogen sources at different light intensities (60 μmol m−2 s−1 ≤ I ≤ 240 μmol m−2 s−1). The type of carbon source (pure CO2 or CO2 from fermentation) did not show any appreciable influence on the mai...

This chapter comments on fed-batch cultivation of Arthrospira platensis under different carbon and nitrogen sources, pH, temperature, light intensity, type of photobioreactor and typical parameters of the fed-batch process, such as feeding time, addition protocol and flow rate. Inexpensive nitrogen sources, such as urea, ammonium salts and nitrogen...

Similar to other photosynthetic microorganisms, the cyanobacterium Arthrospira platensis can be used to produce pigments, single cell proteins, fatty acids (which can be used for bioenergy), food and feed supplements, and biofixation of CO(2) . Cultivation in a specifically designed tubular photobioreactor is suitable for photosynthetic biomass pro...

BACKGROUND: Fed-batch culture allows the cultivation of Arthrospira platensis using urea as nitrogen source. Tubular photobioreactors substantially increase cell growth, but the successful use of this cheap nitrogen source requires a knowledge of the kinetic and thermodynamic parameters of the process. This work aims at identifying the effect of tw...

Urea has been considered as a promising alternative nitrogen source for the cultivation of Arthrospira platensis if it is possible to avoid ammonia toxicity; however, this procedure can lead to periods of nitrogen shortage. This study shows that the addition of potassium nitrate, which acts as a nitrogen reservoir, to cultivations carried out with...

Arthrospira platensis has been studied for single-cell protein production because of its biomass composition and its ability of growing in alternative media. This work evaluated the effects of different dilution rates (D) and urea concentrations (N(0)) on A. platensis continuous culture, in terms of growth, kinetic parameters, biomass composition a...

The present study aimed at evaluating the production of Arthrospira platensis in tubular photobioreactor using CO2 from ethanol fermentation. The results of these cultivations were compared to those obtained using CO2 from cylinder at different protocols of simultaneous ammonium sulfate and sodium nitrate feeding. Maximum cell concentration (X-m),...

Bioenergetic analysis may be applied in order to predict microbial growth yields, based on the Gibbs energy dissipation and mass conservation principles of the overall growth reaction. The bioenergetics of the photoautotrophic growth of the cyanobacterium Arthrospira (Spirulina) platensis was investigated in different bioreactor configurations (tub...

Arthrospira platensis was cultivated in tubular photobioreactor in order to evaluate growth and biomass production at variable photosynthetic photon flux density (PPFD = 60, 120, and 240 µmol photons m(-2)s(-1)) and employing three different systems for cell circulation, specifically an airlift, a motor-driven pumping and a pressurized system. The...

Previous work demonstrated that a mixture of NH(4)Cl and KNO(3) as nitrogen source was beneficial to fed-batch Arthrospira (Spirulina) platensis cultivation, in terms of either lower costs or higher cell concentration. On the basis of those results, this study focused on the use of a cheaper nitrogen source mixture, namely (NH(4))(2)SO(4) plus NaNO...

Carbon dioxide released from alcoholic fermentation accounts for 33% of the whole CO(2) involved in the use of ethanol as fuel derived from glucose. As Arthrospira platensis can uptake this greenhouse gas, this study evaluates the use of the CO(2) released from alcoholic fermentation for the production of Arthrospira platensis. For this purpose, th...

The effects of light intensity and temperature in S. platensis cultivation with potassium nitrate or urea as nitrogen source were investigated, as well as the biomass chlorophyll contents of this cyanobacteria, through the Response Surface Methodology. Experiments were performed at temperatures from 25 to 34.5ºC and light intensities from 15 to 69...

Semicontinuous cultures were carried out at different dilution rates (D) and light intensities (I) to determine the maximum productivity of Arthrospira platensis cultivated in helicoidal photobioreactor up to the achievement of pseudo-steady-state conditions. At I=108 μmol photons m(-2) s(-1), the semicontinuous regime ensured the highest values of...

This work is focused on the influence of dilution rate (0.08 ≤ D ≤ 0.32 d−1) on the continuous cultivation and biomass composition of Arthrospira (Spirulina) platensis using three different concentrations of ammonium chloride (cNo = 1.0, 5.0 and 10 mol m−3) as nitrogen source. At cNo = 1.0 and 5.0 mol m−3 the biomass protein content was an increasi...

Arthrospira platensis was cultivated in tubular photobioreactor using different photosynthetic photon flux densities (PPFD) and protocols of (NH₄)₂SO₄ fed-batch supply. Results were evaluated by variance analysis selecting maximum cell concentration (X(m)), cell productivity (P(x)), nitrogen-to-cell conversion factor (Y(X/N)) and biomass, protein a...

Arthrospiraplatensis was cultivated in minitanks at 13 klux, using a mixture of KNO(3) and NH(4)Cl as nitrogen source. Fed-batch daily supply of NH(4)Cl at exponentially-increasing feeding rate allowed preventing ammonia toxicity and nitrogen deficiency, providing high maximum cell concentration (X(m)) and high-quality biomass (21.85 mg chlorophyll...

Arthrospira (Spirulina) platensis (Nordstedt) Gomont was autotrophically cultivated for biomass production in repeated fed-batch process using urea as nitrogen source, with the aim of making large-scale production easier, increasing cell productivity and then reducing the production costs. It was investigated the influence of the ratio of renewed v...

This study dealt with the influence of both the feeding time and light intensity on the fed-batch culture of the cyanobacterium Spirulina (Arthrospira) platensis using ammonium chloride as a nitrogen source. For this purpose, a 2(2) plus star central composite experimental design combined with response surface methodology was employed, and the maxi...

This work is focused on the influence of dilution rate (0.08⩽D⩽0.32 d−1) on the kinetics of continuous cultivation of Spirulina platensis at two different concentrations of ammonium chloride (N0=1.0 and 10 mM) as nitrogen source. Cell productivity increased in both series of runs up to D≅0.12–0.16 d−1, and then decreased. While at N0=1.0 mM biomass...

Arthrospira platensis was cultivated photoautotrophically at 6.0 klux light intensity in 5.0-L open tanks, using a mineral medium containing urea as nitrogen source. Fed-batch experiments were performed at constant flowrate. A central composite factorial design combined to response surface methodology (RSM) was utilized to determine the relationshi...

The influence of the nitrogen source on the production of extra-cellular amylolytic enzymes by a new Trichoderma sp. isolate was investigated. Preliminary tests performed using a mixture of urea and ammonium sulfate demonstrated that this microorganism was able to effectively degrade ungelatinized soluble starch (20 g l-1) yielding 420±30 U l-1 -am...

Spirulina platensis was autotrophically cultivated by fed-batch addition of urea as a nitrogen source. Continuous and pulse feeding regimes of this nitrogen source (time intervals of 24 h) were compared using a constant mass flow rate. Both series of experiments were carried out at three different temperatures (25, 28 and 31 °C) and total times of...

The performance of a new Trichoderma sp. isolate to produce extracellular α‐amylase and glucoamylase from raw sorghum starch was evalutated. To reduce the costs of starch saccharification and the consumption of amylolytic enzymes, this microorganism has been used for the first time in cultivations using such a carbon source without any prior gelati...

Arthrospira (Spirulina) platensis (Nordstedt) Gomont was cultivated under light-limited conditions in 5-L open tanks by daily supplying NH4Cl as nitrogen source. Exponentially increasing feeding rates were adopted to prevent ammonia toxicity. The total feeding time (T) was varied between 12 and 20 days, and the starting (m0) and total (mT) quantiti...

The cyanobacterium Spirulina platensis is an attractive alternative source of the pigment chlorophyll, which is used as a natural color in food, cosmetic, and pharmaceutical products. In this work, the influence of the light intensity and urea supplementation as a nitrogen source using fed-batch cultivation for S. platensis growth and chlorophyll c...

The influence of light intensity reduction on Spirulina platensis cultivation was investigated, using urea and KNO3 as nitrogen sources. The reduction of light intensity from 5 to 2klux was studied both on the 9th and the 13th day of cultivation. Increases of up to 29% in the total chlorophyll production were observed for the cultivations with ligh...

The cyanobacterium Spirulina platensis was cultivated in bench-scale miniponds on bicarbonate/carbonate solutions using urea as nitrogen source. To minimize limitation and inhibition phenomena, urea was supplied semicontinuously using exponentially increasing feeding rates. The average growth rates obtained alternately varying the total mass of ure...

Different carbon sources were tested for the simultaneous cultivation and pro-duction of extracellular α-amylase and glucoamylase by a new Trichoderma sp. isolate, namely sorghum, soluble (potato), corn, and cassava starches as well as maltose. Although maltose behaved better than the other carbon sources in terms of α-amylase activity (about 28,00...

Previous results of Spirulina platensis cultures, carried out by supplying intermittently urea as nitrogen source at exponentially increasing feeding rate, have been used to perform a bioenergetic and thermodynamic study on the growth of this cyanobacterium as well as on its photosynthetic efficiency. Simple material, enthalpy and Gibbs energy bala...

Simplified modeling based on material balances for biomass, ethanol and substrate was used to describe the kinetics of fed-batch alcohol fermentation of sugarcane blackstrap molasses. Maintenance requirements were previously shown to be of particular significance in this system, owing to the use of massive inoculum to minimize inhibitions; therefor...

We studied the effect of reactor filling time (T) (3–5 h), initial mass of inoculum (M) (1000–2100 g), and exponential time decay constant for the substrate feed rate (K) (0.6–1.6 h−1) on ethanol production by Saccharomyces cerevisiae grown in sugarcane blackstrap molasses through a fed-batch culture. The highest ethanol productivity (16.9 g/[Lh])...

A photosynthesizing microorganism culture, like Spirulina platensis, can be an alternative source of protein for human food and feed purposes, with the possibility of obtaining other products like pigments (carotenoids, phycocyanin and chlorophyll), vitamins and lipids. The biomass obtained can be introduced directly in the diet and it can also be...

Spirulina platensis is a cyanobacterium that has a high protein content and therefore, a high nutritional value. It can be cultivated either in a liquid or in a solid culture. When cultivated in aqueous culture the cell growth can be determined by following the optical density. On the other hand, when produced by solid cultivation the growth can be...

Spirulina platensis is a cyanobacterium that has a high protein content and therefore, a high nutritional value. It can be cultivated either in a liquid or in a solid culture. When cultivated in aqueous culture the cell growth can be determined by following the optical density. On the other hand, when produced by solid cultivation the growth can be...

Chlorophyll is a pigment used as colorant in the food, pharmaceutical and cosmetic industries. It can be obtained in considerable quantities from Spirulina platensis biomass. In this work, the cultivation of the microalga was done using urea as the nitrogen source by a fed-batch process. The addition of urea was done in four different modes: interm...

Fed-batch cultures of Sacchoromyces cerevisiae were carried out in a 14 l fermenter (NBS, Microferm), containing sugar-cane blackstrap molasses supplemented with urea (0.5 g l−1) and penicillin V (500 ui/l), under the following conditions: 32(±1)°C; pH 4.5–5.0; N=200 min−1; inoculum and mash volume equal to 3.0 l and 7.0 l, respectively. The parame...

The fermentation kinetics for the conversion of rice straw hemicellulosic hydrolysate to xylitol by the yeast Candida guilliermondii was evaluated under batch conditions. The fermentation was accomplished in a 1 L working volume stirred-tank reactor with aeration of 1.3 vvm and agitation of 300 rpm (kLa=15/h). The maximum specific rate of xylitol f...

The effect of overall oxygen mass transfer coefficient (k La) on the conversion of xylose to xylitol by Candida guilliermondii FTI 20037 was investigated in batch experiments. Rice straw hemicellulose hydrolysate obtained by acid hydrolysis was employed as a xylose-rich medium. The results showed that this bioconversion strongly depended on the aer...

Hydrolysis of the hemicellulosic fraction of sugarcane bagasse by sulphuric acid was performed in laboratory (25 mL) and semi-pilot (25 L) reactors under different conditions of temperature, time and acid concentration. On the laboratory scale, the three highest recovery yields were obtained at: 140ºC for 10 min with 100 mgacid/gdm (yield=73.4%); 1...

Sugar cane bagasse hemicellulosic fraction submitted to hydrolytic treatment with 100 mg of sulfuric acid per gram of dry mass, at 140 degrees C for 20 min, was employed as a substrate for microbial protein production. Among the 22 species of microorganisms evaluated, Candida tropicalis IZ 1824 showed TRS consumption rate of 89.8%, net cell mass of...

Sugar cane bagasse hemicellulosic fraction was hydrolyzed by treatment with 100 mg of sulfuric acid per gram of dry mass at 140 °C for 20 min. The hydrolyzate was used as the substrate to grow Candida tropicalis IZ 1824 in a 1.0-1 bioreactor at 30 °C; aeration at 1.0 and 2.0 vvm; stirring at 400 rpm and initial pH of 6.0. The kinetic parameters, ca...

The effect of inoculum level on xylitol production by Candida guilliermondii was evaluated in a rice straw hemicellulose hydrolysate. High initial cell density did not show a positive effect in this bioconversion since increasing the initial cell density from 0.67 g L-1 to 2.41 g L-1 decreased both the rate of xylose utilization and xylitol accumul...

Xylitol production by the yeastCandida guilliermondii was evaluated in a rice straw hemicellulose hydrolysate under different conditions of initial pH and nitrogen source. Xylitol production was significantly affected (p <0.05) by the nitrogen source, pH, and the interaction between these factors. The best yield and productivity were observed at in...

Different substrates based on hydrolyzed hemicellulosic fractions of agroindustrial residues were used for xylitol production by Candida guilliermondii FTI 20037 under semi-aerobic conditions. Batch fermentation performances were characterized and compared with those attained in a synthetic medium using d-xylose as a major carbon source. For all me...

The bioconversion of xylose to xylitol by the yeast Candida guilliermondii FTI 20037 was evaluated under different nutritional conditions using rice straw hemicellulose hydrolysate. Statistical designs were used to determine the fermentation medium composition. Ammonium sulfate and rice bran have been identified as required nutrients in the hydroly...

Summary Rice straw was used as a lignocellulosic source to provide rich pentose media. By using a well characterized yeast strain,Candida guilliermondii FTI 20037, the hydrolysate obtained was converted to xylitol with an efficiency of 75% and production of 27 g of xylitol per liter in 48 hours. The satisfactory results reported here can be attribu...

Fed-batch ethanol fermentation tests of sugar cane blackstrap molasses were carried out at 32 C and ph 4.5–5.0, using pressed yeast as inoculum, and with no air supply. Two values of the fermentor filling-up time were adopted: 5 h and 7 h. The feeding rates obeyed equation F=F0–Kt, with K equal to 0.0, 0.2, 0.4, 0.6 and 0.8 h–1. The average yeast y...

The ethanol yield was not affected and the ethanol productivity was increased when exponentially decreasing feeding rates were used instead of constant feeding rates in fed batch ethanol fermentations. The influences of the initial sugar feeding rate on the ethanol productivity, on the constant ethanol production rate during the feeding phase and o...

Summary The ethanol yield was not affected and the ethanol productivity increased (˜10%) when linearly decreasing feeding rates were used instead of constant feeding rates in fed-batch ethanol fermentations.

Dissertação (Mestrado).

Dissertação (Mestrado).