Characterization of allelochemicals from Pistia stratiotes extracts and their effects on the growth and physiology of Microcystis aeruginosa.

Due to the public and environmental health impact of cyanotoxins, investigations have been focused on finding environmental friendly algaecides from aquatic plants. The present study had the objective to evaluate the population control and physiological response of Microcystis aeruginosa (Kützing) Kützing (strain BCCUSP232) exposed to Pistia stratiotes L. extracts. Aqueous and ethanolic extracts of P. stratiotes at different concentrations (10, 25, and 50 mg L-1) were submitted to M. aeruginosa and reduced significantly (p<0.05) the cyanobacterium cell density. The ethanolic extract presented the greatest growth inhibition of the strain at the highest concentration. During exposure to P. stratiotes extracts, intracellular hydrogen peroxide levels, malondialdehyde content, and antioxidant enzymes (peroxidase, catalase, and glutathione S-transferase) activities increased in M. aeruginosa, while total protein concentration decreased when compared to the control group. Superoxide dismutase (SOD) activities presented a sharp decline, suggesting superoxide radical and peroxide accumulation. This implied that SOD was a target for bioactive substance(s) from aqueous and ethanolic extracts of P. stratiotes. Phytochemical screening of the extracts revealed that the ethanolic extract presented 93.36 mg gallic acid equivalent (GAE) per gram dry weight (g-1 DW) total polyphenols and 217.33 mg rutin equivalent (RE) per gram dry weight total flavonoids, and for the aqueous extract, 5.19 mg GAE g-1 DW total polyphenols and 11.02 mg RE g-1 DW total flavonoids were detected. Gas chromatography (GC)/mass spectrometry (MS) analyses of the ethanolic and aqueous extracts presented palmitic acid ethyl ester as major allelochemical. In view of these results, it can be concluded that P. stratiotes showed potential in controlling M. aeruginosa populations.

Fibrinolytic enzyme from Arthrospira platensis cultivated in medium culture supplemented with corn steep liquor.

Artrhospira (Spirulina) platensis produced fibrinolytic enzyme under mixotrophic conditions using corn steep liquor (CSL). The enzyme was extracted, purified by combination of two chromatographic techniques and biochemically characterized. Maximum fibrinolytic production (268.14 U mg-1) was obtained using liquid medium culture composed by 0.2% CLS after 10th day of cultivation. Fibrinolytic activity was higher when extracted by homogenization methods and was purified 32.72-fold with specific activity of 7988 U mg-1. Fibrin zymography showed an active band, indicated acts as a plasmin-like protein with molecular weight of 72 kDa. Fibrinolytic enzyme have optimum pH of 6.0, stable in the range of 6.0 to 10.0 during 24 h and optimum temperature at 40 °C with a stability below 50 °C. Fibrinolytic enzyme is a serine metalloprotease by to be enhanced by Fe2+ and inhibited by PMSF. The enzyme has higher enzymatic activity than most other fibrinolytic enzymes and is stable at temperature and pH human physiological. Overall, the fibrinolytic enzyme from A. platensis has attractive biochemical properties to potential applications in the treatment of thrombosis.

Biotransformations, Antioxidant System Responses, and Histopathological Indexes in the Liver of Fish Exposed to Cyanobacterial Extract.

Radiocystis fernandoi, a microcystin (MC) producer, has been common in cyanobacterial blooms in tropical regions. Microcystin is a hepatotoxin that causes tissue damage and even death in animals, including humans; its detoxification process may involve biotransformation and activation of the antioxidant defense system. We evaluated the detoxification pathway, examined the antioxidant defense system responses, and determined the alterations and the organ histopathological indexes in the liver of the tropical fish Hoplias malabaricus after acute and subchronic intraperitoneal exposure to microcystin. The crude microcystin extract of R. fernandoi had predominantly MC-RR and MC-YR. The detoxification process was activated by increasing ethoxyresorufin-O-deethylase activity, whereas glutathione S-transferase was inhibited. The activity of the antioxidant defense enzymes superoxide dismutase (SOD) and glutathione peroxidase decreased after acute exposure; the SOD-catalase system and the glutathione level increased after subchronic exposure. The carbonyl protein level, lipid peroxidation (LPO), and DNA damage were unchanged after acute exposure, whereas protein carbonyl was unchanged, LPO decreased, and DNA damage increased after subchronic exposure. Histopathological alteration indexes differed between acute and subchronic exposure, but the histopathological organ indexes indicate liver dysfunction in both exposure periods. We conclude that MC-RR and MC-YR induce different liver responses depending on the time of exposure, and the antioxidant defense responses after subchronic exposure may help to partially restore the liver function. Environ Toxicol Chem 2020;39:1041-1051. © 2020 SETAC.

Efecto de ácidos húmicos sobre el crecimiento y la composición bioquímica de Arthrospira platensis / Effect of humic acids on the growth and the biochemical composition of Arthrospira platensis

RESUMEN Con el propósito de evaluar el efecto de tres concentraciones de ácidos húmicos (AH) 1, 10, 100 mg/L contra una concentración de ácido indol acético (AIA), sobre la producción de biomasa, pigmentos, proteínas, carbohidratos y lípidos de A. platensis; se realizaron cultivos en discontinuo en medio Zarrouk 25% suplementados con AH y AIA, bajo condiciones de aireación constante y fotoperiodos de 12:12 horas, durante 30 días. Se encontró que la producción máxima de biomasa fue mayor en el cultivo suplementado con 10 mg/L de AH, comparado con el control y los cultivos suplementados con AIA. De la misma manera fue observado en este tratamiento la producción más alta de pigmentos, proteínas y carbohidratos. Por tanto, se logró incrementar el crecimiento y la producción de metabolitos de A. platensis, lo cual permite observar el uso potencial de estas sustancias como estimulantes biológicos orgánicos.

ABSTRACT The purpose of this research was to evaluate the effect of three concentrations of humic acids (HA) 1, 10, 100 mg/L against a concentration of indole acetic acid (IAA) on production of biomass, pigments, proteins, carbohydrates and lipids of A. platensis. Cultures discontinuous in Zarrouk 25% medium supplemented with HA and IAA under conditions of aeration constant and photoperiod from 12:12 hours, during 30 days were made. It was found that the maximum biomass production was higher in the culture supplemented with 10 mg / L of AH, compared to the control and cultures supplemented with AIA. In the same way the highest production of pigments, proteins and carbohydrates were observed in this treatment. Therefore, the growth and production of metabolites of A. platensis was increased, which makes it possible to observe the potential use of these substances as organic biological stimulants.

Osmotic stress alters UV-based oxidative damage tolerance in a heterocyst forming cyanobacterium.

Cyanobacteria are successful in diverse habitats due to their adaptation strategies. Their mechanisms to cope with individual stresses have been studied. However, the response to combined stress conditions as found in nature remains unclear. With this aim, we studied the dual effect of 24h-osmotic and 3h-UV irradiation on the cyanobacterium Calothrix BI22. Our approach included the study of redox homeostasis, oxidative damage, reactive oxygen species production-consumption processes and photosynthetic activity. Superoxide in vivo determination with confocal image processing showed the highest accumulation under UV. However, no lipoperoxidation occurred due to a high SOD activity. This cyanobacterium was less prepared to cope with the osmotic stress assayed. Under this condition, O2 photoevolution decreased abruptly and oxidative damage was produced by reactive species other than superoxide. In this situation the cellular control of the amount of ROS failed to prevent oxidative damage and photosynthesis was seriously disturbed in spite of maximum quantum photosynthetic efficiency remained unchanged. Calothrix BI22 presented the more severe oxidative damage when both stressors were applied. The osmotic stress disentangled the mechanisms developed by this cyanobacterium to deal with 3h-UV irradiation alone.

Toxic concentrations of metronidazole to Microcystis protocystis / Concentrações tóxicas de metronidazol para Microcystis protocystis

Antimicrobials are among the most commonly used drugs and have become a class of contaminants with great environmental importance. Metronidazole is an antimicrobial used for the therapeutic management of several human diseases. The toxicity of antimicrobials on aquatic species may affect sensitive microorganisms and reduce metabolic processes. Cyanobacteria is a group of organisms that are of great ecological importance in aquatic environments. Studies indicate that cyanobacteria are very sensitive to some antimicrobials. Therefore, it is necessary to evaluate the effects of metronidazole contamination on phytoplankton. The aim of this study was to investigate the effects of metronidazole on the growth of the cyanobacterium Microcystis protocystis and to evaluate the stability of this antimicrobial agent in the culture medium over a period of 96 hours. M. protocystis was resistant to growth inhibition by metronidazole. The EC50 of this antimicrobial for M. protocystis was 117.3 mg L–1. Under the growth inhibition test conditions, neither a significant change in the MNZ concentration nor the presence of drug metabolites or degradation products was observed. These results indicate low cellular uptake of the antimicrobial agent and its persistence in the culture medium.

Antimicrobianos estão entre os fármacos mais usados e tem se tornado uma classe emergente de contaminantes com grande importância ambiental. A toxicidade dos antimicrobianos sobre as espécies aquáticas podem afetar microrganismos sensíveis e reduzir seus processos metabólicos. O Metronidazol é um antimicrobiano usado para o manejo terapêutico de várias doenças humanas. Cyanobacteria é um grupo de organismos de grande importância ecológica no ambiente aquático. O estudo visou investigar os efeitos do metronidazol- MNZ sobre o crescimento da cianobactéria Microcystis protocystis e avaliar a persistência do antimicrobiano no meio de cultivo durante 96h. A M. protocystis mostrou-se resistente à inibição de crescimento pelo MNZ. A EC50% do MNZ para a espécie foi 117,3 mg L–1. Nas condições do teste de inibição de crescimento não foi observada variação significativa da concentração de MNZ nem a presença de metabólitos ou produtos de degradação do fármaco, indicando baixa captação celular do antimicrobiano e sua persistência no meio de cultivo.

Toxic concentrations of metronidazole to Microcystis protocystis

Antimicrobials are among the most commonly used drugs and have become a class of contaminants with great environmental importance. Metronidazole is an antimicrobial used for the therapeutic management of several human diseases. The toxicity of antimicrobials on aquatic species may affect sensitive microorganisms and reduce metabolic processes. Cyanobacteria is a group of organisms that are of great ecological importance in aquatic environments. Studies indicate that cyanobacteria are very sensitive to some antimicrobials. Therefore, it is necessary to evaluate the effects of metronidazole contamination on phytoplankton. The aim of this study was to investigate the effects of metronidazole on the growth of the cyanobacterium Microcystis protocystis and to evaluate the stability of this antimicrobial agent in the culture medium over a period of 96 hours. M. protocystis was resistant to growth inhibition by metronidazole. The EC50 of this antimicrobial for M. protocystis was 117.3 mg L1. Under the growth inhibition test conditions, neither a significant change in the MNZ concentration nor the presence of drug metabolites or degradation products was observed. These results indicate low cellular uptake of the antimicrobial agent and its persistence in the culture medium.

Antimicrobianos estão entre os fármacos mais usados e tem se tornado uma classe emergente de contaminantes com grande importância ambiental. A toxicidade dos antimicrobianos sobre as espécies aquáticas podem afetar microrganismos sensíveis e reduzir seus processos metabólicos. O Metronidazol é um antimicrobiano usado para o manejo terapêutico de várias doenças humanas. Cyanobacteria é um grupo de organismos de grande importância ecológica no ambiente aquático. O estudo visou investigar os efeitos do metronidazol- MNZ sobre o crescimento da cianobactéria Microcystis protocystis e avaliar a persistência do antimicrobiano no meio de cultivo durante 96h. A M. protocystis mostrou-se resistente à inibição de crescimento pelo MNZ. A EC50% do MNZ para a espécie foi 117,3 mg L1. Nas condições do teste de inibição de crescimento não foi observada variação significativa da concentração de MNZ nem a presença de metabólitos ou produtos de degradação do fármaco, indicando baixa captação celular do antimicrobiano e sua persistência no meio de cultivo.

Toxic concentrations of metronidazole to Microcystis protocystis / Concentrações tóxicas de metronidazol para Microcystis protocystis

Antimicrobials are among the most commonly used drugs and have become a class of contaminants with great environmental importance. Metronidazole is an antimicrobial used for the therapeutic management of several human diseases. The toxicity of antimicrobials on aquatic species may affect sensitive microorganisms and reduce metabolic processes. Cyanobacteria is a group of organisms that are of great ecological importance in aquatic environments. Studies indicate that cyanobacteria are very sensitive to some antimicrobials. Therefore, it is necessary to evaluate the effects of metronidazole contamination on phytoplankton. The aim of this study was to investigate the effects of metronidazole on the growth of the cyanobacterium Microcystis protocystis and to evaluate the stability of this antimicrobial agent in the culture medium over a period of 96 hours. M. protocystis was resistant to growth inhibition by metronidazole. The EC50 of this antimicrobial for M. protocystis was 117.3 mg L–1. Under the growth inhibition test conditions, neither a significant change in the MNZ concentration nor the presence of drug metabolites or degradation products was observed. These results indicate low cellular uptake of the antimicrobial agent and its persistence in the culture medium.(AU)

Antimicrobianos estão entre os fármacos mais usados e tem se tornado uma classe emergente de contaminantes com grande importância ambiental. A toxicidade dos antimicrobianos sobre as espécies aquáticas podem afetar microrganismos sensíveis e reduzir seus processos metabólicos. O Metronidazol é um antimicrobiano usado para o manejo terapêutico de várias doenças humanas. Cyanobacteria é um grupo de organismos de grande importância ecológica no ambiente aquático. O estudo visou investigar os efeitos do metronidazol- MNZ sobre o crescimento da cianobactéria Microcystis protocystis e avaliar a persistência do antimicrobiano no meio de cultivo durante 96h. A M. protocystis mostrou-se resistente à inibição de crescimento pelo MNZ. A EC50% do MNZ para a espécie foi 117,3 mg L–1. Nas condições do teste de inibição de crescimento não foi observada variação significativa da concentração de MNZ nem a presença de metabólitos ou produtos de degradação do fármaco, indicando baixa captação celular do antimicrobiano e sua persistência no meio de cultivo.(AU)

The protective effect of dietary Arthrospira (Spirulina) maxima against mutagenicity induced by benzo[alpha]pyrene in mice.

Benzo[alpha]pyrene (B[α]P) was used to test the possible antimutagenic effects of Arthrospira (Spirulina) maxima (SP) on male and female mice. SP was orally administered at 0, 200, 400, or 800 mg/kg of body weight to animals of both sexes for 2 weeks before starting the B[α]P (intraperitoneal injection) at 125 mg/kg of body weight for 5 consecutive days. For the male dominant lethal test, each male was caged with two untreated females per week for 3 weeks. For the female dominant lethal test, each female was caged for 1 week with one untreated male. All the females were evaluated 13-15 days after mating for incidence of pregnancy, total corpora lutea, total implants and pre- and postimplant losses. SP protected from B[α]P-induced pre- and postimplant losses in the male dominant lethal test, and from B[α]P-induced postimplantation losses in treated females. Moreover, SP treatment significantly reduced the detrimental effect of B[α]P on the quality of mouse semen. Our results illustrate the protective effects of SP in relation to B[α]P-induced genetic damage to germ cells. We conclude that SP, owing mainly to the presence of phycocyanin, could be of potential clinical interest in cancer treatment or prevention of relapse.

Cultivos discontinuos alimentados con urea de la cianobacteria Phormidium sp. en función de la salinidad y edad del cultivo / Urea fed-batch cultures of the cyanobacterium Phormidium sp. as a function of the salinity and age of cultures

Se comparó la eficiencia de sistemas de cultivos discontinuos alimentados versus cultivos discontinuos convencionales, en cuanto a concentración de nitrógeno, adicionando 0,2 mM de urea cada tres días al final de la fase exponencial, durante 21 días. Se realizaron cultivos con un volumen de 1500 mL a 15 y 35 UPS de salinidad, enriquecidos con medio ALGAL 8mM NaNO3, a 238 µmol q m-2 s-1, aireación constante, fotoperiodo 12:12 horas y temperatura de 29 ±3°C. Phormidium sp. posee la capacidad de hidrolizar la urea; mostrando una asimilación de 65±7,07% de la misma, con la mayor producción (p<0,05) de clorofila a, ficocianina y proteínas de 20,26±1,24; 203,47±12,83 y 707,87±28,47 µg mL-1en los cultivos alimentados. La producción de pigmentos vario en el tiempo, independientemente a la salinidad y sistema de cultivo, mientras que la producción de proteínas y carbohidratos totales fue directamente proporcional a la edad del cultivo, con valores máximos de 612,74 ± 5,41 µg mL-1 y 8,96±0,08 mg mL-1 respectivamente a los 31 días. La síntesis de lípidos y EPS fueron influenciadas (p<0,05) por la salinidad, presentando los máximos de lípidos a 15 UPS con 12,22±2,91µg mL-1, y los EPS se incrementaron a 35 UPS con 2,00 ± 0,26 y 2,03 ± 0,15 mg mL-1. Estos resultados determinan que los cultivos de Phormidium sp. alimentados con urea y a salinidades de 15 y 35 UPS, representan una alternativa económica para la producción de clorofila a, ficocianina y proteínas, incrementándose un 31,04; 40,72 y 31,94 % respectivamente en comparación con cultivos no alimentados.

Fed-batch system efficiency versus batch cultures was compared in relation to nitrogen concentration, adding 0,2mM urea at the end of the exponential phase, during 21 days. Cultures were carried out in 1500 mL to 1.5 and 3.5 UPS of salinity, enriched with Algal medium 8mM NaNO3, 238 mol q m-2 s-1, constant aeration, photoperiod 12:12 h. and 29 ±3°C. Phormidium sp. is able to hydrolyze urea; showing a total assimilation of 65±7.07%, with the highest (p< 0.05) chlorophyll a, phycocyanin and protein production of 20.26 ± 1.24, 203.47 ± 12.83 and 707.87 ± 28.47 µg mL-1 in the fed-batch cultures. On the other hand, pigment production varies in time, regardless salinity and culture system. Proteins and total carbohydrate production were directly proportional to the age of cultures, with maximum values of 612.74 ± 5.41 µg mL-1 and 8.96 ± 0.08 mg mL-1, respectively. Lipid and EPS were influenced (p< 0.05) by salinity, showing maximum of lipids at 15 UPS with 12.22±2.91 µg mL-1, and EPS at 15 and 35 UPS with 2.00 ± 0.26 and 2.03 ± 0.15 mg mL-1. These results determine that Phormidium sp. cultures fed with urea, to salinities of 15-35 UPS, represent an economic alternative for chlorophyll a, phycocyanin and protein production, with an increase of 31.04, 40.72 and 31.94% respectively in comparison with non-fed cultures.

Uso da Spirulina platensis na recuperação de ratos submetidos à dieta de restrição proteica / Use of Spirulina platensis for recovering rats under protein restriction diet feeding

O presente estudo avaliou a ação da espirulina como fonte protéica na recuperação do estado nutricional de ratos machos adultos. Foram estudados 48 animais, divididos em quatro grupos de acordo com a dieta: grupo controle de caseína (CC) e grupo controle de espirulina (CE), que receberam dieta equilibrada durante todo o experimento; grupo recuperado de caseína (RC) e grupo recuperado de espirulina (RE), que consumiram dieta com restrição protéica durante 60 dias e, a seguir, receberam a dieta equilibrada à base de caseína e espirulina, respectivamente, durante 90 dias. Foram analisadas a composição centesimal e a microbiológica da Spirulina platensis, bem como o ganho em peso dos animais. Após o sacrifício dos animais, foram realizadas as análises para determinação do peso do fígado e do aspecto histopatológico, da gordura corporal e dos constituintes sanguíneos. A espirulina utilizada continha 59,65% de proteína, 3,72% de lipídios, 17,53% de resíduo mineral fixo e 7,81 de umidade, e não apresentou contaminação por microrganismos. Não houve diferenças significativas quanto à gordura corporal e constituintes protéicos séricos entre os quatro grupos de animais. Em relação ao ganho de peso não foi constatada diferença entre os grupos CC e CE, nas diferentes semanas de números 1, 5, 6, 7 e de 10 a 18, contudo esta ocorrência não foi observada nos grupos RC e RE. O peso relativo do fígado diminuiu nos animais com restrição protéica, principalmente no grupo RC, porém sem alterações histopatológicas, e os constituintes lipídios tiveram valores diminuídos. Conclui-se que o uso da Spirulina platensis na recuperação de ratos com dieta de restrição protéica reduz a lipemia.

This investigation aims at evaluating the effects of spirulin as a protein source for recovering the nutritional status of adult male rats. Forty-eight animals were studied and divided by four groups according to the feed diet: casein control (CC) group and spirulin control (SC) group, which received balanced diet during the whole experiment; recovered casein (RC) group and recovered spirulin (RS) group, which received a protein-restriction diet for 60 days and, afterwards, they were fed with balanced diet based on casein and spirulin, respectively, for 90 days. The centesimal and microbiologicalcomposition of Spirulina platensis and animals weight gains could be evaluated. After being euthanized the animal’s liver weight and its histopathologic aspects were analyzed, besides the body fat and blood components. The spirulinused contained 59.65% of protein, 3.72% of lipids, 17.53 of fixed mineral residue and 7.81% of humidity, and showed no microorganism contamination. Significant differences on body fat and serum protein contents could not be observedamong the four animal groups. Regarding the weight gains, there was no difference among the animals of groups CC and SC in different weeks of experiments numbers 1, 5, 6, 7 and from 10 to 18, but these findings were not observed among the RC and RS groups. The relative liver weight decreased in animals under protein restriction, mainly in the group RC, but no histopathological alterations could be observed, and lipid contents decreased. In conclusion, the useof Spirulina platensis for recovering rat on protein restriction diet induces a reduction of lipemia.

Use of Spirulina platensis for recovering rats under protein restriction diet feeding / Uso da Spirulina platensis na recuperação de ratos submetidos à dieta de restrição proteica

This investigation aims at evaluating the effects of spirulin as a protein source for recovering the nutritional status of adult male rats. Forty-eight animals were studied and divided by four groups according to the feed diet: casein control (CC) group and spirulin control (SC) group, which received balanced diet during the whole experiment; recovered casein (RC) group and recovered spirulin (RS) group, which received a protein-restriction diet for 60 days and, afterwards, they were fed with balanced diet based on casein and spirulin, respectively, for 90 days. The centesimal and microbiological composition of Spirulina platensis and animals weight gains could be evaluated. After being euthanized the animals liver weight and its histopathologic aspects were analyzed, besides the body fat and blood components. The spirulin used contained 59.65% of protein, 3.72% of lipids, 17.53 of fixed mineral residue and 7.81% of humidity, and showed no microorganism contamination. Significant differences on body fat and serum protein contents could not be observed among the four animal groups. Regarding the weight gains, there was no difference among the animals of groups CC and SC in different weeks of experiments numbers 1, 5, 6, 7 and from 10 to 18, but these findings were not observed among the RC and RS groups. The relative liver weight decreased in animals under protein restriction,

O presente estudo avaliou a ação da espirulina como fonte proteica na recuperação do estado nutricional de ratos machos adultos. Foram estudados 48 animais, divididos em quatro grupos de acordo com a dieta: grupo controle de caseína (CC) e grupo controle de espirulina (CE), que receberam dieta equilibrada durante todo o experimento; grupo recuperado de caseína (RC) e grupo recuperado de espirulina (RE), que consumiram dieta com restrição proteica durante 60 dias e, a seguir, receberam a dieta equilibrada à base de caseína e espirulina, respectivamente, durante 90 dias. Foram analisadas a composição centesimal e a microbiológica da Spirulina platensis, bem como o ganho em peso dos animais. Após o sacrifício dos animais, foram realizadas as análises para determinação do peso do fígado e do aspecto histopatológico, da gordura corporal e dos constituintes sanguíneos. A espirulina utilizada continha 59,65% de proteína, 3,72% de lipídios, 17,53% de resíduo mineral fixo e 7,81 de umidade, e não apresentou contaminação por microrganismos. Não houve diferenças significativas quanto à gordura corporal e constituintes proteicos séricos entre os quatros grupos de animais. Em relação ao ganho de peso, não foi constatada diferença entre os grupos CC e CE, nas diferentes semanas de números 1, 5, 6, 7 e de 10 a 18, contudo esta ocorrência não foi observada nos grupos RC e RE. O peso relativo d

Outdoor cultivation of Spirulina maxima. I. Winter / Cultivo de Spirulina maxima ao ar livre - I. Inverno

Biomass of photosyntethesizing microorganisms has a tremendous potential for both human and animal feeding due to their over 50% protein content on a dry matter basis. Cultures kept in laboratory require an artificial source of light for their satisfactory growth whereas the large scale production systems take advantage of solar light. Thus, these systems are also afected by environmental conditions such as ambiental temperature, culture temperature, relative humidity of air and rainfall.The effect of these factors in winter season on production of Spirulina maxima biomass were evaluated. Also protein content as well as amino acids profile were determined. A biomass production graph plotted againstperiod of day (morning, afternoon and evening) indicated that the best production period was from 8:00 a.m. to 1:00 p.m. while a growth curve showed maximum yield of 8:08 g/square meter/day. Lack of rainfall and water losses due to evaporation required reposition of water equivalent to 72.14 mm of rain.

Era função da necessidade de produção de proteína para alimentação humana e animal, a biomassa de microrganismos fotossintetizantes vem sendo utilizada devido a teores protéicos superiores a 50%. Culturasmantidas em laboratório exigem uma fonte de luz artificial para o seu crescimento. Na produção de espirulina em escala industrial utiliza-se luz solar, estando seu crescimento influenciado por fatores tais como: temperatura ambiente; temperatura da cultura; umidade relativa do ar e pluviosidade. Neste trabalho foram estudados os principais fatores supra descritos que influenciam na produção de biomassa de Spirulinamaxima em um aquário de vidro, mantido ao ar livre, durante o inverno de Pirassununga - SP. Teores de proteína, bem como perfil de aminoácidos da espirulina foram determinados. Um gráfico de ganho de biomassa nos diferentes períodos experimentais (matutino, vespertinoe noturno) indicaram que o melhor período de produção de biomassa durante o dia foi das 8 - 13 h e a produtividade atingiu valor máximo de 8,08 g/metro quadrado/dia. Durante todo o experimento foi necessário adicionar água ao sistema, devido à ausência de chuvas; e o total acrescentado equivaleu a 72,14 mm de chuva.