Cultivo de microalgas para produção de biossurfactantes
Resumo
Há uma crescente procura por alimentos mais saudáveis e seguros para atender uma
população cada vez maior e mais exigente. Nos últimos anos o interesse por surfactantes de
origem microbiana tem aumentado significativamente em decorrência de serem naturalmente
biodegradáveis diminuindo assim o impacto ambiental. Uma grande variedade de microorganismos
produz biossurfactantes, sendo que o tipo, a quantidade e a qualidade do
biossurfactante são influenciados pelos constituintes do meio, tais como, fontes de carbono,
nitrogênio e sais inorgânicos, além das condições de cultivo, como pH, temperatura, agitação e
disponibilidade de oxigênio. Os biossurfactantes são metabólitos microbianos de superfície ativa
que apresentam uma vasta aplicação no setor industrial. Os objetivos deste trabalho foram
selecionar microalgas com potencial para produzir biossurfactantes e estudar a produção por
microalgas em diferentes fotobiorreatores e condições nutricionais. O trabalho foi dividido em
quatro etapas: 1) cultivo autotrófico e mixotrófico de microalgas para produção de
biossurfactantes; 2) Seleção de microalgas para produção de biossurfactantes; 3) Produção de
biossurfactantes por microalgas em diferentes fotobiorreatores e 4) Cultivo outdoor da microalga
marinha Tetraselmis suecica OR para produção de biossurfactantes. Na primeira etapa
Spirulina sp. LEB-18, Synechococcus nidulans LEB-25, Chlorella vulgaris LEB-106, Chlorella
minutissima LEB-108 e Chlorella homosphaera foram cultivadas com glicose (cultivo
mixotrófico). Spirulina sp. LEB-18 apresentou concentrações máximas de biomassa (2,55 g.L-1
)
quando foi utilizada 5 g.L-1
de glicose no meio de cultivo. A tensão superficial dos meios das
microalgas foi reduzida de 70 para 43 mN.m-1
para as microalgas estudadas utilizando glicose
como fonte de carbono. Resultados da segunda etapa mostraram que a microalga
Scenedesmus sp. 3PAV3 apresentou valor de atividade emulsificante óleo em água (AE o/a)
superior (339,8 UE.g-1
) ao encontrado para as demais microalgas. Os menores valores de
tensões superficiais variaram de 27,4 a 31,2 mN.m-1
. Na terceira etapa verificou-se que a
microalga Chlorella sp. PROD1 apresentou valor de AE o/a semelhante (258,2 UE g
-1
) ao
encontrado para o emulsificante comercial lecitina de soja (257,0 UE g
-1
) e ambas as
microalgas estudadas alcançaram valores de tensões superficiais abaixo de 30 mN.m
-1
. Na
última etapa, Tetraselmis suecica OR cultivada em fotobiorreator do tipo Green Wall Panel
apresentou menores valores de tensões superficiais para cultura com limitação de nitrogênio.
Os resultados demonstraram a potencialidade das microalgas estudadas na produção de
biossurfactantes, tanto pela redução da tensão superficial e interfacial, como pelo aumento da
atividade emulsificante, confirmando uma possível aplicação como emulsificante, detergente,
lubrificante, estabilizante, entre outras.
There is a growing demand for healthier foods and insurance to listen a growing population and more demanding. In recent years interest in surfactants of microbial origin has increased significantly due to being naturally biodegradable thus reducing environmental impact. A wide variety of microorganisms produce biosurfactants and the type, quantity and quality of biosurfactant are influenced by medium constituents such as carbon source, nitrogen source and inorganic salts, beyond growth conditions such as pH, temperature, agitation and oxygen availability. The biosurfactants are microbial metabolites active surface with can be used in wide industrial sectors. The objectives this work were to identify algae with potential to produce biosurfactant and study the production of microalgae in different photobioreactors and nutritional conditions. This work was divided into four stages: 1) autotrophic and mixotrophic microalgae cultivation for biosurfactant production, 2) selection of microalgae for biosurfactant production, 3) Production of biosurfactants by microalgae in different photobioreactors and 4) outdoor cultivation of microalgae Tetraselmis suecica OR for biosurfactant production. In the first stage Spirulina sp., Synechococcus nidulans, Chlorella vulgaris, Chlorella minutissima and Chlorella homosphaera were cultured with glucose (mixotrophic culture). Spirulina sp. showed maximum concentrations of biomass (2.55 gL-1 ) was used when 5 gL-1 glucose medium. The surface tension reduction of the microalgae medium was 70 to 43 mNm-1 for the microalgae Studied, using glucose as carbon source. The results of the second stage was showed that the microalga Scenedesmus sp. 3PAV3 showed value of oil in water emulsion activity (EA o/a) higher (339.8 EU.g-1 ) to that found for other microalgae. The lower values of surface tensions ranging from 27.4 to 31.2 mNm-1 . In the third step we verified the microalgae Chlorella sp. PROD1 showed the value of AE o/a similar (258.2 EU g -1 ) to that found for the commercial emulsifier soy lecithin (257.0 EU g -1 ) and both microalgae Studied reached values of surface tensions below 30 mNm - 1 . In the last step, Tetraselmis suecica cultured in Green Wall Panel photobioreactor was showed lower surface tension for the culture with nitrogen limitation. The results demonstrated the potential of microalgae studied biosurfactant production, both by reducing surface and interfacial tension, and expansion of the emulsifying activity, confirming a possible application as an emulsifier, detergent, lubricant, stabilizer, among others.
There is a growing demand for healthier foods and insurance to listen a growing population and more demanding. In recent years interest in surfactants of microbial origin has increased significantly due to being naturally biodegradable thus reducing environmental impact. A wide variety of microorganisms produce biosurfactants and the type, quantity and quality of biosurfactant are influenced by medium constituents such as carbon source, nitrogen source and inorganic salts, beyond growth conditions such as pH, temperature, agitation and oxygen availability. The biosurfactants are microbial metabolites active surface with can be used in wide industrial sectors. The objectives this work were to identify algae with potential to produce biosurfactant and study the production of microalgae in different photobioreactors and nutritional conditions. This work was divided into four stages: 1) autotrophic and mixotrophic microalgae cultivation for biosurfactant production, 2) selection of microalgae for biosurfactant production, 3) Production of biosurfactants by microalgae in different photobioreactors and 4) outdoor cultivation of microalgae Tetraselmis suecica OR for biosurfactant production. In the first stage Spirulina sp., Synechococcus nidulans, Chlorella vulgaris, Chlorella minutissima and Chlorella homosphaera were cultured with glucose (mixotrophic culture). Spirulina sp. showed maximum concentrations of biomass (2.55 gL-1 ) was used when 5 gL-1 glucose medium. The surface tension reduction of the microalgae medium was 70 to 43 mNm-1 for the microalgae Studied, using glucose as carbon source. The results of the second stage was showed that the microalga Scenedesmus sp. 3PAV3 showed value of oil in water emulsion activity (EA o/a) higher (339.8 EU.g-1 ) to that found for other microalgae. The lower values of surface tensions ranging from 27.4 to 31.2 mNm-1 . In the third step we verified the microalgae Chlorella sp. PROD1 showed the value of AE o/a similar (258.2 EU g -1 ) to that found for the commercial emulsifier soy lecithin (257.0 EU g -1 ) and both microalgae Studied reached values of surface tensions below 30 mNm - 1 . In the last step, Tetraselmis suecica cultured in Green Wall Panel photobioreactor was showed lower surface tension for the culture with nitrogen limitation. The results demonstrated the potential of microalgae studied biosurfactant production, both by reducing surface and interfacial tension, and expansion of the emulsifying activity, confirming a possible application as an emulsifier, detergent, lubricant, stabilizer, among others.
Descrição
Palavras-chave
Biossurfactantes, Fotobiorreatores, Limitação de nitrogênio, Microalgas, Biosurfactant, Photobioreactors, Nitrogen limitation, Microalgae
Citação
RADMANN, Elisângela Martha. Cultivo de microalgas para produção de biossurfactantes. 2011. 152 f. Tese ( Doutorado em Engenharia e Ciência de Alimentos) - Escola de Química e Alimentos, Universidade Federal do Rio Grande, Rio Grande, 2011.