Produção de levana por Zymomonas mobilis CCT 4494 em meio de cultura sacarose e caracterização do sistema enzimático responsável pela hidrólise de sacarose e de formação de levana
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Data
2009-01-30
Autores
Bofo, Daniele Cristina dos Santos [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A levana é um polissacarídeo formado basicamente de unidades de frutose ligadas em (2 6). Este biopolímero possui diversas aplicações tanto na indústria alimentícia quanto na área da saúde. A levana é produzida pela bactéria Gram-negativa Zymomonas mobilis. Por fermentação de um meio contendo sacarose, esse microrganismo lança ao meio de cultura duas enzimas extracelulares: a sacarase extracelular e a levanasacarase. A enzima sacarase extracelular (SacC) tem uma alta atividade específica de hidrólise de sacarose e a enzima levanasacarase (SacB) é responsável tanto pela hidrólise do dissacarídeo quanto pela formação de levana. Dentre os fatores que regulam as atividades enzimáticas podemos citar o tampão utilizado (pH), a temperatura, a concentração de sacarose e a presença de íons metálicos. O presente projeto teve por objetivos determinar os melhores parâmetros para a produção do biopolímero levana e seu extrato enzimático, após fermentação do meio de cultura por Zymomonas mobilis CCT 4494. Além disso, foi caracterizado o extrato enzimático quanto à atividade de hidrólise de sacarose e de formação de levana. Os resultados obtidos mostraram que a maior produção de levana ocorreu em 96horas de fermentação, num meio contendo 200g/L de sacarose, incubado a 30°C, 200rpm e pH inicial de 6,0. Entretanto, o extrato enzimático bruto com maior atividade de sacarase foi obtido num meio com 200g/L de sacarose, 200rpm, 30°C, pH inicial de 7,0 e 6 horas de incubação. Para a caracterização deste extrato enzimático bruto, quanto a sua atividade de hidrólise de sacarose, inicialmente determinou-se o período ideal de reação com o substrato, sendo o mesmo definido como 10 minutos. Posteriormente foram determinados o pH, a temperatura e a concentração de sacarose ótimos, sendo de 4,0, 40°C e 0,15M, respectivamente. O sistema enzimático teve a maior...
The levan is a polysaccharide formed basically of units of fructose connected in (2 6). This biopolymer has many applications in both the food industry as in health. The levan is produced by Gram-negative bacteria Zymomonas mobilis. By fermentation of a medium containing sucrose, this microorganism launches to the middle of culture two enzymes extracellular: the extracellular sucrase and levansucrase. The enzyme extracellular sucrase (SacC) has a high specific activity of hydrolysis of sucrose and the enzyme levansucrase (SacB) is responsible for hydrolysis of both disaccharides as the formation of levan. Among the factors that regulate the enzymatic activities can cite the buffer used (pH), the temperature, concentration of sucrose and the presence of metal ions. This project aimed at determining the best parameters for the production of the biopolymer levan and its enzymatic extract, after fermentation of the mean of culture by Zymomonas mobilis CCT 4494. Moreover, was characterized the enzymatic extract as the activity of hydrolysis of sucrose and training of levan. The results showed that the majority production of levan occurred on 96hours of fermentation, in a medium containing 200g/L of sucrose, incubated at 30°C, 200rpm and initial pH of 6.0. Meanwhile, the crude enzymatic extract with higher activity of sucrase was achieved in a medium with 200g/L of sucrose, 200rpm, 30°C, initial pH of 7.0 and 6 hours of incubation. For the characterization of this crude enzymatic extract, as its activity in hydrolysis of sucrose, initially it was determined the ideal period of reaction with the substrate, being the period defined as 10 minutes. Later were determined the pH, the temperature and the concentration of sucrose great, being 4.0, 40°C and 0,15M respectively. The enzymatic system was more stable at pH 4.0, keeping 100% of your activity of sucrase, and pH values of 5,5 and 6,5... (Complete abstract click electronic access below)
The levan is a polysaccharide formed basically of units of fructose connected in (2 6). This biopolymer has many applications in both the food industry as in health. The levan is produced by Gram-negative bacteria Zymomonas mobilis. By fermentation of a medium containing sucrose, this microorganism launches to the middle of culture two enzymes extracellular: the extracellular sucrase and levansucrase. The enzyme extracellular sucrase (SacC) has a high specific activity of hydrolysis of sucrose and the enzyme levansucrase (SacB) is responsible for hydrolysis of both disaccharides as the formation of levan. Among the factors that regulate the enzymatic activities can cite the buffer used (pH), the temperature, concentration of sucrose and the presence of metal ions. This project aimed at determining the best parameters for the production of the biopolymer levan and its enzymatic extract, after fermentation of the mean of culture by Zymomonas mobilis CCT 4494. Moreover, was characterized the enzymatic extract as the activity of hydrolysis of sucrose and training of levan. The results showed that the majority production of levan occurred on 96hours of fermentation, in a medium containing 200g/L of sucrose, incubated at 30°C, 200rpm and initial pH of 6.0. Meanwhile, the crude enzymatic extract with higher activity of sucrase was achieved in a medium with 200g/L of sucrose, 200rpm, 30°C, initial pH of 7.0 and 6 hours of incubation. For the characterization of this crude enzymatic extract, as its activity in hydrolysis of sucrose, initially it was determined the ideal period of reaction with the substrate, being the period defined as 10 minutes. Later were determined the pH, the temperature and the concentration of sucrose great, being 4.0, 40°C and 0,15M respectively. The enzymatic system was more stable at pH 4.0, keeping 100% of your activity of sucrase, and pH values of 5,5 and 6,5... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Polissacarideos microbianos, Levana, Caracterização de levanasacarase, Zymomonas mobilis
Como citar
BOFO, Daniele Cristina dos Santos. Produção de levana por Zymomonas mobilis CCT 4494 em meio de cultura sacarose e caracterização do sistema enzimático responsável pela hidrólise de sacarose e de formação de levana. 2009. 105 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2009.