Características reológicas do exopolissacarídeo botiosferana produzido pelo Botryosphaeria rhodina MAMB-05 em três fontes de carbono: glucose, frutose e sacarose
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Data
2008-06-02
Autores
Bongiovani, Raphael Alves Macedo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os exopolissacarídeos (EPS) são polímeros produzidos por uma grande variedade de microrganismos e podem possuir propriedades físicas, estruturais e químicas diferentes. Considerando o interesse crescente das indústrias na busca de polissacarídeos que apresentem comportamento reológico compatível com sua aplicação, tanto nos setores de alimentos como farmacêutico, cosmético e têxtil, pesquisas vêm sendo realizadas com a esperança da descoberta de novas moléculas promissoras para tais aplicações. O objetivo deste trabalho foi determinar as características reológicas do exopolissacarídeo (botriosferana) produzido pelo Botryosphaeria rhodina MAMB-05 em três fontes de carbono: glucose (EPSGLU), sacarose (EPSSAC) e frutose (EPSFRU). A análise da composição monossacarídica, após hidrólise ácida, mostrou que todos os polímeros são constituídos exclusivamente por glucose e a cromatografia de filtração em gel indicou baixo grau de polidispersividade. Experimentos com o corante Congo Red evidenciaram a presença de tripla hélice nos três polímeros produzidos pelo fungo B. rhodina MAMB-05. Os três polissacarídeos comportaram-se como fluidos não-Newtoniano com características de soluções pseudoplásticas e tixotrópicas e com diminuição da viscosidade quando em presença de NaCl. As soluções aquosas de EPSGLU, EPSSAC e EPSFRU apresentaram comportamento viscoelástico, com características de gel forte em 5 e 25°C, não sofrendo mudanças no comportamento, mesmo em presença de NaCl, a 25°C. As soluções polissacarídeos mantiveram as características de géis fortes, com propriedades termoestáveis e termorresistentes, entre 5 a 95°C de temperatura. Esses resultados permitiram concluir que os EPS produzidos pelo fungo B. rhodina MAMB-05 possuem propriedades químicas e físicas, passíveis de utilização nas indústrias de alimentos, farmacêutica, cosmética e biomédica.
Exopolysaccharides (EPS) are polymers produced by a great variety of microorganisms and can possess different physical and chemical properties, and structural features. Considering the growing interest in commercial applications of polysaccharides that show rheological compatible behavior within the application, as in the food, pharmaceutical, cosmetic and textile sectors, research have been developed in attempts to discover new promising biomolecules for such applications. The objective of the work presented was to determine the rheological characteristics of the exopolysaccharide botryosphaeran produced by Botryosphaeria rhodina MAMB-05 on three different sole carbon sources: glucose (EPSGLU), sucrose (EPSSUC) and fructose (EPSFRU). The analysis of monosaccharide composition, after acid hydrolysis, showed glucose as the only component and the gel permeation chromatography indicated that the EPSs have an excellent purity grade. All three biopolymers produced by B. rhodina MAMB-05 were found to exist in the triple helix conformational state. The three exopolysaccharides showed non-Newtonian behavior, with pseudoplastic and thixotropic characteristics, and showed a slight decrease in viscosity in presence of NaCl. The three biopolymer gels showed viscoelastic behavior, with characteristics of strong gelling at 5 ºC and 25 ºC, without suffering behavioral changes, even in the presence of NaCl at 25 ºC. The polysaccharide solutions kept the strong gel characteristics possessing thermo-stable and thermo-resistant properties when evaluating the influence of temperature (5 – 95 ºC) over the viscoelastic behavior of solutions. The results concluded that the EPS’s produced by fungus B. rhodina MAMB-05 have physical and chemical properties amenable for use in the food, pharmaceutical, cosmetic and biomedical industries.
Exopolysaccharides (EPS) are polymers produced by a great variety of microorganisms and can possess different physical and chemical properties, and structural features. Considering the growing interest in commercial applications of polysaccharides that show rheological compatible behavior within the application, as in the food, pharmaceutical, cosmetic and textile sectors, research have been developed in attempts to discover new promising biomolecules for such applications. The objective of the work presented was to determine the rheological characteristics of the exopolysaccharide botryosphaeran produced by Botryosphaeria rhodina MAMB-05 on three different sole carbon sources: glucose (EPSGLU), sucrose (EPSSUC) and fructose (EPSFRU). The analysis of monosaccharide composition, after acid hydrolysis, showed glucose as the only component and the gel permeation chromatography indicated that the EPSs have an excellent purity grade. All three biopolymers produced by B. rhodina MAMB-05 were found to exist in the triple helix conformational state. The three exopolysaccharides showed non-Newtonian behavior, with pseudoplastic and thixotropic characteristics, and showed a slight decrease in viscosity in presence of NaCl. The three biopolymer gels showed viscoelastic behavior, with characteristics of strong gelling at 5 ºC and 25 ºC, without suffering behavioral changes, even in the presence of NaCl at 25 ºC. The polysaccharide solutions kept the strong gel characteristics possessing thermo-stable and thermo-resistant properties when evaluating the influence of temperature (5 – 95 ºC) over the viscoelastic behavior of solutions. The results concluded that the EPS’s produced by fungus B. rhodina MAMB-05 have physical and chemical properties amenable for use in the food, pharmaceutical, cosmetic and biomedical industries.
Descrição
Palavras-chave
Exopolysaccharides, Botryosphaeria rhodina MAMB-05, Botryosphaeran, Rheological analyses, Microbiologia industrial, Exopolissacarídeo, Polissacarideos microbianos, Botriosferana, Análises reológicas
Como citar
BONGIOVANI, Raphael Alves Macedo. Características reológicas do exopolissacarídeo botiosferana produzido pelo Botryosphaeria rhodina MAMB-05 em três fontes de carbono: glucose, frutose e sacarose. 2008. 112 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2008.