Estudo da composição de meios de cultura para a produção de cefamicina C por Streptomuces clavuligerus
Carregando...
Data
2007-12-12
Autores
Antonio, Tatiana [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os grupos de antibióticos mais importantes clinicamente são os dos b-lactâmicos, aminoglicosídeos e tetraciclinas. Streptomyces clavuligerus produz vários compostos b- lactâmicos, com destaque para os antibióticos envolvidos na rota biossintética da cefalosporina C (penicilina N, deacetoxicefalosporina C e cefamicina C) e o ácido clavulânico (AC) que, embora não tenha atividade biológica significativa, é um potente inibidor de b-lactamases (penicilinases e cefalosporinases). A cefamicina C (CefC) é uma 7-metoxi-cefalosporina que apresenta maior atividade que a cefalosporina C (CPC), produzida somente por fungos, por ser resistente a b-lactamases. Apesar das rotas biossintéticas de AC e CefC serem completamente independentes em S. clavuligerus, são controladas pelo mesmo elemento multifuncional (ccaR), o que dificulta a indução da produção de um ou outro composto durante o processo fermentativo. No presente trabalho, procurou-se obter maiores concentrações de CefC manipulando-se componentes em meio solúvel de cultivo de S. clavuligerus, selecionados dentre compostos que, segundo a literatura, atuam como agentes reguladores da síntese daquele antibiótico. As fermentações foram realizadas em frascos agitados (28ºC, 260 rpm) para selecionar fontes de C e de N e, então, avaliar o processo no melhor meio-padrão, variando-se concentrações combinadas de L-lisina (10 a 108 mM) e -cetoglutarato (3 a 110 mM) através de metodologia de planejamento experimental. A presença de -cetoglutarato acarretou em aumento indesejável de pH, afetando negativamente o processo e os melhores resultados (entre 300 e 400 mg CPC totais/L após 72 horas de fermentação) foram obtidos no meio adotado como meio-controle, contendo amido e extrato protéico de semente de algodão como principais fontes de C e N, respectivamente, e L-lisina.
The most important groups of antibiotics, from a clinical standpoint, are -lactams, aminoglycosides and tetracyclines. Streptomyces clavuligerus produces several -lactam compounds, primarily the antibiotics involved in the biosynthetic route of cephalosporin C (penicillin N, deacetoxycephalosporin C and cephamycin C) and clavulanic acid (CA), which, despite its slight biological activity, is a potent inhibitor of -lactamases (penicillinases and cephalosporinases). Cephamycin C (CMC) is a 7-methoxycephalosporin with higher bioactivity than cephalosporin C (CPC) because it is more resistant to -lactamases. Although the biosynthetic routes of CA and CMC are completely independent in S. clavuligerus, they are controlled by a common multi-functional element (ccaR), which hinders induction of the production of one or the other compound during the fermentation process. In this work, we sought to obtain higher concentrations of CMC by handling compounds in a soluble medium of S. clavuligerus, which were selected from compounds that, according to the literature, act as regulating agents in the synthesis of that antibiotic. Fermentation was carried out in flasks under shaking (28ºC, 260 rpm), in order to select sources of C and N. The process was then evaluated in the best standard medium, by varying combined concentrations of lysine (10 to 108 mM) and -ketoglutarate (3 to 110 mM) using an experimental planning methodology. The presence of -ketoglutarate caused an undesirable increase in pH, negatively affecting the process. The best results (between 300 and 400 mg/L of total CPC after 72 h of fermentation) were obtained in the medium used as the control, which contained starch and cottonseed protein extract as main sources, respectively, of C and N, and L-lysine.
The most important groups of antibiotics, from a clinical standpoint, are -lactams, aminoglycosides and tetracyclines. Streptomyces clavuligerus produces several -lactam compounds, primarily the antibiotics involved in the biosynthetic route of cephalosporin C (penicillin N, deacetoxycephalosporin C and cephamycin C) and clavulanic acid (CA), which, despite its slight biological activity, is a potent inhibitor of -lactamases (penicillinases and cephalosporinases). Cephamycin C (CMC) is a 7-methoxycephalosporin with higher bioactivity than cephalosporin C (CPC) because it is more resistant to -lactamases. Although the biosynthetic routes of CA and CMC are completely independent in S. clavuligerus, they are controlled by a common multi-functional element (ccaR), which hinders induction of the production of one or the other compound during the fermentation process. In this work, we sought to obtain higher concentrations of CMC by handling compounds in a soluble medium of S. clavuligerus, which were selected from compounds that, according to the literature, act as regulating agents in the synthesis of that antibiotic. Fermentation was carried out in flasks under shaking (28ºC, 260 rpm), in order to select sources of C and N. The process was then evaluated in the best standard medium, by varying combined concentrations of lysine (10 to 108 mM) and -ketoglutarate (3 to 110 mM) using an experimental planning methodology. The presence of -ketoglutarate caused an undesirable increase in pH, negatively affecting the process. The best results (between 300 and 400 mg/L of total CPC after 72 h of fermentation) were obtained in the medium used as the control, which contained starch and cottonseed protein extract as main sources, respectively, of C and N, and L-lysine.
Descrição
Palavras-chave
Biotecnologia, Streptomyces clavuligerus, Fermentação, Cefamicina C, Beta-lactâmicos, Cephalosporin C
Como citar
ANTONIO, Tatiana. Estudo da composição de meios de cultura para a produção de cefamicina C por Streptomuces clavuligerus. 2007. 67 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química., 2007.