Infuência de diferentes limitações nutricionais sobre a produção de retamicina por Streptomyces olindensis ICB20.

Abstract

The aim of the present work was to assay the influence of different nutrient limitation on the production of retamycin by Streptomyces olindensis ICB20. A series of continuous cultures was performed using carbon-limited, phosphate-limited or nitrogen-limited media, varying the dilution rate (D) between 0.025 and 0.075 h-1. The analysis of the cultures data showed that the production of retamycin was favored under phosphate limitation, resulting in values of specific production rate (qRTM) as high as 9.2 mg/g.h at D=0.075 h-1 , additionally, qRTM varied linearly with D, hence, with the specific growth rate; however such relationship was not observed in carbonlimited neither nitrogen-limited cultures. The use of nitrogen-limited medium led to the lowest production rates, with a maximum value of 4.2 mg/g.h at D=0.043 h-1. Cultures using carbon-limited medium resulted in intermediary values of qRTM, varying between 3.0 and 6.6 mg/g.h. The highest values of biomass yield (Y X/GLC) were obtained in cultures using carbon-limited medium, approximately 0.40, while under nitrogen and phosphate limitation, Y X/GLC varied around 0.30. To study the effect of different glucose concentration in the feed medium, continuous cultures using phosphate-limited medium with glucose concentration varying between 10 g/L and 25 g/L were performed. The culture results showed that the use of glucose concentration higher than 10 g/L in the feeding medium led to lower production of retamycin, possibly due to catabolic repression. The data of image analysis showed no clear relation between nutrient limitation and morphology neither between objects dimensions and retamycin production. However, there seems to be a relation between the percentage in area of different morphological classes and retamycin production, apparently the production is inversely proportional to the percentage of clumps.

Modelagem matemática do processo fermentativo de produção de retamicina por microrganismo filamentoso Streptomyces olindensis.

“…Politécnica da USP (DEQ-EPUSP) (Guimarães, 2000;Martins, 2001;Pamboukian, 2003;Guimarães, 2005;Inoue, 2006 antibiótico antitumoral retamicina (Lyra et al, 1968apud Pamboukian, 2003. A fim de se aumentar a produtividade em retamicina, foi obtida uma cepa mutante de Streptomyces olindensis, denominada ICB20, pelo Laboratório de Genética do Instituto de Ciências Biomédicas da USP (ICB-USP), a qual apresentou uma produtividade em retamicina significativamente superior à da linhagem selvagem (Pamboukian, 2003).…”

Estudo da produção do antibiótico antitumoral retamicina em biorreatores com células imobilizadas de Streptomyces olindensis ICB20.

“…O estudo da produção do antitumoral retamicina pela linhagem Streptomyces olindensis ICB20 encontra-se em desenvolvimento no Laboratório de Engenharia Bioquímica do Departamento de Engenharia Química da Escola Politécnica da USP (LEB/DEQ/EPUSP) desde o final da década de 1990. Alguns trabalhos realizados anteriormente estudaram temas como: diferentes formas de condução do processo (PAMBOUKIAN, 2003), a influência das fontes de carbono e nitrogênio e de limitações nutricionais (GUIMARÃES, 2005;INOUE, 2006) e a comparação de diferentes suportes para a imobilização das células (AZEVEDO, 2005).…”