Effect of simple and complex carbon sources, low temperature culture and complex carbon feeding policies on poly-3-hydroxybutyric acid (PHB) content and molecular weight (Mw) from...

• Autores: Quagliano, J. C.; Amarilla, Fernando Enrique; Fernandes, E. G.; Mata, D.; Miyazaki, S. S.
• Año de publicación: 2001
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Química; Ciencias Exactas; Azotobacter chroococcum 6B; culture temperature; molasses; molecular weight; poly-3-hydroxybutyrate
• Institución: Universidad Nacional de La Plata

The molecular weight (Mw) of poly-3-hydroxybutyrate (PHB), produced by shake-flask culture of Azotobacter chroococcum showed little variation with increasing glucose concentration as carbon source (being in the range of 400–500 kDa), while M; w increased from 300–400 to 640 kDa when grown with increasing concentration of sugar cane molasses. Molecular weight increased nearly 30% from 48 to 72 h culture time when 5% molasses as carbon source was used, while with glucose the highest M; w was reached at 48 h. Under fermentor cultivation A. chroococcum produced PHB with a relatively high M; w of 1590 kDa at 53 h culture time when grown in modified Burk's medium with glucose as carbon source at an initial C/N ratio (molar basis) of 69 under fermentor cultivation. A batch glucose-grown ammonium-limited fermentor culture was repeatedly fed with sugar cane molasses (initial C/N ratio 69) and it was observed that PHB content curve decreased at a slower rate than in the fed-batch culture in which glucose and sucrose were not consumed in the culture medium after the feed.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas