Aspergillus terreus Broth Rheology, Oxygen Transfer, and Lovastatin Production in a Gas-Agitated Slurry Reactor
详细信息 查看全文
- 作者：E. M. Rodrí ; guez Porcel ; J. L. Casas Ló ; pez ; J. A. Sá ; nchez Pé ; rez ; J. M. Ferná ; ndez Sevilla ; J. L. Garcí ; a Sá ; nchez ; and Y. Chisti
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2006
- 出版时间：June 21, 2006
- 年：2006
- 卷：45
- 期：13
- 页码：4837 - 4843
- 全文大小：376K
- 年卷期：v.45,no.13(June 21, 2006)
- ISSN：1520-5045
文摘
A 20 L gas-agitated slurry bubble column bioreactor was used to investigate the effects of nonmechanicallow-intensity agitation on development of broth rheology and fungal pellet morphology during production oflovastatin by the filamentous fungus Aspergillus terreus. Fermentations were carried out under elevateddissolved oxygen levels (400% of air saturation) at gassing rates that ranged from 0.5 to 1.5 vvm. Variousinitial concentrations of the growth limiting nitrogen source were used to attain different total biomassconcentrations, to observe the effect of this variable on development of pellets and the rheology of thefermentation broth. The non-Newtonian rheology of the fermentation broth was influenced both by the biomassconcentration and the size of the fungal pellets. The stable pellet diameter ranged from ~2300 to ~2900 
m.Too low turbulence (gassing rate of 0.5 vvm) and low dissolved oxygen levels adversely affected lovastatinproduction. The best biomass specific production of lovastatin was attained at high biomass concentrationsunder oxygen-rich conditions that were not excessively turbulent. In fermentation broths with various rheologies,the oxygen-transfer coefficient in the bubble column correlated with the aeration velocity, biomass concentration,and effective viscosity of the broth. The correlations obtained were significantly different for broths withpelleted growth and those with filamentous growth.
m.Too low turbulence (gassing rate of 0.5 vvm) and low dissolved oxygen levels adversely affected lovastatinproduction. The best biomass specific production of lovastatin was attained at high biomass concentrationsunder oxygen-rich conditions that were not excessively turbulent. In fermentation broths with various rheologies,the oxygen-transfer coefficient in the bubble column correlated with the aeration velocity, biomass concentration,and effective viscosity of the broth. The correlations obtained were significantly different for broths withpelleted growth and those with filamentous growth.