Impact of bioreactor scale on lovastatin biosynthesis by Aspergillus terreus ATCC 20542 in a batch culture

摘要

Biosynthesis of lovastatin (a polyketide metabolite of Aspergillus terreus) in bioreactors of differentworking volume was studied to indicate how the change of scale of the process influences theformation of this metabolite. The experiments conducted in shake flasks of 150 ml working volumeallowed to obtain lovastatin titres at the level of 87.5 mg LOV l-1, when two carbon sources, namelylactose and glycerol were used. The application of the same components in a large stirred-tankbioreactor of 5.3-litre working volume caused a decrease of lovastatin production by 87% comparedto the shake flask culture. The deficiency of nitrogen in this bioreactor did not favour the formationof lovastatin, in contrast to the small bioreactor of 1.95-litre working volume, in which lovastatintitres comparable to those in the shake flasks could be achieved, when organic nitrogenconcentration was two-fold decreased. When the control of pH and/or pO2 was used simultaneously,an increase in lovastatin production was observed in the bioreactors. However, these results werestill slightly lower than lovastatin titres obtained in the shake flasks.