Abstract:

The effect of a second carbon source and amino acids on the production of cylcosporin A (CyA) in a medium optimized by one factor at a time and orthogonal array method was studied. The one factor at-a-time method was adopted to investigate the effects of medium components (i.e. carbon, and nitrogen) and environmental factors (i.e. initial pH) on biomass growth and CyA production. Subsequently, L16 orthogonal matrix was used to evaluate the significance of glucose, ammonium sulphate, K2HPO4 and inoculum size. The effects of media components were ranked according to their effects on the production of CyA as glucose > ammonium sulphate > K2HPO4 > inoculum size. The production increased from 58.35 mg/l to 148 mg/l when maltose (1 %) was added as a second carbon source after 8 days of fermentation. Evaluation of various amino showed that the addition of L-valine (6 g/l) and L-leucine (4 g/l) after 24 h fermentation enhanced the CyA production dramatically to 794 mg/l.