Controlled batch fermentations were carried out as follows: Media were prepared in demineralized water. Precultures of 100 ml (106 spores/ml) in 500 ml baffled Erlenmeyer flasks were inoculated for two days. As described previously, fermentations were carried out in 5 L Benchtop Fermentors (BioFlo 3000, New Brunswick Scientific Co., Inc.), at 33 degree. Air was used for sparging
the bioreactor at a constant flow of 0.25 vvm (vol. gas (vol. liquid-1 min-1), dissolved oxygen tension (D.O.) was maintained minimal at 25 % coupled with stirred speed of 400–1000 rpm, pH was initiated at 3.5 adjusted by 1.5 M H3PO4 (acid) and kept at 2.3 by addition of 4 M KOH (base). Struktol (Schill and Seilacher) was applied as antifoam agent though-out the fermentation.