EFFECT OF TEMPERATURE-CHANGE AND AERATION ON THE PRODUCTION OF THE ANTIFUNGAL PEPTIDE ANTIBIOTIC ITURIN BY BACILLUS-SUBTILIS NB22 IN LIQUIDCULTIVATION

The effects of temperature and air supply on the production of the ant ifungal lipopeptide antibiotic, iturin by Bacillus subtilis NB22 in a 5-d course of liquid cultivation were investigated on a flask scale. C hanging the temperature from 30-degrees-C to 25, 37, 42, or 48-degrees -C for one day during the 5-d cultivation reduced the amount of iturin producted in comparison with cultivation at a constant 30-degrees-C. The temperature on the first day was notably critical. When the air su pply was varied by changing the pings of the shaking flasks, the air s upply was also critical on the first day. When cells spent the first d ay with an inappropriate temperature or air supply, the decrease in it urin production could not be compensated for during the subsequent 4-d cultivation at an adequate temperature and air supply. Although ituri n production was significant on the second and third days when the gro wth of the bacterium had leveled off, the initial conditions severely affected the yield of the product.