TRANSCRIPT LEVELS OF THE IPNA GENE FROM ASPERGILLUS-NIDULANS GROWN INA 2-1 STIRRED-TANK REACTOR

Aspergillus nidulans was grown in a 2-1 stirred tank reactor containin g a complex medium and repressing levels of glucose (30 g l(-1)). When batch cultivations were carried out with the pH controlled at 5, ipnA mRNA was not detectable at any time during the cultivation. When pH w as controlled a; 6.5 however, ipnA mRNA was detectable in both the exp onential and stationary phases. The levels of ipnA mRNA remained const ant throughout growth, relative to actin mRNA. Maintenance of dissolve d oxygen tension above 30%, which resulted in an increase in growth ra te during the exponential phase, did not affect ipnA transcript levels in cultivations carried out at either pH 5 or 6.5. (C) 1997 Elsevier Science B.V.