Effect of ultrasound on inulinase production from aspergillus niger fermentation

To improve the inulinase yield from Aspergillus niger by using ultrasound irradiation,the irradiation time,ultrasound frequency and different fermentation periods are examined.In the postponing phase and the first logarithmic growth phase(30 h) of Aspergillus niger,the ultrasuond of 40 kHz or 59 kHz has a marked inhibition on the inulinase produce from Aspergillus niger,and the higher frequency shows more stronger influence with a decrease of 47.1%.In the late logarithmic growth phase(36 h) of Aspergillus niger,on the contrary,the ultrasound of the two frequencies has a remarkable promotion on the inulinase produce,and the lower frequency shows more stronger influence with an increase of 29.3%.The results implied that ultrasound could promote enzymes production with microorganism fermentation under a certain condition.