title: The influence of ultrasonic waves, alone and in presence of certain salts on the microbial production of citric acid by Aspergillus niger.
abstract: The influence of ultrasonic waves, alone and in presence of different (0.1, 0.5, and 1.0%) concentrations of NaCl, KH2PO4 and NH4Cl on the microbial production of citric acid by Aspergillus niger was studied. It was observed that in presence of sonic waves alone the yield of citric acid was generally better than that of control. Besides, some morphological changes in the diameter of the conidiophore of the of the mould was also noted. The effect of sonics in presence of NaCl was inconspicuous since at all sonic doses taken for the study, the yield of citric acid was less in comparison to the control. However, in presence of 0.5% KH2PO4 the yield was comparatively better (42.2%) over the control. The best result obtained amongst these treatments was found with the effect of sonics in presence of 0.5% NH4Cl in which the optimum yield of citric acid produced was greater than that of the control by 52.4%.
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology*; D001234:Aspergillus niger / Q000187:drug effects / Q000378:metabolism*; D002951:Citrates / Q000096:biosynthesis*; D005285:Fermentation; D010710:Phosphates / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D014465:Ultrasonics
chemical_list: D002951:Citrates; D010710:Phosphates; D000643:Ammonium Chloride; D012965:Sodium Chloride