%0 Journal Article
%T Production of Polygalacturonases by Aspergillus section Nigri Strains in a Fixed Bed Reactor
%A Mar¨ªlia Maciel
%A Cristiane Ottoni
%A Cledir Santos
%A Nelson Lima
%A Keila Moreira
%A Cristina Souza-Motta
%J Molecules
%D 2013
%I MDPI AG
%R 10.3390/molecules18021660
%X Polygalacturonases (PG) are pectinolytic enzymes that have technological, functional and biological applications in food processing, fruit ripening and plant-fungus interactions, respectively. In the present, a microtitre plate methodology was used for rapid screening of 61 isolates of fungi from Aspergillus section Nigri to assess production of endo- and exo-PG. Studies of scale-up were carried out in a fixed bed reactor operated under different parameters using the best producer strain immobilised in orange peels. Four experiments were conducted under the following conditions: the immobilised cells without aeration; immobilised cells with aeration; immobilised cells with aeration and added pectin; and free cells with aeration. The fermentation was performed for 168 h with removal of sample every 24 h. Aspergillus niger strain URM 5162 showed the highest PG production. The results obtained indicated that the maximum endo- and exo-PG activities (1.18 U¡¤mL £¿1 and 4.11 U¡¤mL £¿1, respectively) were obtained when the reactor was operating without aeration. The microtitre plate method is a simple way to screen fungal isolates for PG activity detection. The fixed bed reactor with orange peel support and using A. niger URM 5162 is a promising process for PG production at the industrial level.
%K Aspergillus niger
%K orange peel
%K immobilization cells
%K polygalacturonases
%K fixed bed reactor
%U http://www.mdpi.com/1420-3049/18/2/1660