Production of Polygalacturonases by Aspergillus section Nigri Strains in a Fixed Bed Reactor

Molecules. 2013;18(2):1660-1671 DOI 10.3390/molecules18021660


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Journal Title: Molecules

ISSN: 1420-3049 (Print)

Publisher: MDPI AG

LCC Subject Category: Science: Chemistry: Organic chemistry

Country of publisher: Switzerland

Language of fulltext: English

Full-text formats available: PDF, HTML



Marília Maciel
Cristiane Ottoni
Cledir Santos
Nelson Lima
Keila Moreira
Cristina Souza-Motta


Blind peer review

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Time From Submission to Publication: 11 weeks


Abstract | Full Text

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.