Aspergillus niger Morphology and Citric Acid Production in Submerged Batch Fermentation: Effects of Culture pH, Phosphate and Manganese Levels
Maria Papagianni1*, Michael Mattey, Marin Berovič2 and Bjorn Kristiansen3
Department of Bioscience and Biotechnology, University of Strathclyde, Glasgow, UK
1Department of Chemical Engineering, Ohio University, Athens, Ohio 45 701, U.S.A.
2 Department of Biotechnology, Faculty of Chemistry and Chemical Technology University of Ljubljana, Slovenia
3 Borregaard Industries, P.O. Box 162, Sarpsborg, Norway
Received March 18, 1999
Accepted June 14, 1999
Aspergillus niger, citric acid, morphology, pH, phosphate, manganese, agitation
The effects of culture pH, phosphate and manganese levels on citric acid production and Aspergillus niger morphology were studied under various agitation conditions in submerged batch culture. These factors were found to play important roles in both morphological development and process productivities. In all cases morphology was closely related to productivity and, irrespective of the parameter studied, similar morphological types were obtained. Lower citric acid productivities resulted always from the form of loose clumps with small central cores and a diffuse mass of filaments around them.
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