Semicontinuous and Continuous Production of Citric Acid with Immobilized Cells of Aspergillus niger

1987 ◽  
Vol 42 (4) ◽  
pp. 408-413 ◽  
Author(s):  
H. Eikmeier ◽  
H. J. Rehm
Keyword(s):  
Citric Acid ◽  
Aspergillus Niger ◽  
Immobilized Cells ◽  
Continuous Production ◽  
Continuous Process ◽  
Batch Experiments ◽  
Medium Exchange ◽  
Free Cells ◽  
Semicontinuous Cultivation ◽  
Ca Alginate

Abstract The citric acid excretion of Ca-alginate-immobilized cells of Aspergillus niger in batch culture decreased with a half-time of approximately 19 days. Reactivation of the biocatalysts by regeneration in growth medium was possible, but it was followed by a submerged sporulation of the fungus, and medium was highly contaminated with free cells. Citric acid production could better be prolonged by semicontinuous cultivation with medium exchange every 7 or 14 days, respectively. After 32 days the remaining activity in semicontinuous culture was 1.4-fold higher than in comparable batch experiments. Similar improvements were obtained with a continuous process at a dilution rate of 0.125 v/v · d, whereby medium efflux completely free of detaching mycelia.

Cyclodextrin glycosyltransferase production by free cells of Bacillus circulans DF 9R in batch fermentation and by immobilized cells in a semi-continuous process

2015 ◽  
Vol 38 (6) ◽  
pp. 1055-1063 ◽  
Author(s):  
Hernán Costa ◽  
Jorgelina Rodríguez Gastón ◽  
Julia Lara ◽  
Camila Ortiz Martinez ◽  
Cristiane Moriwaki ◽  
...  
Keyword(s):  
Batch Fermentation ◽  
Immobilized Cells ◽  
Continuous Process ◽  
Bacillus Circulans ◽  
Cyclodextrin Glycosyltransferase ◽  
Free Cells

Production of Gallic Acid by Immobilized Aspergillus niger Using Polyurethane Foam as Solid Support

2011 ◽  
Vol 7 (6) ◽  
Author(s):  
Anita Srivastava ◽  
Rita Kar
Keyword(s):  
Aspergillus Niger ◽  
Gallic Acid ◽  
Polyurethane Foam ◽  
Acid Production ◽  
Immobilized Cells ◽  
Continuous Production ◽  
Solid Support ◽  
Simultaneous Increase ◽  
Acid Decarboxylase ◽  
Optimal Conditions

The present study was aimed at finding the optimal conditions for maximum gallic acid production using polyurethane-immobilized Aspergillus niger cells and determining the operational stability of recycled cells for gallic acid production. Maximum gallic acid (142 µg/ml) was produced with 1% tannic acid at 40°C, pH 5.0, with polyurethane foam size of 1.5 cm3 cubes after 48 h under submerged fermentation at 220 rpm, as compared to free cells, which produced 72 µg /ml gallic acid in 72 h at 37°C and pH 5.0. Continuous production of gallic acid by recycling of the immobilized cells resulted in maximum gallic acid production of 199 µg/ml after the fourth cycle, and thereafter remained stable till the seventh cycle and could be continued till the tenth cycle. Pyrogallol, a degradation product of gallic acid and gallic acid decarboxylase (GADC), was also monitored under static and aerobic states and showed comparable values, in contrast to bacteria where aeration caused inhibition. However, 72.73% inhibition of GADC activity by oxidizing agents with simultaneous increase in gallic acid production was observed. This is the first report of gallic acid production by immobilized A. niger cells, producing higher amounts of gallic acid in a shorter cultivation time.

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