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Citric Acid Production (citric + acid_production)

Distribution by Scientific Domains
Life Sciences83%

Selected Abstracts

Citric acid production by Aspergillus niger ATCC 9142 from a treated ethanol fermentation co-product using solid-state fermentation

LETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009
G. Xie
Abstract Aims:, To investigate the ability of the citric acid-producing strain Aspergillus niger ATCC 9142 to utilize the ethanol fermentation co-product corn distillers dried grains with solubles for citric acid production following various treatments. Methods and Results:, The ability of A. niger ATCC 9142 to produce citric acid and biomass on the grains was examined using an enzyme assay and a gravimetric method, respectively. Fungal citric acid production after 240 h was higher on untreated grains than on autoclaved grains or acid-hydrolysed grains. Fungal biomass production was enhanced after autoclaving and acid-hydrolysis of the grains. Phosphate supplementation to the grains slightly stimulated citric acid production while methanol addition decreased its synthesis. Using the phosphate-supplemented grains, the optimal incubation temperature, initial moisture content of the grains and the length of fermentation time for ATCC 9142 citric acid production were determined to be 25°C, 82% and 240 h, respectively. Conclusions:,A. niger ATCC 9142 synthesized citric acid on corn distillers dried grains with solubles. The phosphate-treated grains increased citric acid production by the strain. Significance and Impact of the Study:, The ethanol fermentation co-product corn distillers dried grains with solubles could be useful commercially as a substrate for A. niger citric acid production. [source]

Biosensor online control of citric acid production from glucose by Yarrowia lipolytica using semicontinuous fermentation

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2010
Lucie Moeller
Abstract Our study aimed at the development of an effective method for citric acid production from glucose by use of the yeast Yarrowia lipolytica. The new method included an automated bioprocess control using a glucose biosensor. Several fermentation methodologies including batch, fed-batch, repeated batch and repeated fed-batch cultivation were tested. The best results were achieved during repeated fed-batch cultivation: Within 3 days of cycle duration, approximately 100,g/L citric acid were produced. The yields reached values between 0.51 and 0.65,g/g and the selectivity of the bioprocess for citric acid was as high as 94%. Due to the elongation of the production phase of the bioprocess with growth-decoupled citric acid production, and by operating the fermentation in cycles, an increase in citric acid production of 32% was achieved compared with simple batch fermentation. [source]

Organic acids: old metabolites, new themes

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2006
Israel Goldberg
Abstract Fumaric, L -malic and citric acids are intermediates of the oxidative tricarboxylic acid (TCA) cycle which in eukaryotes is localized in mitochondria. These organic acids are synthesized and accumulated in the medium to very high concentrations by filamentous fungi such as Aspergillus spp. and Rhizopus sp. This article reviews basic research on the unusual acid production capability and the associated metabolic pathways operating under defined stress conditions in these specific fungi. In particular, we describe and discuss the importance of the cytosolic reductive TCA pathway, which includes the cytosolic activities of pyruvate carboxylase, malate dehydrogenase and fumarase, for production of fumaric and L -malic acids. This article also describes the differences between fumaric acid, L -malic acid and citric acid production by different organisms (filamentous fungi, yeast, and higher eukaryotes), and the possible application of novel technologies (genetic engineering and bioinformatics) to fungal systems which may offer new industrial potential of filamentous fungi for the production of valuable metabolites. Copyright © 2006 Society of Chemical Industry [source]

Citric acid production by Aspergillus niger ATCC 9142 from a treated ethanol fermentation co-product using solid-state fermentation

LETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009
G. Xie
Abstract Aims:, To investigate the ability of the citric acid-producing strain Aspergillus niger ATCC 9142 to utilize the ethanol fermentation co-product corn distillers dried grains with solubles for citric acid production following various treatments. Methods and Results:, The ability of A. niger ATCC 9142 to produce citric acid and biomass on the grains was examined using an enzyme assay and a gravimetric method, respectively. Fungal citric acid production after 240 h was higher on untreated grains than on autoclaved grains or acid-hydrolysed grains. Fungal biomass production was enhanced after autoclaving and acid-hydrolysis of the grains. Phosphate supplementation to the grains slightly stimulated citric acid production while methanol addition decreased its synthesis. Using the phosphate-supplemented grains, the optimal incubation temperature, initial moisture content of the grains and the length of fermentation time for ATCC 9142 citric acid production were determined to be 25°C, 82% and 240 h, respectively. Conclusions:,A. niger ATCC 9142 synthesized citric acid on corn distillers dried grains with solubles. The phosphate-treated grains increased citric acid production by the strain. Significance and Impact of the Study:, The ethanol fermentation co-product corn distillers dried grains with solubles could be useful commercially as a substrate for A. niger citric acid production. [source]