BACKGROUND The spore germination rate and growth characteristics were compared between the citric acid high-yield strain Aspergillus niger CGMCC 5751 and A. niger ATCC 1015 in media containing antimycin A or DNP. We inferred that differences in citric acid yield might be due to differences in energy metabolism between these strains. To explore the impact of energy metabolism on citric acid prod...

BACKGROUND Increasing interest of non-conventional yeasts has been observed for many years due to their biochemical characteristics and potential applications. Well-studied, oleaginous yeast Y. lipolytica is an attractive host for converting a low-cost glycerol, into value-added products such as erythritol (sweetener) or citric acid. Glycerol is an important renewable feedstock and is the main ...

the Stokes' equation (4). The anomalous appearance of the curves might suggest that a non-random sample had been selected, but examination of the frequencies of cells appearing in different size ranges reveals a normal distribution indicating that a random sample had been selected. The diameters of cells and the correspondent frequencies are: 3.5-2; 4.0-7; 4.5-10; 5.0-20; 5.5-17; 6.0-8; 6.5-2; ...

Response surface methodology (RSM) was employed to study the effects of four medium components (L-glutamic acid, citric acid, glycerol and NH4Cl) on the production of poly-γ-glutamic acid (PGA) in flask cultures by Bacillus licheniformis CCRC 12826 (ATCC 9945) with initial medium pH 6.5. The optimal PGA yield (35.34 g/L, average of four repeats) was appeared at the region where the respective c...

Today, biofuels represent a hot topic in the context of petroleum and adjacent products decrease. As biofuels production increase, so does the production of their major byproduct, namely crude glycerol. The efficient usage of raw glycerol will concur to the biodiesel viability. As an inevitable waste of biodiesel manufacturing, glycerol is potentially an attractive substrate for the production ...

Citric acid is the most widely used organic acid in the field of foods and beverages as an acidulant as well as in pharmaceutical and chemical products. Generally, surface or submerged fungal fermentation mainly with aspergillus niger is utilized for citric acid production. However, the submerged fermentation method is the most used method for citric acid production.1,2 The method of calcium sa...

Citric acid is mainly produced by solid state fermentation by the filamentous fungus Aspergillus niger. Production of citric acid depends strongly on an appropriate strain and on operational conditions such as aeration, type and concentration of carbon source, nitrogen and phosphate limitation, pH, temperature, concentration of trace elements and morphology of the producer organism. The yield o...

Abstract Background Citric acid, an intermediate product of the Krebs cycle, has a wide usage area in food industry since it some functions such as acidulant, flavouring agent, preservative and antioxidant. Although molds are most commonly used microorganisms citric acid production, is known that there significant advantages using yeasts. Purpose scope The microbial production mechanism needs t...