Topic
Citric acid
About: Citric acid is a research topic. Over the lifetime, 17745 publications have been published within this topic receiving 277125 citations. The topic is also known as: citrate & H3cit.
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TL;DR: In this paper, hot air (40°C, 2 ¼ d) treatment (HAT) was found to have significant effects on both degradation of the organic acids, especially on citric acid, and accumulation of soluble sugars, particularly on fructose and glucose.
108 citations
TL;DR: The oxygen transfer coefficient increases with the agitation rate and the oxygen consumption rate increased almost linearly with the biomass concentration; however, substrate consumption was highest at HOT conditions.
107 citations
TL;DR: The optimal cultivation conditions ensuring the maximal rate of citric acid (CA) biosynthesis by glycerol-grown mutant Yarrowia lipolytica NG40/UV7 were found to be as follows: growth limitation by inorganic nutrients, 28 °C, pH 5.0, dissolved oxygen concentration (pO2) of 50 % (of air saturation), and pulsed addition of Glycerol from 20 to 80 g L−1 depending on the
Abstract: The optimal cultivation conditions ensuring the maximal rate of citric acid (CA) biosynthesis by glycerol-grown mutant Yarrowia lipolytica NG40/UV7 were found to be as follows: growth limitation by inorganic nutrients (nitrogen, phosphorus, or sulfur), 28 °C, pH 5.0, dissolved oxygen concentration (pO₂) of 50 % (of air saturation), and pulsed addition of glycerol from 20 to 80 g L⁻¹ depending on the rate of medium titration. Under optimal conditions of fed-batch cultivation, in the medium with pure glycerol, strain Y. lipolytica NG40/UV7 produced 115 g L⁻¹ of CA with the mass yield coefficient of 0.64 g g⁻¹ and isocitric acid (ICA) amounted to 4.6 g L⁻¹; in the medium with raw glycerol, CA production was 112 g L⁻¹ with the mass yield coefficient of 0.90 g g⁻¹ and ICA amounted to 5.3 g L⁻¹. Based on the activities of enzymes involved in the initial stages of raw glycerol assimilation, the tricarboxylic acid cycle and the glyoxylate cycle, the mechanism of increased CA yield from glycerol-containing substrates in Y. lipolytica yeast was explained.
107 citations
TL;DR: An acetate negative mutant of Yarrowia lipolytica Wratislavia AWG7 was found to be suitable for the production of high amounts of citric acid in long-term repeated-batch cultures.
Abstract: An acetate negative mutant of Yarrowia lipolytica Wratislavia AWG7 was found to be suitable for the production of high amounts of citric acid in long-term repeated-batch cultures. When 40% of fresh replaced medium was fed, this strain produced 154 g l−1, on average, which corresponded to a 0.78 g g−1 yield and a productivity of 1.05 g l−1 h−1. The activity of the culture remained stable for more than 1,650 h, i.e., 16 cycles of the repeated-batch bioreactors.
107 citations
TL;DR: The results show a correlation between absorption pattern and chemical structure; e.g. hydroxyl groups, in addition to carboxyls, were connected with a positive influence.
Abstract: It has previously been suggested that organic acids enhance iron absorption. We have studied the effect of nine organic acids on the absorption of Fe(II) and Fe(III) in the human epithelial cell line Caco-2. The effect obtained was dose-dependent, and the greatest increase (43-fold) was observed for tartaric acid (4 mmol/L) on Fe(III) (10 micromol/L). Tartaric, malic, succinic, and fumaric acids enhanced Fe(II) and Fe(III) uptake. Citric and oxalic acid, on the other hand, inhibited Fe(II) uptake but enhanced Fe(III) uptake. Propionic and acetic acid increased the Fe(II) uptake, but had no effect on Fe(III) uptake. Our results show a correlation between absorption pattern and chemical structure; e.g. hydroxyl groups, in addition to carboxyls, were connected with a positive influence. The results may be important for elucidating factors affecting iron bioavailability in the small intestine and for the development of foods with improved iron bioavailability.
107 citations