a solid state fermentation method was developed for the production of citric acid from date pulp (obtained of date syrup production from the process) by aspergillus niger ptcc 5010. poor yield was obtained when potassium ferrocyanide treated date pulp were used as substrate, but methanol at a 3-4% concentration markedly increased the forma-tion of citric acid from the waste. the optimum range o...

2.2 Significance of decarboxylation 2.2.1 Role in biosynthetic pathways In the biochemical milieu, decarboxylation is a ubiquitous step for transformation of amino acids into various other secondary metabolites using specific enzymes termed decarboxylases [Liu and Zhang (2006)]. More importantly, nature has also employed decarboxylation as a central tool for linking metabolic pathways like glyc...

The inhibiting effect of ascorbic acid, citric acid and sodium chloride on Polyphenoloxidase (PPO) of Golden Delicious apple cubes was studied. Dipping in ascorbic acid (0.2-10 g/L range) and in NaCl (0.2-1 g/L range) solutions for 5 min increases the PPO activiry. Citric acid solutions (0.2-10 g / L range) have little or no inhibition of PPO. A 90-100% PPO inhibition was obtained with a 5 min ...

In view of the often-cited theory that citric acid accumulation is caused by an inhibition of aconitase activity, the equilibrium of the reaction of aconitase was investigated by comparing in vivo steady-state concentrations of citrate and isocitrate in Aspergillus niger grown under various citric acid-producing conditions. With the equilibrium catalyzed by the A. niger enzyme in vitro, similar...

Rumen microorganisms rapidly metabolize citric acid to carbon dioxide and acetic acid. The rate of metabolism varied between 0.00008 and 0.76 mumoles per g per min, the rate becoming higher as the citric acid concentration increased. The addition of potassium chloride to rumen contents decreased the rate of utilization. The results indicate that dietary citric acid is unlikely to accumulate in ...

Three types of methods have been proposed for the determination of citric acid in urine. Salant and Wise (1) used the unspecific mercuric sulfate reagent of Deniges (2) in a study of the toxicity of citrates. Thunberg (3) developed an enzymatic method employing a dehydrogenase said to be specific for citrate. The remaining methods depend on the so called pentabromoacetone method of Stahre (4), ...

Citric acid has been reported to increase utilization efficiency of dietary phytate-bound phosphorus and protein. Objective of this study was to determine the effects of citric acid on growth performance and nutrient retention of broiler chickens fed diets having two levels of non-phytate phosphorus and rice bran. Giving a completely randomize design in 2 × 2 × 2 factorial arrangement, 144 broi...

Novel citric acid based photoluminescent dyes and biodegradable polymers are synthesized via a facile "one-pot" reaction. A comprehensive understanding of the fluorescence mechanisms of the resulting citric acid-based fluorophores is reported. Two distinct types of fluorophores are identified: a thiozolopyridine family with high quantum yield, long lifetime, and exceptional photostability, and ...

The inherent non-linearity of citric acid fermentation from Aspergillus niger renders its control difficult, so there is a need to fine-tune the bioreactor performance for maximum production of citric acid in batch culture. For this, fuzzy logic is becoming a popular tool to handle non-linearity of a batch process. The present manuscript deals with fuzzy logic control of citric acid accretion b...