Gluconic acid is an organic compound with a molecular formula of C6H12O7 and condensed structural formula HOCH2 (CHOH)4 COOH. It is one of the 16 stereoisomers of 2, 3, 4, 5, 6-pentahydroxyhexanoic acid commonly known as dextronic acid.
In aqueous solution at neutral pH, gluconic acid forms the Gluconate ion. The salts of gluconic acid are known as "Gluconates". Gluconic acid, gluconate salts, and gluconate esters occur widely in nature as these compounds arise from the oxidation of glucose. Some drugs are injected in the form of gluconates.
The chemical structure of gluconic acid consists of a six-carbon chain with five hydroxyl groups terminating in a carboxylic acid group. In aqueous solution, gluconic acid exists in equilibrium with its cyclic ester glucono delta-lactone. Gluconic acid occurs naturally in fruits, honey, Kombucha tea, and wine.
Gluconic acid can be obtained by chemical synthesis, on account of its superior selectively; however microbial production is highly preferred. A series of microorganisms under the genus of Aspergillus, Penicillin, Gluconobacter, Pseudomonas, Phytomonas, Achromobacter, Klebsiella, Zymomonas, and Acetobacter have already been used for microbial production of gluconic acid. A yeast-like fungal culture,Aureobasidium pullulans was also known for the production of small amounts of gluconic acid.
For microbial production of gluconic acid, predominantly, Aspergillus niger or Gluconobacter suboxidans are in industrial use. Aspergillus niger is difficult to handle, as it causes clogging and unsuitable for the continuous production. This is mainly due to the drawback that cell growth and gluconic formation would not be possible simultaneously. On the other hand, Gluconobacter has been found to produce a relatively large quantity of keto acids during production. These keto acids complicate the processing and isolation of the pure gluconic acid.
Gluconic acid is a multifunction carbonic acid and it is used extensively in various applications with its physiological and chemical characteristics.
Used as a raw material for the manufacturing of gluconate salts with minerals like Calcium, Sodium, Potassium, and Manganese etc.