Biodegradation of tannic acid by Citrobacter freundii isolated from a tannery effluent.
A bacterial strain capable of utilizing tannic acid as sole carbon source was isolated from the effluent of a tannery and was identified as Citrobacter freundii. This organism could grow at concentrations as high as 5% (w/v) of tannic acid and produced extracellular tannase to hydrolyze the same. When grown in minimal medium containing 1% tannic acid (w/v) at 30 degrees C, this strain produced 1.87 U/ml of tannase at 6 h. At that time, tannic acid degradation products, namely glucose and gallic acid, were detectable in the culture filtrate; the other intermediate metabolites formed were pyrogallol (extracellular) and pyruvate (intracellular). 2-hydroxymuconic acid is presumed to form as a result of ortho-cleavage of pyrogallol. The proposed biochemical pathway for the degradation of tannic acid by Citrobacter freundii is: Tannic acid-->[Glucose + Gallic acid]-->Pyrogallol -->2-hydroxymuconic acid -->[?]-->Pyruvate.
Kumar
R A
RA
Department of Microbial Technology, School of Biological Sciences, Madurai Kamaraj University, India.
Gunasekaran
P
P
Lakshmanan
M
M
D001673:Biodegradation, Environmental; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D016971:Citrobacter freundii / Q000201:enzymology / Q000378:metabolism*; D005707:Gallic Acid / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D047348:Hydrolyzable Tannins / Q000378:metabolism*; D007218:Industrial Microbiology; D011748:Pyrogallol / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D013997:Time Factors
D047348:Hydrolyzable Tannins; D011773:Pyruvates; D011748:Pyrogallol; D005707:Gallic Acid; D002265:Carboxylic Ester Hydrolases; C022711:tannase; D005947:Glucose