Degradation of tannins using microbes

Degradation of tannins using microbes
Tannins are water-soluble polyphenolic compounds that are present in food, plants, animals, etc. They play a very important role in the leather industry to convert the animal skin and hides into leather. During the conversion process, the effluent that is released consists of a certain amount of tannin which has an adverse effect on the environment where it is released. Tannin compounds are also present in the foodstuff, such as fruits, spices, chocolates, etc. In these substances, tannin is found to be nontoxic because of its less availability. But in pomegranate, coconut coir, banana peel and green tea, the content of tannin is above 5% which causes toxic nature. Foodstuff with tannin content above 2% has a toxic effect to humans. Tannin and its compounds have antinutritional and antimicrobial properties and hence there is a need to degrade tannin to reduce its toxicity level.

Tannin degradation is very much important to reduce the antinutritional and antimicrobial properties. For this, the extracellular enzyme called tannase which is produced by certain microbes is required. This enzyme uses tannin as its substrate and produces tannase. Tannase cleaves the tannin into glucose and gallic acid. By this degradation, the adverse effect can be controlled.

The microbial flora that produces tannase enzyme includes Klebsiella pneumonia, Lactobacillus sp., Psudomonas sp., Serratia marcessens and some fungal species too. These microbes produce tannase enzyme in specific media, such as MMT medium and TAA medium. In these media, the organisms actively produce tannase by utilising tannic acid as the substrate. To identify whether the organism has produced tannase enzyme, many experiments have been carried out like Miller’s method, UV-spectrophotometric method, and spectrophotometric method. These methods are done to estimate the amount of glucose produced which is a result of tannin degradation.

Tannin degradation has to be carried out in more fastened manner to prevent the harmful effects to microbes because of its antimicrobial properties. Although tannins have a positive part, their negatives have to be neglected and still studies are being carried out to decrease its harmfulness.


How to cite this article:
Dharsani J. Degradation of tannins using microbes. BioLim O-Media. 16 June, 2016. 4(6).
Available from: http://www.biolim.com/read/BOMA0123.