Washing water

Microbes can rid polluted water of toxic metals and colours
Washing water

A TEAEM of researchers from the BanarasHindu University in Varanasi, UttarPradesh, has isolated two fungal andone bacterial strains which are capableof removing colour and heavy metalsfrom polluted water. Mycologist R SUpadhyay and his research-studen( R KMaurya are striving to develop a watertreatment technology based on the useof these microbial strains which havebeen named RKM-1, RKM-2 and RK&f-3respectively.

Varanasi is a major centTC for themanufacture of sarees (traditional dressworn by Indian women) and carpets -industries in which large amounts ofsynthetic dyes are used. Effluents com-ing out from these units are loaded withsynthetic dyes and colours containingvarious kinds ef highly toxic heavymetals such as copper, lead, chromium,zinc and cadmium. These metals areknown to hamper life processes inaquatic plants and animals. Besides,they are carried to other animals andhuman beings through the food chainand drinking water, causing variousdiseases as a consequence. Upadhyay isoptimistic about developing a cheapindigenous technology for Pollutioncontrol in the local units.

Effluents loaded with dyes directlyaffect the transparency of water bodies.Decline in transparency means thatlesser light enters these bodies and thereis a reduction in photosynthetic activity.Any decline in photosynthesis affectsthe entire aquatic system, most pro-minently its oxygen content. Decreaseprimary production of oxygen createsdistortions in the food chain. In extremecases, an entire water body may becomelifeless.

The new microbial strains removecolour as well as heavy metals from polhated water, thereby making it colourless and non-toxic. Laboratory testshave shown that they are highly effiderlt. RKM-1 and RKM-2 belong to the filamentous group of lungi, which havefine thread-like filaments on their body.They reproduce fast by simple cell division and within a short span of time,they can grow into a thick filamentousMat. RKM-3 is a species of pseudomonas(rod-shaped bacteria generally found insoil) which grows very fast. It is not yetknown how these fungi mike the waterclean. Fungi have several mechanismswhich help them actively accumulatedifferent kinds of pollutants. Upadhyayand Maurya are trying to explore whatmechanisms are being utilised by thesestrains.

One possible method is that metalsare being adsorbed through the wails ofthe fungi] cells. This process of activebioaccumulation could help the fungicollect large amounts of heavy metals inlayers of their cell wails. For decomposition of dyes, they may be using the peroxiclase group of enzymes which are strongoxidising agents. Upadhyay believes thatthe fungal strains oxidise dyes with thehelp of these enzymes and make the watercolourless. If the two researchers succeedin their efforts, Varanasi's waters willnever be the same again.

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