An enzyme called laccase, generated by a group of fungi, has been found capable of degrading a variety of hazardous organic dye molecules that are drained into waterbodies.
This characteristic, which scientists call ‘substrate promiscuity’ (ability to catalyse more than one substrate), can have deep implications in designing enzyme-coated cassettes to treat heavily dye-polluted water through a natural solution, says a press release.
Laccase was earlier known for its ability to degrade various organic molecules. Hence scientists saw its scope in developing a technology to treat dye effluents from textile industries.
A joint team of Prof Ranjit Biswas and Dr Suman Chakrabarty from SN Bose National Centre for Basic Sciences, Kolkata, tested the efficacy of laccase in degrading dye molecules like methyl green, crystal violet, thioflavin T, coumarin 343, and brilliant blue.
About 10-15 per cent of the dyes used do not bind to the fibre.
The traditional textile finishing industry consumes about 100 litres of water to process about 1kg of textile fibre.
Several physicochemical methods ranging from coagulation to adsorption, ozonation, electrolysis, photocatalytic processes, reverse osmosis, advanced oxidation, membrane filtration, ion exchange and so on have been employed in the treatment of dye-containing wastewater to achieve decolorisation, degradation and detoxification.
However, the major disadvantages of these methods are high energy consumption, high cost, inability to completely remove recalcitrant azo dyes and/or their organic metabolites, generation of a significant amount of sludge, and use of chemicals that may cause secondary pollution.
The use of laccase in dye treatment is not new. Biswas and Chakrabarty have found out the origin and mechanism behind the enzyme’s ‘substrate promiscuity’ using computational modelling and simulation.
Toughened hydrogel
Wearable sensors such as smartwatches, fitness bands, and glasses help in the early detection of diseases and serve as good diagnostic tools for recording the health of a person.
Hydrogels, cross-linked polymers that have an affinity for water but do not dissolve in it, are finding use in the development of flexible electronic sensors, load-bearing materials, drug delivery systems, and artificial tissues. But the problem with hydrogels is that they have low mechanical properties.
To overcome this problem, scientists at IIT Madras developed three ‘double network hydrogels’ using chitosan, tetraethylene glycol and polyacrylic acid. All three hydrogels were found to have high mechanical strength, flexibility, self-healing ability, reversible adhesiveness, and conductivity.
One of them was found to have the highest degree of desirable properties such as self-adhesiveness and motion sensing ability, besides self-healing ability with nearly 95 per cent healing efficiency. This gel can be used as an adhesive motion detector on human skin.
Given the importance of hydrogel-based bandages for various applications, including wound healing, their contemporary design involves incorporating multifunctionality in a single material. Additionally, they can self-heal, enabling long-term usage during stretching and bending motions.
The material can act as a strain sensor and caution the patient when the wound is subjected to over-stretching that may compromise healing.