Decolorization of biomethanated distillery effluent by immobilized enzymes

Abstract

The massive quantity of colored distillery wastewater called molasses spent wash (MSW), if disposed untreated can cause considerable stress on the water sources leading to widespread damage to aquatic life. Microbial decolourization is an environment-friendly technique for removing this color.Recent research has focused on the development of enzymatic processes for the treatment of wastewaters. Enzymes like peroxidases, oxid oreductases, cellulolytic enzymes cyanidase, proteases, amylases, etc.from variety of different plants and microorganisms have been reported to play an important role in waste treatment. Practical problems, such as the high-cost isolation, purification, instability in organic media and high temperatures, restrict their use. In present work, the possibility of using immobilized enzyme to enhance the biodegradability of the distillery-spent wash has been investigated. Four bacterial strains showing decolorization of 30% Biomethanated wastewater were isolated from the sites where distillery effluent being discharged. The extracellular enzyme responsible for decolorization was purified, using a series of purification steps that included ammonium sulphate precipitation and gel permeation using sephadex G-100 column chromatography. The purified enzymes from each isolate were with a molecular mass of 68.7 kDa and were capable of 61.8%decolorization of 60% effluent. Alginate immobilization of these enzymes led to 62.97% decolorization after 120 hours. Re usability of the immobilized enzyme showed that it could be used with similar efficiency for 3 cycles and thereby it decreased. This data can be referred to in developing a technology for the removal of a specific colorant from effluent in future.