Archives

Laccase producing bacteria, Pseudomonas putida LUA15.1 was isolated from rice rhizospheric soil samples of paddy fields of Una district, Himachal Pradesh (India). Malachite green (60 mg/l) was 87.7% decolorized within 48 hrs by Pseudomonas putida strain LUA15.1. Purification of laccase enzyme was done by using ammonium sulfate precipitation, dialysis, gel filtration chromatography and ion exchange chromatography and 92.47% decolorization of malachite green (60 mg/l) was observed by purified laccase of Pseudomonas putida LUA15.1. UV-Visible absorption spectrum showed the decolorization of malachite green, and phytotoxicity studies revealed the degradation of malachite green into non-toxic products by purified laccase of Pseudomonas putida LUA15.1. Seed germination, length of plumule and radicle of Phaseolus aureus were significantly affected by malachite green than its degradative metabolites indicating less toxic nature of degradation metabolites as compared to dye. It was therefore concluded that Pseudomonas putida LUA15.1 and its extracellular laccase has a good potential for use in the treatment of industrial effluent containing malachite green.
Keywords: Decolorization, Pseudomonas putida, malachite green, phytotoxicity, Phaseolus aureus