Hyper-Production of Laccase By Pseudomonas putida LUA15.1 through Mutagenesis

Laccases (benzenediol: oxygen oxidoreductases, EC 1.10.3.2) are multicopper blue oxidases that are widely distributed in higher plants, some insects, fungi and bacteria [1]. Microbial enzymes continue to draw greater attention as alternative to chemical processes which would enable the industries to meet the increasingly stringent environment requirements to reduce the pollution load. The highly-stable bacterial laccases can function within a wider pH range and at high temperatures and these are less dependent on metal ions and less susceptible to inhibitory agents [2]. Thus, bacterial laccases have significantly more potential industrial applications, especially in decolorization of industrial textile dye effluents which constitute a major threat to soil and ground water reservoirs worldwide. Furthermore, bacterial systems are easier to handle than fungal ones [3]. Laccase activity has also been demonstated in a number of bacteria including Bacillus subtilis, Bacillus vallismortis, Bacillus pumilus, Bordetella compestris, Caulobacter crescentus, Escherichia coli, Mycobacterium tuberculosum, Pseudomonas putida, Pseudomonas syringae, Pseudomonas aeruginosa, Yersinia pestis and Geobacillus thermocatenulatus [4-11].