Beyond natural laccases: extension of their potential applications by protein engineering

Laccases bring exciting promises into the green industries, and the development of enzymes with improved properties is further raising their exploitation potential. Molecular engineering methods to build highly efficient catalysts both through rational and random mutagenesis were extensively applied. Moreover, computational approaches are becoming always more reliable in aiding proper design of efficient and tailored catalyst for specific applications. In this review, the results of the last 10 years about industrial application of engineered laccases in different fields are analyzed. Tailoring laccase towards a target substrate and defining a proper screening strategy for the selection of the "jackpot mutant" represent the keys of a winning mutagenesis pathway. Likewise, laccase chimerae, built by the fusion of laccases with relevant proteins, emerged as an added value in the designing of flexible and well-rounded biocatalysts. Despite being promising in most of the reported examples, evolved laccases are currently tested at a laboratory scale and a feedback from the industry world is continuously required to strengthen the biotechnological exploitation of these improved enzymes.