TITLE:
Laccases from Actinobacteria—What We Have and What to Expect
AUTHORS:
Tatiana Alves Rigamonte Fernandes, Wendel Batista da Silveira, Flávia Maria Lopes Passos, Tiago Domingues Zucchi
KEYWORDS:
Actinomycetes, Lignin Degradation, Multicopper Oxidase, Laccases
JOURNAL NAME:
Advances in Microbiology,
Vol.4 No.6,
May
9,
2014
ABSTRACT:
Laccases
are blue multicopper enzymes, capable of oxidizing diverse aromatic and
non-aromatic compounds of industrial interest, concomitantly with reduction of
molecular oxygen to water. Tolerance to extreme conditions, such as high
temperature, salinity or extreme pH, is required for practical industrial
applications. Here we focus on bacterial laccases from the phylum Actinobacteria, notably the order Actinomycetales. Currently, less than 10
enzymes have been properly characterized, all belonging to genus Streptomyces, but it is noteworthy that
all of them have exhibited industrially important properties. Furthermore,
studies with enzymes from this phylum revealed a novel molecular structure of
laccases, providing the basis for a distinct family, the two-domain laccases.
The relevant traits of actinomycetes laccases emphasize the need for more
studies involving the isolation of this bacterial group from lignin-rich
environmental samples, detection of their laccase activity and thereafter,
characterization of the proteins and related genes. The nonhomogeneous
responses of actinomycetes laccases to traditional inhibitors, substrates or
metal ions have challenged the currently accepted “laccase concept”. Finally,
considering that distinguishing laccase activity in vitro from other ligninolytic enzymes becomes a difficult task
due to overlaps in catalytical properties of the enzymes, we proposed a simple
flow chart to help experimental assays.