First description of a laccase-like enzyme in soil algae

Abstract

Laccases (EC 1.10.3.2) are versatile multi-copper oxidases so far found in higher plants, fungi, insects, prokaryotes and lichens. In the present study, the production of an extracellular laccase-like enzyme by the coccoid green soil alga Tetracystis aeria was investigated and the enzyme was partly characterized, thereby providing the first description of a laccase-like enzyme in soil algae. Enzyme production in algae cultures was considerably increased by addition of the fungal laccase inducer copper sulphate. Maximal enzyme production was observed during the stationary growth phase. Peroxidase or tyrosinase activity was not detected. The native enzyme exhibits an apparent molecular mass of about 212 kDa as observed with size exclusion chromatography and about 210-260 kDa as estimated by zymograms. The enzyme efficiently oxidizes 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), 2,6-dimethoxyphenol (2,6-DMP), syringaldazine (SGZ) and the anthraquinone dye Acid Blue 62, while guaiacol and Remazol Brilliant Blue R are only poorly oxidized. The apparent kinetic parameters obtained for ABTS, 2,6-DMP and SGZ oxidation are within the range reported for fungal laccases. Oxidation of the phenolic substrate 2,6-DMP displays a remarkably high pH optimum (pH 8.0-8.5), which is interesting with respect to potential biotechnological applications.

Depth profiles of microbial colonization in sandstones

“…It is known that many algae may grow well heterotrophically and produce glucan hydrolases like chitinase and laccase (Reisser 2007;Otto et al 2012) and even degrade phenolic compounds (Semple et al 1999). When these substrates effectively fuel the algal metabolism, ecologically relevant growth of algae in aphotic ecosystems, including rock, may be possible.…”

Two Decades of Laccases: Advancing Sustainability in the Chemical Industry

“…Historically, laccases have been isolated predominantly from plants and fungi. However, in recent years, the laccase toolbox has been expanding, with the enzymes also being detected in bacteria, insects, and algae . The physiological functions of laccases from different sources are highly diverse.…”

Insights into laccase producing organisms, fermentation states, purification strategies, and biotechnological applications

“…Since then, characteristics of laccases from other insect species have been determined . In the silkworm, Bombyx mori , a cuticle laccase is highly expressed a few hours after ecdysis . This 70 kDa dimer polypeptide plays an important role in cuticle sclerotization .…”

“…44 This 70 kDa dimer polypeptide plays an important role in cuticle sclerotization. 44 Coy et al 65 reported the functional expression of two recombinant laccase genes of the insect termite (Reticulitermes flavipes), designated as RfLacA and RfLacB, using a baculovirus-insect expression system. Oxidation of cuticular catechols, assisted by phenoloxidases, tyrosinase, and laccases, is essential for cuticle hardening and pigmentation in many insects, such as Riptortus pedestris, Nysius plebeius, and Megacopta punctatissima.…”