Laccase from prokaryotes: a new source for an old enzyme

Abstract

Laccases (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) are multi-copper-containing enzymes capable of catalyzing the oxidation of a wide range of phenolic and non phenolic aromatic compounds. The available data indicates that laccases from prokaryotes are promising biological tools for green chemistry based applications, especially in decolorization of industrial textile dye effluents which constitute a major threat to soil and ground water reservoirs worldwide. Another appropriate application of prokaryotic laccases is bio-bleaching of different kind of pulps where there is indiscriminate use of hazardous chlorine based chemicals for brightness of the paper. In recent years, researchers have shown interest in the identification and characterization of laccases from prokaryotic sources. This catalyst is not commonly reported from this kingdom, although prokaryotes have immense environmental adaptability and biochemical versatility. Moreover, true laccases or laccase-like enzymes exist in many gram-negative, gram-positive bacteria and actinomycetes. Corresponding genes have been identified and functionally expressed in genetically developed hosts. This review summarizes the research efforts to characterize laccases and their properties from different prokaryotic sources, including bacteria and actinomycetes.

Characterization of a novel high-pH-tolerant laccase-like multicopper oxidase and its sequence diversity in Thioalkalivibrio sp

“…Although several bacterial laccases were described in recent years, the focus has remained on fungal laccases. Therefore, our knowledge on bacterial laccases is limited to only a few purified enzymes from a narrow range of bacterial taxa that have been studied to a different extent (reviewed in Claus 2003;Sharma et al 2007;Singh et al 2011). A widespread occurrence of laccases within the prokaryotes was predicted (Alexandre and Zhulin 2000) and recently supported by two studies showing high genetic diversity of bacterial laccases in soil (Kellner et al 2008;Ausec et al 2011a).…”

“…Low pH optima and/or thermostability is often restrictive of industrial or biotechnological applications of fungal laccases, and pH-tolerant laccases are often needed. On the contrary, bacteria are much more diverse than fungi in terms of their metabolism and habitats and may therefore represent an important source of more robust laccases (Singh et al 2011). Recent reports of highly pH-tolerant bacterial laccases (Reiss et al 2011;Singh et al 2007;Ye et al 2010;Zheng et al 2011;Sondhi et al 2014) highlight the importance of studying these enzymes in more depth.…”

Efficient secretory production of CotA-laccase and its application in the decolorization and detoxification of industrial textile wastewater

“…Effluents produced by textile industries are often strongly colored; thus, their disposal into receiving waters reduces light penetration and subsequently disrupts the photosynthetic activity of aquatic plants (Singh et al 2011;Giardina et al 2010). Affected wastewaters may also be toxic to aquatic organisms because of the presence of metals, chlorides, and dye breakdown products (Khlifi et al 2010).…”

“…Approximately 10 to 15 % of the total dyes from various textile and other industries are discharged in wastewater, causing extensive pollution worldwide (Robinson et al 2001;Keharia and Madamvar 2003). Therefore, the treatment of industrial effluents that contain aromatic compounds is necessary prior to their discharge to the environment (Singh et al 2011).…”

Immobilization of Laccase on Magnetic Carriers and Its Use in Decolorization of Dyes

“…Laccase with its wide substrate specificity and oxidation properties is used in many industrial applications. It is used in the food and paper industry, synthetic chemistry, bioremediation and biodegradation of phenolic pollutants or in analytical applications 3,4 . Laccase also catalysed reactions with various kinds of textile dyes and degrades them 5 .…”