The textile industries currently responsible for two-thirds of the total dyestuff market and was found to consume large quantity of water and chemicals for wet processing of textiles 218. In all these processes chemical reagents used are of diverse chemical structures ranging from inorganic compounds to polymers and organic products 219. It has been reported that there are about 1 00, 000 commercially available dyes that are responsible for producing 7 x 105 tones of dyestuff annually 220, and due to their chemical structure which became resistant on exposure to light, water and different chemicals it is very difficult due to their synthetic origin.
Most of the existing processes to treat dye wastewater are not economical and ineffective. Therefore, for dye of various chemical structures development of degradation processes based on laccase seems to be more effective 223 and also for currently used synthetic dyes in the industry 224.
Biosensor and biofuel cells
Due to the broad substrate specificity laccase is used for the detection of broad range phenolics; however this does disallow detection of specific constituents 246,247. Detection of phenolic compounds, such as catechols in tea 247,phenolic compounds in wine, lignin and phenols in wastewaters 248 can be done using biosensor technology that uses laccase includes an electrode.
Phenolic compounds in food 1, 40, 41, for environmental 2, 42 and medical applications 43, 44
Main principle behind using laccase in biosensor technology is based on its ability to reduce molecular oxygen to water and oxygen consumption was monitored by sensors during oxidation of analyte. As reviewed by Rodriguez Couto and Herrera 4 several researchers have reported successful fabrication of laccase based biosensors or other similar sensors combining other phenol oxidizing enzymes such as tyrosinase 158 while others incorporate laccase mediator system 159,160.
Food industry
Due to their ability to improve food products and processes in a specific manner with minimal cost and side effects enzymes are widely used in food industries. Coupling reaction mediated by laccase has been used in number of food industries but mostly in beverages industry.
In terms of organoleptic properties laccase was found to be superior over other enzymes such as tannase, phenolase, and anthocyanase for removing polyphenols from wine 169 however further treatments were also required for better results such as sulphur dioxide treatments, clarification and filtration.
Protein cross linking catalysed by laccase 188-190 and peptide polymerization 191 offers an opportunity for developing value added products in the food industry.
Laccase can be used to modify colour of food products or beverages. Laccase was also found to be of great importance in elimination of undesirable phenolics, which is responsible for browning, haze formation and turbidity formation in fruits juices, beer and also in wine. Due to its ability of cross linking it is currently of interest in baking. Laccase from Trametes hirsuta, a white rot fungus increased the maximum resistance of dough and decrease the dough extensibility in both flour and gluten dough as reported by Selinheimo et al. (2006)
Pharmaceutical industry
Nowadays laccase has widely been used in pharmaceutical industries due to its ability to catalysed homomolecular and heteromolecular coupling for synthesis of pharmaceutical products, or modification of existing ones. In the past two decades research interest in this area has therefore increased. Laccase mediated coupling has also been used in the synthesis of various compounds with their potential biologicall effects such as ant oxidative 201-206, hormonal 26, 27,209,210, anti-inflammatory 211, central stimulant 211, analgesic 211, central depressant 211, anti-secretory 211, anti-proliferative 212, anti-neoplastic 212 and 5-lipogenasesuppressive 212 effects.
Organic synthesis
Laccase has been widely used in organic synthesis. Various application of laccase in organic synthesis has been summarized by Witayakran and Ragauskas 9 such as transformation of compounds such as steroid hormones, alkaloids, flavonols, procyanidin B-2, and N-(2- alkylamino-4-phenylimidazol-1-yl)-acetamides; (ii) synthesis of natural or artificial products by polymerization and heteromolecular coupling reactions, and (iii) synthesis of quinones. Laccase also catalyzed oxidative deprotection reaction, synthesis of pharmaceutically important compounds such as 2-amino-3H-phenoxazin-3-ones (actinocin, cinnabarinic acid and questiomycin), sulfonate analogue of cinnabarinic acid, and the antioxidant dehydro dimer of trans-resveratrol (3,5,4_- trihydroxystilbene), antioxidant gelatin–catechin conjugate, and dimerized antibiotics. Synthetic applications of laccase have been summarized 9. Recently by using industrial laccase synthetised phenolic colourants named Suberase® (Novo Nordisk A/S, Bagsvaerdt, Denmark) was synthesized by Mustafa et al. (2005)
Bioremediation
Soil contamination is one of the major problem that world is facing today. Polycyclic aromatic hydrocarbons (PAHs) along with other xenobiotic are a major source of contaminant, their fore their degradation is of great importance. Due to the catalytic properties of laccase were able to degrade such compounds. Coupling of reduced 2,4-6- trinitrotoluene (TNT) metabolite to an organic soil matrix resulted in detoxification of the munition residue.(Durán and Esposito, 2000).
Cosmetics
The cosmetic world has not been indifferent to the application of laccase: More recently, cosmetic and dermatological preparations containing proteins for skin lightening have also been developed (Golz-Berner et al., 2004).