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Laccase producing fungus Pleurotus floridanus was isolated from Siruvani forest, Tamil Nadu, India. The potential of P. floridanus to produce laccase by using various lignocellulosic substrates was screened under submerged fermentation. Laccase production in the presence of lignocellulosic substrates such as rice, wheat and maize bran as a sole source of carbon as well as an additional supplement was examined. Laccase activity of P. floridanus using varied substrates was observed in the order of rice bran > wheat bran > maize bran. The isolate showed maximum laccase activity of 13.29±0.01 U/mL using rice bran as a carbon source within 11 days. This was 18 fold higher than the control media that lacks lignocellulosic substrates. The diclofenac tolerance was assessed in solid media at various concentrations and the results showed that the mycelia growth is not significantly affected by the drug. Finally, the laccase mediated degradation of diclofenac at a concentration of 10 mg/L showed 98% degradation in 2 h. The phytotoxicity of the crude laccase treated diclofenac was lower than the untreated diclofenac. In conclusion, findings suggested direct application of crude laccase produced from P. floridanus using agro-residues as ideal substrate for environmental applications.

Biodegradation of crystal violet (CV) by Trichoderma asperellum laccase was herein reported. The process parameters viz., enzyme concentration, dye concentration, pH and incubation time were experimentally optimized for the maximum dye degradation. The degradation of CV was physico-chemically characterized by UV–vis spectroscopy, FTIR, HPTLC, HPLC and GC–MS analyses. In UV–vis spectroscopy, a major reduction in characteristic peak from 588 nm to 575 nm has suggested the disappearance of triphenyl methane chromophore. From the FT-IR spectra, the formation of new peaks at 3707 cm −1 ( OH stretching) and 1726 cm −1 (C O stretching) indicates the successful transformation of the crystal violet. Similarly, the existence of a prominent peak (R f − 0.39) in HPTLC and a significant reduction in peak intensity of crystal violet had suggested the laccase mediated dye degradation. GC–MS analysis of crystal violet degraded metabolites were identified as Leucocrystal violet, Olivetol dimethyl ether (1,3-Dimethoxy-5-pentylbenzene) and 1,3,5-trimethoxybenzene by a hydride ion (H-) transfer followed by oxidative methylation. The genotoxicity studies by Allium cepa assay has shown that the degraded intermediates of CV are minimally toxic than the original dye. Owing to the above-discussed significance, T.asperellum laccase may be considered for the development of more environmental friendly treatment processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enzymatic cross-linkage occurs under mild, physiological condition. • Laccase based hydrogel is an eco-friendly approach with good mechanical stability. • Their cytocompatibility makes them ideal for biomedical applications. • Research progress of the enzymatic approach with different polymers are discussed. The unique physiochemical properties and the porous network architecture of hydrogel seek the attention to be explored in broad range of fields. In the last decade, numerous studies on the development of enzymatically cross-linked hydrogels have been elucidated. Implementing enzyme based cross-linking for fabrication of biomaterials over other cross-linking methods harbor various advantages, especially hydrogels designed using laccase exhibits mild reaction environment, high cross-linking efficiency and less toxicity. To our knowledge this is the first report reviewing the formulation of laccase mediated cross-linking for hydrogel preparation. Here, laccase catalyzed synthesis of hydrogel using polysaccharide viz. arabinoxylan, sugar beet pectin, galactomannan, chitosan etc. and proteins namely soy protein, gelatin, silk fibroin were discussed on highlighting their mechanical properties and its possible field of application. We have summarized the role of phenolic acids in laccase mediated cross-linking particularly ferulic acid which is a component of lignocellulose, serving cell rigidity via cross-linkage. The review also discusses on various biomedical applications such as controlled protein release, tissue engineering, and wound healing. It is anticipated that this review will give a detailed information on different laccase mediated reaction strategies that can be applied for the synthesis of various new biomaterials with tailor made properties. [ABSTRACT FROM AUTHOR]