Laccase Production by a Novel White-Rot Fungus Pseudolagarobasidium acaciicola LA 1 Through Solid-State Fermentation of Parthenium Biomass and Its Application in Dyes Decolorization

摘要

Parthenium sp., a belligerent noxious herbaceous wasteland weed, became a threat to environment and biodiversity, so its management is necessary to prevent future problems. A new laccase producing strain of white-rot fungus Pseudolagarobasidium acaciicola LA 1 was isolated and evaluated for laccase production through solid-state fermentation of different lignocellulosics biomass. Parthenium biomass was selected as a suitable substrate for laccase production and optimization studies were undertaken. The maximum laccase (34,444 U/g of dry weight) was achieved with Parthenium biomass as solid substrate within 7 days at 30 A degrees C under optimized condition. SDS-PAGE and zymography confirmed the presence of single laccase of 62.8 kDa. Laccase functioned optimally at pH 4.5 and temperature of 60 A degrees C with ABTS (2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid). The enzyme retained 94 % of its original activity at 60 A degrees C for 30 min and was found to be highly stable within the pH ranges 4.0-7.0 for 24 h. The presence of Cu+2 (10 mM) and ethanol (10 % v/v) enhanced the laccase activity. Crude laccase was applied for decolorization of Remazol Brilliant Blue R (RBBR) and Reactive Black 5 (RB5). The biodegradation was monitored by UV-vis spectroscopy and 90 % decolorization of RBBR (100 mg/L) was observed within 4 h of incubation. This study shows the potential of P. acaciicola for production of thermostable laccase using Parthenium biomass and its application for dye decolorization.