Juan S Chirivi-Salomon
University of the Andes, Colombia
Title: Enhancement of laccase activity in semi-solid culture of Pleurotus ostreatus by Cordyceps extract supplementation
Biography
Biography: Juan S Chirivi-Salomon
Abstract
Laccases are multinuclear copper-containing proteins that catalyze the oxidation of aromatic and non-aromatic compounds in presence of molecular oxygen. Laccases are naturally produced by higher plants, insects, bacteria, and fungi. Nevertheless, white-rot mushrooms are currently desirable for the biofuel industry because of their diversity and versatility. From this group, the edible mushroom Pleurotus ostreatus (oyster mushroom) has been recently, widely studied due to its capacity to colonize several lignocellulosic substrates, among other properties. A previous research study showed the metabolomic profile and bioactivity potential of the raw extracts from Cordyceps nidus. Based on the biochemical nature of these extracts, we aimed to evaluate their effect in the laccase activity of P. ostreatus. We used a semi-solid-state system, using rice husk as substrate and a cupric-ion stimulant supplementation, as is previously recommended. A complete experimental design was implemented for metabolites extracted from Cordyceps mycelium growth in four different culture media, with three different solvents. Measurements of 2,2'-azino-bis (3-ethylbenzothiazolin-6-sulfonic acid) oxidation and extracellular glucose-content were performed as response variables. Peaks of enzymatic activity were found reaching over 8.000 U L-1 within the studied time. However, only water-fractioned extracts were found significantly different from experimental controls (p-value<0.05), without Cordyceps extracts addition. In conclusion, aqueous extracts of C. nidus cultured in Sabouraud dextrose agar with yeast
extract and brown rice medium significantly enhanced the laccase activity of P. ostreatus in the pre-stablished culture system. This study is the first report of the application of Cordyceps extracts in the enhancement of recycling treatment processes for lignocellulosic wastes. Studying opportunities by using P. ostreatus in the pre-treatment of lignocellulosic biomass for biofuel production is necessarily increasing. Accordingly, we need to deeply understand the mechanisms by which we could enhance laccase activity of white-rot fungi. A characterization of the bioactive compound is also recommended for future researches.
