Optimization of β-glucosidase activity in Schizophyllum commune LBM026 using lignocellulosic substrates and synthetic nitrogen sources

BARUA RC; CONIGLIO,R.O.; FONSECA, MI.

Congreso; XVIII Congreso de la Sociedad Argentina de Microbiologia General SAMIGE; 2023

β-Glucosidases (BGL) are enzymes that catalyze the hydrolysis of glycosidic bonds in compounds containing glucose in their structure and are produced by organisms such as fungi. Due to their versatility, BGL enzymes have value in various biotechnological applications. Currently, there is an interest in enhancing the production of BGL fungal enzymes by fungi, and these fungi could potentially serve as an economical source for enzyme production. For this reason, the aim of this study was to analyze how, different lignocellulosic substrates and synthetic nitrogen sources impact on the BGL activity of the LBM026 strain, with the primary objective of optimizing enzyme production.The fungus used was Schizophyllum commune LBM026, available in the Biotecmol-InBioMis culture collection. The strain was reactivated on Petri dishes containing Agar medium (15 g/L) and Malt Extract (12.7 g/L), incubated for 10 days. An initial screening was performed by inoculating a mycelial disc into 100 mL Erlenmeyer flasks containing 20 mL of Czapek medium to quantify the BGL activity. Subsequently, a screening assay involving 32 runs plus 4 central points was conducted, and the effect of 10 factors (5 lignocellulosic substrates at 10 g/L and 3 nitrogen sources at 5 g/L) were evaluated in various combinations using a 1/32 2^10-5 factorial design created by STATGRAPHICS CENTURION software. Factors that had a positive and significant effect on BGL enzyme production were selected, and a response surface (RS) assay was performed using a central composite design to optimize BGL activity. A validation assay was carried out using the optimal substrate quantities to confirm the accuracy of the RS results. For the screening, RS, and validation assays, a mycelial disc was inoculated into 100 mL Erlenmeyer flasks with 20 mL of basic medium (NaNO3 2 g/L, KH2PO4 1 g/L, KCl 0.5 g/L, MgSO4 7H2O 0.5 g/L, and FeSO4 7H2O 0.01 g/L), along with the corresponding substrate combinations based on the experimental design.In the initial screening, the maximum recorded BGL activity was 278.157 U/L after 16 days of incubation. The screening assay revealed that factors influencing positive BGL activity (p