PRODUCTION OF OXIDATIVE AND HYDROLYTIC ENZYMES BY Hornodermoporus martius LBM 224 UNDER SOLID-STATE FERMENTATION USING LIGNOCELLULOSIC WASTE AS SUBSTRATE

ACOSTA GA; BENÍTEZ SF; FONSECA MA; ZAPATA PD

Congreso; XVII Congreso Argentino de Microbiología General; 2022

Fungi are known to secrete numerous enzymes of biotechnological interest. In this sense, theAgaricomycete Hornodermoporus martius LBM 224 has shown the ability to secrete various enzymecomplexes. The aim of this work was to produce oxidative and hydrolytic enzymes under solid-statefermentation (SSF) using lignocellulosic waste as substrate. Enzyme production was carried out underSSF using sugarcane bagasse (SCB), previously reported as an inexpensive substrate, which wasgenerated by agroforestry industries of Misiones, Argentina. This was sampled from a sugarcane millat San Javier, Misiones, Argentina. Initial moisture content was adjusted to 75 % w/w either withdistilled water or Czapek medium. SCB (5 g; 40-mesh) was inoculated with five agar plugs from MEAplates and incubated at 28 ± 1 °C for 18 days under static conditions. After incubation, enzymes were extracted by adding 50 mL of distilled water and shaking at 150 rpm for 60 min at 28 ± 1 °C. The extractwas filtered with filter paper and centrifuged at 4400 x g for 10 min. Endoxylanase and endoglucanaseactivity were assayed using beechwood xylan and carboxymethylcellulose as substrates, respectively.Reducing sugars obtained were determined by the 3,5-dinitrosalycillyc acid (DNS) method. For bothenzymes, activity was expressed in units (U), defined as the amount of enzyme needed to produce 1μmol of reducing sugars per min at 50 °C. β-Glucosidase and Cellobiohydrolase activity weredetermined using p-nitrophenyl-β-D-glucopyranoside and p-nitrophenyl-β-D-cellobioside assubstrate, respectively. The amount of p-nitrophenol released was measured at 405 nm after additionof Na2CO3. Enzyme activity was expressed in U, defined as the amount of enzyme necessary to release1 μmol of p-nitrophenol per minute at 50 °C. Amylase activity was determined using soluble starch assubstrate. Reducing sugars obtained were determined by DNS method. Amylase activity wasexpressed in U, defined as the amount of enzyme needed to produce 1 μmol of reducing sugar permin at 50 °C. Laccase activity was measured using 5 mM of DMP. The absorbance increase wasmonitored at 469 nm (E469 = 27.5mM−1 cm−1). Lac activity was expressed in U, defined as the amountof enzyme needed to produce 1 µmol product per min at 30 °C. Higher enzymatic production wasobtained when SCB initial moisture was adjusted with Czapek medium. Endoxylanase (803.00 ± 33.91U/L) and Endoglucanase (729.27 ± 90.97 U/L) presented the highest yields, followed by Amylase(532.60 ± 55.85 U/L) and Laccase (470.40 ± 49.79 U/L). β-Glucosidase (7.50 ± 0.37 U/L) andCellobiohydrolase (5.32 ± 0.10 U/L) showed the lower yields. These results suggest that SCB is asuitable substrate to produce oxidative and hydrolytic enzymes from H. martius LBM 224, withpotential biotechnological applications.