Universidad de La Frontera, Chile
Heidi Schalchli has completed her PhD from Universidad de La Frontera. She is a Postdoctoral Researcher at the Scientific and Technological Bioresource Nucleus (BIOREN) and Teacher at the Chemical Engineering Department, Universidad de La Frontera
White-rot fungi play important roles in ecosystems mainly because of their extracellular enzymatic system and their production of chlorinated aromatic compounds that act as decomposers of organic matter, antibiotics for protecting fungi, methyl donors and/or substrates for H2O2-generating oxidases. In this study, we evaluated the production of ligninolytic enzymes and antifungal volatile organic compounds (VOCs) by A. discolor Sp4 using Potato Peels (PP) and Discarded Potato (DP) as nutritional support. The manganese-dependent peroxidase (MnP) was evaluated by monit oring the oxidation of 2, 6-dimethoxyphenol. Beside the production of MnP, the discoloration of remazol brilliant blue R (RBBR) was also determined using a qualitative assay. The antifungal activity of VOCs against Mucor miehei and Fusarium oxysporum was evaluated using a bi-compartmented plate assay. Finally, VOCs released from mycelial cultures were analyzed by headspace solid phase micro-extraction and gas chromatography mass spectrometry. The highest MnP and MiP activities (163 U L-1 and 24 U L-1) were obtained at day 15 of incubation and a complete RBBR discoloration was observed. Although both potato wastes supported the ligninolytic activity, a higher MnP activity was obtained using PP than DP. The A. discolor volatiles inhibited approximately 62% and 76% the mycelial growth of M. miehei on PP agar and DP agar media, respectively. Nevertheless, the plant pathogen F. oxysporum was slightly inhibited (approximately 10%). The major VOCs detected were chlorinated aromatic compounds (over 50% relative area). The obtained natural products have multiple biotechnological applications among which are pollutant degradation and plant protection.
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