Isolation and Characterization of Cell Wall and Extracellular Polysaccharides from Cultures of the Mycoparasitic Strain Trichoderma koningiopsis.

Abstract

Using Response Surface Methodology (RSM) to optimise cultivation conditions showed that Trichoderma koningiopsis EPS biosynthesis depended on an alkaline pH (>9.0) and a high nitrogen concentration (≥20 g/L). This resulted in a yield increase of over 60% compared to the control conditions. Three wall polymer fractions were extracted from the obtained biomass: cold water soluble (WPSZ), hot water soluble (WPSC), and alkali soluble (WPSNaOH). These accounted for 13.3, 1.8, and 20.2% of the dry weight of the mycelium, respectively. Structural analyses revealed that the obtained EPS was mannan, with the WPS fractions consisting predominantly of (1→4)-Glc residues branching at the (1→3,6) and (1→4,6) positions. FT-IR and FT-Raman analyses revealed that α-bonds predominated in the WPSZ and WPSC fractions, whereas β-bonds predominated in the EPS and WPSNaOH fractions. This was confirmed by NMR analysis. The obtained polymer fractions (PS) exhibited antioxidant properties using the ABTS, DPPH, and FRAP methods, as well as the ability to bind bisphenol A from an aqueous environment. The most significant property of PS polymers is their ability to reduce germination and inhibit mycelial growth of the phytopathogenic Fusarium culmorum strain. These polymers exhibit various bioactive properties and have potential applications in many areas of human life.