Alteration of the characteristics of extracellular polymeric substances (EPS) extracted from the fungus Phanerochaete chrysosporium when exposed to sub-toxic concentrations of nickel (II). (April 2018)

• Record Type: Journal Article
• Authors: Cao, Feishu; Bourven, Isabelle; Guibaud, Gilles; Rene, Eldon R.; Lens, Piet N.L.; Pechaud, Yoan; van Hullebusch, Eric D.
• Is Part Of: International biodeterioration & biodegradation. Volume 129(2018)
• Page Start: 179
• Page End: 188
• Publication Date: 2018-04
• Subjects: Phanerochaete chrysosporium -- Fungi -- EPS -- Nickel -- Hydrophobicity -- Molecular size; Biodegradation -- Periodicals; Bioremediation -- Periodicals; Biodegradation -- Periodicals; Biodégradation -- Périodiques; Biorestauration -- Périodiques; Electronic journals; 620.11223
• DOI: 10.1016/j.ibiod.2018.02.009
• Languages: English
• ISSNs: 0964-8305

Abstract

Abstract: The fungus Phanerochaete chrysosporium was incubated at five sub-toxic concentrations of Ni 2+ (0.5, 1, 5, 10 and 25 mg/L, respectively), and its metal immobilization ability as well as the alteration of some characteristics regarding the extracellular polymeric substances (EPS) were investigated. With the increased Ni 2+ concentrations in the broth, higher Ni 2+ amounts were measured in both intact fungal cells (biomass before EPS extraction) and EPS-free biomass (biomass after EPS extraction). The Ni 2+ immobilization ability of the extracted EPS displayed a similar level at Ni 2+ concentrations higher than 1 mg/L. The presence of Ni 2+ in the broth decreased the zeta-potential of the intact biomass and increased cell surface hydrophobicity (CSH). Fourier transform infrared spectroscopy (FT-IR) analyses identified the presence of some functional groups, such as carboxyl, phosphoryl and hydroxyl groups, in the extracted EPS. The high hydrophobicity (>60%) of the extracted EPS was decreased by the increased Ni 2+ concentration. The protein (PN) and polysaccharide (PS) content in the EPS was also affected by the increased Ni 2+ concentration, and the abundance of PN-like molecules ranging from 0.5 kDa to 14 kDa was enriched. However, the fluorescence characteristics and apparent molecular weight (aMW) of the extracted EPS were not affected by the Ni 2+ concentration. Therefore, one possible defense mechanism developed by the fungus towards Ni 2+ stress is the adjustment of its EPS composition. Highlights: The nickel immobilization ability of the extracted fungal EPS maintained a similar level at Ni 2+ concentrations higher than 1 mg/L. Fluorescence spectra and apparent molecular weight distribution of the fungal EPS exhibited similar features, regardless the Ni 2+ concentration. Zeta-potential and EPS hydrophobicity gradually decreased when the Ni 2+ concentration increased. Protein and polysaccharide content in the extracted EPS demonstrated an opposite trend when increasing the Ni 2+ concentration.