Cr(VI) Removal on Fungal Biomass of Neurospora crassa: the Importance of Dissolved Organic Carbons Derived from the Biomass to Cr(VI) Reduction

• Published in: Environmental science & technology Vol. 44; no. 16; pp. 6202 - 6208
• Main Authors: Hsu, L.C, Wang, S.L, Lin, Y.C, Wang, M.K, Chiang, P.N, Liu, J.C, Kuan, W.H, Chen, C.C, Tzou, Y.M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15-08-2010
• Subjects: Applied sciences; Biodegradation, Environmental; Biomass; Biomedical materials; Carbon - analysis; Chromium; Chromium - isolation & purification; Darkness; Dissolution; Environmental Processes; Exact sciences and technology; Hydrogen-Ion Concentration; Kinetics; Magnetic Resonance Spectroscopy; Mold; Neurospora crassa - growth & development; Neurospora crassa - metabolism; Organic chemicals; Organic Chemicals - analysis; Oxidation; Oxidation-Reduction; Pollution; Solubility; Spectroscopy, Fourier Transform Infrared; Studies; Time Factors; Pollutant behavior; Scavenging; Biomass; Dissolution; Heavy metal; Fungi; Aeration; Dissolved organic carbon; Trace element; Ecosystem; Chromium; Poison; Oxidation; Fungi Imperfecti; Photooxidation; Photochemical degradation; Functional group
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es1017015

Interactions of toxic Cr(VI) with renewable biomaterials are considered an important pathway for Cr(VI) removal in ecosystems. Biomaterials are susceptible to dissolution, and their dissolved derivatives may provide an alternative to surface-involved pathway for scavenging of Cr(VI). In this study, dissolved organic carbon (DOC) derived from Neurospora crassa biomass was investigated. The proportion of Cr(VI) reduction by DOC to that on biomass was determined to evaluate the importance of DOC to Cr(VI) reduction. A rapid increase in DOC concentration from 145.6 to 193.7 mg L−1 was observed when N. crassa-biomass was immersed in 0.01 M KCl solution at pH of 1−5, and polysaccharides, peptides, and glycoproteins with carboxyl, amide, and -NH functional groups, are the major compositions of DOC. On reaction of 96.2 μM Cr(VI) with N. crassa-biomass or DOC, it was estimated that DOC contributed ∼53.8−59.5% of the total Cr(VI) reduction on biomass in the dark. Illumination enhanced Cr(VI) reduction via photo-oxidation of biomass/DOC under aeration conditions, which formed superoxide for Cr(VI) reduction. At pH 1, photoinduced Cr(VI) reduction by DOC proceeded more rapidly than reduction on the biomass surface. However, at pH >3, with a decrease in Cr(VI) reduction by DOC, photon-excited biomass may become an important electron source for Cr(VI) photoreduction.