Influence of pH and natural organic matter on zinc biosorption in a model lignocellulosic biofuel biorefinery effluent

• Published in: Bioresource technology Vol. 146; pp. 169 - 175
• Main Authors: Palumbo, Amanda J., Daughney, Christopher J., Slade, Alison H., Glover, Chris N.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2013; Elsevier
• Subjects: Absorption; Bacteria; Bacteria - metabolism; Bioavailability; Biodegradation, Environmental; Biofuel production; Biofuels; Biological and medical sciences; Biomass; Bioreactors; Bioremediation; Biotechnology; Candida tropicalis; Candida tropicalis - metabolism; Closed cycle mills; Effluents; Energy; Environment and pollution; Fuels; Fundamental and applied biological sciences. Psychology; Heavy metals; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Industrial Waste; Lignin - chemistry; Membrane bioreactors; Methods. Procedures. Technologies; Microorganisms; Nitrogen - metabolism; Novosphingobium; Organic Chemicals - chemistry; Refining; Various methods and equipments; Waste Disposal, Fluid; Water Pollutants, Chemical - chemistry; Water Purification - methods; Zinc; Zinc - chemistry; Closed cycle mills; Bioavailability; Bioremediation; Membrane bioreactors; Heavy metals; Organic matter; Pollution control; Biofuel; Lignocellulosics; Modeling; Zinc; Heavy metal; Membrane reactor; Bioreactor; Biosorption; pH; Biorefinery; Effluent
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2013.07.053

•Zn biosorption was tested in a biorefinery wastewater rich with organic matter.•Effects of pH and NOM were first characterized in batch culture.•Zn removal in membrane bioreactors at pH 6.5 and 8 was 26% and 91%, respectively.•Natural organic matter inhibited Zn removal.•pH manipulation dramatically increased Zn removal. The effect of dissolved natural organic matter (NOM) and pH on microbial biosorption of Zn was evaluated in a model lignocellulosic biofuel refinery effluent rich in NOM. Batch culture experiments conducted with two model microorganisms (yeast, Candida tropicalis; bacteria Novosphingobium nitrogenifigens Y88T), showed an inhibitory effect of NOM, and an optimum pH for Zn removal at 7.5–8.0. Membrane bioreactors with mixed autochthonous organisms were operated at pH 6.5 and pH 8.0 to better simulate real-world remediation scenarios. More Zn was removed at the high (91%) than at the low (26%) pH, presumably because the higher pH freed negatively-charged functional groups on the cellular biomass for passive Zn binding. Manipulating the pH of bioreactors can significantly improve metal removal in NOM rich wastewater. Such reactors could maintain water quality for closed-cycle biorefineries, leading to reduced water consumption, and a more sustainable biofuel.