Minisart 0.2 m pore size cellulose nitrate syringe filters

Final oxalate concentrations in the reactive spent culture filtrate were measured using a Dionex UltiMate 3000 HPLC system (Dionex Ltd., Camberley, UK) using appropriate standard solutions and a 5 mM H₂SO₄ mobile phase. Standards and samples were filtered using Sartorius Minisart 0.2 µm pore size cellulose nitrate syringe filters and the mobile phase was vacuum filtered through 0.45 µm cellulose nitrate membrane filters prior to analysis. A Biorad Fast Acid Analysis HPLC column #125‐0100 (Bio‐Rad Laboratories Ltd., Watford, UK) was used for analysis and data processing was conducted using the Chromeleon 6.8 data system. A flow rate of 1 ml min^‐1 was used, with a 5 min sample run time and a nominal temperature of 40 °C.

Metal recovery efficiency was determined using an AAnalyst 400 AA Spectrometer (PerkinElmer Ltd, Beaconsfield, UK) using the appropriate lamps and standard solutions. All samples were filtered using Sartorius Minisart 0.2 µm pore size cellulose nitrate syringe filters (Sartorius Stedim UK Ltd., Epsom, UK) and diluted to an appropriate concentration using 1% HNO₃ prior to analysis. Analyses were conducted in triplicate and reported concentrations are means of three individual readings. Data processing was conducted using Microsoft Excel (Microsoft Corporation, Reading, UK).