5-36: Evaluation of novel oxalate decarboxylases in industrial bleaching filtrates and in pulp mill experiments

Precipitation of sparsely soluble calcium oxalate causes scaling problems in the pulp and paper industry. Four novel oxalate decarboxylases were evaluated in experiments with 16 pH-adjusted bleaching filtrates collected from mills producing mechanical pulp or kraft pulp. The novel enzymes were compared with two other oxalate decarboxylases previously studied in experiments with the bleaching filtrates [Sjöde et al. (2008) Enzyme Microb. Technol. 43, 78–83]. The enzyme that performed best in the screening with 16 filtrates was selected for an experiment in a mill producing mechanical pulp. In an experiment that lasted for one hour, the enzyme degraded 70% of the oxalic acid in the fresh filtrate without pH adjustment and at the temperature prevailing in the process.