Evaluation of oxalate decarboxylase and oxalate oxidase for industrial applications.
Increased recirculation of process water has given rise to problems with formation of calcium oxalate incrusts (scaling) in the pulp and paper industry and in forest biorefineries. The potential in using oxalate decarboxylase from Aspergillus niger for oxalic acid removal in industrial bleaching plant filtrates containing oxalic acid was examined and compared with barley oxalate oxidase. Ten different filtrates from chemical pulping were selected for the evaluation. Oxalate decarboxylase degraded oxalic acid faster than oxalate oxidase in eight of the filtrates, while oxalate oxidase performed better in one filtrate. One of the filtrates inhibited both enzymes. The potential inhibitory effect of selected compounds on the enzymatic activity was tested. Oxalate decarboxylase was more sensitive than oxalate oxidase to hydrogen peroxide. Oxalate decarboxylase was not as sensitive to chlorate and chlorite as oxalate oxidase. Up to 4 mM chlorate ions, the highest concentration tested, had no inhibitory effect on oxalate decarboxylase. Analysis of the filtrates suggests that high concentrations of chlorate present in some of the filtrates were responsible for the higher sensitivity of oxalate oxidase in these filtrates. Oxalate decarboxylase was thus a better choice than oxalate oxidase for treatment of filtrates from chlorine dioxide bleaching.
Cassland
Pierre
P
Applied Microbiology, Lund University/Lund Institute of Technology, P.O. Box 124, 22100 Lund, Sweden.
Sjöde
Anders
A
Winestrand
Sandra
S
Jönsson
Leif J
LJ
Nilvebrant
Nils-Olof
NO
D001234:Aspergillus niger / Q000201:enzymology; D002262:Carboxy-Lyases / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D001467:Hordeum / Q000201:enzymology; D007218:Industrial Microbiology; D007220:Industrial Waste; D019815:Oxalic Acid / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism
D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D007220:Industrial Waste; D010940:Plant Proteins; D019815:Oxalic Acid; D010088:Oxidoreductases; C020598:oxalate oxidase; D002262:Carboxy-Lyases; C021915:oxalate decarboxylase