Effects of ionic substances in bleaching filtrates and of lignosulfonates on the activity of oxalate oxidase from barley

Abstract

The effects of ionic substances in seven industrial filtrates from kraft pulping, mechanical pulping, and sulfite pulping on the activity of oxalate oxidase from barley were investigated by pre‐treatment of the filtrates with ion‐exchange resins prior to enzymatic degradation of the oxalic acid in the filtrates. The pre‐treatment resulted in increased oxalic acid degradation rates in all filtrates, except for one that was obtained from sulfite pulping. The possibility that lignosulfonates, which were present in the filtrate from sulfite pulping, could affect oxalate oxidase was investigated in a separate set of experiments involving four different preparations of lignosulfonates. At a lignosulfonate concentration of 50 mg/mL and a pH of 3.8, only 2–16% of the activity of oxalate oxidase remained. The results show the effects of anionic and cationic substances in bleaching filtrates on oxalate oxidase and indicate that there is an interaction between the enzyme, which has a positive net charge at pH 3.8, and the polymeric anionic lignosulfonates.

Novel lignosulfonate/N,N‐dimethylacrylamide/γ‐methacryloxypropyl trimethoxy silane graft copolymer as a filtration reducer for water‐based drilling fluids

“…The main structure of LS is n ‐phenylpropane. When LS grafts are added to drilling fluid as filtrate reducer, they are adsorbed on clay particles through n‐phenylpropane as hydrophobic main chain, and sulfonic acid groups enhance the electrostatic repulsion force between particles, which has a good dispersion effect on the system …”