Title
Effects of pH variation on efficiency of old newspaper deinking by pectinase derived from Aspergillus niger
Authors
MOGHADASE AKBARI HOSSEIN RESALATI and POUYA MARZBANI

Received July 16, 2018
Published Volume 53 Issue 5-6 May-June
Keywords enzymatic deinking, old newspaper, pectinase, pH treatment

Abstract
Enzymes are protein molecules with complex structure that accelerate biochemical reactions. The activity of these chemical compounds is limited to a specific range of pH and temperature. The effect of pH variations on deinking efficiency of old newspaper (ONP) by pectinase was investigated in this study. Old newspaper was repulped in a laboratory disintegrator for 10 minutes at 5% consistency and 26500 rpm. Enzymatic treatment of recycled ONP was carried out for 20 minutes at 0.1% enzyme concentration and 10% consistency, and pH levels of 3.5, 4, 4.5, 5, 5.5 and 6. The results showed that more efficient pectinase deinking of old newspaper can be achieved at pH level of 4-4.5, as indicated by the improved optical and mechanical properties of standard handsheets obtained by enzymatic deinking at pH levels of 4 to 5.