Title
Evaluation of recycling potential of virgin mixed hardwood pulp treated with cellulase and chemicals
Authors
NISHI K. BHARDWAJ, PUNEET PATHAK, CHAKARVATI SANGO, ANSHUL SABHARWAL, RAJEEV K. KAPOOR and PRATYOOSH SHUKLA

Received June 30, 2022
Published Volume 59 Issue 9-10 October-December
Keywords recycling, mixed hardwood pulp, cellulase, alkaline treatment, pulp properties, optical properties, strength properties

Abstract
The global demand for paper continues to rise, increasing pressure on wood resources. Recycling waste paper provides a sustainable way to reduce reliance on virgin fibre. This study evaluated virgin mixed hardwood kraft pulp (VMHP) through nine recycling loops using either an alkaline chemical system or a cellulase-based enzymatic treatment. After each cycle, handsheets were prepared and assessed for pulp wetness, bulk, formation, tensile strength (breaking length), tear factor, burst factor, and optical properties (brightness, whiteness, yellowness). Enzymatic treatment offered better strength preservation, reflected in higher breaking length and burst factor compared to chemically treated pulp, though tear strength declined more sharply. In contrast, chemical treatment delivered superior optical performance, maintaining higher brightness and whiteness with lower yellowness. Overall, cellulase-based recycling better retained fibre strength, while chemical treatment enhanced optical quality. These findings highlight the potential of enzyme assisted recycling as an environmentally friendly method for sustaining fibre performance across multiple cycles.