Hiew, Tzechingi, creator author. text my 2025 2025 monographic eng xiii, 60 pages : illustrations ; Laccase is a multi-copper biocatalyst that catalysed the oxidation of phenolic components through a radical-mediated process. Its potential applications in various industrial sectors, including juice clarification, have been progressively developed. The naturally formed polyphenols in fruits offer nutritional benefits, but excessive presence can cause unpleasant turbidity and haze formation. This study focused on the oxidation of phenols in apple juice by utilising in-situ immobilised laccase-bacterial cellulose (BC) biocatalyst. This research aims to evaluate the effects of enzyme loading and reaction duration on the efficiency of phenolic oxidation and then investigate the reusability of the biocatalyst for juice clarification. Methodologically, laccase was immobilised on BC produced from pineapple peel waste through an in-situ synthesis process. The impact of enzyme loading was assessed by varying the biocatalyst amount and measuring the removal of phenolic content, juice clarification and colour reduction. Subsequently, the juice treatment was followed by altering different reaction times based on the best enzyme loading with the same evaluation. Then, reusability was analysed by subjecting the immobilised laccase to multiple cycles of juice treatment and monitoring its residual activity. The results indicated that increased enzyme loading improved catalytic oxidation, enhancing phenolic content removal at 40.3 ± 0.4% while reducing juice clarification for 15.9 ± 2.2% and colour for 23.3 ± 0.7%, respectively, at the best enzyme loading of 0.20 U. Additionally, 120 minutes was the best reaction duration for juice treatment by considering catalytic efficiency and economic feasibility. The result showed the deduction of 35.4 ± 3.5% of total phenolic content, 23.7 ± 1.2% of juice clarity and 26.9 ± 0.5% of its colour. The immobilised enzyme also exhibited excellent operational stability by retaining its activity up to 50% after three batch reactions. This study highlighted the utilisation of low-cost support for laccase immobilisation with application in apple juice clarification. specialized Hiew Tzeching Faculty of Chemical and Process Engineering Technology Final Year Report (Bachelor of Chemical Engineering ) -- Universiti Malaysia Pahang Al-Sultan Abdullah - 2025 Include bibliographical reference Faculty of Chemical and Process Engineering Technology Dissertations Universities and colleges Dissertations Theses Dissertations THE0010681 (Local) UMPSA 260708 20260708180016.0 eng