<P><B>Abstract</B></P> <P>In this study, nanocellulose (NC) was successfully extracted from oil palm frond leaves (OPFL) using a combination of bleaching, alkaline treatment and acid hydrolysis. X-ray diffractogram revealed the extracted NC was crystalline with a crystallinity index of 70.2%. This indicates its suitability as nano-fillers for preparing the chitosan/nanocellulose (CS-NC) supports to immobilize <I>Candida rugosa</I> lipase (CRL) to produce the CRL/CS-NC biocatalysts. FTIR, FESEM and TGA characterizations of the CRL/CS-NC confirm the CRLs were successfully conjugated to the CS-NC supports. The air-dried CS-NC supports gave satisfactory immobilization of the CRLs (5.2mg/g) with the resultant CRL/CS-NCs catalysed conversions of ≥80% of butyl butyrate within 6h. Time course reaction profile revealed that 76.3% butyl butyrate conversion was achieved at 4h immobilization time using 3mg/mL of CRL/CS-NCs. NMR analyses on the purified butyl butyrate confirmed that the ester was successfully synthesized.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanocellulose (NC) from oil palm fronds gave crystallinity index of 70.2%. </LI> <LI> Nanocellulose was used as nanofiller in the chitosan-nanocellulose (CS-NC) support. </LI> <LI> Air-dried CS-NC gave higher attachment of CRL at 5.2mg/g. </LI> <LI> The CRL/CS-NCs gave 76.3% yield of butyl butyrate in 4h. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>