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Extensive work on bacterial cellulose (BC) cultivation is crucial in optimizing BC performance and versatility in application. Herein, this study aims to investigate the lignin content in oil palm frond (OPF) juice medium that could affect the BC production by Acetobacter xylinum 0416 in static culture. The effects of lignin content were observed by the performances of BC production from the raw and pre-treated OPF juice medium fermentation with Hestrin-Schramm (HS) medium as a point of comparison. The TAPPI methods analysis outlined up to 3.719 g/L of total lignin content in raw OPF juice and FTIR analysis depicted the functional group of a typical lignin compound, thus confirming its presence as a component inhibitor. The raw OPF juice was further pre-treated using an alkaline precipitation method resulting in acid-insoluble lignin removal up to 75.47% of the total lignin content. The results revealed that the BC yield from the raw OPF juice fermentation was lower compared to the HS medium with dried BC content of 0.152 g/L and 2.52 g/L, respectively. The BC cultivation using the pre-treated OPF juice medium was improved as the BC yield significantly increased to 1.91 g/L. Therefore, a proper pre-treatment strategy on OPF juice medium for lignin content removal could improve the medium capability in BC cultivation for higher-scale production. [ABSTRACT FROM AUTHOR]

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Dehydration of wet bacterial cellulose (BC) mainly focuses on the physical characteristic or mechanical strength, but its polymorph crystal structure and thermal properties were rarely discussed. Herein, this study utilizes the drying method of hot-pressed and freeze-dried to the wet BC to elucidate the BC polymorph crystal structure in correlation with the BC crystallinity and thermal properties. The results indicate that dehydration of BC using hot-pressed (BC-HP) method reduced the cellulose Iα allomorph fraction by ± 5.0%, increased the crystallinity by ± 5.0%, but lower in thermal stability compared to freeze-dried (BC-FD) method. Additionally, BC-HP shows an exothermic reaction of melting at lower enthalpy value which is contradict to BC-FD and plant cellulose that presented an endothermic reaction with higher enthalpy values. Thus, investigation on BC polymorph crystal structure and thermal properties may offer an important role to regulate the desired characteristic of the dried BC. [ABSTRACT FROM AUTHOR]

Nanocellulose fibre is comprised of nanosized cellulose fibrils that can be isolated from plants due to the lignocellulosic components. Empty fruit bunch (EFB) is a waste product that produced after the sterilization process of the fresh fruit bunches, which contributes around 24 wt.% of the solid waste in oil palm mill and it has high cellulose content. Therefore, the isolation of cellulose nanofiber (CNF) from EFB can increase the value of EFB for high end product. CNF has high specific strength and stiffness, high aspect ratio, large specific surface area and high reinforcing potential. In this work, the characteristics of the CNF isolated from EFB through nano-grinding treatment will be investigated. The cellulose was firstly extracted from the EFB through thermal-chemical process before undergoing nano-grinding treatment to isolate the CNF. The morphology, chemical composition, thermal stability and crystallinity of the cellulose, and CNF were analysed using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray Diffraction (XRD). From the morphology analysis, nano-dimensioned cellulose fibers can be observed, with a reduction of mean diameter of cellulose from 8.25 μm to CNF; which is approximately 17.85 nm. Based on the chemical composition; such as C O C stretching of pyranose ring and thermal analysis (T max of degradation =354 °C) of the CNF, the nano-grinding treatment does not give significant changes on chemical and thermal behaviour compared to cellulose. The crystallinity of the fibre shows a minimum increment after the mechanical treatment. Thus, the isolated CNF from EFB shows a promising characteristic and nano-grinding treatment is a potential method for the CNF isolation. [ABSTRACT FROM AUTHOR]

The production of valuable materials from biomass into nanosized become the principal focus of the developing industries on achieving green-based composite product, designed for extensive range of applications. This study principally, focused on discovering green method for the utilisation of N36 Ananas comosus leaves fibre (PALF) to highly potential material. Nanofibrillated cellulose (NFC) were successfully isolated from PALF by ball milling with presence of isopropyl alcohol. The effect of isopropyl alcohol and the milling time on nano fibrillation were analysed through characterisation of NFCs including Field Emission Scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Zeta-potential (ZP), Fourier transform infra-red (FTIR) and Particle size analysis (PSA). Comparatively, the 1:4─15 min NFC sample which milled for 15 mins with 1 mL of cellulose suspension and 4 mL of IPA, express desirable features in the concern of morphology, fibre size, yield, crystallinity, thermal stability, and homogeneity on disintegration of PALF fibre. High thermal degradation temperature of 323 ℃ and crystallinity index of 67%, reveal the potential on reinforcing to improve the composite's thermal stability and mechanical properties. Moreover, it exhibits excellent surface morphology, stability with low self-agglomeration, and uniformity in defibrillation with fibre diameter of 25.84 ± 8.30 nm, zeta-potential of − 32.31 ± 2.51 and PDI of 0.103. Besides, the high yield of NFC (>90%), increase the feasibility of NFC production. Hence, addition of IPA gives significant impact on defibrillation by disrupt the intermolecular hydrogen bond, so that less milling time is convenient on production of NFC without causes severe damage on other properties. • Isolation of nanofibrillated cellulose from N36 Ananas comosus leaf via ball milling with green solvent. • Influence of isopropyl alcohol on the properties of the cellulose nanofibre was investigated. • Effect of milling time and IPA contents on nanofibrillated cellulose were characterised. • NFC presented homogenous defibrillation, good thermal stability, high crystallinity, and high yield. [ABSTRACT FROM AUTHOR]