No abstract

In this study, bacterial cellulose (BC) was produced by Acetobacter xylinum using oil palm frond (OPF) juice as a carbon source, where the effect of cultivation time in the range of 2-14 days on BC production was investigated. The highest BC production of 0.3365 g/L was obtained at cultivation time of 9 days. Structural analysis by FTIR showed that the properties of BC to be similar regardless of cultivation time. FESEM analysis revealed that the BC produced was composed of randomly packed and loosely fine cellulose fibers. The present study showed the feasibility of using OPF juice as an alternative in the production of BC which could reduce the production cost of BC.

In this study, silica nanoparticles entrapped with rifampicin has successfully been synthesized by using micelles entrapment approach. The goal of this study is to investigate the effects of synthesis parameters; surfactant (Tween 80), solvent (water) and stirring rate on the particles size and distribution of silica nanoparticles entrapped rifampicin. The results showed that without surfactant, larger mean particles (176.4 nm to 207.70 nm) of silica nanoparticles were produced while uniform and smaller spherical particles sizes (42.37 nm -70.44 nm) were formed with the addition of surfactant. But, when the amount of surfactant increased from 3.0 g to 9.0 g, larger silica nanoparticles with uniform size and thinner walls were observed until critical micelle concentration (CMC) of surfactant equivalent to 11.0 g was reached. The effect of water content shows the particle size slightly increased from 55.92 nm to 56.99 nm when the water content was increased from 150 mL to 200 mL, and decreased rapidly from 56.99 nm to 18.55 nm as the amount of water was increased from 200 mL to 350 mL. Meanwhile, for the effect of stirring rate, the mean particles sizes were recorded in the range of 39.11 to 80.15 nm. The largest size was observed at the lowest stirring rate (120 rpm) and the smallest size was observed at the highest stirring rate (520 rpm). The significant effect of these synthesis parameters can be used in developing a rational basis in tuning the size of silica nanoparticles for drug delivery system.

Water holding and release properties are important characteristics for a dressing material in wound healing. In the present study, the water holding capacity (WHC) and water release rate (WRR) of BC films produced from oil palm frond (OPF) juice were investigated. The juice was inoculated with Acetobacter xylinum in 24-well plates and incubated at 30 °C for 7 days under static conditions. The films were further dried by three different methods; air-, oven-and freeze-drying. The dried BC was characterized for its size and surface morphology by field emission-scanning electron microscopy (FE-SEM) and for its water holding and release properties. BC produced from OPF juice exhibited good WHC and WRR comparable to BC films produced from Hestrin and Schramm (HS) medium. The loosely arranged fibrils in freeze-dried BC has also resulted in highest WHC and WRR value compared to the oven-and air-dried BC. This study suggested that water holding and release properties are greatly dependent on the use of fermentation medium and drying method.

Bacterial cellulose (BC) is a form of cellulose produced by Acetobacter xylinum via fermentation process. BC contains impurities such as medium broth or the cell biomass. This study aims to determine the effect of purification method on the BC produced from oil palm frond (OPF) juice. Three purification method was presented in this study; first, BC was treated with different NaOH concentration at constant temperature of 70°C. Second, the BC was treated with different temperature while the NaOH concentration was fixed at 0.1M. Lastly, the BC was further purified in distilled water at different temperature. Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscope (FESEM) analysis revealed that chemical composition of BC is similar to the natural cellulose without the present of biomass impurities as no peak at 1800 – 1500 cm−1 can be detected. Higher percentage for loss of biomass, 22.03 % can be obtained when the BC was treated with 1.0 M NaOH at 90°C and further purified in distilled water at 90°C. As conclusion, pure BC which are free from any impurities can be obtained by using proposed method.