Isolation of Alkalophilic Pectinolytic Bacteria and their Bio Retting Effect on Kenaf Fiber Compositions

Retting is the most limiting process of high-quality cellulosic kenaf bast fiber production which facilitating the separation of useable fiber from the plants' cell wall matrix. Existing traditional water retting approach confronts ineptitude and eutrophication related complications. Aiming to enhance the kenaf bio-retting process, sixty-seven alkalophilic bacterial colonies were isolated from paddy land soil sediments and kenaf retting water. These isolates were subsequently screened, of that two isolates were selected based on hyper qualitative and quantitative pectinolytic enzymatic measures. 16s rDNA gene sequence analysis revealed that both two strains were closely related to Bacillus pumilus species and designated as KRB56 and KRB22. These strains were applied in augmented non-sterile kenaf tank retting to investigate their kenaf retting efficiency and yielded fiber were analyzed for chemical compositions. Results revealed that, stains KRB56 and KRB22 significantly improve the retting process by degradation of 82.78% and 75.28% non-cellulosic gums, respectively comparing with uninoculated treatment niche (62.12%). Based on un retted raw kenaf fiber maximum fiber bundle weight was reported in MTW with 16.04% material losses, while the SW, and FW treatments showed 24.38%, and 21.03% material losses, respectively. These bacterial treated fiber samples showed thinner, smooth, and cleaner fibers surface morphology by SEM indicates sufficient non cellulosic gums (NCGs) removal comparing with URKF. Moreover, yielded fibers were examined for chemical composition, FTIR, XRD test. Results revealed that compare to un retted and un inoculated kenaf fiber, bacterial treated kenaf fiber increases cellulose portions, and their crystallinity index increases 35.50-41.30 % due to sufficient NCGs removal. This study's findings indicate that isolated alkalophilic bacterial strains KRB56 and KRB22 were effectively to be used as kenaf bio retting agents to produce quality kenaf fiber.

Preparation of Fibrillated Cellulose from Kenaf Bast Fiber using High Speed Homogenizer without Pressure

The aim of the study is to characterize the fibrillated cellulose (FC), which has been extracted from kenaf bast fiber using high speed homogenizer (HSH). The FC was prepared by applying 10,000, 15,000 and 20,000 rpm of homogenization process for 10, 15 and 20 mins. Morphological observation via Field Emission Scanning Electron Microscope (FESEM) was carried out in order to observe the sur-face morphology of FC while Fourier Transform Infrared (FTIR) spectroscopy was performed to determine the changing of functional groups. Thermogravimetric Analysis (TGA) was done for thermal decomposition of FC. Results showed that the diameter of the FC from kenaf bast was determined below 100 nm. The Fourier Transform Infrared (FTIR) spectroscopy showed that lignin and hemicellulose were almost completely removed during the bleaching process at peak 1,737 cm-1. In addition, thermogravimetric analysis (TGA) displayed 272°C as the highest temperature for thermal stability of FC. In conclusion, by controlling the speed during homogenization process, FC was successfully obtained. Such FC can be applied as beneficial main ingredients in papermaking and packaging industry, which dedicat-ed to mechanical strength properties.

Effect of Modification Time of Kenaf Bast Fiber with Maleic Anhydride on Tensile Properties of Kenaf-Glass Hybrid Fiber Unsaturated Polyester Composites

Natural fiber reinforced polymer composites are generally lower in mechanical performance compared to synthetic fiber reinforced polymer composites. However, this disadvantage can be improved via chemical modification of the natural fiber and hybridization with synthetic fiber. In this study, kenaf bast fiber was used as reinforcement in unsaturated polyester composites. It was subjected to chemical modification with maleic anhydride at various treatment time i.e. 60, 90 and 120 minutes prior to composites production. The untreated and MA treated kenaf bast fiber were hybridized with 10 weight percent of glass fiber to produce kenaf bast/glass fiber reinforced unsaturated polyester composites. The effect of treatment time on weight percent gain and functional group changes via infra-red spectra of kenaf bast fiber were investigated. The effect of treatment time on tensile properties of kenaf bast fiber and kenaf bast/glass fiber reinforced unsaturated polyester composites were also studied. It was revealed that the weight percent gain of kenaf bast fiber increased with the increasing of treatment time. The increasing of treatment time resulted in the enhancement of tensile strength and modulus of kenaf bast fiber and kenaf bast/glass fiber reinforced unsaturated polyester composites which were attributed to the presence of C=C bonds of maleic anhydride and has been proven through fourier transform infrared spectrum.

Transverse and Longitudinal Flexural Properties of Untreated and Maleic Anhydride Treated Kenaf Bast Fiber Reinforced Unsaturated Polyester Composites

Kenaf bast fibers were prepared into two types as untreated and maleic anhydride (MA) treated. Unsaturated polyester (UPE) resin was used as matrix and applied onto the kenaf bast fibers using hand lay-up method. Transverse and longitudinal flexural properties of unidirectional long kenaf bast fiber reinforced unsaturated polyester composites were performed and the effect of fiber modification and loading were studied. It is found that the transverse flexural strength of both types of composites decreases with the increasing of kenaf loading. Contrary, longitudinal flexural strength of both composites increases with the increasing of kenaf loading. Improved transverse and longitudinal flexural properties are shown by MA treatment of kenaf bast fiber. The interactions between fiber and matrix of fractured flexural surface were also observed by scanning electron microscope (SEM).