Bast was immersed in 0.85% solution of Triton X-100 at 40 ⁰C for 10 min, followed by soaking in sodium hydroxide (NaOH) solution at varies concentrations (1, 2 4, 6 and 8%) at 100 ⁰C for 60 min. For enzymatic retting, the fiber was treated with chelating agent, enthylenediamine-tetraacetic acid, then immersed in 0.85% solution of Triton X-100 at 40 ⁰C for 10 min, followed by adding of pectinase at different concentrations (0.25, 0.5, 1.0 and 3%) at 50 ⁰C for an hour. They concluded all treatment resulted in reduction of lignin and addition of 3% pectinase into the treatment produced optimum decreased by almost one-half of lignin content compared to unretted fibers. Lee et al. (2004) concluded that chemical retting is more effective to remove hemicellulose, whilst enzymatic retting was more effective to remove lignin. Zhang (2000) studied on chemical retting of kenaf stalks which involved boiling in NaOH and sodium bisulfite (NaHSO3) solution, neutralized with acid, washing with water and drying in the oven. Different concentration of NaOH and NaHSO3, as well as boiling time were applied for the study. Ratio fiber to liquid (w/v) was 1:20. The fibers were washed under warm tap water and then were submerged into 0.3% Hydrochloric acid (HCl) solution for 5 min, before it was rinsed with water again. The fibers were then soaked in commercial softener (3.0 g/l) with ratio of 1:10 …show more content…
(2015). Green ramie stem was decorticated to remove outer bark/epidermis and bast from inner woody core. Two bacterial strains of C. felsineum were selected as their high pectinolytic activity. The cultured bacteria was transferred into 17 L capacity jar and anaerogen was placed to create anaerobiosis. The jar was then placed at 37 ⁰C for 96 h. For each retting, 100 g dry bast samples (replicate 4) was placed in 9 L plastic tanks. The fiber ratio and water was 1:50 and left for 7 days at 30 ⁰C. For chemical retting, 2% of NaOH solution was prepared. Bast sample and NaOH were placed in glass container airtight and boiled in water for 2 h. The retted fibers were then washed with cold water and dried. The fiber were combed using special comb in order to separate the long fibers for quality assessment. NaOH retting produced fiber with higher cellulose and lower hemicellulose compared to microbe retting. It also produces least gum, consistent long and smooth surface within a short time. There was no significant difference in tensile strength although microbe resulted slightly higher strength for composite compared with chemical