Isolation of Natural Polymer from the By‐Product of Hydrolysis of Oil Palm Empty Fruit Bunch for Bioethanol Production

Summary The natural polymer was isolated from black liquor as the product of bioethanol pretreatment process by means of precipitated method. The natural polymer was precipitated by addition of sulfuric acid to obtain various pH conditions (10 to 1) of the mixtures at room temperature. In addition, variation of temperatures agitation was also conducted in the precipitation of natural polymer from black liquor at different initial of pH. The results showed that percentage of yield of precipitated natural polymer is increasing from 5.5 to 30.1% with the decreasing of the pH of black liquor from 10 to 1. In addition, the increasing temperature of precipitation from 50 °C to 90 °C results in increasing the yield of precipitated natural polymer. Furthermore, the distribution of particles of natural polymer recovered from precipitation process at different pH was then analyzed by Particle Size Analysis and the non‐volatile residue of precipitate was determined by furnace temperature program. The average of particle size of natural polymer is decreasing from 262 to 64 μm with the increasing of the precipitation pH from 1 to 10. The non‐volatile residue of natural polymer isolated by precipitation at higher pH was larger than at lower pH.