TEMPERATURE AND PH OPTIMIZATION OF CAR THERMOPHILIC BACTERIA FOR THE PRODUCTION OF XILANASE THE BLEACHING OF ENVIRONMENTALLY FRIENDLY INKED PAPER WASTE

Xylanase is an extracellular enzyme capable of hydrolyzing hemicellulose so that it can convert xylan into xylose. Xylanase enzymes can be used in the pulp and paper industry. This study aims to determine the effect of temperature, pH on enzyme production by immobilized thermophilic bacteria using rice straw xylan extract as a substrate and to see the effect of xylanase administration on the whiteness level of inked paper waste. This study was an experimental study and used a completely randomized design (CRD). Enzyme activity was measured using a spectrophotometer at a wavelength of 540 nm. Enzyme activity data were analyzed using the ANOVA test and continued with the DMRT (Duncan Multiple Range Test) further test with a level of 5% and the whiteness of the paper was determined by testing the kappa number. The results obtained were that the temperature of immobilize thermophilic bacteria using rice straw xylan extract as a substrate affected the xylanase enzyme activity with an optimum temperature of 75°C having the highest average value of enzyme activity 4.668 U/mL. Meanwhile, the optimum pH for immobilized thermophilic bacteria to produce xylanase was pH 8.5 with the highest average value of enzyme activity 4.854 U/mL. The addition of xylanase enzyme in the fermentation process of inked paper waste was able to increase the brightness of the inked paper with a lower average value of kappa number of 2.762 compared to the higher control of 5.525.