POTENTIAL INHIBITION OF XYLANASE BY LIGNOCELLULOSIC DERIVATIVES

• Main Author: Maulana Hidayatullah, Ibnu
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/38712
• Institution: Institut Teknologi Bandung

The dominant polymer chain of hemicellulose is xylan which can be hydrolyzed to xylose by xylanase. The product of xylose reduction is xylitol which has a high selling value and is used in the pharmaceutical and food industries. In carrying out hemicellulose hydrolysis, xylose cannot be converted properly due to inhibiting factors. This inhibiting factor is in the form of compounds that have the potential inhibitors that appear from the results of pretreatment, hydrolysis, and fermentation of lignocellulose compounds so that the concentration of xylose becomes low and has an impact on the yield of xylitol produced slightly. This report presents the results of the potential inhibition of xylanase by lignocellulose derivative compounds through 3 groups of compounds tested, namely: furan and aliphatic acids (furfural, 5-hydroxymethylfurfural, acetic acid and formic acid), aromatic compounds (vanilin, salicylic acid and 4 - hydroxybenzaldehyde), and hydrolysis - fermentation products (glucose, xylose, ethanol and xylitol). The hydrolysis reaction is carried out in conditions without inhibition (control) and inhibited. Hydrolysis using beechwood xylan at temperature of 50oC within 150 minutes with variations in enzyme concentration of 0.55 g/l and 1.65 g/l. Xylose quantification using High Performance Liquid Chromatography (HPLC). Variations were carried out on substrate concentrations and types of compounds that have potential as inhibitors The data collected based on analysis of xylose concentrations that are measured against a certain time unit. The inhibition test results showed that formic acid, vanilin, and ethanol were the strongest inhibitors of each group (a decrease of 35.52%; 44.49%; and 43.56% against the rate of hydrolysis without inhibition). The mechanism of inhibition of these compounds occurs in a mixed, un-competitive, and competitive. In addition, vanilin has the strongest inhibitory effect when observed from xylanase performance (catalytic constant 0.23 hour-1; specific constant 0.08 l/g.hour; degree of inhibition 48.18%; enzymatic digestibility 2.45; inhibition constant 0.13 g/l; and Km/KI ratio 23.94).