ISOLATION and SOME PROPERTIES of XYLANASE from SOIL-TERMITE GUTS and INFLUENCE of ENZYMES in BAKING

Abstract

The bacteria which has been isolated from gut of soil-termites that captured in around of College The University of Jember can secretes of xylanolytic enzymes. These enzyme acts as catalyst in hydrolysis of xylan synergically. The xylanolytic enzymes showed activities toward oat-spelts xylan was 4.78 U (referred as endo-β-1,4-D-xylanases), whereas activities toward p-nitrophenyl derivative substrates were 1.94 U (referred as α-L-arabinofuranosidases) and 2.64 U (referred as α-D-glucuronidases). The xylanolytic enzymes did not showed any activities of both exo-β-1,4-D-xylosidases and acetyl-xylan esterases. Attemp to purify of enzyme endo-β-1,4-D-xylanases also has been performed. Purification have so far been carried out were partially by ion-exchange column chromatography. Activity endo-β-1,4-D-xylanases was determined by DNS method, whereas the protein content was determined by Bradford method. The highest releasing-fractions of enzyme endo-β-1,4-D-xylanase on ion-exchange column chromatography obtained at saturation of 0.5 M NaCl with specific activity 1.62 U.mg-1. Enzyme has an optimum pH and temperature at 5.0 and 40oC, respectively. These enzyme were stable at temperature of 400C for four hours and range of pH 5.0 -8.0. The relative molecular mass possessed of endo-β-1,4-D-xylanases is around of 45,000- 66,200 Dalton by SDS-PAGE, whereas analysis of zymogram using SDS-Xylan-Page used to confirm that it contained endo-β-1,4-D-xylanase activity at the range of 45,000- 66,200 Dalton. These analyses revealed that enzymes could degrade oat-spelts xylan as substrates. Based on their both activity and characteristics, the potential of endo-β-1,4- D-xylanases as technological aids in baking was clearly demonstrated. Baking trials were performed with five wheat dough prepared with 0.0 ml (control), 12.5 ml, 25.0 ml, 37.5 ml, 50.0 ml, and 62.5 ml enzyme volume against 2,500 g wheat flour. In bread baking, endo-β-1,4-D-xylanase produce an effect that can result in many desirable benefits including increased of physico-chemical performance (moisture, reducing-sugar contents equivalent with glucose and xylose, mass, product volume, porosity and texture), improved crumb softness and organoleptic aspects (shelf-life, taste and aroma). The presence of endo-β-1,4-D-xylanase at volume 25.0 ml in the dough led to improvements in the breadmaking quality (i.e. product volume, porosity, and reducing- sugar content) on breads compared to control.