ABSTRACT
The potential of alkaline cellulo-xylanolytic enzymes from non-pathogenic Bacillus subtilis strain was tested for deinking of photocopier waste paper. Cellulase and xylanase play a crucial role in deinking of different types of waste paper. Partial purification of cellulo-xylanolytic enzymes was carried out using ultrafiltration followed by ammonium sulfate precipitation. The ultrafiltered enzyme was used for deinking the photocopier waste paper along with chemical deinking. An enzyme dose of 0.6 IU/g and reaction time of 60 min for ultrafiltered cellulo-xylanolytic enzyme significantly increased deinking efficiency, tear index (9.52%) and folding endurance (5±2%) as compared to chemical deinking. There was improvement in strength properties such as tear index and double-fold along with freeness of pulp (18%). There was slight decrease in tensile index (0.6%) and burst index (16%) while ISO brightness remained unaffected. Enzymatic deinking (74.3%) by ultrafiltered cellulo-xylanolytic from Bacillus subtilis was found significant over conventional chemical deinking.
Subject(s)
Cellulase , Ink , Endo-1,4-beta Xylanases , PaperABSTRACT
To improve the process economy of reactivity improvement, crude cellulase from Bacillus subtilis was employed for the treatment and significant dissolving pulp properties were analyzed. With increase in enzyme dose from 0.25 to 2 U/g o.d. pulp, improvement in Fock reactivity and alkali solubilities (S10 and S18) were observed with simultaneous reduction in viscosity and yield. Fourier transform infrared spectroscopy and scanning electron microscopy were used to observe the molecular level effects on dissolving grade pulp. The most suitable cellulase dose for reactivity improvement with lowering of viscosity was 0.25 U/g o.d. pulp. With increases in enzyme dose, alkali solubilities (S10 and S18) of dissolving pulp showed continuous increment, while alpha-cellulose of pulp showed reduction due to chain scission of long cellulose fiber fraction.
