Xylanase Bleaching of Paper Pulps

AU-PE89 Xylanase is a paper enzyme which can effectively degrade xylan, and improve paper pulp bleaching

AU-PE89

Xylanase for Improved Bleaching of Paper Pulps

1. INTRODUCTION

AU-PE89 Xylanase is an enzyme specifically for  removing xylan and does not degrade cellulose. Xylanases produced by different microorganisms operate optimally over a range of pH and temperature. The product is prepared as a concentrated liquid or light brown powder.

2.TECHNOLOGICAL ADVANTAGE

The main driving factors for acceptance of this technology in pulp mills have been the economic and environmental advantages over chemical bleaching.

AU-PE89 used as a pre-bleaching agent for wood and non-woody pulps can reduce chemical bleach consumption from between 15 to 50%.

3.SPECIFICATIONAU-PE89 is a product derived from the culture of a strain of Bacillus subtilis.

AU-PE89 is prepared with a xylanase activity of about 85,000 XU/mL. AU-PE89 is a light brown powder with a density of 1.1 g/mL. It is readily miscible with water. 

4.BENEFITS OF AU-PE89

Reduce Organochlorines in WastewaterFor mills using active chlorine as a bleaching chemical, AU-PE89 can eliminate or substantially reduce the chemical and environmental load of toxic organochlorines in mill effluent.

Reduce Chemical Costs

AU-PE89 has the potential to reduce bleaching chemical by15 to 50%.

Increase Pulp Production CapacityPre-bleaching pulps with AU-PE89 allows pulp production capacity to be increased where on-site chlorine dioxide production is a limiting factor.

Higher Pulp BrightnessAU-PE89 can increase the pulp brightness by 2 to 6%. providing the mill with a better quality paper.

Easily IncorporatedAU-PE89 is easily incorporated into existing bleach lines. Typically, installation requires only a mixing tank and dosage pump.

Reduce Effluent LoadApplication of AU-PE89 can significantly reduce COD, BOD and color of effluent.          

5.APPLICATION

AU-PE89 xylanase can be added to pulp after cooking or oxygen delignification and prior to bleaching for the improvement of pulp bleachability. The optimal dosage can also depend on the temperature, pH and consistency of the pulp. However, the following general application optimal conditions apply.

Dosage               200-250g/ T pulp (o.d.basis)Pulp properties   PH between 6.5 and9.5Temperature        between 45 and 55°CPulp consistency  between 6 and 10% (recommended 8%)Residence time    above 1 hour

6.STORAGEAU-PE89 maintains its stated activity for at least six months when stored at temperatures below 25°C. The product maintains its activity for considerably longer when stored at lower temperatures. The product should not be frozen.

7.HANDLING PRECAUTIONSAU-PE89 is non-toxic and biodegradable. However, unnecessary contact with the product should be avoided. Long term exposure to protein based products such as AU-PE89 may sensitise certain individuals to the product 

Xylanase Bleaching of Paper Pulps