Xylanase Protocols

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These protocols are used to screen for and measure xylanase activity.

Plate Screen

This is a quick procedure to screen for xylanase activity.


  • 2.5g Xylan
  • 2.5g RBB (Remazol Brilliant Blue)
  • 60ml Water
  • 20ml Sodium Hydroxide Solution (1.5g in 20ml)
  • 20ml Sodium Acetate Solution (0.675g in 20ml)
  • 200ml 96% Ethanol
  • 1L Wash solution (660ml Ethanol, 330ml Water, 1.35g Sodium Acetate)
  • Acetone

Preparing the Dyed Xylan

  1. Add 2.5g RBB dye and 2.5g Xylan to 60 ml Water.
  2. Add 20ml Sodium Acetate solution to RBB-Xylan solution.
    1. Add dropwise over 5 minutes while stirring at room temp.
  3. After mixing add 20ml Sodium Hydroxide solution.
  4. Stir for 90 minutes at room temperature.
  5. Add two volumes of 96% Ethanol to precipitate the xylan-RBB.
  6. Filter using a vacuum flask and watman filter paper.
  7. Wash the precipitate sequentially with 1L of wash solution.
    1. The filtrate should now be colorless.
  8. Wash the precipitate with 100ml 75% Ethanol.
  9. Wash the precipitate with 50ml Acetone.
  10. Dry at room temp overnight.


  1. Add 1% RBB-Xylan (weight per volume) to your agar media of choice after autoclaving.
  2. Pour the plates immediately being sure to swirl frequently.
  3. Drop 5μL of overnight culture onto the plates
  4. Incubate for two days
  5. Observe clearing zones around xylanase producing cultures.


This assay measures the release of reducing sugars (including xylose and arabinose) during the enzymatic treatment of xylan. If you have reducing sugars (e.g. glucose) in your media, it will also be detected, so you will always have to compare to a control culture with no xylanase.


  • Arsenic Acid
  • Copper Sulfate
  • Molybdic Acid
  • Sodium Acetate
  • Sodium Bicarbonate
  • Sodium Carbonate
  • Sodium Potassium Tartrate
  • Sodium Sulfate
  • Sulfuric Acid
  • Xylan (purified)
  • Xylose (purified)

Preparing the Reagents

If you prepare the amounts listed you will be able to run 10 samples (not including the standard curve)

Dissolve and add the following in one container with 20 mL of water for each sample:

  • Copper Sulfate
  • Sodium Sulfate
  • Sodium Carbonate
  • Sodium Bicarbonate
  • Sodium Potassium Tartrate

Dissolve and add the following in one container with 20 mL of water for each sample:

  • Molybdic Acid
  • Arsenic Acid
  • Sulfuric Acid

Substrate Solution

  1. Dissolve the following in 10ml of water:
82mg Sodium Acetate
0.2g Xylan
  1. Bring the volume up to 20ml by adding water.

Copper Solution

Acid Solution


Standard Curve


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