Paper products subjected to a surface treatment comprising enzyme-treated surface enhanced pulp fibers and methods of making the same

1. A method of making a paper product, the method comprising:

forming a substrate from a first furnish that comprises a plurality of pulp fibers;

at least partially dewatering the substrate;

treating a second furnish that comprises a plurality of surface enhanced pulp fibers (SEPF) at least by adding one or more enzymes to the second furnish, the SEPF having a length weighted average fiber length that is greater than or equal to 0.20 millimeters (mm) and an average hydrodynamic specific surface area that is greater than or equal to 10 square meters per gram (m2/g), the one or more enzymes being configured to reduce a viscosity of the second furnish;

sizing the dewatered substrate at least by depositing the treated second furnish onto at least one of opposing first and second surfaces of the dewatered substrate; and

drying the sized substrate.

2. The method of claim 1 , comprising adding starch to the treated second furnish before depositing the treated second furnish.

3. The method of claim 2 , wherein adding starch to the treated second furnish is performed such that, in the treated second furnish, the weight of the SEPF is between 10% and 90% of the weight of the starch.

4. The method of claim 3 , wherein adding starch to the treated second furnish is performed such that, in the treated second furnish, the weight of the SEPF is between 40% and 60% of the weight of the starch.

5. The method of claim 1 , wherein adding the enzyme(s) to the second furnish is performed such that the weight of the enzyme(s) in the second furnish is between 0.005% and 10% of the weight of the SEPF in the second furnish.

6. The method of claim 1 , wherein the enzyme(s) comprise an endoglucanase and an exoglucanase.

7. The method of claim 6 , wherein the exoglucanase is a cellobiohydralase.

8. The method of claim 1 , wherein dewatering the substrate is performed such that less than or equal to 40%, by weight, of the dewatered substrate is water when the treated second furnish is deposited.

9. The method of claim 1 , wherein depositing the treated second furnish is performed with a size press.

10. The method of claim 1 , wherein between 1% and 6%, by weight, of the treated second furnish is the SEPF when the treated second furnish is deposited.

11. The method of claim 1 , wherein about 4%, by weight, of the treated second furnish is the SEPF when the treated second furnish is deposited.

12. The method of claim 1 , wherein depositing the treated second furnish is performed such that, for each of the surface(s) of the dewatered substrate onto which the treated second furnish is deposited, the basis weight of the SEPF on the surface is between 0.2 and 3.0 grams per square meter (gsm).

13. The method of claim 1 , wherein forming the substrate comprises depositing the first furnish onto a moving surface.

14. The method of claim 1 , wherein: the pulp fibers of the first furnish comprise hardwood pulp fibers; and the SEPF are hardwood pulp fibers.

15. The method of claim 1 , wherein the one or more enzymes have between 0.005 percent and 10 percent of a weight of the SEPF in the second furnish.

16. The method of claim 1 , wherein sizing the dewatered substrate is performed by depositing the treated second furnish onto the opposing first and second surfaces of the dewatered substrate.

17. The method of claim 1 , wherein the first furnish and the second furnish are different.