Process for the preparation of a sugar product and a fermentation product

1 . Process for the preparation of a sugar product from cellulosic material, comprising the following steps:

a) enzymatic hydrolysis of the cellulosic material using an enzyme composition to obtain the sugar product, wherein oxygen is added to maintain an oxygen concentration during enzymatic hydrolysis of

i. 0.0002-0.002 mol O 2 /m 3 when the reactor stirrer speed is 100 rpm;

ii. 0.002-0.016 mol O 2 /m 3 when the reactor stirrer speed is 120 rpm;

iii. 0.016-0.047 mol O 2 /m 3 when the reactor stirrer speed is 140 rpm;

so that xylonic acid is formed in an amount of 500 to 1100 μmol xylonic acid/kg xylan in the cellulosic material per hour, and

b) recovery of the sugar product.

2 . Process for the preparation of a fermentation product from cellulosic material, comprising the following steps:

a) enzymatic hydrolysis of the cellulosic material using an enzyme composition to obtain a sugar product, wherein oxygen is added to maintain an oxygen concentration during enzymatic hydrolysis of

i. 0.0002-0.002 mol O 2 /m 3 when the reactor stirrer speed is 100 rpm;

ii. 0.002-0.016 mol O 2 /m 3 when the reactor stirrer speed is 120 rpm;

iii. 0.016-0.047 mol O 2 /m 3 when the reactor stirrer speed is 140 rpm;

so that the xylonic acid is formed in an amount of 500 to 1100 μmol xylonic acid/kg xylan in the cellulosic material per hour,

b) fermentation of the hydrolysed cellulosic material to produce a fermentation product, and

c) recovery of the fermentation product.

3 . Process according to claim 1 , wherein the cellulosic material is pretreated before enzymatic hydrolysis.

4 . Process according to claim 1 , wherein the dry matter content in the enzymatic hydrolysis is from 10% to 40% (w/w).

5 . A process according to claim 1 , wherein the enzyme composition is in the form of a whole fermentation broth of a fungus.

6 . Process according to claim 1 , wherein the reactor for the enzymatic hydrolysis has a volume of 1 m 3 or more.

7 . Process according to claim 1 , wherein the reactor for the enzymatic hydrolysis has a volume of 50 m 3 or more.

8 . Process according to claim 1 , wherein the enzymatic hydrolysis is conducted at a temperature of from 50° C. to 70° C.

9 . A process according to claim 1 , wherein the enzymatic hydrolysis takes place in a batch, fed batch and/or continuous culture reactor.

10 . A process according to claim 1 , wherein oxygen is added to maintain an oxygen concentration of 0.0002-0.047 mol O 2 /m 3 during enzymatic hydrolysis.

11 . A process according to claim 1 , wherein the enzyme composition comprises at least a cellulase and/or at least a hemicellulase.

12 . A process according to claim 1 , wherein the enzyme composition comprises a beta-glucosidase (BG), an endoglucanase (EG), a lytic polysaccharide monooxygenase (LPMO), a cellobiohydrolase (CBH), a beta-xylosidase and an endoxylanase (EX).

13 . Process according to claim 2 , wherein the fermentation is conducted with a microorganism that is able to ferment at least one C5 sugar.