1. Optimization of enzymatic hydrolysis on nanofibers production for their use on nanopapers production
Quim Tarrésa*, M. Àngels Pèlacha , Manuel Alcalaa, Fabiola Vilasecaa, Marc Delgado-Aguilara, Pere Mutjéa

2. Introduction
Nanocellulose and its derivatives have become a topic of great interest by the scientific and technological community due to its availability, lightweight and properties.
Among their potential applications, such as transparent membranes for electronics, aerogels for oil absorbing and bionanocomposites, cellulose nanofibers (CNF) have been widely used for paper reinforcement.

3. Introduction
In recent years, nanocellulose has generated great interest in the scientific and technological community.
Katja and Kautto (2013)

4. Characterization of CNF
Introduction
Cellulose nanofibers (CNF)
Fiber pretreatment
Mechanical beating
Oxidation catalyst by TEMPO
Acid hydrolysis
Enzymatic hydrolysis
Desestructuration
High press homogenizer
Microfluidizer
Grinder (MAZUKO)
Characterization of CNF
Degree of polymerization
Cationic demand
Carboxylic content
Specific surface
Diameter
Standard performance

5. Objective The main objectives of this work are:
Optimize enzymatic hydrolysis conditions by pH, concentration of pulp, temperature, time and enzyme dosage for CNF production.
Evaluate the effect of enzyme concentration and application time on the characteristics of the obtained CNF.
Determine reinforcement potential of CNF as papermaking additive.
Study the mechanical and optical properties of nanopapers produced from different obtained CNF.

6. Methodology BHKP Mechanical Beating Enzymatic hydrolysis
Desestructuration
CNF

7. Papermaking with 3% of CNF
Methodology
CNF
Applications
Papermaking with 3% of CNF
Nanopapers
production
Characterization
- Cationic demand
- Specific Surface
- Diameter
- Yield of nanofibrilation
- Transmittance
- Degree of polymerization

8. Results and discussion
Effect of Temperature, pH and concentration of pulp:
Treatment
Temperature
(ºC)
Time
(h)
Enzyme concentration
(g/t)
Fiber concentration
(%) pH 1 50 2
160 3 7 5 4 60

9. Results and discussion
Evaluation of the effectiveness of obtained CNF on a reference suport
100%
Working conditions:
- 50ºC
- 5% fibra
- pH 5
Different letters indicate significant differences in treatment effect (P<0,05)

10. Results and discussion
Characterization of obtained CNF
Enzyme conc.
Time
Cationic demand
Specific surface
Diameter
Yield
Transmittance at 800 nm DP
(g/t)
(h)
(µeq·g/g)
(m2/g)
(nm)
(%) 80 2
175
64,8
38,6
14,2
28,7
450 3
179
66,7
37,5
19,5
30,4
431 4
187
70,6
35,4
20,5
31,5
412
160
183
68,7
36,4
16,3
419
215
84,3
29,7
20,1 30
346
255
103,7
24,1
29,4
34,5
320
240
252
102,3
24,4
27,9
317
253
102,8
24,3
28,9
33,6
315
258
105,2
23,8 34
38,9
307
246
99,3
25,2
29,2
31,9
324
250
101,3
24,7
32,1
318
36,1
309
TEMPO
5 mmols
1170
183,6
13,6
>95
80,8
490
Enzyme conc.
(g/t)
Time
(h)
Cationic demand
(µeq·g/g)
Specific surface
(m2/g)
Diameter
(nm)
Yield
(%)
Transmittance at 800 nm DP
160 4
255
103,7
24,1
29,4
34,5
320
240
258
105,2
23,8
34,0
38,9
307 2
246
99,3
25,2
29,2
31,9
324 3
250
101,3
24,7
28,7
32,1
318
36,1
309
TEMPO
5 mmols
1170
183,6
13,6
>95
80,8
490

11. Results and discussion
Influence of enzyme dosage on specific surface of CNF

12. Results and discussion
Evolution between cationic demand and degree of polymerization for different enzyme dosage

13. Results and discussion
Evaluation of CNF production cost
Type of CNF
Production cost (€/t CNF)*
Pretreatment cost
Cost of desestructuration
Total Cost
Chemical cost
Enzymatic cost
Energetic cost
TEMPO basic pH €
0,00 €
30 €
1.530 € €
TEMPO neutral pH € €
Enzymatic hydrolysis
160 g/t 4 h €
320 €
61,80 € €
240 g/t 4 h
480 € €
320 g/t 2 h
640 €
30,90 € €
320 g/t 3 h
46,30 € €
320 g/t 4 h €
*Energetic cost was calculated by 0,08 €/kWh

14. Results and discussion
Nanopapers characterization
Enzyme conc.
(g/t)
Time
(h)
Cmax
(MPa)
A. Fmax
(%)
MYoung
Transmittance
800 nm
Thickness
(nm) 80 4
50,5±3,1a
3,0±1,0a
3714,0±312,6a
11,6
0,035
160
70,1±2,1b
3,4±0,4b
4565,4±412,5b
13,8
0,025
240
82,4±1,2c
4,1±0,7c
5077,0±315,7c
14,9
0,028
320
112,9±2,1d
5,7±0,3d
6002,9±365,4d
22,5
0,026
TEMPO
5 mmols
135,21±0,7
3,59±0,2
11880,0±227,1
46,0
0,023
Different letters indicate significant differences in treatment effect (P<0,05)
(A)
(B)

15. Conclusions The main conclusions of this work are:
It has been shown that the optimum conditions for carrying out the enzymatic hydrolysis are T = 50 °C, C = 5% , pH 5 and t≥2h to enzyme doses that are between 160 and 320 g/t.
Nanofibers obtained from enzymatic hydrolysis have characteristics lower than those obtained by TEMPO catalyzed oxidation. However, these are equally effective in terms of increases in mechanical properties applied in papermaking.
Moreover, from a technical and economic point of view, the five previous cases that have similar effectiveness has been determined that the use of a smaller amount of enzyme is economically more profitable

16. Conclusions
The results, demonstrate that by enzymatic hydrolysis pretreatment is not possible get CNF with the same quality as by TEMPO oxidation.
On the films or nanopapers production has shown that nanofibers produced by enzymatic hydrolysis have a lower degree of transparency and also inferior mechanical properties.

17. Conclusions
Is shown that on the equivalence between intrinsic properties of fibers and quantity of links to obtain good mechanical properties of nanopapers, the number of links that they are able to produce is a predominant factor.
Finally, it has been found that the production of cellulose nanofibers using enzymatic hydrolysis represents a reduction of more than 90% of the production costs.

18. Thanks for your attention