1. Wood bark as valuable raw material for compounds with biological activity
Valentin I.Popa
Gheorghe Asachi Technical University of Iasi
Faculty of Chemical Engineering and Environmental Protection
Blvd. Mangeron No.71, Iasi, , Romania

2. Structure of the bark
Bark is a highly heterogeneous and chemically complex section of woody biomass. It is usually divided into the living inner bark and dead outer bark, representing % of the total weight of the tree.

4. Component Softwoods Hardwoods Wood Bark
Composition by mass of lignin, polysaccharide, extractive and ash
in woods and barks. The non-extractive components are based on
extractive-free material. Taken from (USDA, 1971)
Component
Softwoods
Hardwoods
Wood
Bark
Lignin
25-30
40-55
18-25
40-50
Polysaccharides
66-72
30-48
74-80
32-45
Extractives
2-9
2.-25
2-5
5-10
Ash
Up to 20
Bark contains useful products waiting for the right economic conditions or the development of satisfactory commercial processes

5. Typical substances removed in whole or part
Fractionation of bark
Solvent
Typical substances removed in whole or part
Petroleum ether
ether, benzene, chloroform
Alcohol, acetone, aqueous alcohol, aqueous acetone
Hot or cold water
Aqueous alkali
Acid hydrolysis
Terpenes and their derivatives, fats, waxes, free and wax acids and alcohols, sterols, resins.
Simple polyphenols and their glycosides, tannins, mono- and disaccharides (sugars).
Disaccharides, starch, gums, pectins, tannins, mucilages.
Phlobaphenes, phenolic acids, some bark lignin and hemicelluloses, suberin fragments.
Simple sugars and uronic acids derived from holocellulose, leaves residue of “lignin.”

6. Chemical composition of bark
Chemical compounds, %
Softwood bark
Hardwood bark
Alcohol-benzene extract
Cold water extract
Hot water extract
Extract with NaOH,1 %
Cellulose
Lignin
Pentosans
Tannin -
C.I.Simionescu, V.I.Popa et al., Holzforschung und Holzverwertung,40(6), 136 (1988)

7. BARK biochemical degradation burning additives compost fodder
lignocelluloses
SEPARATION
BARK
EXTRACTION OF SECONDARY COMPOUNDS
Rough mixture of
hemicelluloses + polyphenols
Hcell-OH
PF-OH
softwoods
24-26%
hardwoods
15-20%
-furfural
- galacotse
- glucose
- arabinose
- xylose
phenol
substitute
(adhesives)
10-12%
4-6%
- C6 phenols
- C6-C1 phenolic acids
- C6-C2 acetophenone
- C6-C3 coumarone
- C6-C1-C6 xanthone
- C6-C3-C6 stilbens
-(C6-C3)2 lignans

8. Obtaining phenolformaldehyde resins with vegetal alkaline extracts
Compound, g R1 R2 R3 R4 R5
Phenol
Extract from:
hardwood bark
softwood bark
Formaldehyde, 37 %
Paraformaldehyde
Sodium hydroxide solution, 40 %
150 55
200 9 17 60
180 8 40
181 6 65
207 12 16 70
215 10

9. Shear strength of plywood glued (N/mm2) with modified phenolformaldehyde resins
Plywood made of:
Fenoplac R1 R2 R3 R4 R5
3 veneer
minimum
maximum
5 veneer
1.5 -
2.1
1.8
2.6
2.7
3.0
2.4
2.2
2.8
1.6
2.5

10. Influence of addition of the alkaline extract from beech bark on the properties of wood fiber boards (Transversal, L-longitudinal)
Degree of resin substitution, %
Strength, kg/cm2
Density,
Kg/cm3
Water absorption, %
Swelling, % 10 20 30 40
T 340
L 340
T 665
L 568
T 350
L424
T 430
L 386
T 505
L 446
1000
1150
1100
1090
30.00
13.70
23.30
23.68
23.90
17.5
12.5
12.8
11.5
15.2

11. Physico-mechanical properties of wood fiber board obtained at industrial level (compared with standard level)
Characteristics
First quality
Second quality
Experimental values
Apparent density,kg/m3
Water absorption (after 24 h immersion), %
Thickness swelling (after 24 h immersion), %
Static bending strength, daN/cm2
Internal transversal cohesion, daN/cm2
1000
(+10%,-5 %) 30 18
400
8.38 40 25
300

12. Nano- and micro cellulose
Bark
Extraction
(II)
Resins
(I)
Polyphenols
Fractionation
Hemicelluloses
Cellulose
Composting
Bioremediation
Lignin
Acid hydrolysis/ enzymatic
Nano- and micro cellulose
NaOH solution

13. Polyphenols Secondary metabolites (more than 8000 compounds)
Properties:
antioxidants; prooxidants; anticancer agents; apoptosis-inducing; antibacterial, antiparasite; anti-HIV activities; amelioration of cardiovascular diseases; improvement of endothelial function; modulation of gamma-glutamylcysteine synthase expression; improvement of health and survival on high –fat diet; colouring agents; chelating agents

15. 15

16. Polyphenols were tested in:
Seed germination
Plant cultivation
Bioremediation
Plant grafting
Tissue plant culture
Microorganism cultivation (carotenes pigments obtaining, mutagenesis)
Modulation of sugars metabolism (diabete and alcoholic fermentation)
O.C. Bujor, I. A. Talmaciu, I. Volf, and V. I. Popa
Biorefining to recover aromatic compounds with biological properties,
Tappi J.,14 (3) (2015)

17. POLYPHENOLS ENCAPSULATION BY ELECTROSPINNING TO OBTAIN SUBSTRATES WITH BIOLOGICAL ACTIVITY
Polyphenols (gallic, vanillic, syringic acids, catechine, spruce bark extract) were encapsulated in nanofibrous membranes, using biocompatible polymers: [poly (2-hydroxyethyl methacrylate (pHEMA), poly [(lactic acid)-co-(glycolic acid)] (PLGA)]
Roxana-Elena Ghitescu, Ana-Maria Popa, Valentin I. Popa, Rene M. Rossi, Giuseppino Fortunato
Encapsulation of polyphenols into pHEMA e-spun fibers and determination of their antioxidant activities
International Journal of Pharmaceutics, 494, 278–287(2015) 17

18. The immobilized polyphenols were tested with very good results to inhibit the reactive oxygen species produced by carbon nanotubes in the cells A549 originated from an explant culture of lung carcinomatous tissue from a 58-year-old Caucasian male.

19. 19

20. Hemicelluloses based products

21. Valentin I.Popa -Hemicelluloses in pharmacy and medicine in Polysaccharides in medicinal and pharmaceutical application, Edited by Valentin I.Popa, Smithers, Rapra, 2011 21

22. Residue (pure cellulose)
Filtrate
discarded
sodium chlorite oxidation
Residue (Holocellulose)
Extractive-free wood bark
(Pectic substances
and water-soluble
polysaccharides)
* Yield – %
(Mixture of pectic
substances and
acidic xylan)
Residue
Filtrate (Xylan, “glucan”
and water-soluble galacto-
glucomann)
(Mainly glucomannan)
Yield – 2.5%
Residue (pure cellulose)
Yield – 30.3%
Three successive preparations with aqueous barium hydroxide
Pure glucomannan (alkali-soluble)
Yield – 2.0%; Percent composition:
Galactose -4; Glucose – 25; Mannose – 71.
*All yields reported in this scheme are based on dry extractive- free bark
Hot ammonium oxalate solution
10% (w/w) sodium
carbonate solution
24% (w/w)
Potassium hydroxide
Yield – 4.3%
Yield – 8.5%
17% (w/w)
sodium hydroxide
+ 4% boric acid
Fig.1 Fractionation scheme for Extraction of Hemicelluloses from Bark of Engelmann Spruce

23. 24% Potassium hydroxide Extract
Fig.2 Fractionation scheme for Extraction of Hemicelluloses from Bark of Engelmann Spruce: Resolution of 24% Potassium hydroxide Extract
24% Potassium hydroxide Extract
Uronic acid – 7.3; Galactose – 8.8; Glucose – 29.4;
Mannose – 3.3; Arabinose – 8.8; Xylose – 42.5
Composition:
(relative percent)
Precipitate
Yield – 2.2 %
Filtrate
(see fig. 3)
Uronic acid – 3.3; Galactose – 11.4; Glucose – 6.64;
Mannose – 10.8; Arabinose – Trace; Xylose – 27.9
Insoluble Portion
Yield – 0.3%
Soluble Portion
Yield – 1.8%
Uronic acid – 2; Galactose – 10; Glucose –38;
Mannose – 40; Arabinose – Trace; Xylose – 10
Uronic acid – 2; Galactose – 11; Glucose – 57;
Mannose – 2; Arabinose – Trace; Xylose – 28
Three successive
Precipitations with
Fehling’s solution
Aqueous
Barium hydroxide (5%)
(This fraction consist mainly of the water-soluble galactoglucomannan )
(This fraction consist mainly of the heteropolymeric “glucan”)

24. Filtrate remaining after addition of Fehling’s Solution to Potassium hydroxide extract (See fig. 2)
Yield – 6.0%
Uronic acid – 7.9; Galactose – 9.1; Glucose – 25.1; Mannose – Nil;
Arabinose – 14.3; Xylose – 43.6
Composition:
(relative percent)
Insoluble Portion
Yield – 0.5%
Soluble Portion
Yield – 4.8%
Uronic acid – 10; Galactose – 12; Glucose – 15; Mannose – Nil;
Arabinose – 33; Xylose – 30
Uronic acid – 7; Galactose – 20; Glucose – 25.1; Mannose – Nil;
Arabinose – 10; Xylose -56
Yield – 4.5%
Small precipitate
(Discarded)
Uronic acid – 7; Galactose –6; Glucose – 12; Mannose – Nil;
Arabinose – 10; Xylose – 65
Aqueous barium hydroxide
CTA-OH + aqueous
Sodium hydroxide
(This fraction consist mainly of the acidic arabinoxylan)
Fig.3 Fractionation scheme for Extraction of Hemicelluloses from Bark of Engelmann Spruce: Resolution of 24% Potassium hydroxide Extract (continued) 24

25. Reactions:
Acid hydrolysis
Enzymatic hydrolysis
Esterification
Etherification
Enzymatic modification (treatment with laccase of hemicelluloses from annual plants allow obtaining gels)

26. Directions to use hemicelluloses:
ethanol-fermentation C6
polyols-2,3 butylene glycol-aerobic fermentation
lactic, acetic, butyric acids-fermentation
fodder yeast (50 % proteins; 2-7 % fats-vitamins) Candida utilis
xylitol- xylose reducing- sweetener
furfural-furfurilic alcohol,furan resins, poly(amide) -4,6

27. Derivatives of de xylan:
-acetates; -butyrates;
-benzoates- extrusion agents for fatty acids
-carboxymethylxylan- (surfactants, flocculants, adhesives for paper coating);-eating packages;
-xylan sulfate- (antiHIV, antitumor, antioxidant, anticoagulant, antimicrobial, decrease of cholesterol);
-biofilms (xyloglucan/chitosan) –immobilisation of streptomicyn, antioxidants, antifungal and, antimicrobials agents, dyes, nutrients, packagings).

28. -4-O-methylglucuronoxylan-antitumor.
-arabinoxylans- emulsifying agents; thickening, food stabilisers, immunotherapy agents;
-4-O-methylglucuronoxylan-antitumor.
Advantages to use hemicelluloses in pharmacy, cosmetics and medicine:
- are accessible
-are not toxic
-can be chemically and enzymatically modified
-are biodegradable
-are biocompatible

29. Health benefic effects:
-they improve lipids and minerals metabolism;
-they improve the function of colon and assure protection against cancer;
-they reduce the risk of heart diseases
Examples:
-regeneration of tissues
-support for controlled delivery of drugs
--gels for cells immobilisation

30. Cellulose based products

31. Nanocellulose-supermaterial
Eco-friendly
Lightweight
Ductile
Stronger than steel and Kevlar
The super-material is theoretically derived from plant matter that has been reduced to small bit and pieces, and then purified by a homogenizer to remove non-cellulose components like lignin. The remaining cellulose fibers are finally separated and processed into a thick substrate that boasts of long polymers or crystallized structures. This ultimately results in what is termed as nanocrystalline cellulose or nanocellulose ‘paste’, an incredible material with flexibility, malleability, super-strength as well as low-impact credentials.

32. Uses of nanocellulose Composites Paper and boards Food
Hygiene and absorbent products
Emulsion and dispersion
Oil recovery
Medical , cosmetic and phramaceutical

33. V.I.Popa
Nanotechnology and nanocellulose
Celuloză şi Hârtie, 63 (4), (2014)
Obtaining of nanocellulose (I)
Celuloză şi Hârtie, 64 (1), 3-10 (2015)
Obtaining nanocellulose (II)
Celuloză şi Hârtie, in press

35. Schematic representation of (a) the homogenizer and (b) the microfluidizer

36. Procedure for individualizing cellulose nanofibers by ultrasonication

37. Nanocellulose

38. 1) High-strength yet lightweight body armor -

39. 2) Low-impact (fuel efficient) yet super-durable vehicles

40. 3) Medical usages

41. 4) Bendable battery systems

42. 5) Flexible electronic displays-

43. 6) Bio-fuel can be a by-product when ‘growing’ nanocellulose
Sugars resulted in the hydrolysis pretreatments colud be used by fermentation to obtain biofuels or other valuable bioproducts, thus contributing to the efficiency of the porocess of nanocellulose fabrication.

44. Lignina

45. Lignin based products

47. Biological properties of lignin
1. Lignins as antibacterials
2. Lignins as antioxidants and photoprotectors
3. Lignins in reduction of carcinogenesis
4. Anti-HIV properties of lignins
5. Lignin as spermicide

48. Valentin I.Popa, Lignin in biological systems
in Polymeric Biomaterials, 2 vol, Founding Editor: Severian Dumitriu, Editor: Valentin I.Popa, 2013, CRC Press 48

49. Conversion of native lignin into lignophenol derivatives and control of their functionality

50. Lignins as antibacterials/Escherichia coli

51. Influence of different lignin samples on pathogenic bacteria sorption (Curan-commercial kraft lignin-Borregaard Ltd)

52. The influence of lignin on phytopatogenic microorganisms

53. Lignins as antioxidants and photoprotectors
Inhibitory effect of different lignin solutions on haemolysis induced by AAPH. [2,2’-azobis (2-amidopropane) dihydrochloride] a peroxyl radical initiator. LG-lignosulfonates, BG –lignin from bagasse, SE lignin from steam explosion and CU- Curan a commercial lignin.

54. Haemolysis and photohaemolysis of CPZ (chlorpromazine a photohaemolytic compound) in the presence and absence of different lignins

55. Relative ABTS-radical scavenging activity of lignin samples
He-hemp, Si-sisal, Ab-abaca, Ju-jute, Fl-1-flax, SW-Ls-1- lignosulfonate from softwood (Boresperse 3A),SW-Kr-1- kraft from softwood (Indulin AT), SW-Ls-2- lignosulfonate from softwood (Wafex P), Fl-2- soda flax (Bioplast), Fl-ox-soda flax oxidised, SW-Kr-2- kraft from softwood (Curan 100), SW-SF-1( soda from softwood (precipitated at high pH), SW-Kr-3-kraft from softwood, HW-organosolv (Alcell) from mixed hardwoods, SW-SF-2- soda softwood (precipitated at low pH), SW-Kr-4-kraft (Curan 2711P
The ABTS+* [ABTS - 2,2’-azino-bis(3-ethylbenzo-thiazoline-6-sulphonate)] cation radicals were generated by an enzymatic system consisting of peroxidase and hydrogen peroxide.

56. Relative chain-breaking antioxidant effect of lignin in lipid peroxidation

57. Precipitated lignin 3mg/mL; melatonin 1µM; quercetin 1µM; commercial lignin 3 mg/mL.
Inhibition percentages of superoxide anion and hydroxyl radical generation
Sample
Superoxide aninon
Hydroxyl radical
Precipitated lignin
51.44 ±1.29
33.68±0.91
Commercial lignin
47.15±2.04
27.81±1.30
Melatonin
79.06±0.32
53.89±1.07
Quercetin
71.46±0.85
53.07±1.13

58. Antimutagenic activity of modified kraft spruce lignin against 4-nitroquinoline-N-oxide

59. LIGNIN The are specialized phagocytic cells that attack foreign substances, infectious microbes and cancer cells through destruction and ingestion

60. CONCLUSION
Wood bark contains useful products waiting for the right economic conditions or the development of satisfactory commercial processes.
By applying the biorefining concept wood bark could be used to obtain compounds of high interest in the biological field.

61. Thank you for your attention!

62. Questions