PHA(Eng)

UNIVERSITA ’ DEGLI STUDI DI CATANIAFACOLTA ’ DI FARMACIA

PhD in Medicinal Chemistry

GIUSEPPE PUZZO

BACTERIAL FERMENTATION AND MICROWAVE-ASSISTED SYNTHESIS FOR THE PRODUCTION OF

BIODEGRADABLE AND BIOCOMPATIBLE POLYMERS USABLE IN THE PHARMACEUTICAL

FIELD.

Tutor:Prof. Alberto Ballistreri.

Ciclo XXIV

Coordinator:Prof. Giuseppe Ronsisvalle.

Introduction

Not biodegradable plastics

Biodegradable plastics

Biodegradable polymers on the market.

Mater-Bi®Ecoflex®Biomax®

EcoPLA® PHA

Polyhydroxyalkanoates (PHA)

PHASCL: short-chain length PHA3-5 carbon atoms

PHAMCL: medium -chain length PHA6-14 carbon atoms

Poly(3-hydroxyalkanoates) with R= alkyl or functional group

n

Physical and chemical properties.

Polymer Tg(°C) Tm (°C) Cristallinity (%) Extension at break (%)

P(3HB) 15 175 50-80 5

P(3HB-co-3HV) -1 145 56 50

P(3HB-co-4HB) -7 150 43 444

PP -15 176 50 400

•Average molecular weight ranging between 5·104 and1·106 Da

•Enantiomerically pure

•Biodegradable and biocompatible

Applications of PHAs in medicine and pharmaceutical s.

•Sutures. •Bone graft substitutes.

•Temporary heart valves. •Carrier for drug delivery.

Role of PHAs in tissue engineering .

The aim of the thesis

Explore new strategies for obtaining new polymers which, in the pharmaceutical field, have feature of biodegradability and biocompatibility with wider opportunity of utilization with respect to poly(3-hydroxybutyrate) (PHB) by:

1. The study on the capabilty to P. aeruginosa to grow and synthesize PHAs from Long Chain Fatty Acids (LCFA) or vegetable oils, with better yields or with new structures and new properties.

2. Chemical synthesis of new coplymers and terpolymers bytransesterification reaction microwave assisted.

PHA’s production by microorganisms.

Corn, sugar cane, potato etc

Substrates for PHA ’s production.

Glucose

Alkanoates(propionic acid,

butyric acid, valeric acid etc.)

Fatty acid

Carbohydrate

Vegetable oils and fats

Agriculture, waste materials

Table 1. PHA production from P. aeruginosa culturedusing odd carbon atoms fatty acids as carbon source.

Fatty acid Dry cell weight(mg/L)

PHA content(% dry cell weight)

PHA yield(mg/L)

Eptadecanoic -N 1600 9,8 157

Nonadecanoic -N 2370 5,3 127

2 737 0,25 7Eneicosanoic-N

GC trace of the products prepared by methanolysis ofPHA from nonadecanoic acid.

V= 3-hydoxyvalerate; H= 3-hydoxyheptanoate; O= 3-hydroxy octanoate; N= 3-hydroxynonanoate; D= 3-hydroxydecanoate; U= 3-hydrox yundecanoate; Θ= 3-hydroxytridecanoate; P = 3-hydroxypentadecanoate

200 MHz 1H-NMR spectra of the PHAs obtained from P. aeruginosa grown on (a) heptadecanoic; (b) nonadecanoic and (c) eneicosanoic acid.

50 MHz 13C-NMR spectra of the PHAs obtained from P. aeuruginosa grown on (a) nonanoic; (b) heptadecanoic and (c) eneicosanoic acid .

Chemical structure of the PHAs .

l m n o p

V H N U∆

Θ

4

5

6

8

9

10

12

13

7

11

4

5

6

8

9

10

7

11

4

5

6

8

9

7

4

5

6

7

4

5

123 123 123 123 123

O CH CH2CO

CH2

CH3

O CH CH2CO O CH CH

2CO O CH CH

2CO O CH CH

2CO

CH2

CH2

CH2

CH3

CH2

CH2

CH2

CH2

CH2

CH3

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH3

CH2

CH

CH

CH2

CH2

CH2

CH2

CH2

CH2

CH3

q

P

4

5

6

8

9

10

12

13

7

11

123

O CH CH2CO

CH2

CH

CH

CH2

CH2

CH2

CH2

CH2

CH2

CH2

14

15

CH2

CH3

Fatty acids Tg (°C) Tm (°C) ∆∆∆∆Hm (J/g) Mw x 10 -3 Mw/Mn

Eptadecanoic -41 50 7,9 77 1,6

Nonadecanoic -43 58 12 97 2

49 5,7 188 1,7

Table 2. Physical characteristics of the PHAs isolated from P. aeruginosa grown on C-odd fatty acids.

Eneicosanoic -39

Thermal degradation of PHAs

A measure of the fit of the calculated oligomers intensiti es tothe experimental ones is given by the agreement factor (AF); the lower AF, the closer fit.

Assuming a Bernoullian (random ) distribution of repeating unitsin these copolymers, the probability of finding a given Ax , By…Nz can be calculated by the Leibnitz formula as follows :

∑∑∑∑

∑∑∑∑ ++++====

ii

iicalci

I

IIAF 2

.exp

2..exp )(

Negative ion ESI mass spectrum of the partial pyrolisate of the PHA fromenicosanoic acid. R may be an un n-etyl, n-butyl, n-hex yl, n-octyl, n-decyl and n-dodecyl group.

R CH CH CO CH

R

O CH2 CO O CH

R

CH2 COOH[ ]n

m/z ESI CalculatedDimers

V-H 227 4 4V-N; H2 255 15 15

V-U; H-N 383 18 18V-Θ; H-U; N2 311 26 26

V-P; N-U; H-Θ 339 20 20H-P; U2; N-Θ 367 12 13

U-Θ; N-P 395 5 5

TrimersC23 411 8 9C25 439 14 16C27 467 23 22C29 495 21 24C31 523 15 18C33 551 10 10C35 579 3 0

Table 3. Experimental and calculated relative amounts ofthe partial pyrolisis products of P. aeruginosa fromeneicosanoic acid.

Brassica carinataproduction’s seeds

Formulation

Remaining

flourDe-oiling

Soil products

As such

Fertilizer products

As such

Lubricants

Agricoltural

oils

Modified

LubrificantsEnergy

Oil

Biofuels

Table 4. PHA production from P. aeruginosa cultured on differents substrates.

Substrate Dry cell weight(mg/L)

PHA content(% dry cell weight)

PHA yield(mg/L)

B. Carinata oil 1000 5,0 50

Oleico acid 380 15,0 57

2 866 9,3 81Erucic acid

416 10.0Nervonic acid 10416 42

Table 5. Comonomer composition (mol% ) of PHA obtainedfrom varius carbon sources, determined by GC.

C= 3-hydroxyhexanoate; O= 3-hydroxyoctanoate; O :1= 3-hydroxy-5-octenoate; D= 3-hydroxydecanoate; D :1= 3-hydroxy-7-decenoate; Δ= 3-hydroxydodecanoate; Δ:1= 3-hydroxy-6-dodecenoate; T :1 = 3- hydroxy-5-tetradecenoate; T :2= 3-hydroxy-5,8-tetradecadienoate; T :3= 3-hydroxy-5,8,11-tetradecatrienoate.

Substrate C O O:1 D D:1Δ Δ:1 T:1 T:2 T:3

B.Carinata oil 3 34 3 32 3 10 1 9 2 3

Oleico acid 4 55 - 27 - 8 - 6 - -

Erucico acid 3 43 - 36 - 10 - 8 - -

Nervonico acid 4 28 - 43 - 14 - 11 - -

200 MHz 1H-NMR spectra of the PHA obtained from erucic acid.

C6, O8, D10,

∆12, T:1 14

T:1

6

C5, O5-7, D5-9,

∆5-11, T:1 8-13

C/O/D/∆/T:1

3

T:1

4

T:1

7

C/O/D/∆/T:1

2

C/O/D/∆

4

T:1

5

(ppm)1.01.52.02.53.03.54.04.55.05.5

50 MHz 13C-NMR spectra of the PHA obtained from erucic acid.

170 120130(ppm)

70 152025303540

C/O/D/∆

1

T:1

1 T:1

6

T:1

5

O/D/∆

3

T:1

3

C3

C4

T:1

2

C/O/D/∆

2

O6 T:1

4

O/D/∆

4

D8

∆10

T:1

12

D6-7

∆6-9

T:1

8-11

T:1

7

D9

∆11

T:1

13

C5

O5D5

D5

O7

D10

∆12

T:1

14

C6

O8

m n o p q

C O D ∆

∆

T:1

4

5

6

8

9

10

12

13

14

7

11

4

5

6

8

9

10

12

7

11

4

5

6

8

9

10

7

4

5

6

8

7

4

5

6

123 123 123 123 123

O CH CH2CO

CH2

CH2

O CH CH2CO O CH CH

2CO O CH CH

2CO O CH CH

2CO

CH3

CH2

CH2

CH2

CH2

CH3

CH2

CH2

CH2

CH2

CH2

CH2

CH3

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH3

CH2

CH

CH

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH3

Chemical structure of the PHAs from oleic, erucic and nervonic acids.

200 MHz 1H-NMR spectra of the PHA obtained from B. carinata oil.

(ppm)1.01.52.02.53.03.54.04.55.05.5

O:1 6

T:2/T:3 6

O:1 5

D:1 7-8

∆:1 6-7

T:2 5, 8-9

T:3 5, 8-9, 11-12

O:1/D:1/∆:1/T:2/T:

3

3

T:2 7

T:3 7, 10

O:1/T:2/T:3

4

O:1 7

D:1 6, 9

∆:1 5, 8

T:2 10

T:3 13O:1/D:1/∆:1/T:2/T:3

2

D:1

∆:1

4

O:1 8, D:1 10, ∆:112, T:2/T:3 14

D:1 5, ∆:1 9-11, T:2 11-13

50 MHz 13C-NMR spectra of the PHA obtained from B. carinata oil.

170 120130(ppm)

70 152025303540

D:1

∆:1

1 O:1

T:2

T:3

1

D:1

∆:1

3

O:1

T:2

T:3

3

O:1

T:2

T:3

2

D:1

∆:1

2

D:1

∆:1

4

O:1

T:2

T:3

4 ∆:1

9

∆:1

12

T:2

14O:1

8

D:1

10

T:3

14

T:2 7

T:3 7, 10

O:1 7, D:1 6/9, ∆:1 5, 8 T:2 10, T:3 13}

(ppm)120122124126128130132134136138

O:1

6

T:1

6

T:3

12

D:1

8

O:1

5

T:1

5

T:3

5

T:2

5

D:1

7

∆:1

6

T:3

8, 11

T:3

9

T:2

8T:2

6

T:2

9∆:1

7

T:3

6

13C-NMR spectra of the PHA obtained from B. carinata oil in the regionof the olefinc signals.

n o p r s

O:1 D:1 ∆:1 T:2 T:3

4

5

6

8

9

10

12

13

14

7

11

4

5

6

8

9

10

12

7

11

4

5

6

8

9

10

7

4

5

6

8

7

4

5

6

123 123 123 123 123

O CH CH2CO

CH2CH

O CH CH2CO O CH CH

2CO O CH CH

2CO O CH CH

2CO

CH

CH2CH

2CH

2CH

CH

CH2CH

2CH

CH

CH2

CH2

CH2

CH2CH

CH

CH2

CH

CH

CH2

CH2

CH2

CH2CH

CH

CH2

CH

CH

CH2

CH

CH

CH2

CH3

7CH2

8CH3

9CH2

10CH3

11CH2

12CH3

13CH2

14CH3

Chemical structure of the PHA from B. carinata oil. This PHA is made up of all the repeating units constituting the PHA from erucic acid, plus the unsatureted ones shown here.

Sustrate Tg (°C) Tm (°C) ΔHm (J/g) Mw x 10 -3 Mw/Mn

B.carinata oil -47 - - 56 1,8

Oleico acid -52 - - 57 2,2

Erucic acid -46 50 16,1 122 1,9

Nervonic acid -43 50 15,5 114 2

Table 6. Physical characteristics of the PHAs isolated fromP. aeruginosa grown on B. carinata oil and on oleic, erucicand nervonics acids.

700

(m/z)

20

60

100Pentameri

EsameriEptameri

x 3

700 800 900 1000 1100

765737 907793 935879

709 8211049

1077851 963 1021 1105 1133991 1161

(m/z)300 400 500 600

20

60

100

Dimeri

TrimeriTetrameri

255 425 623595393 651535 567 679

339

311283

367453 481

509% In

tens

ità%

Inte

nsità

R CH CH CO CH

R

O CH2 CO O CH

R

CH2 COOH[ ]n

Negative ion ESI mass spectrum of the partial pyrolisate of the PHA from erucic acid. R may be a n-propyl, n-pentyl, n-heptyl, n- nonyl or n-undecenyl group.

m/z ESI CalculatedDimers

C-O 255 10 9C-D; O2 283 24 24

C-Δ; O-D 311 26 26O-Δ; D2 339 18 19

O-T:1 365 6 7D-Δ 367 8 7D-T:1 393 6 4Δ-T:1 421 2 2

TrimersC22 397 4 4C24 425 12 12C26 453 20 19C28 481 18 20

C30 :1 507 5 7C30 509 13 13

C32:1 535 10 9C32 537 6 5

C34:1 563 8 6

Table 7. Experimental and calculated relative amounts ofthe partial pyrolisis products of the PHA produced by P. aeruginosa from erucic acid.

Negative ion ESI mass spetrum of the partial pyrolisate of the PHA from B. carinata. R may be a n-pentaenyl, n-heptaenyl, n-nonaenye, n-undecadieyil or n-undecatrienyl group.

300 400 500 600 700(m/z)

20

60

100

651509

255

283 339

311

367393

425453 481

535 567 595 623679

Dimeri

Trimeri

Tetrameri

800 900 1000 1100700 (m/z)

20

60

100

709

737 765 793821

849879

907 935 963991 1021 1049107711051133

Pentameri

Esameri

Eptameri

x 4

% In

tens

ità%

Inte

nsità

R CH CH CO CH

R

O CH2 CO O CH

R

CH2 COOH[ ]n

Heating mechanisms heat exchange Heating with Microwave

Benefits :� Energy saving� Process Efficiency� Restrictions on the use of halogenated

solvents

Design For Efficient Energy : Energy requirements should be recognized for their environmental and economic impacts and should be minimized. Synthetic methods should be conducted at ambient temperature and pressure.

What are the microwave

The microwaves are not ionizing electromagnetic waves having a wavelength between 1 mm ( ν = 300 GHz) and 1 m ( ν = 300 MHz), they are located in the area of the spectrum between t he frequencies of the infrared and the radio waves.The frequency of 2.45 (± 0.05) GHz, corresponding in vac uum at a wavelength ( λ) of 12.2 cm, is that used for applications in the domestic field, scientific, medical, and for many i ndustrial processes.

Chemical synthesis of copolyesters.

1. PTSA·H2O, Chloroform, Toluene (reflux)

2. Azeotropic (dehydration)

+

PCL m

O CH2 CH2 CH

2CH2 C

O

CH2PHB n

O CH CH2

C

OCH3

n

O CH CH2

C

OCH3

m

O CH 2 CH2

CH 2 CH 2 CH2

C

O

P(HB-co-CL)

A 54/46 15 7.8 1,41 0,16 0,3 1/2

B 45/55 23 n.d. n.d. 0,21 0,52 2/2

C 75/25 19 n.d. n.d. 0,42 0,92 3/2

E 55/45 52 5.2 1,3 0,1 0,21 1/2

F 48/52 49 6.4 1,27 0,12 0,25 2/2

G 55/45 30 9 1,2 0,17 0,36 3/2

Sample HB/CL a Yield (%) Mw·10 3 b Mw/Mn c DT d DR e RT(h) f

Conventionalheating

D 55/45 10 7.9 1,3 0,37 0,74 5/2

Microwaveheating

H 46/54 26 12 1,24 0,31 0,63 5/2

Table 8. Transesterification Conditions, Yields, MolecularWeights, and Degree of Transesterification of P(HB -co-CL) Copolymers.

aMolar composition of the resulting copolymers. b Weight-average molecular weight. c Molecular weight distribution. d Degree of transesterification at the end of the secondstage of the reaction. e Degree of randomness at the end of the second stage of th e reaction. f Duration in hours of the two transesterification stages. n.d.: not detemined.

b df he g l

a

cn

O CH CH2

C

OCH3

m

O CH2 CH2 CH2 CH2 CH

2C

O

i

a

b

c

e g

i

f+h

(ppm)

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.5

200 MHz 1H-NMR spectra of the copolymer P(HB– co-45%mol CL) (sample D) obtained with conventional heating.

n’

m+m’

a

bc

e

g

i

f+h

n+n’

(ppm)

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.5

nCH

3

H

H H

H

a

b c dn

O CH CH2

C

OCH3

f he g l m

O CH2

CH2CH

2 CH2CH2

C

O

i

S

O

O

m’

nm

200 MHz 1H-NMR spectra of the copolymer P(HB– co-54%mol CL) (sample H) obtained with microwave heating.

n’

ab

c

d

e

f g

hi

l

(ppm)

0102030405060708090110120130140150160170180 100

b df he g l

a

cn

O CH CH2

C

OCH3

m

O CH2 CH2 CH2 CH2 CH

2C

O

i

50 MHz 13C-NMR spectra of the copolymer P(HB– co-45%mol CL) (sample D) obtained with conventional heating.

ab

c

d

e fi

l

gh

m+m’ n+n’

(ppm)0102030405060708090100110120130140150160170180

CH3

H

H H

H

a

b c dn

O CH CH2

C

OCH3

f he g l m

O CH2

CH2CH

2 CH2CH2

C

O

i

S

O

O

m’ n’

nm

50 MHz 13C-NMR spectra of the copolymer P(HB– co-54%mol CL) (sample H) obtained with microwave heating.

CCC

BCC

BCB

CCB CBC

BBBCBB

168.5169.0169.5170.0170.5171.0171.5172.0172.5173.0173.5174.0174.5

BBC

(ppm)

13C-NMR spectral expansion of the carbonyl region of the copo lymer(sample H).

)(

2

CBBC

BB

II

XL

+=

)(

2

CBBC

CC

II

XL

+=

where XB and XC are the dyad mole fractions of HB and CL calculable by the equations:

)(21

CBBCBBB IIIX ++= )(21

CBBCCCC IIIX ++=

CBBC IIDT += CB LLDR 11 +=

For a random copolymer of 1:1 composition, these paramet ers are expectedto assume the values LB = LC = 2, DT = 0.5 and DR = 1.

200

400

600

800

1000

4500 5000 5500 6000 6500 7000 7500

(m/z)

5750 5850 5950 (m/z)

57

54

57

82

58

10

58

38

58

66

58

94

59

22

59

50

: Spettro MALDI-TOF della frazione eluita dopo il massimo del tracciato GPC del copolimero P(HB-co- 45 mol%CL) (campione D).

MALDI-TOF mass spectrum of the fraction eluting after the maximumof the GPC trace of the copolimer P(HB- co- 45 mol%CL) (sample D).

: Spettro MALDI-TOF della frazione eluita dopo il massimo del tracciato GPC del copolimero P(HB-co- 45 mol%CL) (campione D).

1. PTSA·H2O, Chloroform, Toluene (reflux)

2. Azeotropic (dehydration)

+

PCLm

O CH2

CH2 CH2

CH2CH

2C

O

P(HB-co-HV)n

O CH CH2 C

OCH3

o

CH CH2 C

O

CH3

CH2

O

Chemical synthesis of terpolyesters.

CH

P(HB-co-HV-co-CL)

m

O CH2

CH2 CH2

CH2 CH2 C

O

n

O CH CH2 C

OCH3

o

CH CH2 C

O

3

CH2

O

L 51/15/34 30 6.7 1,36 0,61 1,05 1/2

M 47/12/41 19 11.3 1,16 0,71 1,41 2/2

N 48/13/39 13 8.1 1,12 0,81 1,54 3/2

P 62/14/24 51 8.1 1,3 0,64 1,64 1/2

Q 58/15/27 37.5 9.1 1.9 0,7 1,27 2/2

R 68/13/19 35 6.7 1,2 0,75 1,47 3/2

Sample HB/HV/CL a Resa (%) Mw·103 b Mw/Mn c DT d DR e RT(h) f

Conventionalheating

Microwaveheating

aMolar composition of the resulting terpolymers. b Weight-average molecular weight. c Molecular weight distribution. d Degree of transesterification at the end of the secondstage of the reaction. e Degree of randomness at the end of the second stage of th e reaction. f Duration in hours of the two transesterification stages.

Table 9:Transesterification Conditions, Yields, MolecularWeights, and Degree of Transesterification of P(HB -co-HV-co-CL) Terpolymers.

(ppm)

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.0

m

g+n

c

b+dei+pa

h+o

m

CH

e n

O CH CH2

C

OCH3

o

CH CH2

C

O

CH3

CH2

O

f

g

h li

n

O CH2

CH2

CH2 2

CH2 C

O

ma b c d o p q

Spettro 1H-NMR a 200 MHz del terpolimero P(3HB-co-12%mol 3HV-co-41%mol CL) (campione M).Spettro 1H-NMR a 200 MHz del terpolimero P(3HB-co-12%mol 3HV-co-41%mol CL) (campione M).

200 MHz 1H-NMR spectra of the terpolymer P(HB- co-12%mol HV- co-41%mol CL) (sample M).

n

m

CHe

O CH CH2

C

OCH3

o

CH CH2

C

O

CH3

CH2

Of

g

h li

n

O CH2

CH2

CH2 2

CH2 C

O

ma b c d o p qCH

3

H

H H

H

S

O

O

x’ y’

yx

(ppm)

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.0

m

g+n

c

b+de

i+pa

h+oy+y’ x+x’

7.58.0

200 MHz 1H-NMR spectra of the terpolymer P(HB- co-15%mol HV- co-27%mol CL) (sample Q).

m

g

dc

e

n

b

p

i

a

h

o

l+q

f

(ppm)

0102030405060708090100110120130140150160170180

m

CH

e n

O CH CH2

C

OCH3

o

CH CH2

C

O

CH3

CH2

O

f

g

h li

n

O CH2

CH2

CH2 2

CH2

C

O

ma b c d o p q

50 MHz 13C-NMR of the terpolymer P(HB- co-12%mol HV- co-41%mol CL) (sample M).

H

n

m

CHe

O CH CH2

C

OCH3

o

CH CH2

C

O

CH3

CH2

Of

g

h li

n

O CH2

CH2

CH2 2

CH2

C

O

ma b c d o p qC3

H

H H

H

S

O

O

x’ y’

yx

0

(ppm)

102030405060708090100110120130140150160170

m

g

dce

n

b

p

i

a

h

o

l+q

fy+y’ x+x’

180

50 MHz 13C-NMR spectra of the terpolymer P(HB- co-15%mol HV- co-27%mol CL) (sample Q ).

CC

CV

BC

VCBC

VV

BB

(ppm)168.8169.2169.6170.0170.4170.8171.2171.6172.0172.4172.8173.2173.6

BV,VB

Espansione dello spettro 13C NMR della regione dei carbonili del terpolimero M.Espansione dello spettro 13C NMR della regione dei carbonili del terpolimero M.Espansione dello spettro 13C NMR della regione dei carbonili del terpolimero M.

13C-NMR spectral expansion of the carbonyl region of the terp olymer(sample M).

Espansione dello spettro 13C NMR della regione dei carbonili del terpolimero M.

where XB, XV, and XC are the dyad mole fractions of HB, HV and CL calculable by the equations:

)(

2

VBBVCVBCCB

B

BIIIII

XL

++++=

)(

2

VBBVCVBCCB

VV

IIIII

XL

++++=

)(

2

VBBVCVBCCB

C

CIIIII

XL

++++=

)(21

VBBVCVBCCBBBB IIIIIIX +++++= )(21

VBBVCVBCCBVVV IIIIIIX +++++=

)(21

VBBVCVBCCBCCC IIIIIIX +++++=

VCB LLLDR 111 ++= DT= ICB+IBC+ICV+IVC+IBV+IVB/2XB XC+2XCXV+2XBXV

Conclusion 1

Through bacterial fermentation were obtained for the first time PHA using very long chain fatty acids (VLCFA), more than 20 C atoms and B. carinataI oil. The PHA produced by fatty acid with odd number of carbon atoms are flexible materials whose physical characteristics do not vary significantly as a function of the side chain, although longer pendant groups confer a greater speed of recrystallization.The PHA produced by using erucic and nervonic acids, are transparent as well, partially crystalline and therefore they show rubber-like characteristics. Their proposed use is as scaffold in tissue engineering and in the pharmaceutical delivery system.The PHA from B. carinata oil is a transparent material, totally amorphous. The presence of double bonds allows the derivatization and functionalization.

By chemical synthesis were obtained biodegradable and biocompatible copolymers and terpoIymers. The structure of these polymers is random or microblock depending on the duration of the reaction or the amount of catalyst used and the type of heating used. At equal number of hours of reaction, and degree of transesterification catalyst used, the use of microwaves has allowed to obtain higher yields for both copolymers that for the terpolymers.Copolymers and terpolymers obtained by this method are capable of producing micro-and nanoparticles used in the drug delivery system.

Conclusion 2