1. Production of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) by Ralstonia eutropha
Jae Yong Song, Bong Hee Lee, Nam Soo Han, Beom Soo Kim
Dept. of Chemical Engineering, Food science and technology,
Chungbuk National University, Cheongju, Chungbuk, , Korea
Tel : , Fax : ,
Introduction
1. character and structural formulas of P(3HB-co-4HB)
various property from composition of constructive monomer .
hydrolysis than materials of different PHA faster.
various application (living medical division etc).
R = hydrogen
: 3-hydroxypropionate (3HP)
R = methyl
: 3-hydroxybutyrate (3HB)
R = ethyl
: 3-hydroxyvalerate (3HV)
R = propyl
: 3-hydroxycaproate (3HC)
R = butyl
: 3-hydroxyheptanoate (3HH)
R = pentyl
: 3-hydroxyoctanoate (3HO)
R= hexyl
: 3-hydroxynonanoate (3HN)
R = heptyl
: 3-hydroxydecanoate (3HD)
R = octyl
: 3-hydroxyundecanoate (3HUD)
R = nonyl
: 3-hydroxydodecanoate (3HDD)
general structural formulas of PHA
Fig. 3. Production of P(3HB) by Fed-batch culture of R. eutropha NCIMB
structural formulas of P(3HB-co-4HB)
2. Object of research
researching biosynthesis characters of P(3HB-co-4HB) from
diverse feeding strategy.
fed-batch culture of high concentration.
production of high content polyester.
Fig. 4. Production of P(3HB-co-4HB) by Fed-batch culture of R. eutropha NCIMB
Experimental
Ralstonia eutropha ATCC (KCCM 11972)
Bacterial strains
Ralstonia eutropha NCIMB 11599
Ralstonia eutropha ATCC (KCCM 11972)
Table 1. Medium composition for flask and fed-batch culture.
Component
Flask & batch culture
Fed batch culture
Initial medium
Feed solution
Carbon sources
-Butyrolactone
1,4-Butanediol
(NH4)2SO4
Na2HPO4•12H2O
KH2PO4
Citric acid
MgSO4•7H2O
Various
1.00 g/L
9.00 g/L
1.50 g/L -
0.20 g/L
10 g/L, 20 g/L -
4 g/L
Various
1.70 g/L
1.20 g/L
800 g/L
99% solution -
Fig. 5. Production of P(3HB-co-4HB) by Fed-batch culture of R. eutropha ATCC
Trace element solution
H3BO3
CoCl2•6H2O
ZnSO4•7H2O
MnSO4•4~5H2O
(NH4)6Mo7O24•4H2O
NiCl2•6H20
CuSO4•5H2O
1.00 ml/L
0.30 g/L
0.20 g/L
0.10 g/L
0.03 g/L
0.02 g/L
0.01 g/L
10 ml/L -
Fig. 6. Fed-batch culture of R. eutropha ATCC
Results
Conclusions
Ralstonia eutropha NCIMB 11599
In fed-batch culture of R. eutropha NCIMB 11599, glucose and -butyrolactone were fed as carbon sources with phosphate limitation strategy. When glucose was only fed controlling with on-line glucose analyzer, 201 g/L of dry cell weight containing 86 wt% of P(3HB) homopolymer was obtained.
In two-stage fed-batch culture where dry cell weight was increased to 104 g/L by feeding glucose only and then constant feeding of -butyrolactone at 6 g/h, final dry cell weight at 67h was 106 g/L with a PHA content of 82 wt% but 4HB fraction was only 0.7 mol%.
When the same feeding strategy was applied to the Fed-batch culture R. eutropha ATCC where dry cell weight was increased to 42 g/L by feeding fructose in first step and -butyrolactone feeding (1.5 g/h) on second step, final dry cell weight, PHA content, and 4HB fraction at 74 h were 51 g/L, 35 wt%, and 32 mol%, respectively.
Table 2. Production of P(3HB-co-4HB) from glucose and -butyrolactone by R. eutropha NCIMB for 72 h.
Carbon sources (g/L)
Dry cell
weight
(g/L)
Polyester
Content
(wt%)
Composition (mol%)
Glucose
-butyrolactone
3HB
4HB 20
7.61 86
100 16 4
7.71 86
100 12 8
5.49 77
99.59
0.41 8 12
3.78 78
99.53
0.47
Acknowledgment 4 16
1.70 67
99.38
0.62 20
0.91 59
98.26
1.74
This work was supported by KOSEF.