Recovery and subsequent characterization of polyhydroxybutyrate from Rhodococcus equi cells grown on crude palm kernel oil

Peer review under responsibility of Taibah University.

Figures & data

Fig. 1 PHB polymer recoverd from R. equi using CPKO 1% as carbon source.

Fig. 2 ¹H NMR spectrum of PHB polymer produced from R. equi using CPKO 1% as the carbon source.

Fig. 3 ¹³C NMR spectrum of PHB polymer produced from R. equi using CPKO 1% as the carbon source.

Table 1 Chemical shift signals obtained from the ¹³C NMR spectra for the PHB sample, which are similar to the reported result of commercial PHB in [31].

C atom	PHB sample	Commercial PHB [31]
CH3	19.65	19.65
CH2	40.66	40.66
CH	67.77	67.77
C=O	169.162	169.03

Fig. 4 Melting temperature (T_m) and glass transition temperature (T_g) of PHB produced from R. equi using CPKO 1% as the carbon source.

Fig. 5 Decomposition temperature (T_d) of PHB produced from R. equi using CPKO 1% as the carbon source.

Table 2 Thermal properties of PHB produced from R. equi with CPKO 1% as the carbon source.

Term	Value
Tm	173 °C
Tg	2.79 °C
Td	276 °C

Table 3 Molecular weight of the recovered PHB in comparison with the results of other reports: weight average (${\overline{M}}_{\text{w}}$), number average (${\overline{M}}_{\text{n}}$) and polydispersity (${\overline{M}}_{\text{w}}/{\overline{M}}_{\text{n}}$) as determined using GPC.

Polymer	Producing bacteria	${\overline{M}}_{\text{w}}$ (kDa)	${\overline{M}}_{\text{n}}$ (kDa)	${\overline{M}}_{\text{w}}/{\overline{M}}_{\text{n}}$	References
PHB sample	R. equi	642	373	1.72	This study
PHB (soy)	Cupriavidis necator	790	348.8	2.26	[31]
PHB (molasses and corn steep liquor)	Bacillus megaterium ATCC 6748	3900	2651	1.47	[40]
PHB (pulp industry waste)	Bacillus subtilis MSBN17	640	380	1.68	[11]
PHB-co-PHAV (bagasse extract)	Halomonas campisalis	1394	838.5	1.66	[41]