Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture

AMB Express

Table 2 Molecular weight (number average M _n and weight average M _w ) and molecular weight change \( \left(\left(\frac{{\boldsymbol{M}}_{\boldsymbol{n},\boldsymbol{0}}\hbox{-} {\boldsymbol{M}}_{\boldsymbol{n},\boldsymbol{t}}}{{\boldsymbol{M}}_{\boldsymbol{n},\boldsymbol{0}}}\right)\mathbf{x}\ \mathbf{100}\right) \) of various PHB samples as a function of thermal treatment at 170°C.

Sample	Chemical treatment	PHB purity [wt.%]	Time of thermal treatment at 170°C [min]	M _n [kg/mol]	M _w [kg/mol]	\( \left(\frac{{\boldsymbol{M}}_{\boldsymbol{n},\boldsymbol{0}}\hbox{-} {\boldsymbol{M}}_{\boldsymbol{n},\boldsymbol{t}}}{{\boldsymbol{M}}_{\boldsymbol{n},\boldsymbol{0}}}\right)\mathbf{x}\ \mathbf{100} \) [%]
Commercial PHB	-	99	0	182	647	0
			1	169	583	7
			3	175	541	4
			5	119	391	35
			10	150	435	18
			15	135	373	26
PHB from biomass	-	67	0	135	224	0
			1	51	111	62
			3	33	62	76
			5	30	42	78
			10	25	34	81
			15	19	25	86
	Solvent	99	0	915	1755	0
			1	883	1731	3
			3	824	1573	10
			5	771	1562	15
			10	516	1144	44
			15	560	1255	39
	0.2 M NaOH	85	0	119	315	0
			1	19	39	84
			3	8	13	93
			5	6	8	95
			10	2	3	98
			15	1.8	2.2	98
	0.2 M NaOH + 0.2% SDS	95	0	163	484	0
			1	45	73	72
			3	14	23	91
			5	11	20	93
			10	4	8	98
			15	3	4	98