| Abstract | Maple sap, an abundant natural product especially in Canada, is rich in sucrose and thus may represent an ideal renewable feedstock for the production of a wide variety of value-added products. In the present study, maple sap or sucrose was employed as a carbon source to Alcaligenes latus for the production of poly-?-hydroxybutyrate (PHB). In shake flasks, the biomass obtained from both the sap and sucrose were 4.4�0.5 and 2.9�0.3 g/L, and the PHB contents were 77.6�1.5 and 74.1�2.0%, respectively. Subsequent batch fermentation (10 L sap) resulted in the formation of 4.2�0.3 g/L biomass and a PHB content of 77.0�2.6%. The number average molecular weights of the PHB produced by A. latus from maple sap and pure sucrose media were 300�66�103 and 313�104�103 g/mol, respectively. Near-infrared, 1H magnetic resonance imaging (MRI), and 13C-MRI spectra of the microbially produced PHB completely matched those obtained with a reference material of poly[(R)-3-hydroxybutyric acid]. The polymer was found to be optically active with [?]25 D equaled to -7.87 in chloroform. The melting point (177.0�C) and enthalpy of fusion (77.2 J/g) of the polymer were also in line with those reported, i.e., 177�C and 81 J/g, respectively. |
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