Simultaneous production and characterization of medium-chain-length polyhydroxyalkanoates and alginate oligosaccharides by Pseudomonas mendocina NK-01

摘要

When Pseudomonas mendocina NK-01 was cultivated in a 200-L fermentor using glucose as carbon source, 0.316 gL~(?1) medium-chain-length polyhydroxyalkanoate (PHA_(MCL)) and 0.57 gL~(?1) alginate oligosaccharides (AO) were obtained at the end of the process. GC/MS was used to characterize the PHAMCL, which was found to be a polymer mainly consisting of 3HO (3-hydroxyoctanoate) and 3HD (3-hydroxydecanoate). T_m and T_g values for the PHA_(MCL) were 51.03°C and ?41.21°C, respectively, by DSC. Its decomposition temperature was about 300°C. The elongation at break was 700% under 12 MPa stress. MS and GPC were also carried out to characterize the AO which had weight-average molecular weights of 1,546 and 1,029 Da, respectively, for the two main components at the end of the fermentation process. MS analysis revealed that the AO were consisted of β-D-mannuronic acid and/or α-Lguluronic acid, and the β-D-mannuronic acid and/or α-Lguluronic acid residues were partially acetylated at position C2 or C3.