Isolation and characterization of a new mucoid-free Klebsiella pneumoniae strain for 2,3-butanediol production

摘要

The secretion of mucoid substances by?Klebsiella pneumoniae, a natural 2,3-butanediol (2,3-BD) hyper-producer, hinders its application in large-scale fermentation because of pathogenicity, fermentation instability, and downstream difficulty. In this study, 14?K. pneumoniae?strains were isolated from a waste water treatment plant and their 2,3-BD production efficiencies were assessed with the strain?K. pneumoniaeDSM2026. Among various strains isolated,?K. pneumoniae?GSC010 and GSC112 produced relatively large amounts of 2,3-BD compared to other isolates; and their 2,3-BD production was consistent with DSM2026. Meanwhile, mucoidic characteristics of GSC010 were more or less similar to DSM2026, which was observed by scanning electron microscope (SEM) as a characteristic intercalated thread anchored on the surface of the cells. However, no polysaccharide materials were found in a non-mucoid cell, GSC112. Fed-batch culture of GSC112 with continuous glucose feeding resulted in the production of 2,3-BD at 52.4 g/l with 2,3-BD yield and overall productivity of 0.27 g/g glucose and 0.52 g/l/h, respectively. These results strongly suggest that the newly isolated mucoid-free?K. pneumoniae?GSC112 has potential for industrial production of 2,3-BD.