Redirection of the central metabolism of Klebsiella pneumoniae towards dihydroxyacetone production.
BACKGROUND
Klebsiella pneumoniae is a bacterium that can be used as producer for numerous chemicals. Glycerol can be catabolised by K. pneumoniae and dihydroxyacetone is an intermediate of this catabolism pathway. Here dihydroxyacetone and glycerol were produced from glucose by this bacterium based a redirected glycerol catabolism pathway.


RESULTS
tpiA, encoding triosephosphate isomerase, was knocked out to block the further catabolism of dihydroxyacetone phosphate in the glycolysis. After overexpression of a Corynebacterium glutamicum dihydroxyacetone phosphate dephosphorylase (hdpA), the engineered strain produced remarkable levels of dihydroxyacetone (7.0 g/L) and glycerol (2.5 g/L) from glucose. Further increase in product formation were obtained by knocking out gapA encoding an iosenzyme of glyceraldehyde 3-phosphate dehydrogenase. There are two dihydroxyacetone kinases in K. pneumoniae. They were both disrupted to prevent an inefficient reaction cycle between dihydroxyacetone phosphate and dihydroxyacetone, and the resulting strains had a distinct improvement in dihydroxyacetone and glycerol production. pH 6.0 and low air supplement were identified as the optimal conditions for dihydroxyacetone and glycerol production by K, pneumoniae ΔtpiA-ΔDHAK-hdpA. In fed batch fermentation 23.9 g/L of dihydroxyacetone and 10.8 g/L of glycerol were produced after 91 h of cultivation, with the total conversion ratio of 0.97 mol/mol glucose.


CONCLUSIONS
This study provides a novel and highly efficient way of dihydroxyacetone and glycerol production from glucose.
['Sun|Shaoqi|S|', 'Wang|Yike|Y|', 'Shu|Lin|L|', 'Lu|Xiyang|X|', 'Wang|Qinghui|Q|', 'Zhu|Chenguang|C|', 'Shi|Jiping|J|', 'Lye|Gary J|GJ|', 'Baganz|Frank|F|', 'Hao|Jian|J|http://orcid.org/0000-0002-4403-8188']
D004098:Dihydroxyacetone D004099:Dihydroxyacetone Phosphate D004163:Diphosphoglyceric Acids D005285:Fermentation D005798:Genes, Bacterial D005947:Glucose D005986:Glyceraldehyde 3-Phosphate D005987:Glyceraldehyde-3-Phosphate Dehydrogenases D005990:Glycerol D006863:Hydrogen-Ion Concentration D007711:Klebsiella pneumoniae D060847:Metabolic Engineering D053858:Metabolic Networks and Pathways D017853:Phosphotransferases (Alcohol Group Acceptor) D013816:Thermodynamics
Klebsiella pneumoniae Dihydroxyacetone Glycerol tpiA hdpA