Carbon and electron fluxes during the electricity driven 1,3-propanediol biosynthesis from glycerol.
1,3-Propanediol (1,3-PDO) can be produced biologically through glycerol fermentation. While such a process typically involves a pure culture system, particularly for crude glycerol, there would be operational advantages if a mixed population could be used. However, in the latter case the yield is typically low. Here, we use electrical current as the driving force for a mixed population fermenting glycerol in the cathode of a microbial bioelectrochemical system (BES). The carbon and electron flows were monitored by a titration and off-gas analysis (TOGA) sensor, and the syntrophic interactions in the BES were also investigated. Results show that on a carbon yield basis, current enhanced 1,3-PDO production from 24.8% (without current) to 50.1% (with a polarized biocathode at -0.9 V versus standard hydrogen electrode, SHE). Flux analysis indicated that the reductive current can be integrated into glycerol metabolism to enhance 1,3-PDO yield and that glycerol metabolism was redirected from propionate fermentation to 1,3-PDO production. A polarization of -0.6 V (vs SHE) resulted in more fermentative hydrogen production (from 2.7% to 8.0% on electron basis). 1,3-PDO production was also enhanced with hydrogen supply (37.7% on carbon basis), by suppressing hydrogen fermentation. Moreover, interspecies hydrogen transfer encouraged hydrogenotrophic methanogenesis, which was also accelerated by the cathodic polarization.
Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China.
Mi
M
Zhou
Jingwen
J
Chen
Stefano
S
Freguia
Korneel
K
Rabaey
Jürg
J
Keller
D001419:Bacteria / Q000378:metabolism*; D002244:Carbon; D004560:Electricity; D004583:Electrons; D005990:Glycerol / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D008697:Methane / Q000378:metabolism; D011409:Propylene Glycols / Q000378:metabolism*
D011409:Propylene Glycols; C041787:1,3-propanediol; D002244:Carbon; D006859:Hydrogen; D008697:Methane; D005990:Glycerol