title: Enhanced Product Recovery from Glycerol Fermentation into 3-Carbon Compounds in a Bioelectrochemical System Combined withIn SituExtraction.
abstract: Given the large amount of crude glycerol formed as a by-product in the biodiesel industries and the concomitant decrease in its overall market price, there is a need to add extra value to this biorefinery side stream. Upgrading can be achieved by new biotechnologies dealing with recovery and conversion of glycerol present in wastewaters into value-added products, aiming at a zero-waste policy and developing an economically viable process. In microbial bioelectrochemical systems (BESs), the mixed microbial community growing on the cathode can convert glycerol reductively to 1,3-propanediol (1,3-PDO). However, the product yield is rather limited in BESs compared with classic fermentation processes, and the synthesis of side-products, resulting from oxidation of glycerol, such as organic acids, represents a major burden for recovery of 1,3-PDO. Here, we show that the use of an enriched mixed-microbial community of glycerol degraders andin situextraction of organic acids positively impacts 1,3-PDO yield and allows additional recovery of propionate from glycerol. We report the highest production yield achieved (0.72 mol1,3-PDOmol-1glycerol) in electricity-driven 1,3-PDO biosynthesis from raw glycerol, which is very close to the 1,3-PDO yield reported thus far for a mixed-microbial culture-based glycerol fermentation process. We also present a combined approach for 1,3-PDO production and propionate extraction in a single three chamber reactor system, which leads to recovery of additional 3-carbon compounds in BESs. This opens up further opportunities for an economical upgrading of biodiesel refinery side or waste streams.
authors.affiliation: Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent University , Gent , Belgium.
authors.forename: Hugo
authors.initials: H
authors.lastname: Roume
authors.affiliation: Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent University , Gent , Belgium.
authors.forename: Jan B A
authors.initials: JB
authors.lastname: Arends
authors.affiliation: Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent University , Gent , Belgium.
authors.forename: Camar P
authors.initials: CP
authors.lastname: Ameril
authors.affiliation: Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent University , Gent , Belgium.
authors.forename: Sunil A
authors.initials: SA
authors.lastname: Patil
authors.affiliation: Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent University , Gent , Belgium.
authors.forename: Korneel
authors.initials: K
authors.lastname: Rabaey
keywords: 1,3-propanediol; bioelectrochemical systems; in situ extraction; propionate; resource recovery