title: Efficient production of 1,3-propanediol from fermentation of crude glycerol with mixed cultures in a simple medium.
abstract: The objective of this study was to examine the applicability of mixed cultures for 1,3-propanediol (1,3-PDO) production from crude glycerol. Three different sources of mixed cultures were tested, where the mixed culture from a municipal wastewater treatment plant showed the best results. 1,3-PDO can be produced as the main product in this mixed culture with typical organic acids like acetic and butyric acids as by-products. The yield was in the range of 0.56-0.76 mol 1,3-PDO per mol glycerol consumed depending on the glycerol concentration. A final product concentration as high as 70 g/L was obtained in fed-batch cultivation with a productivity of 2.6 g/L h. 1,3-PDO can be kept in the culture several days after termination of the fermentation without being degraded. Degradation tests showed that 1,3-PDO is degraded much slower than other compounds in the fermentation broth. In comparison to 1,3-PDO production in typical pure cultures, the process developed in this work with a mixed culture achieved the same levels of product titer, yield and productivity, but has the decisive advantage of operation under complete non-sterile conditions. Moreover, a defined fermentation medium without yeast extract can be used and nitrogen gassing can be omitted during cultivation, leading to a strong reduction of investment and production costs.
authors.affiliation: Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Denickestr.15, 21071, Hamburg, Germany, donna.tjahjasari@tuhh.de.
authors.forename: Donna
authors.initials: D
authors.lastname: Dietz
authors.forename: An-Ping
authors.initials: AP
authors.lastname: Zeng
mesh_terms: D046972:Clostridium butyricum / Q000378:metabolism; D003470:Culture Media; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D011409:Propylene Glycols / Q000378:metabolism*; D062065:Wastewater / Q000382:microbiology
chemical_list: D003470:Culture Media; D005990:Glycerol; D011409:Propylene Glycols; D062065:Wastewater; C041787:1,3-propanediol