title: High cell density propionic acid fermentation with an acid tolerant strain of Propionibacterium acidipropionici.
abstract: Propionic acid is an important chemical with wide applications and its production via fermentation is of great interest. However, economic production of bio-based propionic acid requires high product titer, yield, and productivity in the fermentation. A highly efficient and stable high cell density (HCD) fermentation process with cell recycle by centrifugation was developed for propionic acid production from glucose using an acid-tolerant strain of Propionibacterium acidipropionici, which had a higher specific growth rate, productivity, and acid tolerance compared to the wild type ATCC 4875. The sequential batch HCD fermentation at pH 6.5 produced propionic acid at a high titer of ∼40 g/L and productivity of 2.98 g/L h, with a yield of ∼0.44 g/g. The product yield increased to 0.53-0.62 g/g at a lower pH of 5.0-5.5, which, however, decreased the productivity to 1.28 g/L h. A higher final propionic acid titer of >55 g/L with a productivity of 2.23 g/L h was obtained in fed-batch HCD fermentation at pH 6.5. A 3-stage simulated fed-batch process in serum bottles produced 49.2 g/L propionic acid with a yield of 0.53 g/g and productivity of 0.66 g/L h. These productivities, yields and propionic acid titers were among the highest ever obtained in free-cell propionic acid fermentation.
authors.affiliation: William G. Lowrie Department of Chemical & Biomolecular Engineering, The Ohio State University, 140W. 19th Ave, Columbus, OH, 43210.
authors.forename: Zhongqiang
authors.initials: Z
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Jin
authors.forename: Shang-Tian
authors.initials: ST
authors.lastname: Yang
mesh_terms: D061249:Batch Cell Culture Techniques; D019149:Bioreactors / Q000382:microbiology*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011422:Propionates / Q000378:metabolism*; D011424:Propionibacterium / Q000378:metabolism* / Q000502:physiology*
chemical_list: D011422:Propionates; D005947:Glucose; C029658:propionic acid
keywords: Propionibacterium acidipropionici; acid tolerant strain; high cell density fermentation; propionic acid; sequential batch fermentation