Foam-free production of the rhamnolipid precursor 3-(3-hydroxyalkanoyloxy) alkanoic acid (HAA) by Pseudomonas putida

Weiser S, Tiso T, Willing K, Bardl B, Eichhorn L, Blank LM, Regestein L (2022) Foam-free production of the rhamnolipid precursor 3-(3-hydroxyalkanoyloxy) alkanoic acid (HAA) by Pseudomonas putida DChE ,

Abstract

Surfactants represent a large group of industrial relevant substances and can be generated chemically, but also bio-
logically. Important microbial producers are several Pseudomonas species, mainly known for their ability to produce
rhamnolipids. For safety reasons, recombinant Pseudomonas putida is preferred for heterologous production of rham-
nolipids as well as its precursor 3-(3-hydroxyalkanoyloxy) alkanoic acid (HAA), which is a promising platform substance.
The surface-active properties of HAA combined with classical submerged aeration cause strong foam formation making
biotechnological production in stirred tank bioreactors challenging. Therefore, a foam-free bioprocess for HAA produc-
tion was developed in this study. The combination of headspace aeration, overpressure up to 8 bar, and temperature
reduction prevented oxygen limitation, shortened process time, and enhanced the maximum HAA concentration to
1.71 g l − 1 with a space-time yield of 0.08 g l − 1 h − 1 .

Leibniz-HKI-Autor*innen

Bettina Bardl
Lucy Eichhorn
Lars Regestein
Sophie Weiser
Karsten Willing