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

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