3-Hydroxy decanoic acid (3-HDA), derivable from glucose or xylose waste-streams, was successfully upgraded electrochemically into a drop-in oxygenate with promising fuel characteristics.

DH5αλpir pTNS1DH5αλpir harboring plasmid pTNS1 Choi et al., 2005 DH5αλpir pSK02 DH5 αλpir harboring Tn7 delivery vector pSK02 for chromosomal integration; containing rhlAB genes from P. aeruginosa PA01 Bator et al., 2020 P. taiwanensis VLB120 wild type Panke et al., 1998 P. putida DOT-T1E wild type Ramos et al., 1998 S12 wild type Hartmans et al., 1990 KT2440 wild type Bagdasarian et al., 1981

The BioLector® Pro system from m2p‐labs GmbH uses microtiter plates (MTPs) with an integrated microfluidic chip. By using microfluidic technology, the system can successfully carry out small‐scale fed‐batch cultivations. Working volumes of 0.8–1.5 mL are used to conduct cultivations as they were only as yet possible in lab fermenters. The measurements of biomass, fluorescence, pH and dissolved oxygen are performed by non‐invasive optical methods. The control of pH and feeding rates are realized by micro‐valves and micro‐channels. For the first time, these unique microfluidic components achieve continuous feeding and pH control on an MTP format. Altogether, 32 bioreactor wells and 16 reservoir wells are placed on one plate. That means 32 fed‐batch cultivations can be run in parallel, completely automated, with extensive data output.

Here we report a chemoenzymatic approach to synthesize 1-octene from carbohydrates via ethenolysis of rhamnolipids. Rhamnolipids synthesized by P. putida contain a double bond between carbon five and six, which is experimentally confirmed via olefin cross metathesis. Utilizing these lipids in the ethenolysis catalyzed by a Grubbs−Hoveyda-type catalyst selectively generates 1-octene and with good conversions. This study shows the potential of chemoenzymatic approaches to produce compounds for the chemical industry from renewable resources.

The production of biosurfactants is often hampered by excessive foaming in the bioreactor, impacting system scale-up and downstream processing. Foam fractionation was proposed to tackle this challenge by combining in situ product removal with a pre-purification step. In previous studies, foam fractionation was coupled to bioreactor operation, hence it was operated at suboptimal parameters. Here, we use an external fractionation column to decouple biosurfactant production from foam fractionation, enabling continuous surfactant separation, which is especially suited for system scale-up. As a subsequent product recovery step, continuous foam adsorption was integrated into the process. The configuration is evaluated for rhamnolipid (RL) or 3-(3-hydroxyalkanoyloxy)alkanoic acid (HAA, i.e., RL precursor) production by recombinant non-pathogenic Pseudomonas putida KT2440. Surfactant concentrations of 7.5 gRL/L and 2.0 gHAA/L were obtained in the fractionated foam. 4.7 g RLs and 2.8 g HAAs could be separated in the 2-stage recovery process within 36 h from a 2 L culture volume. With a culture volume scale-up to 9 L, 16 g RLs were adsorbed, and the space-time yield (STY) increased by 31% to 0.21 gRL/L·h. We demonstrate a well-performing process design for biosurfactant production and recovery as a contribution to a vital bioeconomy.