Scalable catalyst production process for oleate hydratase whole‐cell biocatalysis

Biotechnology Progress, pp. e88535

Abstract

Abstract The sustainable production of hydroxy fatty acids, such as 10‐hydroxystearic acid (10‐HSA), by biocatalysis is a promising alternative to petrochemical and castor oil‐derived products. However, industrial implementation still requires an efficient and scalable process for biocatalyst production by fermentation, which precedes the biotransformation to 10‐HSA. In general, industrial biocatalysis is commonly performed using whole cells, which are cheaper than purified enzymes. Still, the fermentation process itself is a major cost contributor requiring a high‐yielding and scalable process. Here, we established and scaled a lactose‐induced fed‐batch process to produce an Escherichia coli BL21 (DE3) based whole‐cell biocatalyst containing an oleate hydratase from Stenotrophomonas nitritireducens . The two‐phased process employs an initial growth phase on glucose, followed by an induced feed phase using glycerol and lactose. When comparing two different growth rates during enzyme expression, a higher growth rate was found beneficial, resulting in a higher biomass concentration of 69.2 ± 0.5 g L −1 and a yield increase of 80 % while maintaining biocatalyst activity at >85 % conversion. This highlights the importance of process design variables, such as growth rate settings, for a high‐yielding and economic process. Feasibility of the process was demonstrated by scaling into a 150 L bioreactor, achieving a biomass concentration of 60.6 ± 0.4 g L −1 with a yield of 0.44 g C,Biomass g C −1 and 91.5 ± 1.4 % conversion. Supplemented with an initial test of suitable unit operations for technical biomass separation, this work provides a fermentation route for a whole‐cell oleate hydratase biocatalyst, paving the way for further scaling toward industrial 10‐HSA production.

Authors 7

1. Rebekka Horstmann Aachen AVT‑Biochemical Engineering

   RWTH Aachen University

   Affiliation as printed

   AVT—Biochemical Engineering RWTH Aachen University Aachen Germany

2. Mario Beckers Aachen NGP²—Biorefinery

   RWTH Aachen University

   Affiliation as printed

   NGP²—Biorefinery RWTH Aachen University Aachen Germany

3. Jörn Viell Aachen AVT-Process Systems Engineering NGP²—Biorefinery

   RWTH Aachen University

   Affiliation as printed

   AVT—Process Systems Engineering RWTH Aachen University Aachen Germany

   NGP²—Biorefinery RWTH Aachen University Aachen Germany

4. Fabian A. Watt

   Weidmüller (Germany)

   Affiliation as printed

   UWI—U. Windmöller Innovation GmbH & Co. KG Detmold Germany

5. Valentin Steier Aachen AVT‑Biochemical Engineering

   RWTH Aachen University

   Affiliation as printed

   AVT—Biochemical Engineering RWTH Aachen University Aachen Germany

6. Marcel Mann Aachen AVT‑Biochemical Engineering

   RWTH Aachen University

   Affiliation as printed

   AVT—Biochemical Engineering RWTH Aachen University Aachen Germany

7. Jørgen Barsett Magnus corresponding Aachen AVT‑Biochemical Engineering

   RWTH Aachen University

   Affiliation as printed

   AVT—Biochemical Engineering RWTH Aachen University Aachen Germany