Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1002/bit.26213
Title (Primary) Maximization of cell viability rather than biocatalyst activity improves whole-cell ω-oxyfunctionalization performance
Author Kadisch, M.; Julsing, M.K.; Schrewe, M.; Jehmlich, N. ORCID logo ; Scheer, B.; von Bergen, M.; Schmid, A.; Bühler, B.
Source Titel Biotechnology and Bioengineering
Year 2017
Volume 114
Issue 4
Page From 874
Page To 884
Language englisch
Keywords oxyfunctionalization; alkane monooxygenase; fatty-acid methyl ester; whole-cell biotransformation; industrial biotechnology; metabolic and reaction engineering
UFZ wide themes RU4; ProVIS;
Abstract It is a common misconception in whole-cell biocatalysis to refer to an enzyme as the biocatalyst, thereby neglecting the structural and metabolic framework provided by the cell. Here, the low whole-cell biocatalyst stability, that is, the stability of specific biocatalyst activity, in a process for the terminal oxyfunctionalization of renewable fatty acid methyl esters was investigated. This reaction, which is difficult to achieve by chemical means, is catalyzed by E. coli featuring the monooxygenase system AlkBGT and the uptake facilitator AlkL from Pseudomonas putida GPo1. Corresponding products, that is, terminal alcohols, aldehydes, and acids, constitute versatile bifunctional building blocks, which are of special interest for polymer synthesis. It could clearly be shown that extensive dodecanoic acid methyl ester uptake mediated by high AlkL levels leads to whole-cell biocatalyst toxification. Thus, cell viability constitutes the primary factor limiting biocatalyst stability and, as a result, process durability. Hence, a compromise had to be found between low biocatalyst activity due to restricted substrate uptake and poor biocatalyst stability due to AlkL-mediated toxification. This was achieved by the fine-tuning of heterologous alkL expression, which, furthermore, enabled the identification of the alkBGT expression level as another critical factor determining biocatalyst stability. Controlled synthesis of AlkL and reduced alkBGT expression finally enabled an increase of product titers by a factor of 4.3 up to 229 g Lorg−1 in a two-liquid phase bioprocess setup. Clearly, ω-oxyfunctionalization process performance was determined by cell viability and thus biocatalyst stability rather than the maximally achievable specific biocatalyst activity.
Persistent UFZ Identifier
Kadisch, M., Julsing, M.K., Schrewe, M., Jehmlich, N., Scheer, B., von Bergen, M., Schmid, A., Bühler, B. (2017):
Maximization of cell viability rather than biocatalyst activity improves whole-cell ω-oxyfunctionalization performance
Biotechnol. Bioeng. 114 (4), 874 - 884 10.1002/bit.26213