Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1111/pbi.14113
Licence creative commons licence
Title (Primary) Light‐driven redox biocatalysis on gram‐scale in Synechocystis sp. PCC 6803 via an in vivo cascade
Author Tüllinghoff, A.; Djaya-Mbissam, H.; Toepel, J.; Bühler, B.
Source Titel Plant Biotechnology Journal
Year 2023
Department UMB
Volume 21
Issue 10
Page From 2074
Page To 2083
Language englisch
Topic T7 Bioeconomy
Keywords Cyanobacteria; Baeyer-Villiger oxidation; Photo-biotechnology; Lactonase; Whole-cell biocatalaysis
Abstract The photosynthetic light reaction in cyanobacteria constitutes a highly attractive tool for productive biocatalysis, as it can provide redox reactions with high-energy reduction equivalents using sunlight and water as sources of energy and electrons, respectively. Here, we describe the first artificial light-driven redox cascade in Synechocystis sp. PCC 6803 to convert cyclohexanone to the polymer building block 6-hydroxyhexanoic acid (6-HA). Co-expression of a Baeyer-Villiger monooxygenase (BVMO) and a lactonase, both from Acidovorax sp. CHX100, enabled this two-step conversion with an activity of up to 63.1 ± 1.0 U/gCDW without accumulating inhibitory ε-caprolactone. Thereby, one of the key limitations of biocatalytic reactions, that is, reactant inhibition or toxicity, was overcome. In 2 L stirred-tank-photobioreactors, the process could be stabilized for 48 h, forming 23.50 ± 0.84 mm (3.11 ± 0.12 g/L) 6-HA. The high specificity enabling a product yield (YP/S) of 0.96 ± 0.01 mol/mol and the remarkable biocatalyst-related yield of 3.71 ± 0.21 g6-HA/gCDW illustrate the potential of producing this non-toxic product in a synthetic cascade. The fine-tuning of the energy burden on the catalyst was found to be crucial, which indicates a limitation by the metabolic capacity of the cells possibly being compromised by biocatalysis-related reductant withdrawal. Intriguingly, energy balancing revealed that the biotransformation could tap surplus electrons derived from the photosynthetic light reaction and thereby relieve photosynthetic sink limitation. This study shows the feasibility of light-driven biocatalytic cascade operation in cyanobacteria and highlights respective metabolic limitations and engineering targets to unleash the full potential of photosynthesis.
Persistent UFZ Identifier
Tüllinghoff, A., Djaya-Mbissam, H., Toepel, J., Bühler, B. (2023):
Light‐driven redox biocatalysis on gram‐scale in Synechocystis sp. PCC 6803 via an in vivo cascade
Plant Biotechnol. J. 21 (10), 2074 - 2083 10.1111/pbi.14113