Enlightening the pathways of bacterial long chain hydrocarbon metabolism

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Suvi Santala, Matti Karp, Ville Santala

Tampere University of Technology, Finland

For decades, bacterial luciferase operon has brought light into the molecular biology labs, serving as a sensitive tool for numerous sensor applications. Traditionally the light producing multienzyme complex has been exploited in an orthogonal manner, independent from the host metabolism. The complex can be divided into two functional parts, an aldehyde producing unit LuxCDE, and a fatty acid and light producing unit LuxAB. In our study, these functional units were exploited independently and integrated to the metabolism of an optimal cellular framework, enabling the construction of novel screening tools and synthesis pathways for metabolic engineering applications. The integration of the light producing unit allows detection of endogenous long chain aldehyde formation, and vice versa, the integration of the aldehyde producing unit provides intermediates for the production of customized long chain hydrocarbons. As long-chain aldehydes represent an intermediate in the wax ester synthesis route, LuxAB was exploited in developing a tool for monitoring bacterial wax ester production in Acinetobacter baylyi ADP1 wild type strain. The monitoring system showed correlation between wax ester synthesis pattern and luminescent signal. The system holds potential for real-time screening purposes and studies on bacterial hydrocarbon production. Furthermore, a reverse monitoring system was constructed for studying the kinetics and potential for bacterial degradation of long chain hydrocarbons such as petrodiesel, alkanes, and other pollutants in contaminated soil and water environments, applicable in the field of environmental biotechnology. Finally, the wax ester synthesis route of A. baylyi ADP1 was reconstructed by replacing part of the natural production pathway with LuxCDE, resulting in recircuited production of modified wax esters.