Hyperadherence of Pseudomonas taiwanensis VLB120ΔC increases productivity of (S)‐styrene oxide formation

Abstract

SummaryThe attachment strength of biofilm microbes is responsible for the adherence of the cells to surfaces and thus is a critical parameter in biofilm processes. In tubular microreactors, aqueous‐air segmented flow ensures an optimal oxygen supply and prevents excessive biofilm growth. However, organisms growing in these systems depend on an adaptation phase of several days, before mature and strong biofilms can develop. This is due to strong interfacial forces. In this study, a hyperadherent mutant of Pseudomonas taiwanensis VLB120ΔCeGFP possessing an engineered cyclic diguanylate metabolism, was applied to a continuous biofilm process for the production of (S)‐styrene oxide. Cells of the mutant P. taiwanensis VLB120ΔCeGFP Δ04710, showing the same specific activity as the wild type, adhered substantially stronger to the substratum. Adaptation to the high interfacial forces was not necessary in these cases. Thereby, 40% higher final product concentrations were achieved and the maximal volumetric productivity of the parent strain was significantly surpassed by P. taiwanensis VLB120ΔCeGFP Δ04710. Applying mutants with strong adhesion in biofilm‐based catalysis opens the door to biological process control in future applications of catalytic biofilms using other industrially relevant strains.

Maximizing the stability of metabolic engineering‐derived whole‐cell biocatalysts

“…The markedly high physical stability of biofilms and their resilience against toxic substances have been exploited in continuous biocatalytic syntheses. Prominent examples are the oxygenation of styrene , cyclohexane , or limonene with various Pseudomonads or the dehalogenation of haloalkanes with E. coli . Although biofilms are generally regarded as a stable catalyst form, systematic studies comparing biofilms and suspended cells with respect to process performance and stability are scarce.…”

Microfluidic cultivation and analysis of productive biofilms

“…Recent research on productive biofilms generally uses model reactors of mesoscopic size, e.g. to study the continuous production of lactic acid (Cuny et al, 2019), cyclohexanol (Hoschek et al, 2019), or styrene oxide (Schmutzler et al, 2017). However, microfluidic reactors have also been used for this purpose (Karande et al, 2016), for instance, the segmented flow of microdroplets was utilized for the production of perillic acid (Willrodt et al, 2017).…”

Non-pathogenic Escherichia coli biofilms: effects of growth conditions and surface properties on structure and curli gene expression

“…The robust nature of biofilms that makes their removal difficult in clinical and industrial settings makes them a potentially advantageous platform for biocatalysis (Rosche et al 2009 ; Winn et al 2012 ). For example, Pseudomonas taiwanensis biofilms efficiently catalyse the epoxidation of styrene to (S)-styrene oxide (Karande et al 2014 ; Schmutzler et al 2017 ). Escherichia coli strains K-12 and B are very commonly-used in biotechnology for biocatalysis and recombinant protein production (Overton 2014 ).…”