Assessing the substrate specificity of a micropollutant degrading strain: generalist or specialist?

Schittich, Anna-Ricarda; McKnight, Ursula S.; Stedmon, Colin A.; Smets, Barth F.

doi:10.1039/d2em00197g

Cited by 3 publications

(11 citation statements)

References 52 publications

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“…(A) The predicted pathways of four selected auxiliary substrates that support the growth of KN65.2. For each substrate, the time in parenthesis indicates complete biodegradation, as previously established for single substrate, pure culture experiments with KN65.2 (Schittich et al, 2022). Green arrows indicate expected pathways based on these biodegradation times.…”

Section: Resultsmentioning

confidence: 99%

“…The remaining five compounds (benzoic acid, salicylic acid [SAL], piceol [PI], cinnamic acid, and l ‐phenylalanine) do not support the carbofuran degrader's growth. All growth‐supporting compounds contain a hydroxyl group in the para ‐position of the aromatic ring (Figure 1A), while only one of the non‐transformable compounds (PI) contains this feature (Figure 1B Schittich et al, 2022).…”

Section: Methodsmentioning

confidence: 99%

“…The two cinnamic acids, p-coumaric acid and ferulic acid, form transformation Group 2. Taking into account previously established biodegradation endpoints (i.e., the time until complete substrate biodegradation tested in a single substrate, pure culture experiments with KN65.2; Schittich et al, 2022), it appears likely that both substrates are transformed via the hydroxylation product caffeic acid (Figure 3A, Group 2, green arrows). p-Coumaric acid is degraded faster (28 h) than its possible biodegradation intermediate 4-hydroxybenzoic acid (43 h), making it unlikely that p-coumaric acid forms this compound as an intermediate (Figure 3A, bt0337*, greyed out).…”

Section: Transformation Groups Of Growthsupporting Compoundsmentioning

confidence: 99%

“…Biodegradation experiments were conducted under aseptic conditions as described previously (Schittich et al, 2022). Each mixed substrate experiment contained two carbon sources: the pesticide carbofuran and one of the four auxiliary substrates.…”

Section: Mixed Substrate Experimentsmentioning

confidence: 99%

“…We used a novel approach that applies the Eawag PPS prediction system in combination with laboratory experiments and fluorescence spectroscopy. First, a theoretical Eawag PPS analysis aimed to reveal enzymatic reactions responsible for the transformability of 11 selected model DOM constituents, whose transformation by KN65.2 was tested previously (Schittich et al, 2022). We then selected four growth‐supporting compounds representing different chemical classes (two benzoic acid derivatives and two cinnamic acids), to further elucidate their effects on carbofuran biodegradation together with their transformation mechanisms.…”

Section: Introductionmentioning

confidence: 99%

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Coupling pathway prediction and fluorescence spectroscopy to assess the impact of auxiliary substrates on micropollutant biodegradation

Schittich,

Fenner,

Stedmon

et al. 2024

Environmental Microbiology

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Some bacteria can degrade organic micropollutants (OMPs) as primary carbon sources. Due to typically low OMP concentrations, these bacteria may benefit from supplemental assimilation of natural substrates present in the pool of dissolved organic matter (DOM). The biodegradability of such auxiliary substrates and the impacts on OMP removal are tightly linked to biotransformation pathways. Here, we aimed to elucidate the biodegradability and effect of different DOM constituents for the carbofuran degrader Novosphingobium sp. KN65.2, using a novel approach that combines pathway prediction, laboratory experiments, and fluorescence spectroscopy. Pathway prediction suggested that ring hydroxylation reactions catalysed by Rieske‐type dioxygenases and flavin‐dependent monooxygenases determine the transformability of the 11 aromatic compounds used as model DOM constituents. Our approach further identified two groups with distinct transformation mechanisms amongst the four growth‐supporting compounds selected for mixed substrate biodegradation experiments with the pesticide carbofuran (Group 1: 4‐hydroxybenzoic acid, 4‐hydroxybenzaldehyde; Group 2: p‐coumaric acid, ferulic acid). Carbofuran biodegradation kinetics were stable in the presence of both Group 1 and Group 2 auxiliary substrates. However, Group 2 substrates would be preferable for bioremediation processes, as they showed constant biodegradation kinetics under different experimental conditions (pre‐growing KN65.2 on carbofuran vs. DOM constituent). Furthermore, Group 2 substrates were utilisable by KN65.2 in the presence of a competitor (Pseudomonas fluorescens sp. P17). Our study thus presents a simple and cost‐efficient approach that reveals mechanistic insights into OMP‐DOM biodegradation.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Transformation Groups Of Growthsupporting Compoundsmentioning

confidence: 99%

Section: Mixed Substrate Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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