Enantiomer discrimination in β-phenylalanine degradation by a newly isolated Paraburkholderia strain BS115 and type strain PsJN

Abstract

Despite their key role in numerous natural compounds, β-amino acids have rarely been studied as substrates for microbial degradation. Fermentation of the newly isolated Paraburkholderia strain BS115 and the type strain P. phytofirmans PsJN with β-phenylalanine (β-PA) as sole nitrogen source revealed (S)-selective transamination of β-PA to the corresponding β-keto acid by both strains, accompanied by substantial formation of acetophenone (AP) from spontaneous decarboxylation of the emerging β-keto acid. While the PsJN culture became stationary after entire (S)-β-PA consumption, BS115 showed further growth at a considerably slower rate, consuming (R)-β-PA without generation of AP which points to a different degradation mechanism for this enantiomer. This is the first report on degradation of both enantiomers of any β-amino acid by one single bacterial strain.Electronic supplementary materialThe online version of this article (10.1186/s13568-018-0676-2) contains supplementary material, which is available to authorized users.

Growth optimization and identification of an ω-transaminase by a novel native PAGE activity staining method in a Bacillus sp. strain BaH isolated from Iranian soil

“…It was demonstrated that AcPhe depletion via evaporation in bioreactor was not notable (data not shown). AcPhe decreasing during fermentation was also reported by Buß et al ( 2018a ), who discussed the possibility of bacterial metabolization of AcPhe. Besides, it was shown that alcohol dehydrogenases (ADH) from Lactobacillus kefir accepts AcPhe and converts it to ( R )-alcohol (Yun et al 2003 ).…”

“…from extremophile microorganisms. Buß et al ( 2018a ) studied β-phenylalanine degradation during fermentation of Paraburkholderia . Cultivation of Arthrobacter sp.…”

Screening and Comparative Characterization of Microorganisms from Iranian Soil Samples Showing ω-Transaminase Activity toward a Plethora of Substrates

“…ω-TA activity against 14 has been reported by Mathew et al for ω-TABG, with 50% relative activity in comparison with 13 [30]. A recent study by Buß et al explained the lack of ω-TA activity against 14 (by an ω-TA that was highly active against 13) by sterice hindrance caused by the additional carbon atom located between the amino group and phenyl group [36]. Several substituted derivatives of β-phenylalanine are converted as well.…”

“…Notably, it is difficult to conclude that BaH showed (R)-selectivity since in this study, crude extract was applied. There is a possibility that (R) converted to (S)-enantiomer via enzymatic racemization [36], and then the latter was subjected to ω-TA activity. On the other hand, (R)-preference towards 13r in compare to 13s leads to another hypothesis, in which both R and S transaminases are present in crude extract.…”

“…The cells were harvested by centrifugation at 6000× g for 10 min at 4 • C and resuspended in HEPES buffer (50 mM, pH 7.5). The cell concentration was adjusted to around 20 mg/mL by measuring dry cell mass based on Buß et al [36]. The cells were frozen at −80 • C and thawed at room temperature for cell disruption.…”