Resolution of alkaloid racemate: a novel microbial approach for the production of enantiopure lupanine via industrial wastewater valorization

Abstract

Background: Lupanine is a plant toxin contained in the wastewater of lupine bean processing industries, which could be used for semi-synthesis of various novel high added-value compounds. This paper introduces an environmental friendly process for microbial production of enantiopure lupanine.Results: Previously isolated P. putida LPK411, R. rhodochrous LPK211 and Rhodococcus sp. LPK311, holding the capacity to utilize lupanine as single carbon source, were employed as biocatalysts for resolution of racemic lupanine. All strains achieved high enantiomeric excess (ee) of L-(−)-lupanine (> 95%), while with the use of LPK411 53% of the initial racemate content was not removed. LPK411 fed with lupanine enantiomers as single substrates achieved 92% of D-(+)-lupanine biodegradation, whereas L-(−)-lupanine was not metabolized. Monitoring the transcriptional kinetics of the luh gene in cultures supplemented with the racemate as well as each of the enantiomers supported the enantioselectivity of LPK411 for D-(+)-lupanine biotransformation, while (trans)-6-oxooctahydro-1H-quinolizine-3-carboxylic acid was detected as final biodegradation product from D-(+)-lupanine use. Ecotoxicological assessment demonstrated that lupanine enantiomers were less toxic to A. fischeri compared to the racemate exhibiting synergistic interaction. Conclusions:The biological chiral separation process of lupanine presented here constitutes an eco-friendly and low-cost alternative to widely used chemical methods for chiral separation.

Toxicity and risk of plant-produced alkaloids to Daphnia magna

“…This mixture, however, maximally killed 15% of the daphnids after 96 h, emphasising that the measured alkaloids cannot explain the observed toxicity of the plant extract, which likely stems from other unmeasured phytotoxins, alkaloid metabolites, or the enantiomeric composition of the alkaloids. The enantiomeric composition is likely different in natural extracts compared to the purchased pure compounds, with a study showing that the enantiomeric form of lupanine severely affects bioactivity [36]. Turbidity of the plant extract may be an additional factor affecting daphnid survival, as the high concentration solutions were visually green and turbid.…”

Fractal Features of the Catalytic Performances of Bimodal Mesoporous Silica‐Supported Organocatalysts Derived from Bipyridine‐Proline for Asymmetric Aldol Reaction

“…The most commonly used three approaches have been developed for the production of pure enantiomers, comprising the resolution of the racemic mixture, substrate‐induced chiral synthesis, and enantioselective catalysis in the fields of asymmetric catalysis [1] . In which, chiral catalysis is recognized as one of the most convenient and effective strategies to control enantioselectivity due to the phenomenon of the multiplication of chirality, which is different from the reaction catalyzed by ordinary catalysts, such as yeast, [2] natural enzymes, [3,4] and metal complexes [5] .…”

“…The most commonly used three approaches have been developed for the production of pure enantiomers, comprising the resolution of the racemic mixture, substrate-induced chiral synthesis, and enantioselective catalysis in the fields of asymmetric catalysis. [1] In which, chiral catalysis is recognized as one of the most convenient and effective strategies to control enantioselectivity due to the phenomenon of the multiplication of chirality, which is different from the reaction catalyzed by ordinary catalysts, such as yeast, [2] natural enzymes, [3,4] and metal complexes. [5] Since the report of Knowles, Noyori, and Sharpless (in 2001) in homogeneous asymmetric catalysis for chiral-catalyzed hydrogenation and oxidation reactions, [6] the great advances in this field have been achieved with the design, synthesis, and applications of chiral catalysts over the past two decades.…”