Synthetische nichtnutritive Süßstoffe

Ager, David J.; Pantaleone, David P.; Henderson, Scott A.; Katritzky, Alan R.; Prakash, Indra; Walters, D. E.

doi:10.1002/(sici)1521-3757(19980703)110:13/14<1900::aid-ange1900>3.0.co;2-r

Cited by 19 publications

(7 citation statements)

References 72 publications

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“…The utility of arenesulfonyl chlorides for further chemical manipulation was investigated with regard to the synthesis of saccharin . The photocatalytic chlorosulfonylation of 2‐aminocarbonylbenzenediazonium tetrafluoroborate afforded saccharin as single isolable product in 70 % yield after intramolecular sulfoxamidation.…”

Section: Resultsmentioning

confidence: 99%

Aromatic Chlorosulfonylation by Photoredox Catalysis

2016

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Visible-light photoredox catalysis enables the efficient synthesis of arenesulfonyl chlorides from anilines. The new protocol involves the convenient in situ preparation of arenediazonium salts (from anilines) and the reactive gases SO and HCl (from aqueous SOCl ). The photocatalytic chlorosulfonylation operates at mild conditions (room temperature, acetonitrile/water) with low catalyst loading. Various functional groups are tolerated (e.g., halides, azides, nitro groups, CF , SF , esters, heteroarenes). Theoretical and experimental studies support a photoredox-catalysis mechanism.

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Section: Resultsmentioning

confidence: 99%

Aromatic Chlorosulfonylation by Photoredox Catalysis

2016

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“…Regarding the worldwide production of 11,000 tons in 1998 and 14,000 (estimated) tons in 2002 [1], the aromatic amino acid L-phenylalanine (L-phe) can be considered to be one of the most important commercially produced amino acids representing a necessary building block for the production of the low-calorie sweetener aspartame [2,3].…”

Section: Introductionmentioning

confidence: 99%

Fully integrated L-phenylalanine separation and concentration using reactive-extraction with liquid-liquid centrifuges in a fed-batch process with E. coli

Rüffer

Heidersdorf

Kretzers

et al. 2004

Bioprocess Biosyst Eng

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A novel in situ product recovery (ISPR) approach for the (fully) integrated separation of L-phenylalanine (L-phe) from a 20 l fed-batch process with the recombinant L-tyrosine auxotrophic strain E. coli F-4/pF81 is presented. The strain was rationally constructed for the production of the aromatic amino acid. Glucose and tyrosine control is used. A reactive extraction system consisting of kerosene, the cation-selective carrier D(2)EHPA and sulphuric acid, all circulating in liquid-liquid centrifuges, is applied for the on-line L-phe separation from cell- and protein-free permeate. Permeate is drained off from the bioreactor bypass. Using the novel ISPR approach, a significantly extended product formation period at 0.25 mmol/(g*h) together with a reduced by-product formation and a 28% relative glucose/L-phe yield increase is observed. Thus, the ISPR approach is superior to the reference non-ISPR process and even offers extraction rates approximately three times higher than the published membrane-based process.

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“…A doubling of L-Phe/glucose yield was observed when kerosene/DEHPA was added to the fermentation solution in the bioreactor to experimentally simulate a fully integrated L-Phe separation process. 620 optical density (-) Q stream (L/s) V D volume (donor phase) (L) V module module volume (organic phase) (L) V aq volume (aqueous phase) (L) V org volume (organic phase) (L) w w superficial velocity (average) (m/s) w HF superficial velocity (inside hollow fibre) (m/s) b A mass-transfer coefficient (organic/acceptor phase) (cm/s) b D mass-transfer coefficient (donor/organic phase) (cm/s) m viscosity (m 2 /s) the low calorie sweetener aspartame [1]. In comparison to the currently used chemo-enzymatic process approach based on a racemic mixture of D-and L-Phe, a microbial production of the pure enantiomer by fermentation could be advantageous for aspartame process optimisation.…”

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confidence: 67%

Integrated L-phenylalanine separation in an E. coli fed-batch process: from laboratory to pilot scale

Maass

et al. 2002

Bioprocess and Biosystems Engineering

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Pilot-scale reactive-extraction technology for fully integrated L-phenylalanine (L-Phe) separation in Escherichia coli fed-batch fermentations was investigated in order to prevent an inhibition of microbial L-Phe production by-product accumulation. An optimal reactive-extraction system, consisting of an organic kerosene phase with the cation-selective carrier DEHPA (di-2-ethylhexyl phosphonic acid) and an aqueous stripping phase including sulphuric acid, was found particularly efficient. Using this system with two membrane contactors, mass-transfer coefficients of up to 288 x 10(-7) cm s(-1) for the aqueous/organic and 77 x 10(-7) cm s(-1) for the organic/stripping phase were derived from experimental data using a simple modelling approach. Concentration factors higher than 4 were achieved in the stripping phase as compared to the aqueous donor phase. Reactive extraction enabled a 98% cation portion of L-Phe in the stripping phase, leading to final product purity higher than 99% after L-Phe precipitation. A doubling of L-Phe/glucose yield was observed when kerosene/DEHPA was added to the fermentation solution in the bioreactor to experimentally simulate a fully integrated L-Phe separation process.

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Synthetische nichtnutritive Süßstoffe

Cited by 19 publications

References 72 publications

Aromatic Chlorosulfonylation by Photoredox Catalysis

Aromatic Chlorosulfonylation by Photoredox Catalysis

Fully integrated L-phenylalanine separation and concentration using reactive-extraction with liquid-liquid centrifuges in a fed-batch process with E. coli

Integrated L-phenylalanine separation in an E. coli fed-batch process: from laboratory to pilot scale

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