Real-time measurement and modeling of intraparticle pH gradient formation in immobilized cephalosporin C amidase

Zahel, Thomas; Boniello, Caterina; Nidetzky, Bernd

doi:10.1016/j.procbio.2012.12.003

Cited by 12 publications

(16 citation statements)

References 25 publications

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“…Results of characterization of immobilized enzymes with internal sensing methods support the idea that determination of kinetic and mass-transfer parameters for heterogeneous biocatalysts is strongly supported when the available evidence is not just from the external environment [178]. Internal sensing also provides a powerful tool to distinguish effects of the immobilization on the intrinsic enzyme activity from mass transfer effects [180].…”

Section: Mesoporous Carriers Stability Of Attachment Of Lipases In Comentioning

confidence: 68%

Advanced characterization of immobilized enzymes as heterogeneous biocatalysts

2016

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Section: Mesoporous Carriers Stability Of Attachment Of Lipases In Comentioning

confidence: 68%

Advanced characterization of immobilized enzymes as heterogeneous biocatalysts

2016

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“…Space‐averaged intraparticle pH has been measured for the characterization of heterogeneous biocatalysts involving systematic biotransformations optimization, reaction modelling, reaction control and determination of kinetic and mass transfer parameters . The hydrolysis of β‐lactam substrates (which results in net proton formation) was studied by using FITC‐labeled immobilized amidase in order to quantify the extent of the overall carrier acidification during the operation .…”

Section: Spatio‐temporal Resolution Of O2 and Ph Within Immobilized Ementioning

confidence: 99%

“…Combination of internal data and external data for reaction modelling was then possible and facilitates process understanding and targeted reactor selection . Moreover, the determination of intrinsic kinetic parameters and mass transfer coefficients within porous materials is strongly supported when intraparticle concentrations are used instead of uniquely external data . Recently, lifetime measurements (dual‐lifetime referencing method, DLR) have improved the pH resolution and served to study the influence of the carrier properties on the pH drop and monitor the reaction time course.…”

Section: Spatio‐temporal Resolution Of O2 and Ph Within Immobilized Ementioning

confidence: 99%

“…Space-averaged intraparticle pH has been measured for the characterization of heterogeneous biocatalystsi nvolving systematicb iotransformationso ptimization, reaction modelling, reactioncontrol and determination of kinetic and mass transfer parameters. [17,18,[115][116][117][118][119][120] The hydrolysiso fb-lactams ubstrates (which results in net proton formation) was studied by using FITC-labeled immobilized amidase in order to quantify the extento ft he overall carriera cidification during the operation. [121] The internal pH was determined from pH-sensitive fluorescencei ntensity of FITC, showing ap Hd ifferenceo f3units between the bulk and the interioro ft he particles.…”

Section: Resolution Of Intraparticlephmentioning

confidence: 99%

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Single‐Particle Studies to Advance the Characterization of Heterogeneous Biocatalysts

et al. 2018

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Immobilized enzymes have been widely exploited because they work as heterogeneous biocatalysts, allowing their recovery and reutilization and easing the downstream processing once the chemical reactions are completed. Unfortunately, we suffer a lack of analytical methods to characterize those heterogeneous biocatalysts at microscopic and molecular levels with spatio‐temporal resolution, which limits their design and optimization. Single‐particle studies are vital to optimize the performance of immobilized enzymes in micro/nanoscopic environments. In this Concept article, we review different analytical techniques that address single‐particle studies to image the spatial distribution of the enzymes across the solid surfaces, the sub‐particle substrate diffusion, the structural integrity and mobility of the immobilized enzymes inside the solid particles, and the pH and O2 internal gradients. From our view, such sub‐particle information elicited from single‐particle analysis is paramount for the design and fabrication of optimal heterogeneous biocatalyst.

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“…For reactions catalyzed by proton‐forming enzymes (e.g., penicillin acylase and glucose oxidase), a proton concentration gradient means that the intraparticle pH of the immobilized enzymes is different from the bulk pH, even if alkali is added to control the bulk pH. Theoretical studies and experimental visual inspection of pH gradients in immobilized enzyme catalysis have been performed, including those in proton‐forming reactions . Although reaction pH may affect the apparent enzyme kinetics and protein structure, research on the regulation of microenvironmental pH, which affects the activity and stability of enzymes, is very limited.…”

Section: Introductionmentioning

confidence: 99%

Application of ammonium bicarbonate buffer as a smart microenvironmental pH regulator of immobilized cephalosporin C acylase catalysis in different reactors

Chang

Tong

Luo

et al. 2019

Biotechnology Progress

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In a stirred tank reactor, during catalysis with immobilized cephalosporin C acylase (CCA), the microenvironmental pH dropped to 7.2 in a nonbuffered system (with the pH maintained at 8.5 by adding alkali) due to the existence of diffusional resistance. Moreover, the immobilized CCA only catalyzed five batch reactions, suggesting that the sharp pH gradient impaired the enzyme stability. To buffer the protons produced in the hydrolysis of cephalosporin C by CCA, phosphate and bicarbonate buffers were introduced. When CCA was catalyzed with 0.1 M ammonium bicarbonate buffer, no obvious gradient between the bulk solution and intraparticle pH was detected, and the catalysis of 15 batch reactions was achieved. Accordingly, with 0.2 M ammonium bicarbonate buffer in a packed bed reactor, the immobilized CCA exhibited continuous catalysis with high conversion rates (≥95%) for 21 days. Reactions with ammonium bicarbonate buffer showed significant increases in the stability and catalytic efficiency of the immobilized CCA in different reactors compared to those in nonbuffered systems.

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Real-time measurement and modeling of intraparticle pH gradient formation in immobilized cephalosporin C amidase

Cited by 12 publications

References 25 publications

Advanced characterization of immobilized enzymes as heterogeneous biocatalysts

Advanced characterization of immobilized enzymes as heterogeneous biocatalysts

Single‐Particle Studies to Advance the Characterization of Heterogeneous Biocatalysts

Application of ammonium bicarbonate buffer as a smart microenvironmental pH regulator of immobilized cephalosporin C acylase catalysis in different reactors

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