Hindered diffusion of proteins and polymethacrylates in controlled-pore glass: An experimental approach

Ladero, Miguel; Santos, Aurora; Garcı́a-Ochoa, Félix

doi:10.1016/j.ces.2006.09.040

Cited by 11 publications

(10 citation statements)

References 35 publications

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“…This effect might be the result of a faster incubation with the enzyme (1 h) that promotes only the ionic adsorption of the enzyme on the outer surface of the PEI‐lignin. These results are in agreement with previously reported studies where enzymes immobilized predominantly on the exposed surface of the support (as opposed to those that diffuse through the porous matrix) display a higher activity due to better mass transfer ability from the bulk to the catalyst [33–35] . However, more sophisticated studies would be needed to decipher the exact effect observed.…”

Section: Resultssupporting

confidence: 92%

“…These results are in agreement with previously reported studies where enzymes immobilized predominantly on the exposed surface of the support (as opposed to those that diffuse through the porous matrix) display a higher activity due to better mass transfer ability from the bulk to the catalyst. [ 33 , 34 , 35 ] However, more sophisticated studies would be needed to decipher the exact effect observed. Nevertheless, the particle size of the TALD‐lignin is very similar to the acrylic microbeads as observed by microscopy, which facilitates comparison with previous work (Figure S4B).…”

Section: Resultsmentioning

confidence: 99%

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Dual Valorization of Lignin as a Versatile and Renewable Matrix for Enzyme Immobilization and (Flow) Bioprocess Engineering

et al. 2021

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Lignin has emerged as an attractive alternative in the search for more eco‐friendly and less costly materials for enzyme immobilization. In this work, the terephthalic aldehyde‐stabilization of lignin is carried out during its extraction to develop a series of functionalized lignins with a range of reactive groups (epoxy, amine, aldehyde, metal chelates). This expands the immobilization to a pool of enzymes (carboxylase, dehydrogenase, transaminase) by different binding chemistries, affording immobilization yields of 64–100 %. As a proof of concept, a ω‐transaminase reversibly immobilized on polyethyleneimine‐lignin is integrated in a packed‐bed reactor. The stability of the immobilized biocatalyst is tested in continuous‐flow deamination reactions and maintains the same conversion for 100 cycles. These results outperform previous stability tests carried out with the enzyme covalently immobilized on methacrylic resins, with the advantage that the reversibility of the immobilized enzyme allows recycling and reuse of lignin beyond the enzyme inactivation. Additionally, an in‐line system also based on lignin is added into the downstream process to separate the reaction products by catch‐and‐release. These results demonstrate a fully closed‐loop sustainable flow‐biocatalytic system based exclusively on lignin.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Dual Valorization of Lignin as a Versatile and Renewable Matrix for Enzyme Immobilization and (Flow) Bioprocess Engineering

et al. 2021

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“…In the literature, the values of porosity (ε) found for Novozym ® 435 were 0.35 [50], 0.5 [51], and 0.5 [4]; in this work, we have considered a value of ε = 0.5. Some authors have estimated that σ and τ for Novozym ® 435 are 1 and 6, respectively [51]; however, we considered the tortuosity equal to 12 and a constriction factor of 0.2, taking into account the nature of the support and the large size of the enzyme molecules, which could cause hindered diffusion [52].…”

Section: Internal Mass Transfermentioning

confidence: 99%

Synthesis of Ibuprofen Monoglyceride in Solventless Medium with Novozym®435: Kinetic Analysis

et al. 2020

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This study investigates the enzymatic esterification of glycerol and ibuprofen in a solventless medium catalyzed by immobilized lipase B from Candida antarctica (Novozym®435). Fixing the concentration of this enzymatic solid preparation at 30 g·L−1, and operating at a constant stirring speed of 720 rpm, the temperature was changed between 50 and 80 °C, while the initial concentration of ibuprofen was studied from 20 to 100 g·L−1. Under these conditions, the resistance of external mass transport can be neglected, as confirmed by the Mears criterion (Me < 0.15). However, the mass transfer limitation inside the pores of the support has been evidenced. The values of the effectiveness factor (η) vary between 0.08 and 0.16 for the particle size range considered according to the Weisz–Prater criteria. Preliminary runs permit us to conclude that the enzyme was deactivated at medium to high temperatures and initial concentration values of ibuprofen. Several phenomenological kinetic models were proposed and fitted to all data available, using physical and statistical criteria to select the most adequate model. The best kinetic model was a reversible sigmoidal model with pseudo-first order with respect to dissolved ibuprofen and order 2 with respect to monoester ibuprofen, assuming the total first-order one-step deactivation of the enzyme, with partial first order for ibuprofen and enzyme activity.

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“…For solutes that are large enough to behave as hydrodynamic particles, the constrained space of a nanochannel causes the molecular friction coefficient to exceed its maximum value and leads to steric exclusion. This kind of hindered diffusion has been extensively studied with neutral spheres in cylindrical nanopores 8,[13][14][15][16] . The equilibrium partitioning of solute concentration between inside and outside a nanoslit, assuming there is no surface close to the measurement volume outside the nanochannel, is given by 8,17 : …”

Section: Theorymentioning

confidence: 99%

Direct Observation of Transitions between Surface-Dominated and Bulk Diffusion Regimes in Nanochannels

et al. 2009

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Hindered diffusion of proteins and polymethacrylates in controlled-pore glass: An experimental approach

Cited by 11 publications

References 35 publications

Dual Valorization of Lignin as a Versatile and Renewable Matrix for Enzyme Immobilization and (Flow) Bioprocess Engineering

Dual Valorization of Lignin as a Versatile and Renewable Matrix for Enzyme Immobilization and (Flow) Bioprocess Engineering

Synthesis of Ibuprofen Monoglyceride in Solventless Medium with Novozym®435: Kinetic Analysis

Direct Observation of Transitions between Surface-Dominated and Bulk Diffusion Regimes in Nanochannels

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