An update on smart biocatalysts for industrial and biomedical applications

Abstract

Recently, smart biocatalysts, where enzymes are conjugated to stimuli-responsive (smart) polymers, have gained significant attention. Based on the presence or absence of external stimuli, the polymer attached to the enzyme changes its conformation to protect the enzyme from the external environment and regulate the enzyme activity, thus acting as a molecular switch. Owing to this behaviour, smart biocatalysts can be separated easily from a reaction mixture and re-used several times. Several such smart polymer-based biocatalysts have been developed for industrial and biomedical applications. In addition, they have been used in biosensors, biometrics and nano-electronic devices. This review article covers recent advances in developing different kinds of stimuli-responsive enzyme bioconjugates, including conjugation strategies, and their applications.

Protein‐inorganic calcium‐phosphate supraparticles as a robust platform for enzyme co‐immobilization

“…The overall high retention of unbound activity upon immobilization compares well with other successful immobilization systems such as EziG (Böhmer et al, 2019). In the case of the upward shift of for AmDHZ E , this is a common feature of immobilization into porous materials due to potential diffusion limitations (Shakya & Nandakumar, 2018; Zdarta et al, 2018). The increase of these values is not considered detrimental for future applications.…”

“…Encapsulation methods are often broadly applicable to many enzymes (Espanol, Casals, Lamtahri, Valderas, & Ginebra, 2012; Fujita et al, 2012; Gupta et al, 2016; Nguyen, Qiao, & Olvera de la Cruz, 2018). However, encapsulation can inhibit enzyme motion or diffusion of substrate, product or cofactors, leading to a decrease in catalytic efficiency (Fu & Kao, 2010; Macha et al, 2019; Shakya & Nandakumar, 2018). Crosslinked enzyme aggregates or crystals are another class of “immobilization” (Kowalski et al, 2019; Sheldon, 2007, 2011).…”

Polymer supports for the removal and degradation of hazardous organic pollutants: an overview

“…Smart or stimuli‐responsive polymers are polymers that react to small changes in the medium such as changes in pH, temperature, light, magnetic field and ionic strength . These polymers protect the enzyme through reversible changes in the conformation, conserving the activity in the immobilized enzyme because its structure is not modified . However, the most studied thermoresponsive polymer is probably P(NIPAm).…”

“…Additionally, some polyelectrolyte brushes have been developed using poly(2‐vinylpyridine) and mixtures with methacrylic acid, which change their conformation in response to changes in the pH of the medium . Like thermoresponsive polymers, pH‐responsive polymers also have reversible phase transition properties causing solubility and insolubility as the response to the medium changes . In general, the immobilization on these polymers generates good properties in the immobilized enzymes, eliminates diffusional problems, allows their reuse after enzyme deactivation, and preserves a high activity in the enzyme.…”

“…108 These polymers protect the enzyme through reversible changes in the conformation, conserving the activity in the immobilized enzyme because its structure is not modified. 109 However, the most studied thermoresponsive polymer is probably P(NIPAm). This polymer presents a lower critical solution temperature of approximately 32°C.…”