Abstract
Ni2+-NTA-boosted magnetic porous silica nanoparticles (Ni@MSN) to serve as ideal support for bi-functional enzyme were fabricated for the first time. The versatility of this support was validated by one-step purification and immobilization of bi-functional enzyme MLG consisting of 3-Quinuclidinone reductase and glucose dehydrogenase, which can simultaneously catalyze both carbonyl reduction and cofactor regeneration, to fabricate an artificial bi-functional nanobiocatalyst (namely, MLG-Ni@MSN). The enzyme loading of 71.7 mg/g support and 92.7% immobilization efficiency were obtained. Moreover, the immobilized MLG showed wider pH and temperature tolerance and greater storage stability than free MLG under the same conditions. The nanosystem was employed as biocatalyst to accomplish the 3-quinuclidinone (70 g/L) to (R)-3-quinuclidinol biotransformation in 100% conversion yield with >99% selectivity within 6 h and simultaneous cofactor regeneration. Furthermore, the immobilized MLG retained up to 80.3% (carbonyl reduction) and 78.0% (cofactor regeneration) of the initial activity after being recycled eight times. In addition, the MLG-Ni@MSN system exhibited almost no enzyme leaching during biotransformation and recycling. Therefore, we have reason to believe that the Ni@MSN support gave great promise for constructing a new biocatalytic nanosystem with multifunctional enzymes to achieve some other complex bioconversions.
Highlights
Nanoparticles are widely applied in biomedical and industrial fields due to their unique features such as their porous nature and high surface area [1]
The immobilization based on Ni-nitrilotriacetic acid (NTA)-functionalized magnetic or porous silica nanoparticles can overcome some limitations of IMAC such as poor mechanical stability, limited surface area of agarose bead accessible for binding, etc. [24]
>99.9 a Loading refers to the mass ratio of biocatalysts to substrate. b The mixture of the same amount of purified MLG was fabricated by linking 3-quinuclidinone reductase (MlQR) and glucose dehydrogenase (GDH) used as control experiment
Summary
Nanoparticles are widely applied in biomedical and industrial fields due to their unique features such as their porous nature and high surface area [1]. Extensive research efforts have revealed that porous support is an attractive candidate for enzyme immobilization due to chemical and thermal stability, large surface areas, and tunable pore structures capable of entrapping various enzymes within them, which afford a more stable environment compared with that of a planar surface [3,9,11]. The enzyme immobilized onto porous support in many cases exhibits reduced activity compared with those of the free enzyme and cannot be efficiently recycled due to the enzyme leaching during multiple reuses. The immobilization based on Ni-NTA-functionalized magnetic or porous silica nanoparticles can overcome some limitations of IMAC such as poor mechanical stability, limited surface area of agarose bead accessible for binding, etc. NFi.guFrigeu2rde d2idsdpilsapylaeydetdhethienifnlufleunecneceofomf masasssrartaitoiooof fssuuppppoorrttttoottoottaall proteins on tthhee iimmmmoobbiilliizzaattiioonn..AA rriisseeiinntthheemmaassssrraattioioffrroomm1122:1:1toto1144:1:1ggaavveeaaslsilgighht tinincrceraesaeseininSSEELLfrformom707.08.8toto717.17.7mmg/gg/g ssuuppppoorrtt aanndd an obvious innccrreeaassee ooffEELLEEffrroomm8855.6.6%%toto929.27.%7%. FFiigguurree77..EEffffeeccttooffppHH,,tetemmppeerraatuturere, ,aannddlolonngg-t-etremrmstsotroargaegepepreiroidodononthteheacatcivtiivtyityofoMf MlQlRQRanadndGDH sGubDuHnistubbeufonriet baenfdoraeftaenrdimamfteorbiimlizmatoiboinli;z(aat)iopnH; ;(a(b) )ptHem; (pbe)rtaetmurpee;r(act)uloren;g(-ct)elromngs-ttoerramgesstotarbagileitys.tability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
