Chemically Engineered Whole-cell Surface for Cascade Catalysis

Jian Ning

doi:10.21996/6ky1-fw17

Chemically Engineered Whole-cell Surface for Cascade Catalysis

Jian Ning

Publikation: Afhandling › Ph.d.-afhandling

Abstract

Kombinationen af enzym og kemokatalysator til kemoenzymatisk kaskade har tiltrukket sig meget opmærksomhed i løbet af de sidste par årtier, fordi den drager fordel af høj selektivitet af enzymer og robust alsidig reaktivitet af kemokatalysator. På trods af mange fordele er enzymer let at blive deaktiveret af det ydre barske miljø. Derudover er genanvendelse af enzymer også en udfordring. For at imødegå disse begrænsninger leverede vi en strategi for at konstruere levende celler udtrykt med enzymer indeni med syntetiske katalysatorer af interessante for kemoenzymatisk kaskade, som kan beskytte enzymer mod barske tilstande og gøre enzymer let at genbruge.

Specifikt blev en et-trins in-situ atom transfer radikal polymerisation (ATRP) anvendt til at pode de syntetiske katalytiske polymerer (fotokatalysator og organometallisk katalysator) fra levende E. coli-cellers overflade. De resulterende polymerer kan beskytte enzymer inde i cellen mod UV-bestråling, varme, pH og organiske opløsningsmidler. Desuden, som et proof-of-concept, blev den fotoenzymatiske kaskadereaktion udført af enzym inde i cellen og fotokatalysator på celleoverfladen, hvilket gav 15 gange højere biokonvertering end upolymeriserede kontrolsystemer. Derudover blev katalysatorerne inklusive enzymer og fotokatalysator simpelthen genbrugt i fotoenzymatisk kaskadereaktion ved centrifugering med høj aktivitet.

Derudover blev lag-for-lag indkapslingen også brugt til at fastgøre den syntetiske katalysator (porphyrin) på levende E. coli-cellers overflade. Lagene dannet af alginat beskytter porphyrin mod udvaskning, mens de beskytter cellerne mod UV-bestråling, varme og pH-forhold. Desuden kan den kemoenzymatiske kaskadereaktion udføres ved kombination af porphyrin med CalB-enzym, hvilket giver over 9 gange højere
biokonvertering end kontrolsystemer. Derudover kan genanvendelsen af porphyrin lettes af denne LBL-indkapsling. Således præsenterer vores resultater en enkel og alsidig strategi til effektivt at konstruere cellemembraner til kemoenzymatisk kaskade.

Originalsprog	Engelsk
Bevilgende institution	Syddansk Universitet
Vejledere/rådgivere	Wu, Changzhu, Hovedvejleder
Dato for forsvar	17. jan. 2024
Udgiver	Syddansk Universitet. Det Naturvidenskabelige Fakultet
DOI	https://doi.org/10.21996/6ky1-fw17
Status	Udgivet - 9. jan. 2024

Note vedr. afhandling

Afhandlingen kan læses på SDUs bibliotek. 

Dokumenter og links

10.21996/6ky1-fw17

Citationsformater

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abstract = "The combination of enzyme and chemocatalyst for chemoenzymatic cascade has attracted much attention over the past few decades because it takes advantage of high selectivity of enzymes and robust versatile reactivity of chemocatalyst. Despite many advantages, enzymes are easily to be deactivated by the external harsh environment. In addition, the recycling of enzymes is a challenge. To address these limitations, we provided a strategy of engineering living cell expressed with enzymes inside with synthetic catalysts of interesting for chemoenzymatic cascade, which can protect enzymes from harsh condition and make enzymes to be easily reused. Specifically, a one-step in-situ atom transfer radical polymerization (ATRP) was applied to graft the synthetic catalytic polymers (photocatalyst and organometallic catalyst) from living E. coli cells surface. The resultant polymers can protect enzymes inside cell from UV irradiation, heat, pH, and organic solvents. Moreover, as a proof-of-concept, the photoenzymatic cascade reaction was conducted by enzyme inside cell and photocatalyst on the cell surface, yielding 15 times higher bioconversion than unpolymerized control systems. Additionally, the catalysts including enzymes and photocatalyst were simply reused in photoenzymatic cascade reaction by centrifugation with high activity.In addition, the layer-by-layer encapsulation was also used to attach the synthetic catalyst (porphyrin) on living E. coli cells surface. The layers formed by alginate protect porphyrin from leaching, while protecting cells from UV irradiation, heat, and pH conditions. Moreover, the chemoenzymatic cascade reaction can be conducted by combination of porphyrin with CalB enzyme, yielding over 9 times higher bioconversion than control systems. Additionally, the recycling of porphyrin can be facilitated by this LBL encapsulation. Thus, our findings present a simple and versatile strategy for efficiently engineering cell membranes for chemoenzymatic cascade.",

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AB - The combination of enzyme and chemocatalyst for chemoenzymatic cascade has attracted much attention over the past few decades because it takes advantage of high selectivity of enzymes and robust versatile reactivity of chemocatalyst. Despite many advantages, enzymes are easily to be deactivated by the external harsh environment. In addition, the recycling of enzymes is a challenge. To address these limitations, we provided a strategy of engineering living cell expressed with enzymes inside with synthetic catalysts of interesting for chemoenzymatic cascade, which can protect enzymes from harsh condition and make enzymes to be easily reused. Specifically, a one-step in-situ atom transfer radical polymerization (ATRP) was applied to graft the synthetic catalytic polymers (photocatalyst and organometallic catalyst) from living E. coli cells surface. The resultant polymers can protect enzymes inside cell from UV irradiation, heat, pH, and organic solvents. Moreover, as a proof-of-concept, the photoenzymatic cascade reaction was conducted by enzyme inside cell and photocatalyst on the cell surface, yielding 15 times higher bioconversion than unpolymerized control systems. Additionally, the catalysts including enzymes and photocatalyst were simply reused in photoenzymatic cascade reaction by centrifugation with high activity.In addition, the layer-by-layer encapsulation was also used to attach the synthetic catalyst (porphyrin) on living E. coli cells surface. The layers formed by alginate protect porphyrin from leaching, while protecting cells from UV irradiation, heat, and pH conditions. Moreover, the chemoenzymatic cascade reaction can be conducted by combination of porphyrin with CalB enzyme, yielding over 9 times higher bioconversion than control systems. Additionally, the recycling of porphyrin can be facilitated by this LBL encapsulation. Thus, our findings present a simple and versatile strategy for efficiently engineering cell membranes for chemoenzymatic cascade.

KW - Engineered whole cell

KW - cascade catalysis

U2 - 10.21996/6ky1-fw17

DO - 10.21996/6ky1-fw17

M3 - Ph.D. thesis

PB - Syddansk Universitet. Det Naturvidenskabelige Fakultet

ER -

Chemically Engineered Whole-cell Surface for Cascade Catalysis

Abstract

Note vedr. afhandling

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