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dc.creatorMenghiu, Gheorghita
dc.creatorOstafe, Vasile
dc.creatorProdanović, Radivoje
dc.creatorFischer, Rainer
dc.creatorOstafe, Raluca
dc.date.accessioned2021-04-26T09:34:18Z
dc.date.available2021-04-26T09:34:18Z
dc.date.issued2021
dc.identifier.issn1422-0067
dc.identifier.urihttps://www.mdpi.com/1422-0067/22/6/3041
dc.identifier.urihttps://cherry.chem.bg.ac.rs/handle/123456789/4393
dc.description.abstractChitinases catalyze the degradation of chitin, a polymer of N-acetylglucosamine found in crustacean shells, insect cuticles, and fungal cell walls. There is great interest in the development of improved chitinases to address the environmental burden of chitin waste from the food processing industry as well as the potential medical, agricultural, and industrial uses of partially deacetylated chitin (chitosan) and its products (chito-oligosaccharides). The depolymerization of chitin can be achieved using chemical and physical treatments, but an enzymatic process would be more environmentally friendly and more sustainable. However, chitinases are slow-acting enzymes, limiting their biotechnological exploitation, although this can be overcome by molecular evolution approaches to enhance the features required for specific applications. The two main goals of this study were the development of a high-throughput screening system for chitinase activity (which could be extrapolated to other hydrolytic enzymes), and the deployment of this new method to select improved chitinase variants. We therefore cloned and expressed the Bacillus licheniformis DSM8785 chitinase A (chiA) gene in Escherichia coli BL21 (DE3) cells and generated a mutant library by error-prone PCR. We then developed a screening method based on fluorescence-activated cell sorting (FACS) using the model substrate 4-methylumbelliferyl β-d-N,N′,N″-triacetyl chitotrioside to identify improved enzymes. We prevented cross-talk between emulsion compartments caused by the hydrophobicity of 4-methylumbelliferone, the fluorescent product of the enzymatic reaction, by incorporating cyclodextrins into the aqueous phases. We also addressed the toxicity of long-term chiA expression in E. coli by limiting the reaction time. We identified 12 mutants containing 2–8 mutations per gene resulting in up to twofold higher activity than wild-type ChiA.
dc.languageen
dc.publisherMDPI
dc.relationG. Menghiu acknowledges support from the strategic grant POSDRU/159/1.5/S/137750: Project “Doctoral and postdoctoral programs support for increased competitiveness in exact sciences research” co-financed by the European Social Fund within the Sectorial Operational Program Human Resources Development 2007–2013. This research was funded by the GRANT PNIII-P3- 284, ChitoWound—Biotechnological tools implementation for new wound healing applications of byproducts from the crustacean seafood processing industry.
dc.relation.isversionofhttps://doi.org/10.3390/ijms22063041
dc.relation.isreferencedbyhttps://cherry.chem.bg.ac.rs/handle/123456789/4394
dc.rightsopenAccess
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.sourceInternational Journal of Molecular Sciences
dc.subjectbactericidal effect
dc.subjecterror-prone PCR
dc.subjectFACS
dc.subjectfluorescence assay
dc.subjectimproved enzymes
dc.subjectmutants
dc.subjectprotein engineering
dc.titleA High-Throughput Screening System Based on Fluorescence-Activated Cell Sorting for the Directed Evolution of Chitinase A
dc.typearticleen
dc.rights.licenseBY
dcterms.abstractПродановић, Радивоје; Фисцхер, Раинер; Остафе, Ралуца; Менгхиу, Гхеоргхита; Остафе, Василе;
dc.citation.volume22
dc.citation.issue6
dc.citation.spage3041
dc.identifier.wos000645728100001
dc.identifier.doi10.3390/ijms22063041
dc.citation.rankM21~
dc.description.otherSupplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4394]
dc.type.versionpublishedVersion
dc.identifier.scopus2-s2.0-85102521701
dc.identifier.fulltexthttps://cherry.chem.bg.ac.rs/bitstream/id/26887/A_High-Throughput_Screening_pub_2021.pdf


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