Treated calcium pectinate beads for the covalent immobilization of β- d -galactosidase

Wahba, Marwa I.

doi:10.1016/j.ijbiomac.2016.06.044

Cited by 40 publications

(35 citation statements)

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“…Nevertheless, the most mechanically stable beads were the 0.8M NaHCO 3 ‐processed beads, which retained a whole of 94.92 ± 1.12% of their initial weight after the 1 min vortexing process. This value was close to the 96.57% weight retained after the 20 sec vortexing process of the calcium pectinate beads, which were coated with a layer of high molecular weight hyper branched polyethyleneimine and were also treated with GA in order to improve their mechanical stability . Upon employing the NaHCO 3 at a 1M concentration, the mechanical stability of the NaHCO 3 ‐processed beads started to drop as was evident from the 85.32 ± 1.85% retained weight percent…”

Section: Resultssupporting

confidence: 67%

“…This would enhance the gel's reaction with GA which would be beneficial as the cross‐linking of gels with GA was previously proven to improve their mechanical properties . Moreover, GA provided the reactive groups necessary to covalently immobilize enzymes . Accordingly, the enhanced GA reaction with the NaHCO 3 ‐gelled chitosan would be expected to improve both the gel's mechanical stability and immobilization ability.…”

Section: Introductionmentioning

confidence: 99%

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Sodium bicarbonate‐gelled chitosan beads as mechanically stable carriers for the covalent immobilization of enzymes

Wahba

2017

Biotechnology Progress

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The poor mechanical stability of chitosan has long impeded its industrial utilization as an immobilization carrier. In this study, the mechanical properties of chitosan beads were greatly improved through utilizing the slow rate of the sodium bicarbonate-induced chitosan gelation and combining it with the chemical cross-linking action of glutaraldehyde (GA). The GA-treated sodium bicarbonate-gelled chitosan beads exhibited much better mechanical properties and up to 2.45-fold higher observed activity of the immobilized enzyme (β-D-galactosidase (β-gal)) when compared to the GA-treated sodium tripolyphosphate (TPP)-gelled chitosan beads. The differences between the sodium bicarbonate-gelled and the TPP-gelled chitosan beads were proven visually and also via scanning electron microscopy, elemental analysis, and differential scanning calorimetry. Moreover, the optimum pH, the optimum temperature, the apparent K , and the apparent V of the β-gals immobilized onto the two aforementioned types of chitosan beads were determined and compared. A reusability study was also performed. This study proved the superiority of the sodium bicarbonate-gelled chitosan beads as they retained 72.22 ± 4.57% of their initial observed activity during the 13 reusability cycle whereas the TPP-gelled beads lost their activity during the first four reusability cycles, owing to their fragmentation. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:347-361, 2018.

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Section: Resultssupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Sodium bicarbonate‐gelled chitosan beads as mechanically stable carriers for the covalent immobilization of enzymes

Wahba

2017

Biotechnology Progress

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“…Imobilizacija v/na ustrezen medij lahko stabilizira encim na spremembe temperature in pH. Imobiliziran encim lahko večkrat uporabimo, kar zmanjša stroške zaradi ponovnega pridobivanja in čiščenja encima (Wahba, 2016). Namesto izolacije encima lahko imobiliziramo celice, v katerih se encim nahaja.…”

Section: Imobilizacijaunclassified

“…Imobilizirana β-galaktozidaza je ohranila 82 % prvotne aktivnosti po 15-ih zaporednih šaržah uporabe (Kishore in Kayastha, 2012). Wahba (2016) je kovalentno imobilizirala β-galaktozidazo iz nitastih gliv vrste A. oryzae na podlago iz kalcijevega pektinata, tretiranega s polietileniminom in glutaraldehidom. Po imobilizaciji β-galaktozidaze na omenjen nosilni material je encim pokazal premik optimalne temperature delovanja s 55 °C (Vera in sod., 2011) na 60 °C ter večjo toleranco na visoke temperature.…”

Section: Imobilizacijaunclassified

“…Optimalni pH delovanja imobiliziranega encima je v širšem območju pH vrednosti pomaknjen k bolj kislim vrednostim (3,2-5,4) v primerjavi z optimalno pH vrednostjo delovanja samega izoliranega encima (5,3). Gel iz kalcijevega pektinata, tretiranega s polietileniminom in glutaraldehidom, je zaradi svoje mehanske stabilnosti in ugodnega vpliva na aktivnost encima primeren za industrijske aplikacije (Wahba, 2016). Huerta in sod.…”

Section: Imobilizacijaunclassified

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Potential applicaton of β-galactosidase in food science and nutrition

Žibrat

Skrt

Jamnik

2017

AAS

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3 Isti naslov kot: 1 Uporaba β-galaktozidaze na področju živilstva in prehrane β-galaktozidaza je encim s hidrolitično in transgalaktozilacijsko aktivnostjo. Vrsta aktivnosti je odvisna od izvora encima. V industriji uporabljene β-galaktozidaze so pridobljene z rekombinantno produkcijo iz nitastih gliv Aspergillus sp. in kvasovk Kluyveromyces sp. V zadnjem času se vedno bolj preučujejo β-galaktozidaze, ki optimalno delujejo pri nizkih ali visokih temperaturah. V industrijskih procesih se β-galaktozidaza uporablja v obliki prostega encima ali v imobilizirani obliki. Imobilizacija pogosto ponuja večjo stabilnost encima, možnost ponovne uporabe ter znižanje stroškov. β-galaktozidaza se pretežno uporablja na področju živilstva in prehrane, v zadnjem času pa ima znatno vlogo tudi v medicini. Hidrolitična aktivnost β-galaktozidaze se že dolgo izkorišča za zmanjšanje vsebnosti laktoze v mleku, medtem ko z reakcijami transgalaktozilacije iz laktoze lahko sintetiziramo različne produkte, kot so galaktooligosaharidi, laktosaharoza in drugi. Prav slednji imajo velik potencial v živilski industriji zaradi pridobivanja izdelkov z zmanjšano vsebnostjo laktoze in izboljšanja prehranske vrednosti živil s proizvodnjo galaktooligosaharidov. Kljub temu je potrebno bolje razumeti reakcijske mehanizme kot tudi optimizirati procese, da bo uporaba encima za ta namen dosegla industrijsko raven.Ključne besede: prehrana ljudi; živilska industrija; živil-stvo; encimi; beta-galaktozidaza Potential applicaton of β-galactosidase in food science and nutrition β-galactosidase is an enzyme with hydrolytic and transgalactosylation activity. The origin of the enzyme dictates the balance between both activities. Industrially used β-galactosidases are obtained with recombinant production from filamentus funghi Aspergillus sp. and yeasts Kluyveromyces sp. Recently thermostabile β-galactosidases have been subject of many research. The enzyme can be industrially used in free or immobilized form. Immobilization often provides better stability, reusability and lower expenses. Application of β-galactosidase is most common in food processing and nutrition, it is also used in medicine and ecology. Hydrolytic activity of the enzyme has long been used for reducing lactose content in milk, while transgalactosylitic activity is used for synthesis of products such as galactooligosaccharides, lactosucrose and others. The latter have a great potential in food industry for obtaining products with reduced lactose content and increasing of nutritional value by adding dietetic fibers such as galactooligosaccharides. Despite the potential it is vital that reaction mechanisms become better understood and optimization is in place in order to reach the usability of this enzyme at industrial level.

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