| Autor: |
Asitok, Atim, Ekpenyong, Maurice, Akwagiobe, Ernest, Asuquo, Marcus, Rao, Anitha, Ubi, David, Iheanacho, Juliet, Ikharia, Eloghosa, Antai, Agnes, Essien, Joseph, Antai, Sylvester |
| Předmět: |
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| Zdroj: |
Preparative Biochemistry & Biotechnology; 2023, Vol. 53 Issue 7, p827-840, 14p |
| Abstrakt: |
The axenic culture of Aspergillus candidus (Asp-C) produced an anti-leukemic L-asparaginase while Aspergillus sydowii (Asp-S) produced the acrylamide-reduction type. Upon mutagenesis by atmospheric and room-temperature plasma (ARTP), their individual L-asparaginase activities improved 2.3-folds in each of Ile-Thr-Asp-C-180-K and Val-Asp-S-180-E stable mutants. Protoplast fusion of selected stable mutants generated fusant-09 with improved anti-leukemic activity, acrylamide reduction, higher temperature optimum and superior kinetic parameters. Submerged (SmF) and solid-state fermentation (SSF) types were compared; likewise batch, fed-batch and continuous fermentation modes; and fed-batch submerged fermentation was selected on the basis of impressive techno-economics. Fusant L-asparaginase was purified by PEG/Na+ citrate aqueous two-phase system and molecular exclusion chromatography to 69.96 and 146.21-fold, respectively, and characterized by molecular weight, specificity, activity and stability to chemical and physical agents. Michaelis–Menten kinetics, evaluated under optimum conditions gave Km, Vmax, Kcat, and Kcat/Km as 1.667 × 10−3 M, 1666.67 µmol min−1 mg−1 protein, 645.99 s−1 and 3.88 × 105 M−1 s−1 respectively. In-vitro cytotoxicity of HL-60 cell lines by fusant-09 L-asparaginase improved 3.00 and 18.71-folds from mutants Ile-Thr-Asp-C-180-K and Val-Asp-S-180-E, and from 5.73 and 32.55 from respective original strains. Free-radical scavenging and acrylamide reduction improvements were intermediate. Fusant-09 L-asparaginase is strongly recommended for sustainable economic anti-leukemic and food industry applications. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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