A novel strain of Stenotrophomonas acidaminiphila produces thermostable alkaline peptidase on agro-industrial wastes: process optimization, kinetic modeling and scale-up

Asitok, Atim; Ekpenyong, Maurice; Takon, Iquo; Antai, S. P.; Ogarekpe, Nkpa; Antigha, Richard; Edet, Philomena; Antai, Agnes; Essien, Joseph P.

doi:10.1007/s00203-022-03010-9

Cited by 5 publications

(1 citation statement)

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“…Design of experiments for optimization of nutritional, environmental and bioprocess operational conditions by response surface methodology—a statistical approach that is limited to addressing non-noisy quadratic functions—has been copiously reported (Farjaminezhad and Garoosi 2021 ; Asitok et al 2022c ). However, a significant part of process variations owing to input–output interactions is non-linear and stochastic, and may require neural network approaches for elucidation (Ekpenyong et al 2021a ; Asitok et al 2022d ).…”

Section: Introductionmentioning

confidence: 99%

Production, characterization and techno-economic evaluation of Aspergillus fusant l-asparaginase

et al. 2023

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Protoplast fusion is one of the most reliable methods of introducing desirable traits into industrially-promising fungal strains. It harnesses the entire genomic repertoire of fusing microorganisms by routing the natural barrier and genetic incompatibility between them. In the present study, the axenic culture of a thermo-halotolerant strain of Aspergillus candidus (Asp-C) produced an anti-leukemic l-asparaginase (l-ASNase) while a xylan-degrading strain of Aspergillus sydowii (Asp-S) produced the acrylamide-reduction type. Protoplast fusion of the wild strains generated Fusant-06 with improved anti-leukemic and acrylamide reduction potentials. Submerged fed-batch fermentation was preferred to batch and continuous modes on the basis of impressive techno-economics. Fusant-06 l-ASNase was purified by PEG/Na+ citrate aqueous two-phase system (ATPS) to 146.21-fold and global sensitivity analysis report revealed polymer molecular weight and citrate concentration as major determinants of yield and purification factor, respectively. The enzyme was characterized by molecular weight, amino acid profile, activity and stability to chemical agents. Michaelis–Menten kinetics, evaluated under optimum conditions gave Km, Vmax, Kcat, and Kcat/Km as 6.67 × 10–5 M, 1666.67 µmolmin−1 mg−1 protein, 3.88 × 104 min−1 and 5.81 × 108 M−1.min−1 respectively. In-vitro cytotoxicity of HL-60 cell lines by Fusant-06 l-ASNase improved significantly from their respective wild strains. Stability of Fusant-06 l-ASNase over a wide range of pH, temperature and NaCl concentration, coupled with its micromolar Km value, confers commercial and therapeutic value on the product. Free-radical scavenging and acrylamide reduction activities were intermediate and the conferred thermo-halo-stability could be exploited for sustainable clinical and food industry applications.

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