In:
Waste and Biomass Valorization, Springer Science and Business Media LLC, Vol. 13, No. 12 ( 2022-12), p. 4823-4837
Kurzfassung:
Enzyme cost and stability are the main problems facing industrial applications. Consequently, Aspergillus niger NRC1ami was isolated from rotten orange and recorded a promising pectinase activity (13.8 U/ml). The enzyme was optimized using citrus peel pectin as the sole carbon source and recorded (40 U/ml). It was purified by two steps purifications and recorded 632 purification folds. The pure enzyme showed 14.7% carbohydrate content and consists of 15 amino acids. Glutamic acid was the major (22%) followed by leucine (10.67%) and threonine was the minor (2.70%). A. niger NRC1ami pectinase was conjugated by covalent coupling to sodium periodate (NaIO 4 ) activated polysaccharides. Galactomannan showed the highest recovered activity (85%) and 94.34% reduction in viscosity. The optimum temperature for the pure enzyme shifted from 40 to 45 °C after the conjugation process. Also, the free enzyme showed its optimum activity at pH 5 compared to pH 4, 5 in the conjugated form case. The thermal stability of the free enzyme greatly improved after the modification process. The conjugated process reduced the activation energy to 36%, prolonged the enzyme half-life 5.6-fold at 60 °C, and increase the deactivation energy (Ed) by about 19% in comparison to the free form. The D value of the conjugated enzyme increased to 13.2-fold at 50 °C compared to the free form. Gibbs's free energy (ΔG) of the enzyme increased after the modification process, while the enthalpy (ΔH) and entropy (ΔS) decreased. Na + and Zn 2+ had a stimulating effect on both enzyme forms. Graphical Abstract
Materialart:
Online-Ressource
ISSN:
1877-2641
,
1877-265X
DOI:
10.1007/s12649-022-01838-2
Sprache:
Englisch
Verlag:
Springer Science and Business Media LLC
Publikationsdatum:
2022
ZDB Id:
2541900-6
