Microbial Cell Factories (Dec 2024)

Aspergillus foetidus as a potent producer for β-galactosidase utilizing lemon peels and coffee waste powder: production optimization, purification, kinetic and thermodynamic characterization

  • Walaa A. Abdel Wahab,
  • Shireen A. A. Saleh,
  • Nermeen H. Elzairy,
  • Samia A. Ahmed,
  • Eman R. Zaki,
  • Walaa H. Salama,
  • Faten A. Mostafa

DOI
https://doi.org/10.1186/s12934-024-02600-0
Journal volume & issue
Vol. 23, no. 1
pp. 1 – 13

Abstract

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Abstract Background The main obstacle facing the utilization of microbial enzymes in industrial applications is the high cost of production substrates. As a result of the mentioned different wastes (coffee powder waste, dates nawah powder, molokhia stems, pea peels, lemon peels, and corn cobs) were investigated as low-cost nutritional substrates for the production of microbial β-galactosidase in this study. The purification of the enzyme and its kinetic and thermodynamics were investigated. Results β-galactosidase was effectively produced by Aspergillus foetidus utilizing lemon peels and coffee powder waste by solid-state fermentation technique. The production yield was improved through Plackett-Burman Design declaring the significant effect of lemon peels and coffee waste powder, and beef extract quantities on A. foetidus β-galactosidase production. Followed by Central Composite Design investigating each factor with five levels resulting in 37363.1 U.ml− 1 production. The enzyme was fully purified by gel filtration technique through Sephadex G-150 giving one band with a molecular weight 40 KDa on SDS-PAGE gel. The maximal β-galactosidase activity was obtained at 50 °C with 0.4% ONPG. Cu2+, Fe2+, and Hg2+ showed severe inhibitory effect on pure enzyme activity. Energy required for enzyme activation (Ea) and denaturation (Ed) were determined to be 17.40, and 43.86 KJ.mol− 1, respectively. Parameters reflecting β-galactosidase thermal stability at 40, 45, and 50 °C as T1/2 and D-values values were determined to be 283.92, 209.43, and 168.56 min, and 943.34, 695.84, and 560.06 min, respectively.

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