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

• Published in: Microbial cell factories 2024-12, Vol.23 (1)
• Main Authors: Wahab, Walaa A. Abdel, Saleh, Shireen A. A, Elzairy, Nermeen H, Ahmed, Samia A, Zaki, Eman R, Salama, Walaa H, Mostafa, Faten A
• Format: Article
• Language: English
• Subjects: Aspergillus; Control; Denaturation; Dextran; Enzymes; Ethylenediaminetetraacetic acid; Fermentation; Identification and classification; Methods; Production processes; Proteins; Thermodynamics
• ISSN: 1475-2859; 1475-2859
• DOI: 10.1186/s12934-024-02600-0

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 [beta]-galactosidase in this study. The purification of the enzyme and its kinetic and thermodynamics were investigated. [beta]-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 [beta]-galactosidase production. Followed by Central Composite Design investigating each factor with five levels resulting in 37363.1 U.ml.sup.- 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 [beta]-galactosidase activity was obtained at 50 °C with 0.4% ONPG. Cu.sup.2+, Fe.sup.2+, and Hg.sup.2+ showed severe inhibitory effect on pure enzyme activity. Energy required for enzyme activation (E.sub.a) and denaturation (E.sub.d) were determined to be 17.40, and 43.86 KJ.mol.sup.- 1, respectively. Parameters reflecting [beta]-galactosidase thermal stability at 40, 45, and 50 °C as T.sub.1/2 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.