Large-scale production of myco-fabricated ZnO/MnO nanocomposite using endophytic Colonstachys rosea with its antimicrobial efficacy against human pathogens

• Published in: Scientific reports Vol. 14; no. 1; p. 935
• Main Authors: El-Moslamy, Shahira H, Abd-Elhamid, Ahmed Ibrahim, Fawal, Gomaa El
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 10.01.2024; Nature Publishing Group UK; Nature Portfolio
• Subjects: Anti-Bacterial Agents - pharmacology; Anti-Infective Agents; Antibacterial activity; Antibiotics; Batch culture; Biofilms; Biomass; Bioreactors; Biotechnology; Candida albicans; Carbon; E coli; Endophytes; Escherichia coli; Excipients; Fabrication; Fermentation; Humans; Multidrug resistance; Nanocomposites; Nitrogen; Pathogens; Spectroscopy; Staphylococcus aureus; Zinc Oxide - pharmacology
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-51398-9

In this study, a ZnO/MnO nanocomposite was myco-fabricated using the isolated endophytic Clonostachys rosea strain EG99 as the nano-factory. The extract of strain EG99, a reducing/capping agent, was successfully titrated with equal quantities of Zn(NO ) ·6H O and Mn(NO ) ·6H O (precursors) in a single step to fabricate the rod-shaped ZnO/MnO nanocomposite of size 6.22 nm. The ZnO/MnO nanocomposite was myco-fabricated in 20 min, and the results were validated at 350 and 400 nm using UV-Vis spectroscopy. In a 7-L bioreactor, an industrial biotechnological approach was used to scale up the biomass of this strain, EG99, and the yield of the myco-fabricated ZnO/MnO nanocomposite. A controlled fed-batch fermentation system with a specific nitrogen/carbon ratio and an identical feeding schedule was used in this production process. Higher yields were obtained by adopting a controlled fed-batch fermentation approach in a 7-L bioreactor with a regular feeding schedule using a nitrogen/carbon ratio of 1:200. Overall, the fed-batch produced 89.2 g/l of biomass at its maximum, 2.44 times more than the batch's 36.51 g/l output. Furthermore, the fed-batch's maximum ZnO/MnO nanocomposite yield was 79.81 g/l, a noteworthy 14.5-fold increase over the batch's yield of 5.52 g/l. Finally, we designed an innovative approach to manage the growth of the endophytic strain EG99 using a controlled fed-batch fermentation mode, supporting the rapid, cheap and eco-friendly myco-fabrication of ZnO/MnO nanocomposite. At a dose of 210 µg/ml, the tested myco-fabricated ZnO/MnO nanocomposite exhibited the maximum antibacterial activity against Staphylococcus aureus (98.31 ± 0.8%), Escherichia coli (96.70 ± 3.29%), and Candida albicans (95.72 ± 0.95%). At the same dose, Staphylococcus aureus biofilm was eradicated in 48 h; however, Escherichia coli and Candida albicans biofilms needed 72 and 96 h, respectively. Our myco-fabricated ZnO/MnO nanocomposite showed strong and highly selective antagonistic effects against a variety of multidrug-resistant human pathogens. Therefore, in upcoming generations of antibiotics, it might be employed as a nano-antibiotic.