Innovative optimization for maximum magnetic nanoparticles production by Trichoderma asperellum with evaluation of their antibacterial activity, and application in sustainable dye decolorization

Abstract

A pioneer microbial-based synthesis of various nanoparticles is gaining more attention due to their potent applications in various industries. The magnetic nanoparticles (M-nps) were fabricated for the first-time using the cell free extract of Trichoderma asperellum. The M-nps bioprocess optimization was performed using Response Surface Methodology and Artificial Neural Network.The bioprocess was significantly (P < 0.05) affected by pH, stirring speed, and incubation period. The M-nps displayed a strong antibacterial efficiency against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus in a dose-dependent manner. The minimum inhibitory concentration (MIC) for E. coli, P. aeruginosa, and S. aureus were respectively found to be 25.0, 6.25, and 3.125 µg/ml. While the minimum bactericidal concentration (MBC) was 25.0, 12.5, and 6.25 µg/ml. The highest inhibition zone of 22 mm was recorded for B. subtilis at 80 µg/ml with MIC and MBC of 3.125 µg/ml. The sodium alginate/M-nps microbeads was successfully prepared without any crosslinkers. The microbeads exhibited the highest adsorptive efficiency (84.32%) for malachite green at pH 8.0, dose 0.1 g, and time 60 min. The experimental data were superlative fitted to Langmuir’s isotherm, hinting monolayer adsorption of MG molecules with 117.65 mg g‐−1 adsorptive capacity. The regenerated beads continued up-to six consecutive cycles and maintained more than 90%, indicating the multiple time use of the prepared material. Hence, the green magnetic nanoparticles display promising application in combating bacterial pathogens. The magnetic microbeads can be employed as an alternative eco-friendly, highly efficient, sustainable, and low-cost biosorbent in removing contaminants from wastewater.