Green synthesis of copper nanoparticles extracted from guar seedling under Cu heavy-metal stress by Trichoderma harzianum and their bio-efficacy evaluation against Staphylococcus aureus and Escherichia coli

F Ahmadi-Nouraldinvand,S Eslamian,S G Elias,M Afrouz

doi:10.1007/s12665-022-10184-4

Abstract

Copper nanoparticles were successfully synthesized with the help of agriculturally beneficial fungus Trichoderma harzianum through a simple green and eco-friendly route. The objectives of this study were to: (1) evaluate the application of T. harzianum and assess the effect of guar plant cultivation on heavy metal contaminated lands of copper in municipal and industrial wastewaters, and (2) develop a method to increase the antibacterial effects on the risk of two bacteria (Staphylococcus aureus and Escherichia coli). Two factors were investigated: (1) two copper (Cu) levels, Natural Hoagland Arnold solution as a control, and application of 100 μL Cu in Hoagland Arnold solution, and (2) two bio-fertilizer levels, no application, and fungus application. TEM and SEM photographs showed that synthesized Cu-NPs had spherical shapes. The formations of Cu-NPs were corroborated by FTIR and XRD analysis. Furthermore, the MIC and MBC of Cu-NPs towards bacterial growth were evaluated. The Cu-NPs and T. harzianum fungi presented antibacterial activity against Gram positive and Gram negative bacteria. The results suggested that green synthesis of nanoparticles using guar extracts can increase their antibacterial effect. The effect of Cu and fungi on biochemical properties of guar was also investigated. The results showed that the highest antioxidant enzymatic activity and proline amino acid were obtained at 100 μL Cu and T. harzianum application. Moreover, the results suggested that the use of T. harzianum can be useful in increasing the resistance to heavy metal stress in plants by increasing the activity of some antioxidant enzymes and secondary metabolites.

Highlights

In recent decades, the production of nanoparticles and their application in the various aspects of plant sciences are increasing
Due to the rapid growth of guar, high tolerance to stress conditions and repairing potential to heavy elements, guar can be used to clean the soils contaminated with heavy metals
In this paper, it is demonstrated that enzymatic antioxidant activities such as catalase, peroxidase and poly phenol oxidase were implicated in the tolerance of Trichoderma harzianum to oxidative the stress caused by exposure to Cu

Summary

Introduction

The production of nanoparticles and their application in the various aspects of plant sciences are increasing. Nanotechnology is a science that has the wide applications today in the pharmaceuticals environmental pollutions control (Ghaedi et al, 2015), the biomedical and pharmaceutical fields as alternative antimicrobial strategies due to the upsurge of infectious diseases and the appearance of antibiotic-resistant strains (Makarov et al, 2014). Biological approaches using microorganisms and plant extracts for metallic nanoparticle synthesis have been identified as viable alternatives to the other reported chemical methods (Bhavyasree & Xavier, 2020). Copper oxide nanoparticles have the antibacterial and antifungal properties (Bhavyasree & Xavier, 2020)

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