Microbial and Plant Assisted Synthesis of Cobalt Oxide Nanoparticles and Their Antimicrobial Activities

Abstract

The development of sustainable, ecofriendly, and cost-effective methods for the synthesis of nanomaterials is an important aspect of nanotechnology these days. The present study was aimed at synthesizing cobalt oxide (Co3O4) nanoparticles by using plant extracts of Aerva javanica, bacterial isolates from rhizospheric soil of Potentilla atrosanguinea, Swertia petiolata, Senecio chrysanthemoides, and from fungus Fusarium oxysporum. X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM) techniques were used in the characterization of the synthesized nanoparticles. The bacterial strain, Bacillus subtilis, isolated from rhizosphere of Potentilla atrosanguinea (N1C1), Fusarium oxysporum, methanolic and aqueous extracts of Aerva javanica reduced the cobalt salts to cobalt oxide nanoparticles. The nanoparticles, synthesized from bacterial isolate N1C1 (Bacillus subtilis) and from Fusarium oxysporum had average particle size of 31.2 nm and 33.4 nm, respectively, whereas, the particle size of Aerva javanica was higher (39.2 nm) and all the nanoparticles were poly shaped. The nanoparticles synthesized from methanolic extract of Aerva javanica, bacterial strain (N1C1) and fungi Fusarium oxysporum showed better performance against Bacillus subtilis and P. aeruginosa, the bactericidal activity was higher against Gram-positive bacterial strains. Methanolic extracts of leaf and flower have shown a wide range of phytochemicals and higher antibacterial activity, and among all strains, Pseudomonas aeruginosa and Bacillus subtilis susceptibility was greater to extracts.

Sustainable and Ecofriendly Nanoparticle Synthesis Using Microbial Strains Isolated From Heavy Metal Rich Industrial Effluent

“…Cobalt nanoparticles have many applications in catalysis, energy storage, as contrast agents in biomedicine, in waste water treatment, and as antimicrobial and anticancer agents [17,3]. Several studies have used plant extracts and bacteria to synthesise cobalt nanoparticles, but in all these studies, the use of high temperature from 80 °C to 850 °C and/or other reagents [18, 19, 20, 21, 22] was required to synthesise the nanoparticles. Thus, our study demonstrates an ecofriendly and sustainable approach to nanoparticle synthesis.…”

Pseudomonas aeruginosa inhibits quorum-sensing mechanisms of soft rot pathogen Lelliottia amnigena RCE to regulate its virulence factors and biofilm formation

“…The desperate attempts require to identify novel antimicrobial agents or developing new procedures to thwart antibiotic resistance (Abdalla et al, 2020 ; Kapadia et al, 2021 ). The advanced and innovative antimicrobial agents developed so far target only the most prominent pathogenic bacteria (Dellit et al, 2007 ), while less severe pathogenic bacteria remain resistant (Masood et al, 2021 ; Mubraiz et al, 2021 ). Therefore, developing innovative strategies which target pathogenesis-responsible compounds are of prime importance for controlling pathogen.…”

Antimicrobial Efficacy of Biogenic Cobalt and Copper Nanoparticles against Pathogenic Isolates

“…The characterization of Cu and CoNPs was performed using ultraviolet-visible spectroscopy (UV-vis; UV-1700, Shimadzu) and Fourier-transform infrared spectroscopy (FTIR; Bruker Alpha Platinum ATR) . For UV-vis spectroscopy, Co and CuNPs solutions were used by absorbing light emitted by substances, thus showing the UV-visible absorption spectrum of Co and CuNPs 14) . FTIR study was performed using the dry powder form of prepared NPs and showed different functional groups present in the Co and CuNPs 12) .…”

“…High surface-to-volume ratios and nano scale sizes are distinguishing characteristics of biogenic NPs, which improve their reaction with pathogenic microbes. 1) 14,15) . E. coli and B. subtilis CuNPs showed higher ZOI against Gram-negative (E. coli) than Gram-positive strain (B. subtilis) .…”