<em>Botryococcus braunii</em> as a bioreactor for the production of nanoparticles with antimicrobial potentialities

Abstract

BackgroundMicroalgae produce metabolites with notable potentialities to act as reducing and capping agents for the synthesis of silver nanoparticles (AgNPs) in a process widely recognized as an eco-friendly and cheaper alternative for the generation of nanoparticles (NPs).MethodsIn the present work, AgNPs were synthesized using live Botryococcus braunii cultures. Two biosynthesis routes were explored: (1) intracellular and (2) extracellular at pH levels of 6–9 using 1–5 mM silver nitrate concentrations.ResultsThe generation of NPs was confirmed via ultraviolet–visible spectroscopy. The morphological characteristics were observed using scanning electron microscopy which revealed that the newly developed AgNPs were mostly spherical in sizes starting from 168 nm. The characteristic peaks in a typical Fourier transform infrared spectroscopy suggested that the exopolysaccharides were the possible reducing and capping agents. The antimicrobial spectrum of the newly developed AgNPs was tested against bacterial strains, both Gram-negative, Gram-positive, and yeast, ie, Escherichia coli (American Type Culture Collection [ATCC] 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), and the yeast Candida albicans (ATCC 10231), respectively. The antimicrobial activity tests showed a stronger inhibition against Gram-negative bacteria. Statistically, the NPs biosynthesized at pH values of 6 and 8 displayed a higher antimicrobial activity.ConclusionOur findings showed that B. braunii is capable of generating AgNPs with antimicrobial potential.

Flacourtia indica based biogenic nanoparticles: development, characterization, and bioactivity against wound associated pathogens

“…Due to increasing hazards using toxic chemicals, capping agents, oxidizing and reducing agents in the synthesis of NPs, researchers have proposed new engineering strategies using the combination of natural resources and nano-biotechnology [4,5]. The nanobiotechnology is promisingly based on the eco-friendly and green routes [6,7]. The biogenic routes have considered as leading paths to get the desired product having a specific shape, size, and surface chemistry, which are still challengeable in the chemical routes [8,9].…”

In Vivo Biosynthesis of Inorganic Nanomaterials Using Eukaryotes—A Review

“…In microalgal mediated NP synthesis processes, the cells are generally washed with deionized water (DIW) to give rise to the washed biomass before being exposed to various precursors [ 5 , 69 , 81 ]. Hereafter, the washed biomass refers to the cells of a given organism that are harvested and washed before being resuspended in deionized water.…”

“…Nevertheless, many studies have reported NP synthesis by this method. For example, Arévalo-Gallegos et al reported the accumulation of nanosilver on the cell surface of Botryococcus braunii that was washed with distilled water before incubation with AgNO 3 [ 5 ]. However, the colloidal stability of the as-produced Ag NPs was not discussed.…”

“…In addition to traditional physico-chemical routes for the synthesis, sustainability, and application of inorganic NPs, biogenic nanomaterials have garnered increasing interest [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. For example, algal cell cultures are an environmentally friendly platform for the biosynthesis of nanomaterials [ 10 , 11 ].…”

“…For example, algal cell cultures are an environmentally friendly platform for the biosynthesis of nanomaterials [ 10 , 11 ]. Typically, the presence of active biomolecules in algae, such as redox enzymes, can promote the in vivo or intracellular synthesis of biocompatible nanomaterials with a uniform size and shape that show pronounced antifungal, anti-bacterial, and antitumor activity [ 5 ]. In addition to intracellular enzymes, the cell surface of algae often plays a vital role in the production of nanomaterials [ 12 ].…”