Biosynthesis of silver nanoparticle and its application in cell wall disruption to release carbohydrate and lipid from C. vulgaris for biofuel production

Abstract

HighlightsThe AgNP was successfully synthesised from soil isolated bacterium Bacillus subtilis.The synthesised AgNPs were confirmed by UV-Spec, FTIR, TEM and XRD.The AgNPs were successfully treated microalga to disrupt its cell wall to release lipids and carbohydrates.The cell wall damages evidenced by LDH assay and SEM.

Impact of gamma-irradiated silver nanoparticles biosynthesized from Pseudomonas aeruginosa on growth, lipid, and carbohydrates of Chlorella vulgaris and Dictyochloropsis splendida.

“…The AgNPs formation from silver nitrate solution incubated with P. aeruginosa supernatant overnight at 35°C was demonstrated by the color change of the reaction mixture to brown. The UV-Vis spectrometry exhibited the maximum absorption of the AgNPs at 455 nm Figure 1(a), which was consistent with the recorded range at 400-475 nm of AgNPs synthesized by various bioreductant such as bacterial supernatant (Abo-State & Partila, 2015Razack et al, 2016;Abo-State et al, 2017;Hussein et al, 2020a), fungal filtrates (Gudikandula et al, 2017), algal extracts (Abdel-Raouf et al, 2017;Arévalo-Gallegos et al, 2018) or plant extracts (Tripathi et al, 2017;Tahir et al, 2018;Ahmad et al, 2020). The AFM image suggested the spherical shape of the AgNPs with a size range of 6-12 nm, monodispersed Figure 1(b).…”

“…In a study on the effect of carbon, ferric oxide, and magnesium oxide NPs on the green alga Scenedesmus obliquus, it is suggested that the algal metabolism modifies its normal pathways toward, in most cases, lipid production (M. He et al, 2017). The AgNPs may break open the cell wall of C. vulgaris for the excretion of biomolecules such as proteins or lipids for biodiesel production (Razack et al, 2016). Table 4 shows the lipid profile of C. vulgaris and D. splendida before and after AgNPs treatment.…”

“…Metal NPs have unique physicochemical characteristics including catalytic and antimicrobial activities and the incorporation of nanomaterials are increasing in a number of commercial products such as cosmetics, medicine, food packaging, odor-resistant textile, household applications, and medical devices (Chaudhari et al, 2012). With their nano-sizes and highly precise surface areas, the metal NPs can easily penetrate the cell wall and interact with internal cellular biomolecules (Razack et al, 2016). The use of trace or low NPs concentrations has reportedly induced stimulation of algal biomass and pigment content with enhanced lipid production (Kang et al, 2014;He et al, 2017;Sibi et al, 2017;González-Fernández et al, 2020;Tayemeh et al, 2020).…”

“…Huang et al, 2016), and the eukaryotic green algae (Dash et al, 2012) have been well documented. The AgNPs have reportedly disrupted the cell wall and promoted the release of intracellular components such as carbohydrate and lipid from C. vulgaris for biofuel (Razack et al, 2016). The AgNP-Algae interactions may actually cause oxidative stress from excessive Reactive Oxygen Species (ROS) (D. He et al, 2012), which ultimately diverts the algal metabolic pathway away from the growth pathways into the production of hydrocarbon (lipids or carbohydrates) as storage compounds (Sibi et al, 2017).…”

“…The biosynthesis from biological sources such as microorganisms, algae, and plants has evolved as a green alternative to the traditional chemical synthesis (Biswal & Misra, 2020). The biosynthesis may occur intracellularly or the NPs may be extracellular released to the reaction solution from which the NPs can be separated out by physical means (Razack et al, 2016). Several compounds such as the hydroxyl or carbonyl groups, terpenoids, phenolics, alkaloids, proteins, amines, and pigments, in the biological filtrate may act as reducing agents to trigger the metal NPs biosynthesis (Asmathunisha & Kathiresan, 2013).…”