Arumugam Sengottaiyan

Eco-friendly biosynthesis and characterization of silver nanoparticles using Tinospora cordifolia (Thunb.) Miers and evaluate its antibacterial, antioxidant potential

Abstract The present study reports an eco-friendly, rapid and easy method for synthesis of silver nanoparticles (AgNPs) using Tinospora cordifolia as a reducing and capping agent. The different factor such as silver nitrate (AgNO3) concentration, fresh weight of T. cordifolia leaf, incubation time, and pH affecting silver reduction was investigated using Response surface methodology based Box–Behnken design (BBD). The optimum conditions were AgNO3 (1.25 mM), incubation time (15 h), Temperature (45 °C) and pH (4.5). T. cordifolia leaf extract can reduces silver ions into AgNPs within 30 min after heating the reaction mixture (60 °C) as indicated by the developed reddish brown color. The UV-Vis spectrum of AgNPs revealed a characteristic surface plasmon resonance (SPR) peak at 430 nm. AgNPs were characterized X-ray diffraction (XRD) revealed their crystalline nature and their average size of nanoparticles was 30 nm as determined by using Scherrers equation. Fourier transform infrared (FTIR) spectroscopy affirmed the role of T. cordifolia leaf extract as a reducing and capping agent of silver ions. Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) showed spherical shaped and confirming presence of elemental silver. The synthesized AgNPs was found higher antioxidant activity than plant extract by dot plot assay. In addition, antibacterial activity against Staphylococcus sp. (NCBI-Accession: http://ncbi-n:KC688883.1) and Klebsiella sp. (NCBI-Accession: http://ncbi-n:KF649832.1), showed maximum zone of inhibition of 13 mm and 12.3 mm, respectively, at 10 μg/mL of AgNPs. From the results it is suggested that the synthesized AgNPs showed higher antioxidant and antibacterial activity than the plant extract, thus signification of the present study is the production of biomedical products.

Process optimization of cellulase production from alkali-treated coffee pulp and pineapple waste using Acinetobacter sp. TSK-MASC

The aim of this study was to assess the mixed combination of coffee pulp waste (CPW) and pineapple waste (PW) residues for cellulase production using newly isolated Acinetobacter sp. TSK-MASC in solid state fermentation. Response surface methodology based Box–Behnken design (BBD) was employed to optimize variables such as pH, incubation time, concentrations of CPW and PW. The BBD design investigation showed a sound adjustment of the quadratic model with the experimental statistics. Statistics based 3-D plots were generated to evaluate the changes in the response surface and to understand the relationship between the enzyme yield and culture parameters. The higher production (888 U mL−1) was achieved after 60 h of incubation with 3.0 g L−1 of CPW and PW at pH 7.0.

Acorus calamus rhizome extract mediated biosynthesis of silver nanoparticles and their bactericidal activity against human pathogens

Silver nanoparticle (AgNP) synthesis and characterization is an area of vast interest due to their broader application in the fields of science and technology and medicine. Plants are an attractive source for AgNP synthesis because of its ability to produce a wide range of secondary metabolites with strong reducing potentials. Thus, the present study describes the synthesis of AgNPs using aqueous rhizome extract of Acorus calamus (sweet flag). The AgNP formation was evaluated at different temperatures, incubation time and concentrations of AgNO3 using Response surface methodology based Box–Behnken design (BBD). The synthesized AgNPs were characterized by UV–Visible spectroscopy, Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS). The surface plasmon resonance found at 420 nm confirmed the formation of AgNPs. SEM images reveal that the particles are spherical in nature. The EDS analysis of the AgNPs, using an energy range of 2–4 keV, confirmed the presence of elemental silver without any contamination. The antibacterial activity of synthesized AgNPs was evaluated against the clinical isolates Staphylococcus aureus and Escherichia coli and it was found that bacterial growth was significantly inhibited in a dose dependent manner. The results suggest that the AgNPs from rhizome extract could be used as a potential antibacterial agent for commercial application.