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Adithan Aravinthan,1,* Muthusamy Govarthanan,2,3,* Kandasamy Selvam,4 Loganathan Praburaman,2,3 Thangasamy Selvankumar,3 Rangachari Balamurugan,1 Seralathan Kamala-Kannan,2 Jong-Hoon Kim1 1College of Veterinary Medicine, Biosafety Research Institute, Chonbuk National University, Jeonju, South Korea; 2Division of Biotechnology, Advanced Institute of Environment and Bioscience, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, South Korea; 3PG and Research Department of Biotechnology, Mahendra Arts and Science College, Kalippatti, Namakkal, Tamil Nadu, India; 4Centre for Biotechnology, Muthayammal College of Arts and Science, Rasipuram, Namakkal, Tamil Nadu, India *These authors contributed equally to this work Abstract: A rapid, green phytosynthesis of silver nanoparticles (AgNPs) using the aqueous extract of Helianthus tuberosus (sunroot tuber) was reported in this study. The morphology of the AgNPs was determined by transmission electron microscopy (TEM). Scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS) and X-ray powder diffraction (XRD) analysis confirmed the presence of AgNPs. Fourier transform infrared spectroscopy (FTIR) analysis revealed that biomolecules in the tuber extract were involved in the reduction and capping of AgNPs. The energy-dispersive spectroscopy (EDS) analysis of the AgNPs, using an energy range of 2–4 keV, confirmed the presence of elemental silver without any contamination. Further, the synthesized AgNPs were evaluated against phytopathogens such as Ralstonia solanacearum and Xanthomonas axonopodis. The AgNPs (1–4 mM) extensively reduced the growth rate of the phytopathogens. In addition, the cytotoxic effect of the synthesized AgNPs was analyzed using rat splenocytes. The cell viability was decreased according to the increasing concentration of AgNPs and 67% of cell death was observed at 100 µg/mL. Keywords: cytotoxicity, Helianthus tuberosus, nanobiotechnology, phytosynthesis, splenocytes

Muthusamy Govarthanan,1,2 Thangasamy Selvankumar,2 Koildhasan Manoharan,3 Rajiniganth Rathika,2 Kuppusamy Shanthi,4 Kui-Jae Lee,1 Min Cho,1 Seralathan Kamala-Kannan,1 Byung-Taek Oh11Division of Biotechnology, Advanced Institute of Environment and Bioscience, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, South Korea; 2PG and Research Department of Biotechnology, Mahendra Arts and Science College, Kalippatti, Namakkal, Tamil Nadu, India; 3Department of Botany, Raja Duraisingam Government Arts College, Sivagangai, Tamil Nadu, India; 4Department of Environmental Science, PSG College of Arts and Science, Coimbatore, Tamil Nadu, IndiaAbstract: Synthesis of silver nanoparticles (AgNPs) with biological properties is of vast significance in the development of scientifically valuable products. In the present study, we describe simple, unprecedented, nontoxic, eco-friendly, green synthesis of AgNPs using an Indian traditional farming formulating agent, panchakavya. Silver nitrate (1 mM) solution was mixed with panchakavya filtrate for the synthesis of AgNPs. The nanometallic dispersion was characterized by surface plasmon absorbance measuring 430 nm. Transmission electron microscopy showed the morphology and size of the AgNPs. Scanning electron microscopy–energy-dispersive spectroscopy and X-ray diffraction analysis confirmed the presence of AgNPs. Fourier transform infrared spectroscopy analysis revealed that proteins in the panchakavya were involved in the reduction and capping of AgNPs. In addition, we studied the antibacterial activity of synthesized AgNPs. The synthesized AgNPs (1–4 mM) extensively reduced the growth rate of antibiotic resistant bacteria such as Aeromonas sp., Acinetobacter sp., and Citrobacter sp., according to the increasing concentration of AgNPs.Keywords: green synthesis, panchakavya, antibacterial, environment, nanoparticles

As plastics become more ubiquitous, their impact on the environment and on human health cannot be overlooked. Once generated, micro‐ and nano‐plastics end‐up in the environment, causing widespread health and environmental risks. This is a significant environmental problem given the minuscule sizes of microplastics, and therefore warrants further investigation. This study presents a comprehensive review of the ecotoxicology of microplastics and methods for their degradation and decomposition besides discussing the fate and transport processes, recent progress, emerging strategies, challenges and potential future directions. The authors carefully evaluate the processes through which microplastics cause harm, from molecular interactions in species, to ecological impacts, and end with advances in microplastic biodegradation. Different kinds of microplastics found in the environment include polyethylene, polystyrene, polypropylene, polyvinyl chloride, polycarbonate, polyurethane, polypropylene, and polyethylene terephthalate. Analysis of microbial and enzymatic decomposition provides several swelling mitigation strategies designed to reduce environmental threats. In‐depth investigations of microplastic ecotoxicity and biodegradation are being facilitated by interdisciplinary proposals in the areas of nanotechnology, new analytical methods, and synthetic biology. The extensive study helps understand microplastics comprehensively which in‐turn ensures informed actions to mitigate the challenge of the environmental impact of microplastics for sustainable future. [ABSTRACT FROM AUTHOR]

The replacement of synthetic plastics with eco‐friendly biopolymers is a notable approach in the modern world. Polyhydroxyalkanoates (PHAs) have gained a lot of attention among researchers in recent decades. This study aimed to isolate and screen microorganisms capable of producing PHA from composite samples. Several composting unit samples were collected and used to isolate 15 distinct colonies which were then screened for PHA synthesis. Three isolates‐SS2, SSNA 1a, and SF2‐showed promising PHA production. Among these isolates, SS2 had the highest PHA content of 70.1%. The isolate SS2 was determined as Cellulosimicrobium cellulans DSM 43879 by gene sequencing. The polymer produced by SS2 was further characterized. The presence of carbonyl groups and ester linkages in the PHA polymer was established by Fourier transform infrared analysis. The polymer's crystalline nature was validated by X‐ray powder diffraction measurement. Scanning electron microscope study revealed thread‐like forms with a rough surface while energy dispersive X‐ray analysis revealed a low impurity content that was primarily composed of carbon and oxygen with traces of other elements. Overall, the findings indicate C. cellulans potential as an ideal candidate for efficient PHA synthesis supporting its commercial potential in diverse applications. [ABSTRACT FROM AUTHOR]

Green synthesis of gold nanoparticles (AuNPs) is gaining attention of researchers because of their varieties of biomedical and environmental applications. This study reported the novel eco-friendly synthesis of AuNPs using green macroalgae Halimeda macroloba (HM) extract and evaluate their photocatalytic potential. The green synthesized H. macroloba mediated gold nanoparticles (HM-AuNPs) was characterized using UV-visible spectrophotometry, Fourier-transform infrared (FT-IR) spectroscopy, transmission electron microscope (TEM), scanning electron microscope-energy dispersive spectroscopy, x-ray photoelectron spectroscopy (XPS), and particle size distribution (PSD) anlaysis. The UV-visible spectrum shows a sharp intense plasmonic resonance peak at 543 nm. The bioactive compounds present in HM were primarily responsible for the biological reduction of gold ions validated by FT-IR analysis. XRD analysis proved the crystalline face centered cubic structure of the HM-AuNPs. The average particle size of 18.72 nm and morphological evidences were obtained from the images from TEM. The metallic form of biosynthesised HM-AuNPs was confirmed by XPS results with a distinctive binding energy. The photocatalytic degradation ability of the green synthesized HM-AuNPs was investigated against the methylene blue (MB) and methylene orange (MO) dyes under sunlight irradiation. The HM-AuNPs exhibited 97.23% and 89.91% photocatalytic activity against MB and MO after 90 min of exposure to sunlight, respectively. The overall results of this research indicate that H. macroloba mediated HM-AuNPs can be used as an effective option for the degradation of industrial dyes. [ABSTRACT FROM AUTHOR]