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Author: search.filters.author.Panwar, JitendraSubject: search.filters.subject.Biosynthesis

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    Development of gold nanoparticle-fungal hybrid based heterogeneous interface for catalytic applications
    (Elsiever, 2015-08) Panwar, Jitendra; Gangopadhyay, Subhashis
    Unsupported and free gold nanoparticles (Au NPs) represent great potential in the field of catalysis. However, shortcomings like agglomeration and loss of the precious catalyst has encouraged the development of supported Au NPs as catalyst with increased activity, selectivity, ease of separation from the reaction mixture and recyclability. The present work demonstrates an eco-friendly, rapid and facile synthesis of catalytically active bio-supported Au NPs using a soil fungus, Aspergillus japonicus AJP01. The dual role of the fungal isolate in synthesis as well as immobilization of Au NPs is the remarkable feature of the study. The fungus successfully reduced Au(III) into Au NPs containing principally Au(0) with a small percentage of Au(I) as revealed by X-ray photoelectron spectroscopy. The particles were spherical in shape and well distributed on fungal mycelia with size ranging predominantly between 15 and 20 nm. The as-synthesized nanoparticle-fungal hybrid was found to be highly efficient in catalyzing sodium borohydride mediated reduction reactions of 4-nitrophenol and hexacyanoferrate(III). The versatility of the bionanocatalyst was further demonstrated by catalyzing the A3 coupling reactions for the synthesis of propargylamines.
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    Utilizing metal tolerance potential of soil fungus for efficient synthesis of gold nanoparticles with superior catalytic activity for degradation of rhodamine B
    (Elsiever, 2016-08) Panwar, Jitendra
    In recent years, the surging demand of nanomaterials has boosted unprecedented expansion of research for the development of high yielding and sustainable synthesis methods which can deliver nanomaterials with desired characteristics. Unlike the well-established physico-chemical methods which have various limitations, biological methods inspired by mimicking natural biomineralization processes have great potential for nanoparticle synthesis. An eco-friendly and sustainable biological method that deliver particles with well-defined shape, size and compositions can be developed by selecting a proficient organism followed by fine tuning of various process parameter. The present study revealed high metal tolerance ability of a soil fungus Cladosporium oxysporum AJP03 and its potential for extracellular synthesis of gold nanoparticles. The morphology, composition and crystallinity of nanoparticles were confirmed using standard techniques. The synthesized particles were quasi-spherical in shape with fcc packing and an average particle size of 72.32 ± 21.80 nm. A series of experiments were conducted to study the effect of different process parameters on particle size and yield. Biomass: water ratio of 1:5 and 1 mM precursor salt concentration at physiological pH (7.0) favoured the synthesis of well-defined gold nanoparticles with maximum yield. The as-synthesized nanoparticles showed excellent catalytic efficiency towards sodium borohydride mediated reduction of rhodamine B (2.5 × 10−5 M) within 7 min of reaction time under experimental conditions. Presence of proteins as capping material on the nanoparticle surface was found to be responsible for this remarkable catalytic efficiency. The present approach can be extrapolated to develop controlled and up-scalable process for mycosynthesis of nanoparticles for diverse applications.
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    Revisiting the architecture, biosynthesis and functional aspects of the plant cuticle: there is more scope
    (Elsiever, 2020-12-25) Panwar, Jitendra
    Having evolutionary significance in establishing colonization of terrestrial plants, cuticle occurs to act as a continuous shield over the plant epidermal cells, facilitating multifunctional communication passage between the plant and outer environment. Cuticle is a hydrophobic layer acting as a fencing between the aerial plant parts viz. primary stem, leaves, trichomes, flowers and fruits, and their external environment. The chemical nature and structure of cuticle may vary during various developmental and growth stages, as well as between various organs, genotypes, and species, depending on the environmental conditions. It is majorly composed of cutin and epicuticular wax depositions. In-depth understanding of the mechanism behind the cuticle biosynthesis remains to be unveiled. This review systematically discusses and sheds light on the structure and composition of cuticle, various genes, transcription factors and molecular pathways involved in the biosynthesis of cuticle, and how their regulation affect the plant health. Moreover, various functions of cuticle in terms of plant protection have been discussed.