Actinomycetes-mediated biogenic synthesis of metal nanoparticles and their antimicrobial activities are well documented. Actinomycetes facilitate both intracellular and extracellular metal nanoparticles synthesis and are efficient candidates for the production of polydispersed, stable and ultra-small size metal nanoparticles. Secondary metabolites and new chemical entities derived from Actinomycetes have not been extensively studied for the synthesis of metal/metal oxide nanoparticles. The present review focuses on biogenic synthesis of metal nanoparticles from Actinomycetes and the scope for exploring Actinomycetesderived compounds (enzymes, organics acids and bioactive compounds) as metal and metal oxide reducing agents for the synthesis of desired nanoparticles. This review also focuses on challenges faced in the applications of nanoparticles and the methods to synthesize biogenic metal nanoparticles with desired physiochemical properties such as ultra-small size, large surface to mass ratio, high reactivity etc. Methods to evade their toxicity and unique interactions with biological systems to improve their chance as an alternative therapeutic agent in medical and pharmaceutical industry are also discussed.

Here we report the synthesis of 2-5 nm size gold nanoparticle labels for surface-enhanced Raman Spectroscopy (SERS) based immunoassay to detect protein molecules. The Au nanoparticles were conjugated with fluorescein isothiocyanate (FITC) and goat anti-h-IgG (immunoglobin) and the resultant particles were used for the detection of h-IgG. Commercially available nitrocellulose strip and silver enhancement method were used for SERS-based immunoassays. The FITC acts as a Raman probe, and vibrational fingerprint of this molecule was used for the detection of h-IgG in concentration ranging from 1 to 100 ng/µl. Our Raman probe is robust and small in size and has high water solubility with minimum steric effect during antigen-antibody binding.

Pongamia oil cake (POC), a bio‐residual waste is obtained during the production of biodiesel as a byproduct. This is used as biosorbent to evaluate the removal of chromium (VI) ions from an aqueous synthetic solution. The effects of various process parameters such as pH, contact time, initial chromium ions concentration and adsorbent dosage have been investigated. The FT‐IR and SEM analysis of the adsorbents was done in the native‐ and Cr(VI)‐loaded state, to explore the position of the functional groups available for binding of chromium ions and the structural morphology of the studied adsorbents respectively. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm were used to study the adsorption mechanism, and it was found that the equilibrium data was better represented by the Freundlich isotherm. The maximal removal of hexavalent chromium ion was found to be at a pH of 2.0 within 2 h. The sorption kinetic follows the pseudo second order kinetic model. The Cr(VI) ions bound to the biosorbent could be effectively removed, using dilute H2SO4 (0.05 mM). The ability of POC to adsorb Cr(VI) ions in packed column was also investigated through the column studies. Bed Depth Service Time model and the Thomas model were used to analyze the experimental data and evaluate the model parameters. POC was shown to be a promising adsorbent for removal of Cr(VI) ions from aqueous solutions. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 342–352, 2014

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35Actinomycetes isolates collected from different environments were screened for 36 antiviral activity against WSSV. One isolate designated as CAHSH-2 showed antiviral 37 activity against WSSV at the concentration of 0.2 mg per shrimp. The laboratory trial of 38 determining antiviral activity of ethyl acetate extract (EtOAcE) of CAHSH-2 against WSSV 39 was carried out 21 times since 2014. CAHSH-2 isolate which showed antiviral activity was 40 characterized and identified as Streptomyces ghanaensis like strain. Among the five fractions 41 obtained from EtOAcE of potential actinomycetes isolate, F1 was found to have strong 42 antiviral activity. The F1A and F1B sub-fractions from F1 fraction were subjected to GC-MS, 43 FTIR, 1 H and 13 C NMR analyses and, the compounds identified were di-n-octyl phthalate and 44 bis (2-methylheptyl) phthalate, respectively. Among these compounds, di-n-octyl phthalate 45 showed strong antiviral activity against WSSV. Molecular docking studies revealed that di-n-46 octyl phthalate was found to have high binding affinity with VP26 and VP28 proteins of 47 WSSV, whereas the bis (2-methylheptyl) phthalate showed low binding affinity with VP26 48 and VP28. The antiviral activity of EtOAcE of actinomycetes against WSSV was confirmed 49 by PCR, RT-PCR, Western blot and ELISA. The EA extract of active isolate was found to be 50 non-toxic to Artemia, post-larvae and adult Litopenaeus vannamei. 51 Importance 52 53White spot syndrome virus (WSSV) is an important shrimp viral pathogen and 54 responsible for huge economic loss to shrimp culture industry worldwide including India. The 55 global loss due to WSSV has been estimated about USD 10 billion and the loss continues at 56 the same extent even now. Various strategies have been followed to prevent or control 57 diseases of aquatic animals. In spite of various preventive and control strategies, WSSV has 58 been still persisting for more than two decades. No control strategies have so far been evolved 59 to put a break to WSSV. In this situation, an attempt was made in the present work to screen 60 some actinomycetes isolates for antiviral activity against WSSV. Among these isolates, one 61 isolate identified as Streptomyces ghanaensis like isolate CAHSH-2 showed activity against 62 WSSV. This article gives the information about the antiviral compound against WSSV and 63 the mechanism of viral inhibition. 64 65 66