Biosorption of Cr(Ⅳ),Cr(Ⅲ),Pb(Ⅱ) and Cd(Ⅱ) from Aqueous Solutions by Sargassum wightii and Caulerpa racemosa Algal Biomass

Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr(VI),Cr(III),Pb(II) and Cd(II) by algal biomass obtained from algae Sargassum wightii(brown) and Caulerpa racemosa(green).Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr(VI),Cr(III),Pb(II) and Cd(II) ions.C.racemosa exhibited 85% biosorption of Cd(II) and Cr(VI),and 50% biosorption of Cr(III) and Pb(II).The results of our study suggest that seaweed biomass can be used efficiently

Biosorption of Cd (Ⅱ) and Pb (Ⅱ) Ions by Aqueous Solutions of Novel Alkalophillic Streptomyces VITSVK5 spp. Biomass

Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment.Bio-sorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution.The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species.The biosorption property of Streptomyces VITSVK5 spp.was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb).Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L-1,cadmium 3.1±0.3μg L-1,zinc 8.4±2.6μg L-1 and copper 0.3±0.1μg L-1,whereas mercury was well below the detection limit.The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated.The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively.The biosorbent dosage was optimized as 3 g L-1 for both the trace metals.Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (–COOH),hydroxyl (–CHOH) and amine (–NH2) groups of biomass with the metal ions.This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp.The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.

Review on dermatomycosis: pathogenesis and treatment

Dermatophytes, a group of keratinophilic fungi thriving on the keratin substrate are the etio-logical agents responsible for causing cutaneous infections. Dermatophytosis is currently treated with the commercially available topical and oral antifungal agents in spite of the existing side effects. Treatment of these cutaneous infections with secondary metabolites produced by marine microorganisms is considered as a novel approach. For many years these organisms have been explored with the view of developing antibacterial, antifungal, antiviral, anti- cancer and antiparasitic drugs. Exploring the unexplored aspect of actinobacteria for developing antidermatophytic drugs is a novel attempt which needs further investigation.

Biosorption of heavy metals from aqueous solution by Gracilaria corticata varcartecala and Grateloupia lithophila

Objective:To study the biosorption of heavy metals viz.,Cr(VI),Cr(III),Hg(II),Pb(II)and Cd(II)using Gracilaria corticata varcartecala(G.corticata varcartecala)and Grateloupia lithophila(G.lithophila)biomass.Methods:Batch biosorption and acid digestion methods were used.Different physical and chemical parameters were optimized for biosorption.Results:Both seaweeds absorb Hg(II)upto 99.9%and 98.2%in batch biosorption method;whereas in acid digestion method,Cr(III)absorbed upto 96.49%by G.corticata varcartecala and Pb(II)absorbed upto 93.71%by G.lithophila.FT-IR analysis was used to know the involvement of different functional groups in the biosorption process.Scanning electron microscopy was carried out to study the morphological cell surface changes due to biosorption.Conclusions:It can be concluded that G.corticata varcartecala and G.lithophila are potential algal species for effective removal of heavy metals namely Cr(VI),Cr(III),Hg(II),Pb(II)and Cd(II)from environmental sources.

Streptomyces ghanaensis VITHM1 mediated green synthesis of silver nanoparticles： Mechanism and biological applications

We present the microbial green synthesis of silver nanoparticles （hiPs） by Streptomyces ghanaensis VITHM1 strain （MTCC No. 12465）. The secondary metabolites in the cell free supernatant of this bacterium when incubated with 1 mmol/L AgNO3, mediated the biological synthesis of AgNPs. The synthesized AgNPs were characterized by UV-visible spectrum, X-ray diffrac- tion （XRD）, atomic force microscope, scanning electron microscopy equipped with energy dispersive spectroscopy, transmission electron microscopy, FT-IR spectroscopy, dynamic light scattering and zeta potential. They were highly stable and, spherical in shape with the average size of 30-50 nm. The secondary metabolites involved in the formation of AgNPs were identified gas chromatographymass spectrography. The 3D structure of the unit cell of the synthesized AgNPs was determined using XRD data base. The synthesized AgNPs exhibited significant antibacterial activity against tested bacterial pathogens, and did not show haemolysis on human red blood cells. This green synthesis could provide a new platform to explore and use AgNPs as antibacterial therapeutic agents.