OBJECTIVE To formulate a simple rapid procedure for bioreduction of silver nanoparticles using aqueous leaves extract of Moringa oleifera (M. oleifera). METHODS 10 mL of leaf extract was mixed to 90 mL of 1 mM aqueous of AgNO3 and was heated at 60 - 80 °C for 20 min. A change from brown to reddish color was observed. Characterization using UV-Vis spectrophotometry, Transmission Electron Micro...

OBJECTIVE To develop a simple rapid procedure for bioreduction of silver nanoparticles (AgNPs) using aqueous leaves extracts of Catharanthus roseus (C. roseus). METHODS Characterization were determined by using UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction. RESULTS SEM showed the formation of silver nanoparticles with an average ...

As part of a program aiming at the selection of yeast strains which might be of interest as sources of natural flavours and fragrances, the bioreduction of (4R)-(-)-carvone and (1R)-(-)-myrtenal by whole-cells of non-conventional yeasts (NCYs) belonging to the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Kazachstania, Kluyveromyces, Lindnera, Nakaseomyces, Vanderwaltozyma and Wick...

Biocatalytic processes are increasingly playing a key role in the development of sustainable asymmetric syntheses, which are central to pharmaceutical companies for the production of chiral enantiopure drugs. This work describes a simple and economically viable chemoenzymatic process for the production of (S)-rivastigmine, which is an important drug for the treatment of mild to moderate dementi...

As a result of the Manhattan Project and the Cold War, it has been estimated that over 1 billion m of groundwater and >75 million m of soil have been contaminated with radionuclides in sites across the United States. In addition to direct disposal to soils, trenches, cribs, etc., large volumes of waste remain in storage at several Department of Energy (DOE) sites. Due to their long half-lives a...

We examined the reduction of nitrobenzene by Shewanella putrefaciens CN32 in the presence of natural organic matter (NOM) and hematite. Bioreduction experiments were conducted with combinations and varied concentrations of nitrobenzene, soil humic acid, Georgetown NOM, hematite, and CN32. Abiotic experiments were conducted to quantify nitrobenzene reduction by biogenic Fe(II) and by bioreduced ...

Proteinaceous microspheres filled with nitroxides dissolved in an organic liquid have been synthesized for the first time using high intensity ultrasound; these were used to measure oxygen concentrations in living biological systems. The microspheres have an average size of 2.5 microns, and the proteinaceous shell is permeable to oxygen. Encapsulation of the nitroxides into the microsphere grea...

The bioreduction of solid TNT by a Pseudomonas fluorescens strain was investigated in a stirred tank reactor. Experiments in which TNT beads were the only solids present indicated that the biodegradation mechanism is dissolution followed by degradation in bulk solution. Dissolution may limit the overall rate, in which case degradation can be enhanced through increased agitation. Since soil slur...

Regio- and stereo-selective reduction of substituted 1,3-aryldiketones, investigated in the presence of different whole cell microorganisms, was found to afford β-hydroxyketones or 1,3-diols in very good yields (up to 95%) and enantiomeric excesses (up to 96%). The enantiomerically enriched aldols, obtained with the opposite stereo-preference by baker's yeast and Lactobacillus reuteri DSM 20016...

A single step protocol to produce biofunctionalized silver nanoparticles (AgNPs) using the aqueous extract of Cassia fistula flower as "natural factory" was investigated. The reaction between silver ions and aqueous flower extract after the bioreduction process has resulted in the formation of reddish brown color colloidal solution. XRD pattern showed the face centered cubic crystalline structu...