Zeolitic imidazolate frameworks-67 (ZIF-67) supported PdCu nanoparticles for enhanced catalytic activity in Sonogashira-Hagihara and nitro group reduction under mild conditions

ABSTRACT Ralstonia eutropha JMP134 utilizes 2-chloro-5-nitrophenol as a sole source of nitrogen, carbon, and energy. The initial steps for degradation of 2-chloro-5-nitrophenol are analogous to those of 3-nitrophenol degradation in R. eutropha JMP134. 2-Chloro-5-nitrophenol is initially reduced to 2-chloro-5-hydroxylaminophenol, which is subject to an enzymatic Bamberger rearrangement yielding 2-amino-5-chlorohydroquinone. The chlorine of 2-amino-5-chlorohydroquinone is removed by a reductive mechanism, and aminohydroquinone is formed. 2-Chloro-5-nitrophenol and 3-nitrophenol induce the expression of 3-nitrophenol nitroreductase, of 3-hydroxylaminophenol mutase, and of the dechlorinating activity. 3-Nitrophenol nitroreductase catalyzes chemoselective reduction of aromatic nitro groups to hydroxylamino groups in the presence of NADPH. 3-Nitrophenol nitroreductase is active with a variety of mono-, di-, and trinitroaromatic compounds, demonstrating a relaxed substrate specificity of the enzyme. Nitrosobenzene serves as a substrate for the enzyme and is converted faster than nitrobenzene.

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Effect of yeast extract on the degradation of organophosphorus insecticides by soil enrichment and bacterial cultures

Canadian Journal of Microbiology ◽

10.1139/m89-185 ◽

1989 ◽

Vol 35 (12) ◽

pp. 1105-1110 ◽

Cited By ~ 34

Author(s):

M. Sharmila ◽

K. Ramanand ◽

N. Sethunathan

Keyword(s):

Nitro Group ◽

Yeast Extract ◽

Methyl Parathion ◽

Enrichment Culture ◽

Bacillus Sp ◽

Laterite Soil ◽

Mineral Salts ◽

Soil Enrichment ◽

Group Reduction ◽

Nitro Group Reduction

Soil enrichment cultures were prepared by repeated additions of methyl parathion to flooded alluvial and laterite soils incubated at 35 °C. These cultures were tested for their ability to degrade methyl parathion in a mineral salts medium in the presence and absence of yeast extract. Addition of yeast extract (0.05% w/v) accelerated the degradation of methyl parathion by both enriched cultures. Methyl parathion was degraded by the enrichment culture from alluvial soil essentially by hydrolysis in the absence of yeast extract and by nitro group reduction in its presence. The enrichment culture from laterite soil degraded methyl parathion (by hydrolysis) only in the presence of yeast extract. A Bacillus sp., isolated from laterite soil, degraded methyl parathion essentially by hydrolysis in the presence of a concentration (w/v) of yeast extract of 0.05%, by both hydrolysis and nitro group reduction at 0.1 and 0.25%, and exclusively by nitro group reduction at 0.5%. A similar trend was also noticed with parathion. However, fenitrothion was degraded by Bacillus sp. mainly by hydrolysis at all concentrations of yeast extract, whereas diazinon was not degraded.Key words: organophosphorothioates, biodegradation, yeast extract dependent pathway.

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