Microbiological Oxidations and Reductions

Microbial and enzymic transformations of steroids have been reviewed. 5a-Pregnane-7,20-dione gave a reasonable yield of the la, 12/3-dihydroxy-derivative on incubation with Calonectria decora High yields of 10 8-hydroxy-19-nortes-tosterone were obtained by incubation of 19-nortestosterone with Rhizopus arr-hizus (Fischer 11). Oxidation of canrenone with a Penicillium species provided the 15a-hydroxy-derivative (348) which is a product of human metabolism of spironolactone.16j8-Hydroxylation of androstenolone, androst-4-ene-3,17- 

Favero, J. Marchand, and F. Winternitz, Bull. Soc. chim. France, 1977, 310. 

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Nealson, K. H. (1982), "Microbiological Oxidation and Reduction of Iron", in H. D. Holland and M. Schidlowski, Eds., Mineral Deposits and Evolution of the Biosphere Dahlem Konferenzen, Springer Verlag, New York, 51 -56. 

Microbiological Oxidation and Reduction Patterns of Monoterpenoids by Aspergillus niger TBUYN-2... 

Tabatabai MA. Sulfur oxidation and reduction in soils. In Hickelson SH (ed.), Methods of Soil Analysis Part 2 Microbiological and Biochemical Properties. Madison, WI Soil Science Society of America 1994, pp. 1068-1078. 

Microbiologically influenced corrosion (MIC) is used to designate corrosion resulting from the presence and activities of microorganisms within biofilms on a material surface. Such microorganisms can accelerate and control corrosion reactions by several mechemisms formation of differential or concentration cells, formation of metabolites, such as sulfides md organic and inorganic acids metal oxidation and reduction, and deactivation of corrosion inhibitors. 

Fig. 4.6 Cyclic voltammograms of a mediator-producing bacterial suspension fed glucose at time 0 (black line), and after 30 min (red line) and 120 min (green line). Arrows indicate peaks while dashed lines that cross between oxidation and reduction peaks intersect the x-axis at the formal potential of the redox couple. The peak at -170 mV disappeared when bacteria were washed by centrifugation, but the peak at 180 mV never disappeared. There were no peaks observed from sterile medium. [From Rabaey et al. (2004), reprinted with permission of the American Society for Microbiology.]...

However, in contrast to microbiological experiments and near-surface studies, modelling of sulfate reduction in pore water profiles with in the ODP program has demonstrated that natural populations are able to fractionate S-isotopes by up to more than 70%c (Wortmann et al. 2001 Rudnicki et al. 2001). Brunner et al. (2005) suggested that S isotope fractionations of around -70%c might occur under hyper-sulfidic, substrate limited, but nonlimited supply of sulfate, conditions without the need of alternate pathways involving the oxidative sulfur cycle. 

Influence of Some Microbiological Species on Corrosion.64 Some bacteria are involved directly in the oxidation or reduction of metal ions, particularly iron and manganese. 

Arsenic species in flooded soils and water are subject to chemically and microbiologically mediated oxidation or reduction and methy-... 

Microbiological Oxidation, Reduction, and Other Reaction Patterns of Monoterpenoids by Euglena gracilis Z... 

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