Bacillus stearothermophilus, a thermophilic bacterium isolated from the Kuwaiti desert, produced a variety of monohydroxy androstene derivatives and an oxidized product when incubated with exogenous testosterone for 24 h at 65 degrees C. The major metabolite was identified as androst-4-en-3,17-dione while minor metabolites included 6 alpha-hydroxyandrost-4-en-3,17-dione, 6 beta-hydroxyandrost-4-en-3,17-dione, 6 alpha-hydroxytestosterone, and 6 beta-hydroxytestosterone. These metabolites were purified by TLC and HPLC followed by their identification using (1)H- and (13)C-NMR and other spectroscopic data.

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Side chain cleavage by biotransformation of 17a-hydroxyprogesterone 1 and 21-hydroxyprogesterone 2 by the thermophile, Geobacillus stearothermophilus was investigated. The side chain cleavage product, androst-4-ene-3,17-dione 1a & 2a, was a common product formed from both substrates. 17a-hydroxy-5a-pregnane-3,6,20-trione 1b and 17a-20a-dihydroxyprogesterone 1c were formed from 1. A rare 17-carboxylic acid analogue of androstene 2b, a transformation product of 2, was also identified. G. stearothermophilus also facilitated hydroxylation of 17a-hydroxyprogesterone at 6a-and 6b-positions resulting in 6b,17a-dihydroxyprogesterone 1d, 6a,17a-dihydroxyprogesterone 1e, 6b,21-dihydroxyprogesterone 2c and 6a,21-dihydroxyprogesterone 2d. All transformation products were identified through their spectral data and comparison with reference compounds.

The present work was carried out to study structural modification of steroids by Geobacillus kaustophilus, a bacterial thermophile present in milk and the environment. Incubation of progesterone and testosterone with G. kaustophilus at 65 degrees C resulted in oxygenated steroid nuclei. The oxygenation of the steroid molecule was stereo specific. Seven metabolites of progesterone horizontal line 6beta/6alpha-hydroxytestosterone, 20-hydroxyprogesterone, 6beta-/6alpha-20-dihydroxyprogesterone, 5alpha-pregnane-3,6,20-trione, and 3beta-hydroxy-5alpha-pregnane-6,20-dione horizontal line were identified. Four compounds horizontal line namely, 66-/6--hydroxytestosterone and 6beta/6alpha-hydroxyandrostenedione horizontal line and androst-4-en-3,17-dione were identified as testosterone metabolites. This shows that G. kaustophilus is capable of modifying steroid nuclei at elevated temperatures. G. kaustophilus is a stable thermophile first isolated from milk. Our results show that endogenous steroids present in milk can be modified by G. kaustophilus, causing detrimental effect on human health.

Tryptophan metabolism has been extensively studied in humans as well as in soil. Its metabolism takes place mainly through kynurenine pathway yielding hydroxylated, deaminated and many other products of physiological significance. However, tryptophan metabolism has not been studied in an isolated thermophilic bacterium. Geobacillus stearothermophilus is a local thermophile isolated from Kuwait desert soil contaminated with petroleum hydrocarbons. The bacterium grows well at 65 °C in 0.05 M phosphate buffer (pH 7), when supplied with organic compounds as a carbon source and has a good potential for transformation of steroids and related molecules. In the present study, we used tryptophan ethyl ester as a carbon source for the bacterium to study the catabolism of the amino acid at pH 5 and pH 7. In this endeavor, we have resolved twenty one transformation products of tryptophan by GC/LC and have identified them through their mass spectral fragmentation.

3-Phenoxy-1-propanols 1a-c and 3-phenylsulfanyl-1-propanols 2a-c containing primary, secondary, and tertiary alcohols were prepared and subjected to gas-phase pyrolysis in a static reaction system. Pyrolysis of 4-phenyl-1-butanol 3, 2-methyl-3-phenyl-1-propanol 4, and 2-methyl-3-phenylpropanoic acid 5 was also studied, and results were compared with those obtained for compounds 1-3. The pyrolytic reactions were homogeneous and followed a first-order rate equation. Analysis of the pyrolysate showed the products to be phenol (from 1a to 1c), thiophenol (from 2a to 2c), and toluene (from 3 to 5) and carbonyl compounds. The kinetic results and product analysis of each of the nine investigated compounds are rationalized in terms of a plausible transition state for the elimination pathway. C 2007 Wiley Periodicals, Inc. Int J Chem Kinet 40: [51][52][53][54][55][56][57][58] 2008