Abbau von Steroiden XVI. Mikrobieller Seitenkettenabbau von strukturmodifizierten Sterolen

Abstract

Different types of sterol derivatives substituted in position 3 have been investigated to be suitable substrates for microorganisms capable of degradating the side chain of sterols. Sterolesters were found to be either unattacked or hydrolyzed followed by complete degradation of the molecule. Derivatives of the alkylether - and ketal type were transformed to the corresponding C19-steroids by fermentation with strains of the genus Mycobacteria. With respect to stability, solubility and transformation rate the sterol-3-carboxymethyloxime-derivatives were shown to be most suitable.

Microbial conversion of sterols

“…Contrary to this observation, total degradation of sterol side chain to AD or ADD has been reported to Fig. lower curve: proton broadband decoupled; numbers at signals indicate numbering of C-atoms; a-values (ppm), TMS = 0. upper curve: as above, but proton offresonance decoupled occur equally weU with cholesterol, sitosterol and sterol derivatives (Nagasawa et al 1970;B6hme and H6rhold 1980). 20 MHz PFT C NMR spectrum of 20-carboxy-pregna-l,4-dien-3-one methyl ester, 0.5 g/ml CDC13; T = 30 C, accumulation of 1,400 pulse interferograms (8 K data points); pulse width 9 #s; pulse interval 3.8 s; spectral width 5,000 Hz.…”

Degradation of steroids by microorganisms. XVIII. The reversibility of steroid‐l‐dehydrogenation during microbial side chain degradation of sterols by Nocardia

“…I n some cases it was proposed to use steroid derivatives with substituents at ring A or B which prevent the introduction of the 1 double bond , Bum et al 1976, HORHOLD et al 1978, BOHME and HORHOLD 1980; however, in other cases the possibility of using special mutants was reported KRAYCHY 1970, ANTOSZ et al 1976). In practice, the first procedure is inadequate since before microbial degradation of the steroid side chain, additional chemical steps are necessary, and besides that, after fermentation steroid derivatives must be transformed back to convenient structures without the protective substituents.…”