Microbial oxidation of ebastine

Abstract

The microbial oxidation of ebastine to carebastine was investigated. Among the 15 micro-organisms examined, only the Cunninghamella strains showed the desired biotransformation. Cunninghamella blakesleeana oxidised the substrate within 7 days, via the intermediates alcohol and aldehyde, mainly to carebastine, the corresponding carboxylic acid. Optimisation of the culture conditions increased the yield from initially 10% up to a reproducible 40%. For the synthesis of carebastine a substrate concentration of 200 mg/l, a starting pH of 5.0 and the addition of 1% poly(vinyl alcohol) is favourable. The results achieved in experiments with shaking flasks are transferable to the fermentation scale and yielded 270 mg carebastine in a 3-1 fermentation of 600 mg ebastine. The progress of the reaction was detected by TLC and HPLC, the products were identified by mass spectrometry and NMR.

Effects of phosphorus on polyphosphate accumulation by Cunninghamella elegans

“…The study of polyP accumulation by microorganisms growing under differential conditions is important to understand the mechanism of biosynthesis, functions, accumulation and further development of removing processes of environmental pollulants (33,44,65,71).…”

“…Some studies revealed that addition of phosphate to cells previously subjected to phosphate starvation also induces rapid accumulation of PolyP; a phenomenon known as polyP overplus (42,65). PolyP are present in large amounts in cells growing on a complete medium with high orthophosphate content.…”

“…PolyP are present in large amounts in cells growing on a complete medium with high orthophosphate content. Conversely, when phosphate-rich cells are grown in a medium lacking phosphate, polyP disappears (42,65).…”

“…There is evidence that polyP accumulates during energy-rich growth conditions and is degraded during energy-poor conditions (31,38,49,61,65,72). In general physiological terms it has been usual to consider polyP in terms of their solubility.…”

“…It is known that various polyP fractions are localized in separate cell compartments. The location of polyP fractions may represent differences in their functions (7,23,57,61,65,69,70,72,74).…”