In vivo and in vitro biosynthesis of free fatty alcohols inEscherichia Coli K‐12

Abstract

In vivo studies have indicated that exogenous free fatty acids may serve as precursors of the free fatty alcohols ofEscherichia coli K‐12. Following disruption of the cells, the enzymatic activity capable of catalyzing the reduction of long chain fatty aldehydes to fatty alcohols was localized in the 100,000 x g supernatant fraction. Nicotinamide adenine dinucleotide phosphate, reduced form, was the required cofactor. The product of the reaction was characterized rigorously as 1‐hexadecanol when hexadecanal was the substrate. Three independent, but complementary, assay methods were developed to assay the aldehyde reductase activity. By employing these methods, an equivalence between nicotinamide adenine dinucleotide phosphate, reduced form, oxidation and 1‐hexadecanol synthesis was established. Two protein fractions catalyzing the reduction of fatty aldehydes to fatty alcohols were detected in the 100,000 x g supernatant fraction following ammonium sulfate fractionation and diethylaminoethyl‐cellulose chromatography. Enzymatic activity (70%) applied to the diethylamino‐ethyl‐cellulose column was eluted at a phosphate concentration of 0.115 M. The remaining 30% was eluted at a concentration of 0.23 M. Following sephadex chromatography, it was observed that the enzyme eluting at 0.115 M phosphate had an apparent mol wt of 250,000 Daltons while that eluting at 0.23 M had an apparent mol wt of 62,000 Daltons. The enzymes were similar with respect to substrate specificity, pH optima, ionic strength optima, and stability with respect to thiol inhibitors, suggesting different sized aggregates of similar subunits.

Occurrence and Patterns of Waxes in Neisseriaceae

“…Further investigations are necessary to verify this, and to explore the extent to which waxes occur in bacteria. The presence of fatty alcohols in the Gram-negative Serratia rnarcescens (Kates, Adams & Martin, 1964) and Escherichia coli (Naccarato et al, 1972(Naccarato et al, , 1974 and in the Gram-positive Bacillus cereus (Kates, Kushner & James, 1962)~ indicates that true waxes may be more widely distributed among bacteria than has previously been recognized.…”

The fermentation pathways of Escherichia coli

“…coli has an NADP linked ADH activity which oxidizes long chain alcohols [72]. This enzyme has been postulated to function in lipid biosynthesis [73]. Other NADP-linked ADH activities using butanol and allyl alcohol as substrates have also been reported [74][75][76].…”

Production of Long-chain Alcohols by Yeasts

“…In oil-degrading micro-organisms, long-chain alcohols are produced as intermediates in terminal oxidation of alkanes, and may also be found esterified with long-chain carboxylic acids which are produced by further oxidation of the alcohols (Ratledge, 1978;Britton, 1984). When grown on carbon sources other than alkanes, some bacteria synthesize long-chain primary alcohols by reduction of CoA esters of long-chain carboxylic acids which arise either from activity of the fatty acid synthase (Day et al, 1970;Naccarato et al, 1972;Lloyd & Russell, 1983) or are supplied exogenously (Naccarato et al, 1974;Lloyd & Russell, 1983).…”