Enantiometric enrichment of R(-)-alkan-2-ols using a stereospecific alkylsulphatase

When grown on nutrient broth, Pseudomonas C12B produces two secondary alkyl 2-sulphatases, designated S1 and S2 on the basis of electrophoretic mobility. Although both enzymes are synthesised at the end of the exponential phase in batch culture, the appearance of S1 preceded S2 by a few hours in either fermentor or shake-flask cultures. Thus extracts prepared from cells harvested in the intervening period contained only the S1 enzyme. Because S1 and S2 are stereospecific in hydrolysing S(+)- and R(-)-alkyl 2-sulphates to R(-)- and S(+)-alkan-2-ols respectively, the exclusive presence of S1 was exploited in the enantiomeric enrichment of R(-)-alkan-2-ols. Extracts containing only S1 according to gel zymography, hydrolysed only about one-half of added racemic octyl or undecyl 2-sulphates, as expected. Extraction and analysis of liberated octan-2-ol by spectral polarimetry or high resolution gas chromatography with chiral derivatisation, indicated an enantiomeric excess around 60%.