초록
<P><B>Abstract</B></P><P>Selective enzyme‐catalysed biotransformations offer great potential in organic chemistry. However, special requirements are needed to achieve optimum enzyme activity and stability. A bicontinuous microemulsion is proposed as reaction medium because of its large connected interface between oil and water domains at which a lipase can adsorb and convert substrates in the oil phase of the microemulsion. Herein, a microemulsion consisting of buffer–<I>n</I>‐octane–nonionic surfactant C<SUB><I>i</I></SUB>E<SUB><I>j</I></SUB> was used to investigate the key factors that determine hydrolyses of <I>p</I>‐nitrophenyl esters catalysed by the lipase B from <I>Candida antarctica</I> (CalB). The highest CalB activity was found around 44 °C in the absence of NaCl and substrates with larger alkyl chains were better hydrolysed than their short‐chained homologues. The CalB activity was determined using two different co‐surfactants, namely the phospholipid 1,2‐dioleoyl‐<I>sn</I>‐glycero‐3‐phosphocholine (DOPC) and the sugar surfactant decyl β‐<SMALL>D</SMALL>‐glucopyranoside (β‐C<SUB>10</SUB>G<SUB>1</SUB>). The results show the CalB activity as linear function of both enzyme and substrate concentration with an enhanced activity when the sugar surfactant is used as co‐surfactant.</P>