Synthesis of sucrose laurate using a new alkaline protease

Sucrose laurate esters were synthesized from sucrose and vinyl laurate in organic solvents using an alkaline protease from a new alkalophilic strain, Bacillus pseudofirmus AL-89. Maximum synthetic activity was observed in the presence of 7.5% v/v water and in the pH range of 7-10. With protease AL-89 esterification occurred predominantly at the 2-O-position while subtilisin A-catalyzed monoester formation predominantly at the 1'-0 position. In the absence of enzyme, buffer salts catalyzed non-specific reactions, resulting in the formation of a number of esters. Non-specific catalysis was also observed upon inhibition of the enzyme using a serine protease inhibitor or upon deactivation of the enzyme at pH above 10. (C) 2003 Elsevier Science Ltd. All rights reserved.