Yang_2012_J.Biotechnol_161_27

As a short chain monoester, sucrose-6-acetate (S-6-a) is a key intermediate in the preparation of an eminent sweetener (sucralose). To replace the traditional multi-step chemical route for sucralose biosynthesis, enzymatic synthesis of S-6-a was investigated, using cross-linked enzyme aggregates (CLEAs) of Lipozyme TL 100 L. The optimal CLEA preparation conditions was obtained as follows: using 33.3% (v/v) PEG600 co-precipitated with additive of D-sorbierite, then cross-linking with 1.5% (v/v) glutaraldehyde at 0 degreeC for 4 h. As a result, the immobilized Lipozyme had high specific bioactivity (34.64 U/g) of transesterification in non-aqueous media. With these immobilized enzymes, the optimum transesterification conditions were investigated systematically, including CLEA loading, the mole ratio of vinyl acetate versus sucrose, temperature and reaction time, etc. The results showed that the highest concentration and yield of S-6-a was 49.8 g/L and 87.46%, respectively. Further experiments showed that the resulting CLEAs also had much higher operational stability than the commercial Lipozyme TLIM. The present work has paved a new path for the large-scale bioproduction of S-6-a with immobilized lipase in the future.