Lázaro Hernández García

Senior Researcher, Enzyme Technology Group, Center for Genetic Engineering and Biotechnology (CIGB) Havana, CUBA

Tuesday, 21 October 2022 | 10:00 am – ICGEB Trieste, ITALY

Introduction of CIGB (Cuba) and Bi- enzymatic transformation of sucrose into tailor-made fructooligosaccharides

Host: V. Venturi

FructoOligoSaccharides (FOSs) are soluble prebiotic fibbers with proven health-promoting effects in humans and animals. Among the currently commercialized linear inulin-type FOSs, the sweet-tasting 1–kestotriose (1K; DP3) stimulates the growth of probiotic bacteria faster than 1,1–kestotetraose (1,1K; DP4) and 1,1,1–kestopentaose (1,1,1K; DP5). Not only the DP but also the linkage type appears to influence the efficiency of FOSs fermentation by the gut microbiota. We have developed a bi-enzymatic cascade system that allows complete depletion of the substrate sucrose and yields short-chain FOSs of varied structures with their sum representing 60–65 % (w/w) of the total carbohydrates in the reaction mixture. Two sequential reactions are performed in the same reactor using fructosyltransferases of different substrate/product specificities. In the first step, sucrose is partially converted into 1K and 1,1K at a ratio 9:1 by the regioselective enzyme sucrose:sucrose 1–fructosyltransferase from Schedonorus arundinaceus (Sa1–SST) produced in the yeast Pichia pastoris. The initiation of the fructose peak in the monitored reaction reflects 1K hydrolysis and indicates the optimal moment for thermal inactivation of Sa1-SST. In the second-step reaction, the remaining sucrose is transformed via hydrolysis and fructosylation by a mutated variant of Gluconacetobacter diazotrophicus levansucrase (Gd_LsdA). The resulting mixture of linear and branched FOSs of short chains (DP 3–5) and varied linkages may stimulate a wider spectrum of intestinal probiotics comparing to traditional inulin-type FOSs.


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