Immobilization and stabilization of levansucrase biocatalyst of high interest for the production of fructooligosaccharides and levan

BACKGROUNDLevansucrase (LS)-catalyzed-transfructosylation reaction is a potential approach for the synthesis of fructooligosaccharides (FOSs) and levan as health promoting compounds. This biocatalytic approach is hindered by low thermal stability of LS and its high rate of hydrolysis. In the present study, LS from Bacillus amyloliquefaciens was immobilized onto modified and unmodified epoxy-activated supports (Eupergit (R) C; Sepabeads (R)) and on modified cross-linked-agarose beads, to increase its thermal stability and modulate its reaction selectivity (hydrolysis/transfructosylation). RESULTSLS bound to Sepabeads (R) HA (98.8%) and glyoxyl agarose-IDA/Cu (67%) retained high initial activity along with good immobilization yields. The thermal stability results indicated that glyoxyl agarose-IDA/Cu and glyoxyl agarose, provided the greatest thermal stability with factors of 14 and 106 times, respectively. Immobilization through Sepabeads (R) HA increased the ratio of transfructosylation/hydrolysis by 2.3 times, although it did not promote the stabilization of LS. Immobilization on glyoxyl agarose-IDA/Cu provided a good compromise of all three properties: retention of activity (67.0%), transfructosylation/hydrolysis ratio (120%) and thermal stability (stability factor of 13.6). CONCLUSIONThe stabilization of LS through immobilization contributes to its potential use commercially. With an increasingly stable enzyme, further work will be directed towards altering LS reaction specificity towards levan and levan-type FOSs. (c) 2015 Society of Chemical Industry