Synthesis of fructooligosaccharides and oligolevans by the combined use of levansucrase and endo-inulinase in one-step bi-enzymatic system

Optimization of levansucrase/endo-inulinase bi-enzymatic system for the production of fructooligosaccharides and oligolevans from sucrose

“…These results are in agreement with our previous findings in which the optimum production of 1-kestose, nystose and 1 F -fructosylnystose was achieved in the initial reaction period (i.e. 0.5-1 h) [19]. As compared to other FOSs, the accumulation of 6-kestose over the reaction time course may reveal that LS was unable to use it efficiently as a fructosyl acceptor.…”

“…Contrary to levanopentaose, the predicted concentrations of levanohexaose and oligolevans increased when LS to endoinulinase ratio was decreased or increased from 1:1 ratio (data not shown). Similar results were reported in our previous work [19] and attributed to (a) the high levels of levan as a result of the high extent of the transfructosylation reaction at high LS to endo-inulinase ratio of 2:1 and to (b) the high availability of acceptors at lower enzyme ratio of 1:2. Fig.…”

“…These results can be due to the fact that the reaction equilibrium may have been reached faster at low sucrose concentrations. The low predicted concentrations of scFOSs at low sucrose concentrations (<0.35 M) are also consistent with high hydrolytic activity of LS (∼74% of total activity) in this range [19]. The increase in the reaction time had a significant negative effect on the predicted concentrations of scFOSs, with the exception of 6-kestose (Fig.…”

“…The hydrolytic activity of endo-inulinase was investigated using low MW levan (5.5 ± 0.5 kDa) as substrate, which was prepared as previously described through LS-catalyzed transfructosylation reaction [19]. Only very minor activity of exo-inulinase (<8%) was detected in the investigated endo-inulinase product.…”

“…Recently, some hypotheses and structural features have been put forward to describe the polymerization/oligomerization ratio [12,13,17,18]. In our previous studies, a bi-enzymatic system, based on the synergistic actions of LS from Bacillus amyloliquefaciens and endo-inulinase from Aspergillus niger, was, for the first time, investigated for the synthesis of FOSs and oligolevans using sucrose as an abundant substrate [19]. LS catalyzes the synthesis of levan from sucrose, whilst the endo-inulinase hydrolyses levan into FOSs and oligolevans.…”