Substrates' and products' inhibition in fructanase production by a new Kluyveromyces marxianus CF15 from Agave tequilana fructan in a batch reactor.

This study focuses on fructanase production in a batch reactor by a new strain isolated from agave juice (K. marxianus var. drosophilarum) employing different Agave tequilana fructan (ATF) concentrations as substrate. The experimental data suggest that the fructanase production may be inhibited or repressed by high substrate (50 g/L) and ethanol (20.7 g/L) concentrations present in culture medium. To further analyze these phenomena an unstructured kinetic mathematical model taking into account substrate and products inhibition was proposed and fitted. The mathematical model considers six reaction kinetics and the ethanol evaporation, and predicts satisfactorily the biomass, fructan, glucose, fructose, ethanol, and fructanase behavior for different raw material initial concentrations. The proposed model is the first to satisfactorily describe the production of fructanase from branched ATF with a new strain of K. marxianus.

Highly cross-linked arabinoxylans microspheres as a microbiota-activated carrier for colon-specific insulin delivery.

In vivo evaluation of arabinoxylans (AX) microspheres showed to protect insulin from degradation in the upper gastrointestinal tract and carrier insulin to colon. Insulin-loaded AX microspheres (50 UI/kg) decreased blood glucose level by 39% in diabetic rats with a maximum effect at 18 h post-administration, indicating that insulin remains bioactive. The continuous administration (4 days) of insulin-loaded AX microspheres improved the polyuria and increased the production of short-chain fatty acids, as well as Bifidobacterium and Bacteroides in diabetic rats compared to untreated diabetic rats. AX microspheres are a potential microbiota-activated carrier for colon-specific drug delivery and could be useful as a complementary treatment for diabetes.