Exo-inulinase production from Aspergillus fumigatus NFCCI 2426: purification, characterization, and immobilization for continuous fructose production

Endo- and exo-levanases from Bacillus subtilis HM7: Catalytic components, synergistic cooperation, and application in fructooligosaccharide synthesis

Levan-type fructooligosaccharides (LFOS) exhibit significant biological activities and selectively promote the growth of certain beneficial bacteria. Levanase is an important enzyme for LFOS production. In this study, two isoforms of levanases, exo- and endo-type depolymerizing enzymes, from Bacillus subtilis HM7 isolated from Dynastes hercules larvae excrement were cloned, expressed, and characterized. The synergistic effect on the levan hydrolysis and kinetic properties of both isoforms were evaluated, indicating their cooperation in levan metabolism, where the endo-levanase catalyzes a rate-limiting step. In addition, homology models and molecular dynamics simulations revealed the key amino residues of the enzymes for levan binding and catalysis. It was found that both isoforms possessed distinct binding residues in the active sites, suggesting the importance of the specificity of the enzymes. Finally, we demonstrated the potential of endo-type levanase in LFOS synthesis using a one-pot reaction with levansucrase. Overall, this study fills the knowledge gap in understanding levanase's mechanism, making an important contribution to the fields of food science and biotechnology.

Insights in inulin binding and inulin oligosaccharide formation by novel multi domain endo-inulinases from Botrytis cinerea

World-wide, pathogenic fungi such as Botrytis cinerea cause tremendous yield losses in terms of food production and post-harvest food decay. Many fungi produce inulin-type oligosaccharides (IOSs) from inulin through endo-inulinases which typically show a two domain structure. B.cinerea lacks a two domain endo-inulinase but contains a three domain structure instead. Genome mining revealed three and four domain (d4) enzymes in the fungal kingdom. Here, three and two domain enzymes were compared in their capacity to produce IOSs from inulin. Hill kinetics were observed in three domain enzymes as compared to Michaelis-Menten kinetics in two domain enzymes, suggesting that the N-terminal extension functions as a carbohydrate binding module. Analysis of the IOS product profiles generated from purified GF6, GF12, GF16 and GF18 inulins and extensive sugar docking approaches led to enhanced insights in the active site functioning, revealing subtle differences between the endo-inulinases from Aspergillus niger and B. cinerea. Improved insights in structure-function relationships in fungal endo-inulinases offer opportunities to develop superior enzymes for the production of specific IOS formulations to improve plant and animal health (priming agents, prebiotics).

Production, purification, and characterization of inulinase from Streptomyces anulatus

Inulinase is an enzyme that catalyzes inulin to d-fructose. This enzyme can be extracted from plants, but it is difficult to obtain it in large quantities, so its production cost is high. Therefore, microbial inulinase has great potential for industrial needs. In the last decade, there have been very few reports on actinobacterial inulinases, especially on purification and characterization of inulinase process extraction. This study aims to select actinomycetes that possess high inulinase activity from the soil. To screen inulinase-producing bacteria, modified Czapex-Dox agar supplemented with 1% inulin powder was used. The most effective isolate was Streptomyces sp. EFBO8, morphological and genotypic identification methods, confirmed that the strain is Streptomyces anulatus and that its nucleotide sequence has been deposited in GenBank under accession number OQ073700. To optimize inulinase production, kinetics were performed by using S. anulatus strain, which proved to be most productive with a value of 24,024 EU/mL. The enzyme was purified from the culture filtrate by precipitation with ammonium sulfate (NH₄ )₂ SO₄ , followed by column chromatography Sephadex (G-50) separation. Purified protein has a molecular mass of 3331.83 Da.

Production, Biochemical Characterization, and Kinetic/Thermodynamic Study of Inulinase from Aspergillus terreus URM4658

Inulinases are enzymes involved in the hydrolysis of inulin, which can be used in the food industry to produce high-fructose syrups and fructo-oligosaccharides. For this purpose, different Aspergillus strains and substrates were tested for inulinase production by solid-state fermentation, among which Aspergillus terreus URM4658 grown on wheat bran showed the highest activity (15.08 U mL−1). The inulinase produced by this strain exhibited optimum activity at 60 °C and pH 4.0. A detailed kinetic/thermodynamic study was performed on the inulin hydrolysis reaction and enzyme thermal inactivation. Inulinase was shown to have a high affinity for substrate evidenced by very-low Michaelis constant values (0.78–2.02 mM), which together with a low activation energy (19.59 kJ mol−1), indicates good enzyme catalytic potential. Moreover, its long half-life (t1/2 = 519.86 min) and very high D-value (1726.94 min) at 60 °C suggested great thermostability, which was confirmed by the thermodynamic parameters of its thermal denaturation, namely the activation energy of thermal denaturation (E*d = 182.18 kJ mol−1) and Gibbs free energy (106.18 ≤ ΔG*d ≤ 111.56 kJ mol−1). These results indicate that A. terreus URM4658 inulinase is a promising and efficient biocatalyst, which could be fruitfully exploited in long-term industrial applications.

Efficient production of inulo-oligosaccharides from inulin by exo- and endo-inulinase co-immobilized onto a self-assembling protein scaffold

Inulin can be hydrolyzed by inulinases to yield inulo-oligosaccharides (IOSs), which have great application potential in the food and nutraceutical industries. However, conventional enzymatic production of IOSs is limited by long hydrolysis times and poor thermo-stability of inulinases. Here, the self-assembling protein scaffold EutM was engineered to co-immobilize exo-inulinase (EXINU) and endo-inulinase (ENINU) for synergistic hydrolysis of inulin to produce IOSs with 3 to 5 monosaccharide units (DP3-5 IOSs). The immobilization of EXINU/ENINU onto the EutM scaffold resulted in an increase of catalytic efficiency, a 65% increase of the V_max of ENINU, as well as an increase of thermo-stability, with 4.26-fold higher residual activity of EXINU after 22 h-incubation at 50 °C. After optimization, two efficient production protocols were obtained, in which the yield and productivity of DP3-5 IOSs reached 80.38% and 70.86 g·(L·h)^-1, respectively, which were at a high level in similar studies. Overall, this study provides an attractive self-assembling protein platform for the co-immobilization of inulinases, as well as optimized bioprocesses with great promise for the industrial production of DP3-5 IOSs.

Isolation and Molecular Identification of Endophytic Mold Schizophillum commune in Red Dahlia (Dahlia sp. L) Tuber as Producing Inulinases

BACKGROUND: Dahlia tuber as the source of isolates in endophytic mold produces Inulinases. Inulinase is used in industry to produce inulin to become fructose through an enzymatic reaction. Fructose from natural substances constitutes low calories used as diet in diabetes mellitus type 2 patients. An important phase is done obtain the inulinase enzyme through mold isolation. AIM: The objective of this research was to isolate and identify the molecular of endophytic mold from red dahlia tuber which had the optimum inulinase activity. METHODS: Mold isolation was done through the stage of surface sterilization and purification. Mold isolation which had the highest inulinase activity was identified in a molecular using the polymerase chain reaction technique with the Internal transcribed spacers ITS region. DNA amplification used primer ITS 1 and ITS 4. RESULTS: The result of the study showed that there was five-mold isolation with the result of screening high inulinase activity found in UD3 (++), UD4 (++), and UD5 (+++), the value of inulinase enzyme activity of UD3 was 0.582716049, UD4 was 0.330864198, and UD5 was 0.685185185. The result of identifying UD5 molecular in eight DNA tapes was successfully amplified with 660 pb. The result of identifying molecular based on BLAST analysis found Schizophillum commune species CONCLUSION: It was found that the highest inulinase activity was the species S. commune, which added new variants of inulinase enzyme from red dahlia tuber which could be used by industry to yield fructose through an enzymatic reaction.