Hydrolysis Of Inulin Research Articles

Fabrication of porous polysulfone microsphere covalently grafted with ionic liquid as catalyst and its catalytic hydrolysis kinetics of inulin

Polysulfone (PSF) material loaded with ionic liquids (ILs), PSF-ILs, was prepared by grafting imidazolyl acid ILs onto PSF by chemical bonding. A porous PSF-ILs microsphere catalyst was prepared via non-solvent induced phase separation (NIPS) method in order to catalyze the biomass inulin hydrolysis. The influences of degree of chloromethylation of PSF, hydrolysis temperature, catalyst dosage, PSF-ILs microsphere morphology, coagulation bath of NIPS and inulin concentration on hydrolysis performance were studied respectively. Under this optimal reaction conditions, 95.65% conversion of inulin into reducing sugar was achieved. The results suggested that the catalytic inulin hydrolysis performance of PSF-ILs microsphere was attractive due to high-density spatial distribution of the active sites on the surface and inner pore wall of microsphere after ILs immobilized. The hydrolysis kinetics was also investigated. The kinetic models of inulin hydrolysis catalyzed by PSF-ILs microsphere were employed to predict the hydrolysis in a wider range of experimental conditions. Furthermore, the stability tests showed that PSF-ILs microsphere catalyst could be effectively separated and recovered from hydrolysates, and has good regeneration ability. The morphology of PSF-ILs microspheres remained intact after eight trials of catalytic hydrolysis, avoiding the crushing phenomenon like a powder polymer material. More importantly, the PSF-ILs microsphere can effectively avoid the potential harm of ILs to the ecological environment, and is a potential green catalyst.

Obtención de alcohol etílico a partir de dos variedades de cabuya: alternativa para su industrialización

Este proyecto de investigación estudia la utilización de plantas nativas de Furcraea cabuya var. integra y Furcraea cabuya var. cabuya del litoral ecuatoriano, cosechadas en los poblados de: Ayampe, Montecristi, Tosagua, Portoviejo, con el objetivo principal de obtener alcohol etílico mediante la fermentación, destilación y filtración y de esta forma conseguir una bebida alcohólica apta para el consumo humano. En el acondicionamiento y desarrollo experimental se consideran los diferentes parámetros como los diferentes tiempos y temperaturas de cocción, las pruebas con diferentes tipos de inóculos y concentraciones de levaduras, además de diferentes suplementaciones nutritivas (con especial atención a la fuente de nitrógeno). Estableciendo como temperatura óptima para la hidrólisis de la inulina 117 °C durante 4 horas y el proceso fermentativo óptimo utilizando levadura seca activa comercial al 1% p/v con respecto al mosto y una suplementación con sulfato de amonio de 0,15 g/100mL de mosto. El mosto de cabuya rectificado genera una bebida con exquisito sabor a Tequila, la cual luego de ser evaluada sensorialmente demostró que el licor producido se encuentra dentro de los parámetros de aceptación de los consumidores. Palabras clave: etanol, cabuya, destilación, fermentación, mosto, tequila.

Production of Short Chain Fructo-oligosaccharides from Inulin of Chicory Root Using Fungal Endoinulinase.

Short chain fructo-oligosaccharides (SC-FOS) are the potential prebiotics possessing diverse applications in both food and feed industries. The present study was aimed to extract inulin from chicory roots followed by its conversion into SC-FOS applying endoinulinase from Aspergillus fumigatus. The inulin was extracted from chicory roots through boiling in hot water, followed by precipitation with ethanol at room temperature or freezing condition. Maximum yield (42%) of inulin was obtained with three volumes of chilled absolute ethanol at room temperature. HPLC analysis of enzymatic hydrolysate detected kestose (GF2), nystose (GF3), and other FOS having higher degree of polymerization (DP). Maximum GF2 (5.79mg/ml) was detected at temperature 50°C, pH5.5 with 2U of enzyme dose after 6h of hydrolysis; while maximum GF3 (4.33mg/ml) was recorded at 60°C, 5.5 pH with 0.5U enzyme dose after 2h of hydrolysis. Nevertheless, complete hydrolysis of inulin was noticed with 99% total oligosaccharide yield at 55°C, 5.5 pH with 0.5U enzyme dose after 4h of hydrolysis with negligible amount of mono- and di-saccharides. The present finding demonstrated the process for higher yield of inulin from chicory roots followed by its conversion into SC-FOS applying fungal endoinulinase.

Enzymatic hydrolysis of inulin by an immobilized extremophilic inulinase from the halophile bacterium Alkalibacillus filiformis

Bacterial inulinases are the key enzymes in the enzymatic hydrolysis of inulin and production of fructooligosaccharides (FOSs) and high fructose syrup (HFS). An extremophilic inulinase was purified from Alkalibacillus filiformis using 80% ethanol precipitation, ultrafiltration, and Q-Sepharose anion exchange chromatography. The purified inulinase was highly active in a wide range of pH, temperature, chemical reagents, and NaCl concentrations. The enzyme immobilization on cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) was carried out by carrier binding method with covalent linkage and showed improved stability and reusability within a broad temperature and pH range, compared with the free enzyme. Using free and immobilized inulinases from A. filiformis, 122 g L−1 and 160 g L−1 fructose with 61% and 80% conversion, respectively, were obtained, with inulin as the substrate. The enzymatic properties, such as notable stability under extreme conditions, make the inulinase from A. filiformis a promising candidate for related biotechnological applications.

A new engineered endo-inulinase with improved activity and thermostability: Application in the production of prebiotic fructo-oligosaccharides from inulin

To construct a high-performance engineered endo-inulinase for fructo-oligosaccharides (FOS) production from inulin, an inulin binding module (IBM) was fused into either N- or C-terminal of an endo-inulinase. After heterologous expression, purification and characterization, the C-terminal fusion one (Eninu-IBM) with better activity, thermostability and inulin binding ability was employed for high-temperature in situ inulin hydrolysis in a 10-L fermentor. During this process, Eninu-IBM was first efficiently produced by the yeast cells at 28 °C for 96 h, and subsequently 1600 g unsterilized inulin per liter fermentation liquor was directly supplemented into the bioreactor for FOS production at 60 °C for 2 h. Finally, high purity of FOS (91.4%) were obtained with FOS titer, yield and productivity of 717.3 g/L, 0.912 gFOS/gInulin and 358.6 g/L/h, respectively. The in vitro prebiotic assay indicated that the final FOS products with main polymerization degrees of 3–5 were preferably fermented by beneficial bifidobacteria and lactobacilli.

Inulinase hyperproduction by Kluyveromyces marxianus through codon optimization, selection of the promoter, and high-cell-density fermentation for efficient inulin hydrolysis

This study aimed to overexpress an inulinase gene in Kluyveromyces marxianus to achieve the inulinase overproduction and preparation of ultra-high-fructose syrup. First, the inulinase gene (INU1 gene) was overexpressed through codon optimization and selection of a suitable promoter. Then, the inulinase was overproduced by high-cell-density fermentation. Finally, ultra-high-fructose syrup was prepared. It was found that optimization of the codons of the native INU1 gene encoding inulinase from Kluyveromyces marxianus KM-0 made a recombinant strain KM-N70 carrying the optimized INU1N gene produce 251.4 U/mL of the inulinase activity. Furthermore, inulinase activity produced by a recombinant KM-KN16 strain carrying the optimized INU1N gene directed by the native TPS1 promoter from K. marxianus KM-0 reached 338.5 U/mL and expression level of the optimized INU1N gene in the recombinant KM-KN16 strain was also greatly enhanced. During a 10-L fermentation, the recombinant KM-KN16 strain could produce 374.3 U/mL of inulinase activity within 24 h, while during a high-cell-density fed-batch fermentation, the recombinant KM-KN16 strain could produce 896.1 U/mL of inulinase activity and OD600nm value of its culture reached 108. The crude inulinase preparation obtained in this study had an inulinase activity of 18,699.8 ± 736.4 U/g of the crude preparation. It was found that 90.3% of 332.4 g/L of inulin was hydrolyzed to produce 41.0 g/L of glucose and 256.0 g/L of fructose and 91.1% of 328.2 g/L of inulin in the extract of the tubers of Jerusalem artichoke was hydrolyzed to produce 48.3 g/L of glucose and 250.5 g/L of fructose by the crude inulinase preparation (75 U/g of the substrate) within 8 h. The hydrolysates contained major monosaccharides and a trace amount of trisaccharides and the monosaccharides were composed of around 85% fructose and 15% glucose. So far, any other yeasts available have produced only up to 120 U/mL of inulinase activity. Together, this made the recombinant KM-KN16 strain be the best inulinase producer at this moment. The inulinase activity of 18,699.8 ± 736.4 U/g of the crude preparation and the ultra-high-fructose syrup with 41.0 g/L of glucose and 256.0 g/L of fructose were obtained. The inulinase activity obtained in this study was the highest among all the inulinase activities produced by yeast, fungal, and bacterial strains obtained so far.

Production of high titer of citric acid from inulin

BackgroundCitric acid is considered as the most economically feasible product of microbiological production, therefore studies on cheap and renewable raw materials for its production are highly desirable. In this study citric acid was synthesized by genetically engineered strains of Yarrowia lipolytica from widely available, renewable polysaccharide – inulin. Hydrolysis of inulin by the Y. lipolytica strains was established by expressing the inulinase gene (INU1 gene; GenBank: X57202.1) with its native secretion signal sequence was amplified from genomic DNA from Kluyveromyces marxianus CBS6432. To ensure the maximum citric acid titer, the optimal cultivation strategy–repeated-batch culture was applied.ResultsThe strain Y. lipolytica AWG7 INU 8 secreted more than 200 g dm− 3 of citric acid during repeated-batch culture on inulin, with a productivity of 0.51 g dm− 3 h− 1 and a yield of 0.85 g g− 1.ConclusionsThe citric acid titer obtained in the proposed process is the highest value reported in the literature for Yarrowia yeast. The obtained results suggest that citric acid production from inulin by engineered Y. lipolytica may be a very promising technology for industrial citric acid production.

PENENTUAN AKTIVITAS INULINASE PADA SUBSTRAT INULIN A1-KG DARI BAKTERI MESOFILIK RIZOSFER UMBI DAHLIA (DAHLIA SP)

Inulinase is an enzyme that can catalyze inulin hydrolysis reaction to fructose and fructooligosaccharide (FOS) which two important compounds in the food industry. This study aims to determine the optimum activity of inulinase on variations in pH (3.5; 4; 4.5; 5; and 5.5), temperature (18oC; 25oC; 28oC; 37oC and 45oC); and substrate concentration (0.5%; 1%, 1.5%, 2% and 2.25%) with an incubation time of 30 minutes. In addition, this study also aims to determine the value of KM, Vmax and determine the type of action of inulinase. Determination of the optimum activity of inulinase was determined by DNS reagents whose absorbance was measured using spice at λ 536 nm. Determination of the type of action of the inulinase enzyme is determined by the TLC method. Inulinase activity found optimum at pH 4; 40oC temperature and 2% substrate concentration. The values of KM and Vmax inulinase are 3.12% (w / v) and Vmax is 0.288 U / mL. The type of action of inulinase enzymes found in Rhizosphere bacteria dahlia isolates A1-KG is endoinulinase. Keywords: inulin, inulinase, inulinase enzyme activity, and type of inulinase action from bacteria.

Aktivitas Enzim Inulinase dan Laju Pertumbuhan Spesifik Isolat Bakteri IS-1 pada Medium Tepung Umbi Dahlia

Dahlia bulbs (Dahlia variabilis) contains carbohydrates in the form of inulin. Inulin is a form of fructose polymer from fructose monomers. Inulin hydrolysis produces a product in the form of fructose.Inulinase enzyme is an enzyme able to purely hydrolyze inulin. This study aims to determine the activity of inulinase enzymes and the specific growth rate of IS_1 bacterial isolates producing inulinase in medium of Dahlia tuber flour. Isolates of inulinase-producing bacteria were isolated directly from decay dahlia tubers and used as an inoculum in creating starter.The measurement of cell growth was carried out by inoculating a 20-hour starter on the production medium. Incubation is done for 24 hours using a rotary shaker with a speed of 120 rpm. Sampling was carried out every 4 hours at 0-hour (T0), 4 hours (T4), 8 hours (T8), 12 hours (T12), 16 hours (T16), 20 hours (T20) and 24 hours (T24) intervals with a sample of 5 mL measured for absorbance of λ 520 nm using spectrophotometer. Production medium culture in each sample was taken 1 mL and centrifuged at 3000 rpm for 10 minutes to obtain supernatant of crude enzyme. Measurement of inulinase enzyme activity was carried out using 3,5-dinitrosalicylic acid (DNS) method and spectrophotometric method at λ 570 nm. IS_1 bacterial isolate showed optimum growth at incubation time of 8 hours with OD of 0.647 and had a specific growth rate (µ) of 0.02 / hour with a generation time of 34.65 hours. The highest enzyme activity produced by IS_1 bacteria at 8 hours incubation time was 0.490 IU. The conclusion of this study is that IS_1 bacteria indicates good growth in medium of dahlia tuber flour and has inulinase enzyme activity which is able to hydrolyze inulin into fructose.  Key words: inulin, bacterial isolate, inulinase, productionÂ

Fructose production from inulin using fungal inulinase immobilized on 3-aminopropyl-triethoxysilane functionalized multiwalled carbon nanotubes

The main objective of the present work was to modify multiwalled carbon nanotubes (MWCNTs) using 3-aminopropyl-triethoxysilane (APTES) to generate amino-terminated surfaces for inulinase immobilization, which can be further used for fructose production. CCRD of response surface methodology was used for optimization of inulinase immobilization on MWCNTs. At optimized parameters (APTES concentration 4%; sonication time 4 h; enzyme coupling time 1.5 h and enzyme load 15 IU), maximal inulinase activity and immobilization yield was 60.7% and 74.4%, respectively. Immobilized inulinase showed same pH optima of free enzyme, while an elevation in temperature optima to 60 °C was observed after its immobilization. Immobilized inulinase also shown enhancement in pH stability and thermostability. Overall, 4.54-fold rise in half-life of inulinase was detected after immobilization at 60 °C. Km and Vmax of inulinase decreased after immobilization. Immobilized inulinase preserved 28% of its residual activity after 10 consecutive batch cycles of inulin hydrolysis for the production of fructose.

Physicochemical and rheological properties of cross-linked inulin with different degree of polymerization

Long-chain inulin (L-In) and short-chain inulin (S-In) from native inulin was separated through the method of alcohol precipitation. Cross-linked inulin with two different degree of polymerization (average DP = 6.88 and 15.10) were prepared in aqueous solutions by using the L-In and S-In respectively as raw material and sodium hexametaphosphate as cross-linker. Structural characteristics of cross-linked inulin were determined by Fourier-transform infrared spectroscopy and scanning electron microscopy. Compared with native L-In and S-In, cross-linked inulin had a higher intrinsic viscosity, stronger stability and moisture absorption capability, but lower water solubility. Only 1% reducing sugar produced when cross-linked inulin was heated within 100 °C, and inulin hydrolysis occurred in acidic environment (pH < 6). Rheological properties of inulin dispersions with different degree of polymerization were investigated and compared. The viscoelastic properties of steady shear measurements indicated that cross-linked inulin dispersions presented shear-thinning behaviors, which could be described by a power law model with determination coefficients (R2 = 0.9312–0.9926). The viscoelastic properties of dynamic frequency sweep measurements indicated that cross-linked inulin dispersion showed more solid viscoelastic properties than corresponding native inulin dispersions.

Characterization of Fructan Metabolism During Jerusalem Artichoke (Helianthus tuberosus L.) Germination.

The inulin-type fructans in Jerusalem artichoke (Helianthus tuberosus L.) tubers exhibit different degrees of polymerization and are critical for germination. We aimed to characterize the sugar metabolism dynamics in the tubers without bud eyes or shoots (T) and BE/S of indoor- and field-grown Jerusalem artichokes during germination. Ht1-FEH II and Ht1-FEH III (1-fructan exohydrolases II and III, inulin-degrading enzymes) expression increased 5 days after planting indoors, whereas Ht1-FEH II expression increased 72 days after planting in the field in T and BE/S. Ht1-SST (sucrose:sucrose 1-fructosyl transferase, inulin synthesis initiator), and Ht1-FFT (fructan:fructan 1-fructosyl transferase, inulin elongator) expression generally decreased in indoor-grown T. The enzyme activities of 1-FEH and 1-FFT were unchanged during germination in both indoor- and field-grown T and BE/S, whereas 1-SST activity decreased in indoor-grown T, while 1-FEH and 1-FFT activities increased as a function of germination time in BE/S of both indoor- and field-grown tubers. The total soluble sugar content gradually decreased in T after germination indoors or in the field, while at the end of germination, the sucrose and fructan contents decreased, and fructose content increased in the field. The enzyme activities of soluble vacuolar (VI) or neutral invertase (NI) did not change significantly, except at the late germination stage. Sucrose synthase (SS) and sucrose-phosphate synthase (SPS) activities were not significantly changed in T and BE/S in indoor-grown artichokes, while SS activity gradually increased, and SPS activity gradually decreased in field-grown artichokes, alongside sucrose degradation. Compared to T, BE/S generally had higher enzyme activities of 1-FEH and 1-FFT, promoting inulin hydrolysis. This work shows that the process of tuber germination is similar indoors and in the field, and germination studies can therefore be conducted in either environment.

Bioconversion of inulin to difructose anhydride III by a novel inulin fructotransferase from Arthrobacter chlorophenolicus A6

The gene encoding difructose anhydride III (DFA III)-forming inulin fructotransferase (IFTase) from Arthrobacter chlorophenolicus A6 was cloned and overexpressed in Escherichia.coli. The recombinant IFTase (DFA III-forming) was purified using one-step nickel affinity chromatography. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration analyses, the enzyme showed a homotrimeric form composed of three identical subunits, each with an apparent molecular mass of 43 kDa. The maximum catalytic activity was shown at 65 °C and pH 5.5, and the specific activity was measured as 902 U mg−1. The enzyme showed remarkable thermostability and over half of the initial activity was retained after incubation at 80 °C for 1 h. The Km and Vmax were estimated to 12.93 mM and 2.89 μmol min−1 ml−1, respectively. After complete hydrolysis of inulin for DFA III production by the purified enzyme, the produced minor products contained sucrose (GF), 1-kestose (GF2), and nystose (GF3). The smallest substrate was identified to be GF3. When 50, 100, and 200 g l−1 of inulin were hydrolyzed by the purified IFTase, the DFA III yield reached 81%, 72%, and 67%, respectively.

HYDROLYTIC HYDROGENATION OF INULIN WITH USE MAGNETIC-SEPARATE Ru-CONTAINING CATALYST

The combined hydrolysis and hydrogenation of inulin was studied on Ru-containing magnetically recoverable catalyst, using subcritical water as solvent. The Ru−Fe3O4−SiO2 catalysts are synthesized by incorporation of magnetite nanoparticles (NPs) in mesoporous silica pores followed by formation of 2 nm Ru NPs. The latter was obtained by thermal decomposition of ruthenium acetylacetonate in the pores. Magnetic properties of Fe3O4−SiO2 are typical for superparamagnetic iron oxide NPs of comparable size and allow to make a fast magnetic separation of the catalyst. The results of liquid nitrogen adsorption measurements are typical for mesoporous materials. The BET surface area of catalyst is 280 m2/g, what is allowed for mesoporous catalytic materials. The XPS spectra of Ru-Fe3O4-SiO2 demonstrate a good homogeneity of the sample. The catalyst was tested in hydrolytic hydrogenation of inulin. Inulin is hydrolyzed with formation of fructose and a small amount of glucose. There is a hydrogenation of fructose and glucose in hydrogen with receiving a mannitol and sorbitol, respectively. Mannitol is widely used in production of medicines and pharmaceutics, liquid fuel, the chemical and food industry, biotechnology and production of cosmetics. Mannitol presents in many plants and seaweeds. However, the extraction of mannitol from these raw materials is not a profitable process. Instead, fermentation and catalytic hydrogenation processes are used industrially. Nowadays, mannitol can be obtained by catalytic hydrogenation of monosaccharides like fructose or from glucose-fructose mixtures, using heterogeneous catalyst. During the researches key parameters of process, such as temperature and time of reaction, partial pressure of hydrogen are varied. At optimum reaction conditions: temperature of 150 °C, partial pressure of hydrogen of 60 bars in 45 min, – conversion of inulin was achieved of 100 %, a mannitol yield was 44.3 %. The used catalyst has shown high activity and stability in hydrothermal conditions. Stable magnetic properties of the catalyst cause his easy separation from reactionary mixture by means of external magnetic field.Forcitation:Ratkevich E.A., Manaenkov O.V., Matveeva V.G., Kislitza O.V., Sulman E.M. The hydrolytic hydrogenation of inulin catalyzed by Ru-containing magnetically recoverable catalyst. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 4-5. P. 76-81

Preparation of Macroporous PEK-C Powders with Chemically Linked Ionic Liquids as Catalyst and Kinetics Study of Biomass

Macroporous cardo polyetherketone (PEK-C) powder catalyst bearing covalently ionic liquids (PEK-C-ILs) was prepared, it exhibited a high catalytic performance for biomass hydrolysis. A hydrolysis mechanism of inulin over this new catalyst was proposed as well. The influences of degree of chloromethylation of PEK-C, catalyst dosage, reaction temperature, pore size of PEK-C-ILs and inulin concentration were investigated. A high conversion of inulin of 99.7% was obtained under the optimal reaction conditions. Meanwhile, the hydrolysis kinetics was studied under different conditions. The proposed kinetic model of inulin hydrolysis catalyzed by PEK-C-ILs was established and it successfully predicted the inulin hydrolysis in wider ranges of experimental conditions. The results demonstrated that the catalytic inulin hydrolysis performance of PEK-C-ILs is better than that of homogenous ILs due to that there was a high-density spatial distribution of active sites on the surface and inner pore wall of PEK-C after the ILs was immobilized. Furthermore, the stability including chemical structure and physical appearance and reusability tests showed that PEK-C-ILs catalyst could be effectively separated and recovered from hydrolysates and has excellent reusability. Importantly, using the PEK-C-ILs as catalyst makes the recycling of ILs simplified, efficient and the hydrolysis process more economical. At the same time, it avoided the potential hazards of homogenous ILs to the environment. Therefore, it is a kind of green catalyst with potential application prospect in many catalysis fields.

Penentuan Kadar Fruktosa Hasil Hidrolisis Inulin dengan DNS sebagai Pengoksidasi

Kadar fruktosa hasil hidrolisis inulin dapat ditentukan secara mudah dan praktis dengan reagen DNS. Tujuan penelitian adalah untuk menentukan kondisi optimum reaksi antara fruktosa dengan reagen DNS dan untuk menentukan kadar fruktosa hasil hidrolisis inulin. Alat yang digunakan dalam penelitian ini adalah spektronik 20 D dan HPLC, Fase gerak pada HPLC adalah etanol:air dengan berbagai perbandingan. Kolom yang digunakan adalah ODS C-18, C-8, dan CLC-Sil. Reaksi fruktosa dengan reagen DNS memiliki λmaks 499 nm, volume optimum larutan fruktosa adalah 100 µL, pH optimum fruktosa adalah 4,5 dan waktu kestabilan warna DNS tereduksi pada waktu menit ke-30. Hasil analisis DNS tereduksi menggunakan HPLC tidak memberikan pemisahan yang baik pada tipe kolom ODS C-18, C-8 dan CLC-Sil dengan beberapa variasi fase gerak etanol:air, sehingga untuk pengukuran selanjutnya digunakan spektronik 20 D. Kadar fruktosa hasil hidrolisis inulin dengan konsentrasi 0,5 %, 1 %, dan 2,5% inulin adalah 183,6 µg/mL, 295,6 µg/mL, dan 512,6 µg/mL.

Immobilization of thermostable exo-inulinase from mutant thermophilic Aspergillus tamarii-U4 using kaolin clay and its application in inulin hydrolysis.

In this study, attempts were made to immobilize purified exo-inulinase from mutant thermophic Aspergillus tamarii-U4 onto Kaolinite clay by covalent bonding cross-linked with glutaraldehyde with an immobilization yield of 66% achieved. The free and immobilized inulinases were then characterized and characterization of the enzymes revealed that temperature and pH optima for the activity of the free and immobilized enzymes were both 65 °C and pH 4.5 respectively. The free inulinase completely lost its activity after incubation at 65 °C for 6 h while the immobilized inulinase retained 16.4% of its activity under the same condition of temperature and incubation time. The estimated kinetic parameters Km and Vmax for the free inulinase as estimated from Lineweaver-Burk plots were 0.39 mM and 4.21 µmol/min for the free inulinase and 0.37 mM and 4.01 µmol/min for the immobilized inulinase respectively. Inulin at 2.5% (w/v) and a flow rate of 0.1 mL was completely hydrolysed for 10 days at 60 °C in a continuous packed bed column and the operational stability of the system revealed that the half-life of the immobilized inulinase was 51 days. These properties make the immobilized exo-inulinase from Aspergillus tamarii-U4 a potential candidate for the production of fructose from inulin hydrolysis.

RETRACTED: Biocatalytic strategies for the production of high fructose syrup from inulin

The consumption of natural and low calorie sugars has increased enormously from the past few decades. To fulfil the demands, the production of healthy sweeteners as an alternative to sucrose has recently received considerable interest. Fructose is the most health beneficial and safest sugar amongst them. It is generally recognised as safe (GRAS) and has become an important food ingredient due its sweetening and various health promising functional properties. Commercially, high fructose syrup is prepared from starch by multienzymatic process. Single-step enzymatic hydrolysis of inulin using inulinase has emerged as an alternate to the conventional approach to reduce complexity, time and cost. The present review, outlines the enzymatic strategies used for the preparation of high fructose syrup from inulin/inulin-rich plant materials in batch and continuous systems, and its conclusions.

Partial Gene Cloning and Enzyme Structure Modeling of Exolevanase Fragment from Bacillus subtilis

Inulin hydrolysis thermophilic and thermotolerant bacteria are potential sources of inulin hydrolysis enzymes. Partial gene that encodes inulin hydrolysis enzymes had been isolated from Bacillus subtilis using polymerase chain reaction (PCR) method with the DPE.slFandDPE.eR degenerative primers. The partial gene was cloned into pGEM-T Easy vector with E. coli as host cells and analyzed using BLASTx, CrustalW2, and Phyre2 programs. Size of thepartial gene had been found539 bp that encoded 179aminoacid residues of protein fragment. The sequences of protein fragment was more similar to exolevanase than exoinulinase. The protein fragment had conserved motif FSGS, and specific hits GH32 β-fructosidase. It had three residues of active site and five residues of substrate binding. The active site on the protein fragment were D (1-WLNDP-5), D (125-FRDPK-129) and E (177-WEC-179). Substrate binding on the protein fragment were ND (1-WLNDP-5), Q (18-FYQY-21), FS (60-FSGS-63) RD (125-FRDPK-129) and E (177-WEC-179).

Controllable modification of polymer membranes by LDDLT plasma flow: Grafting acidic ILs into PPF membrane for catalytic performance

This article focused on the membranes covalent bearing ionic liquid for catalytic performance. The polypropylene fibrous (PPF) membranes was activated by long-distance and dynamic low-temperature plasma flow. Thereafter, it was successfully grafted with 1-vinylimidazole acidic ionic liquids (ILs) through free radical polymerization. The membranes formed were characterized through Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, bubble pressure method filter membrane pore size analyzer, electronic universal testing machine and contact angle meter. Catalytic hydrolysis of inulin polysaccharide into fermentable reducing sugars using the ILs grafted PPF (ILs-g-PPF) membranes was also evaluated by the DNS method. The results confirmed the successful and steady grafting onto the surfaces and the pore walls of PPF membranes. The resulting ILs-g-PPF membrane exhibited high catalytic activity for hydrolysis of inulin and could be easily separated from the reaction mixture. After two rinses and six times of hydrolysis for the same feed, the hydrolysis ratio was close to 100%. Moreover, the spent ILs-g-PPF membrane was of good reusability and stability. Catalytic PPF membranes obtained by the ILs immobilization have advantages over the ILs themselves for chemical industrial application.