Production of aglycone protopanaxatriol from ginseng root extract using Dictyoglomus turgidum β-glycosidase that specifically hydrolyzes the xylose at the C-6 position and the glucose in protopanaxatriol-type ginsenosides

The hydrolytic activity of a recombinant β-glycosidase from Dictyoglomus turgidum that specifically hydrolyzed the xylose at the C-6 position and the glucose in protopanaxatriol (PPT)-type ginsenosides followed the order Rf > Rg₁ > Re > R₁ > Rh₁ > R₂. The production of aglycone protopanaxatriol (APPT) from ginsenoside Rf was optimal at pH 6.0, 80 °C, 1 mg ml^?1 Rf, and 10.6 U ml^?1 enzyme. Under these conditions, D. turgidum β-glycosidase converted ginsenoside R₁ to APPT with a molar conversion yield of 75.6 % and a productivity of 15 mg l^?1 h^?1 after 24 h by the transformation pathway of R₁ → R₂ → Rh₁ → APPT, whereas the complete conversion of ginsenosides Rf and Rg₁ to APPT was achieved with a productivity of 1,515 mg l^?1 h^?1 after 6.6 h by the pathways of Rf → Rh₁ → APPT and Rg₁ → Rh₁ → APPT, respectively. In addition, D. turgidum β-glycosidase produced 0.54 mg ml^?1 APPT from 2.29 mg ml^?1 PPT-type ginsenosides of Panax ginseng root extract after 24 h, with a molar conversion yield of 43.2 % and a productivity of 23 mg l^?1 h^?1, and 0.62 mg ml^?1 APPT from 1.35 mg ml^?1 PPT-type ginsenosides of Panax notoginseng root extract after 20 h, with a molar conversion yield of 81.2 % and a productivity of 31 mg l^?1 h^?1. This is the first report on the APPT production from ginseng root extract. Moreover, the concentrations, yields, and productivities of APPT achieved in the present study are the highest reported to date.     

Characterization of a recombinant cellobiose 2-epimerase from Dictyoglomus turgidum that epimerizes and isomerizes β-1,4- and α-1,4-gluco-oligosaccharides

A recombinant putative N-acyl-d-glucosamine 2-epimerase from Dictyoglomus turgidum was identified as a cellobiose 2-epimerase by evaluating its substrate specificity. The purified enzyme was a 46?kDa monomer with a specific activity of 16.8?μmol?min^?1?mg^?1 for cellobiose. The epimerization activity was maximal at pH 7.0 and 70?°C with a half-life of 55?h. The isomerization of the glucose at the reducing end of β-1,4- and α-1,4-linked gluco-oligosaccharides to a fructose moiety by the enzyme took place after the epimerization of the glucose to a mannose moiety. The enzyme converted cellobiose to 12.8?% 4-O-β-d-glucopyranosyl-d-mannose and 54.6?% 4-O-β-d-glucopyranosyl-d-fructose as an equilibrium and converted lactose to 12.8?% epilactose and 54.3?% lactulose.     

Production,purification, and properties of β-glucosidase from Candida wickerhamii

Summary Candida wickerhamii growing on cellobiose produced -glucosidase with high activity against -nitrophenyl glucoside (PNPG) but low activity against cellobiose. -glucosidase production was constitutive, and was repressed by -glucosides and glucose. -glucosides containing an aromatic moiety in the aglycon were the best substrates for -glucosidase indicating that the enzyme is an aryl--glucosidase. A -glucosidase from C. wickerhamii cells was purified by (NH₄)₂SO₄ precipitation, dialysis, ion-exchange chromatography and gel filtration. The purified enzyme was homogeneous as shown by sodium-dodecyl-sulphate polyacrylamide gel electrophoresis and discontinuous gel electrophoresis. The purified enzyme hydrolysed PNPG but not cellobiose. The K_m of the enzyme was 0.185 mM. Glucose inhibited the enzyme competitively and the K_i was 7.5 mM. The apparent molecular mass was 97,000. The optimum pH and temperature for enzyme activity were between pH 7 and 7.4 and 40°C respectively. At temperatures of 45°C and greater the enzyme was inactivated. The activation energy of the enzyme was 29.4 kJ · mol^-1.     

Production of ginsenosides Rg1 and Rh1 by hydrolyzing the outer glycoside at the C-6 position in protopanaxatriol-type ginsenosides using β-glucosidase from Pyrococcus furiosus

The specific activity of a recombinant β-glucosidase from Pyrococcus furiosus for protopanaxatriol (PPT)-type ginsenosides followed the order Rf > R₁ > Re > R₂ > Rg₂, which were converted to Rh₁, Rg₁, Rg₁, Rh₁, and Rh₁, respectively. No activity was observed with Rg₁ and Rh₁. Thus, P. furiosus β-glucosidase hydrolyzed the outer glycoside at the C-6 position in PPT-type ginsenosides whereas the enzyme did not hydrolyze the inner glucoside at the C-6 position and the glucoside at the C-20 position. The activity for Rf was optimal at 95 °C, pH 5.5, 5 mM ginsenoside, and 32 U enzyme l^?1. Under these conditions, P. furiosus β-glucosidase completely converted from R₁ to Rg₁ after 10 h, with a productivity of 0.4 g l^?1 h^?1 and completely converted Rf to Rh₁ after 1.2 h, with a productivity of 2.74 g l^?1 h^?1.     

Production of hydrogen from α-1,4- and β-1,4-linked saccharides by marine hyperthermophilic Archaea

Nineteen hyperthermophilic heterotrophs from deep-sea hydrothermal vents, plus the control organism Pyrococcus furiosus, were examined for their ability to grow and produce H₂ on maltose, cellobiose, and peptides and for the presence of the genes encoding proteins that hydrolyze starch and cellulose. All of the strains grew on these disaccharides and peptides and converted maltose and peptides to H₂ even when elemental sulfur was present as a terminal electron acceptor. Half of the strains had at least one gene for an extracellular starch hydrolase, but only P. furiosus had a gene for an extracellular β-1,4-endoglucanase. P. furiosus was serially adapted for growth on CF11 cellulose and H₂ production, which is the first reported instance of hyperthermophilic growth on cellulose, with a doubling time of 64 min. Cell-specific H₂ production rates were 29 fmol, 37 fmol, and 54 fmol of H₂ produced cell⁻¹ doubling⁻¹ on α-1,4-linked sugars, β-1,4-linked sugars, and peptides, respectively. The highest total community H₂ production rate came from growth on starch (2.6 mM H₂ produced h⁻¹). Hyperthermophilic heterotrophs may serve as an important alternate source of H₂ for hydrogenotrophic microorganisms in low-H₂ hydrothermal environments, and some are candidates for H₂ bioenergy production in bioreactors.     

β-Glucosidase from Penicillium aculeatum hydrolyzes exo-, 3-O-, and 6-O-β-glucosides but not 20-O-β-glucoside and other glycosides of ginsenosides

A novel β-glucosidase from Penicillium aculeatum was purified as a single 110.5-kDa band on SDS–PAGE with a specific activity of 75.4 U?mg^?1 by salt precipitation and Hi-Trap Q HP and Resource Q ion exchange chromatographies. The purified enzyme was identified as a member of the glycoside hydrolase 3 family based on its amino acid sequence. The hydrolysis activity for p-nitrophenyl-β-d-glucopyranoside was optimal at pH 4.5 and 70 °C with a half-life of 55 h. The enzyme hydrolyzed exo-, 3-O-, and 6-O-β-glucosides but not 20-O-β-glucoside and other glycosides of ginsenosides. Because of the novel specificity, this enzyme had the transformation pathways for ginsenosides: Rb₁?→?Rd?→?F₂?→?compound K, Rb₂?→?compound O?→?compound Y, Rc?→?compound Mc₁?→?compound Mc, Rg₃?→?Rh₂?→?aglycone protopanaxadiol (APPD), Rg₁?→?F₁, and Rf?→?Rh₁?→?aglycone protopanaxatriol (APPT). Under the optimum conditions, the enzyme converted 0.5 mM Rb_2, Rc, Rd, Rg₃, Rg₁, and Rf to 0.49 mM compound Y, 0.49 mM compound Mc, 0.47 mM compound K, 0.23 mM APPD, 0.49 mM?F₁, and 0.44 mM APPT after 6 h, respectively.     

Characterization of recombinant β-glucosidase from Arthrobacter chlorophenolicus and biotransformation of ginsenosides Rb1, Rb2, Rc,and Rd

The focus of this study was the cloning, expression, and characterization of recombinant ginsenoside hydrolyzing β-glucosidase from Arthrobacter chlorophenolicus with an ultimate objective to more efficiently bio-transform ginsenosides. The gene bglAch, consisting of 1,260 bp (419 amino acid residues) was cloned and the recombinant enzyme, overexpressed in Escherichia coli BL21 (DE3), was characterized. The GST-fused BglAch was purified using GST·Bind agarose resin and characterized. Under optimal conditions (pH 6.0 and 37°C) BglAch hydrolyzed the outer glucose and arabinopyranose moieties of ginsenosides Rb1 and Rb2 at the C20 position of the aglycone into ginsenoside Rd. This was followed by hydrolysis into F₂ of the outer glucose moiety of ginsenoside Rd at the C3 position of the aglycone. Additionally, BglAch more slowly transformed Rc to F₂ via C-Mc₁ (compared to hydrolysis of Rb₁ or Rb₂). These results indicate that the recombinant BglAch could be useful for the production of ginsenoside F₂ for use in the pharmaceutical and cosmetic industries.     

Expression of enzymatically active,recombinant barley α-glucosidase in yeast and immunological detection of α-glucosidase from seed tissue

An -glucosidase cDNA clone derived from barley aleurone tissue was expressed in Pichia pastoris and Escherichia coli. The gene was fused with the N-terminal region of the Saccharomyces cerevisiae -factor secretory peptide and placed under control of the Pichia AOX1 promoter in the vector pPIC9. Enzymatically active, recombinant -glucosidase was synthesized and secreted from the yeast upon induction with methanol. The enzyme hydrolyzed maltose > trehalose > nigerose > isomaltose. Maltase activity occurred over the pH range 3.5–6.3 with an optimum at pH 4.3, classifying the enzyme as an acid -glucosidase. The enzyme had a K_m of 1.88 mM and V_max of 0.054 µmol/min on maltose. The recombinant -glucosidase expressed in E. coli was used to generate polyclonal antibodies. The antibodies detected 101 and 95 kDa forms of barley -glucosidase early in seed germination. Their levels declined sharply later in germination, as an 81 kDa -glucosidase became prominent. Synthesis of these proteins also occurred in isolated aleurones after treatment with gibberellin, and this was accompanied by a 14-fold increase in -glucosidase enzyme activity.Abbreviations: AGL, barley seed -glucosidase; rAGL, recombinant barley seed -glucosidase; BMGY, buffered glycerol-complex medium; BMMY, buffered methanol-complex medium; GA, gibberellic acid; UTR, untranslated region.     

Biochemical characterization of digestive α-amylase, α-glucosidase and β-glucosidase in pistachio green stink bug,Brachynema germari Kolenati (Hemiptera: Pentatomidae)

The pistachio green stink bug, Brachynema germari, has 3–5 generations per year and causes severe damages to pistachio crops in Iran. Physiological digestive processes, such as digestive carbohydrases, can be used to design new strategies in IPM programs for controlling this pest. The enzyme α-amylase digests starch during the initial stage of digestion. Complete breakdown of carbohydrates takes place in the midgut where α- and β-glucosidic activities are highest. Alpha-amylase and α- and β-glucosidase activities were found in the midgut and salivary glands of pistachio green stink bug adults. Overall enzyme activities were significantly higher in the midgut than in salivary glands. The highest α-amylase and α- and β-glucosidase activities were in section v3, whereas the lowest activities were in section v4. V_max was higher and K_m was lower in the midgut than in the salivary glands for these enzymes. In the pistachio green stink bug, the optimal pH was pH 5–6.5 and the optimal temperature was 30 °C to 35 °C for these enzymes. Alpha-amylase activity in the midgut and salivary glands decreased as the concentrations of MgCl₂, EDTA and SDS increased. Enzyme activities in both midgut and salivary glands increased in the presence of NaCl, CaCl₂, and KCl. NaCl had a negative effect on alpha-amylase extracted from salivary glands.     

Enzymatic synthesis of cyclohexyl-α and β-d-glucosides catalyzed by α- and β-glucosidase in a biphase system

Two secondary alcohol glucosides, cyclohexyl-α-d-glucoside and cyclohexyl-β-d-glucoside, were synthesized via the condensation reaction of cyclohexanol with d-glucose in a biphase system catalyzed by α-glucosidase and β-glucosidase, respectively. The effects of pH, water content, glucose concentration and metal ions on the yield of glucosides were studied. The optimum catalytic conditions established for α-glucosidase was 25% (v/v) water content, 2.5 mol/L glucose concentration and pH 2.0, and for β-glucosidase was 30% (v/v) water content, 2.0 mol/L glucose and pH 5.0. The maximum yield of glucoside was 13.3 mg/mL for cyclohexyl-α-d-glucoside and 8.9 mg/mL for cyclohexyl-β-d-glucoside. Synthesis progress was monitored by TLC and quantitatively analyzed by pre-derived capillary gas chromatography (GC). The retention time was 12.34 min for the α isomer and 12.96 min for the β isomer, respectively. With an anomeric purity of more than 99.5%, the two glucosides display excellent site-specific catalysis by α- and β-glucosidase. Herein, we present a general method to produce anomerically pure glucosides via a one-step bio-reaction in a biphase system. This method could potentially be applied in glucosylation of primary and secondary alcohols or other reactions requiring glucosylation.     

Production of pharmaceutically important genistein and daidzein from soybean flour extract by using β-glucosidase derived from Penicillium janthinellum NCIM 1171

Genistein and daidzein are isoflavones with well-recognized biological activities. Their glycosidic forms (genistin and daidzin, respectively) are abundant in some plants. In this study, production of β-glucosidase from Penicillium janthinellum NCIM 1171 and its use in the obtaining genistein and daidzein are described. In a response surface methodology (RSM) optimized medium, levels of β-glucosidase under submerged and solid state fermentation conditions were found to be 10.2 ± 0.75 IU/mL and 121 ± 9.3 IU/g, respectively. The supernatants resulting from submerged fermentation were subjected to ion exchange and gel filtration chromatography and the enzyme was purified in a 44.4 fold manner with final recovery of 39.75 %. The β-glucosidase was deduced to be a monomeric protein with a molecular mass of 97.18 kDa. The purified protein showed 46 % sequence coverage matching with β-glucosidase derived from Penicillium sp. ABP88968. The purified enzyme was effective in producing genistein and daidzein from soybean (Glycine max) flour extract with a yield of 92.3 and 95 %, respectively. To the best of our knowledge, this is the first report on the use of a wild type strain of P. janthinellum for the production of genistein and daidzein with high productivity and purity.     

Hydrolysis of natural and synthetic substrates by α-l-fucosidase, β-d-glucuronidase and β-n-acetylhexosaminidase purified from molluscs

• 1.1. Several mollusc glycosidases have been studied for their activities towards natural substrates. α-l-Fucosidases from Chamelea gallina, Tapes rhomboideus and Mytilus edulis hydrolyze oligosaccharides (di, tri and pentasaccharides) with α1 → 2, α1 → 3 and α1 → 4 bonds, fucose-containing glycopeptides from bovine thyroglobulin and the porcine submandibular mucin (devoid of sialic acid); α-l-fucosidase from Littorina littorea hydrolyzes fucose-containing glycopeptides from bovine thyroglobulin.
• 2.2. β-d-Glucuronidase from L. littorea hydrolyzes hyaluronic acid, chondroitin 4-sulfate and heparin with a very low activity; however, it is much more active on oligosaccharides (from the above-mentioned macromolecules) containing non-reducing terminal glucuronyl residues.
• 3.3. β-N-Acetylhexosaminidase from Helicella ericetorum acts mainly with an endo-hydrolase activity on β1 → 4N-acetylhexosamine linkages of ovalbumin, ovomucoid, chitin, hyaluronic acid and chondroitin
• 4.4-sulfate; it has also a secondary exo-hydrolase activity on these substrates.

     

Hydrolysis of the outer β-(1,2)-d-glucose linkage at the C-3 position of ginsenosides by a commercial β-galactosidase and its use in the production of minor ginsenosides

Commercial β-galactosidase from Aspergillus oryzae (SUMILACT L^TM) was used for the bioconversion of the ginsenosides Rb1, Rb2, Rc, Rd, and Rg3 to gypenoside-XVII, compound-O, compound-MC1, F2, and Rh2, respectively. The optimal conditions were pH 4.5, 50?°C, 60?U·mL^?1 enzyme, and 8.0?mM substrate. Interestingly, the enzyme hydrolyzed only the outer β-(1,2)-d-glucose linkage at the C-3 position of ginsenosides. Under optimum conditions, the enzyme completely converted Rb1, Rb2, Rc, Rd, and Rg3 to gypenoside-XVII, compound-O, compound-MC1, F2, and Rh2, respectively, with the highest productivity.     

Inhibition of protein tyrosine phosphatase (PTP1B) and α-glucosidase by geranylated flavonoids from Paulownia tomentosa

Protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase are important targets to treat obesity and diabetes, due to their deep correlation with insulin and leptin signalling, and glucose regulation. The methanol extract of Paulownia tomentosa fruits showed potent inhibition against both enzymes. Purification of this extract led to eight geranylated flavonoids (1–8) displaying dual inhibition of PTP1B and α-glucosidase. The isolated compounds were identified as flavanones (1–5) and dihydroflavonols (6–8). Inhibitory potencies of these compounds varied accordingly, but most of the compounds were highly effective against PTP1B (IC₅₀?=?1.9–8.2?μM) than α-glucosidase (IC₅₀?=?2.2–78.9?μM). Mimulone (1) was the most effective against PTP1B with IC₅₀?=?1.9?μM, whereas 6-geranyl-3,3′,5,5′,7-pentahydroxy-4′-methoxyflavane (8) displayed potent inhibition against α-glucosidase (IC₅₀?=?2.2?μM). All inhibitors showed mixed type Ι inhibition toward PTP1B, and were noncompetitive inhibitors of α-glucosidase. This mixed type behavior against PTP1B was fully demonstrated by showing a decrease in V_max, an increase of K_m, and K_ik/K_iv ratio ranging between 2.66 and 3.69.     

Enzymatic transformation of the major ginsenoside Rb2 to minor compound Y and compound K by a ginsenoside-hydrolyzing β-glycosidase from Microbacterium esteraromaticum

The ginsenoside-hydrolyzing β-glycosidase (Bgp3) derived from Microbacterium esteraromaticum transformed the major ginsenoside Rb2 to more pharmacologically active minor ginsenosides including compounds Y and K. The bgp3 gene consists of 2,271?bp encoding 756 amino acids which have homology to the glycosyl hydrolase family 3 protein domain. Bgp3 is capable of hydrolyzing beta-glucose links and arabinose links. HPLC analysis of the time course of ginsenoside Rb2 hydrolysis by Bgp3 (0.1?mg?enzyme?ml(-1) in 20?mM sodium phosphate buffer at 40?°C and pH 7.0) showed that the glycosidase first hydrolyzed the inner glucose moiety attached to the C-3 position and then the arabinopyranose moiety attached to the C-20 position. Thus, Bgp3 hydrolyzed the ginsenoside Rb2 via the following pathway: Rb2?→?compound Y?→?compound K.     

Production, purification and identification of fructooligosaccharides produced by β-fructofuranosidase from Aspergillus niger IMI 303386

Aspergillus niger IMI 303386 produced higher levels of intra- and extracellular -fructofuranosidase and inulinase on inulin than on sucrose. Intracellular -fructofuranosidase from sucrose medium catalysed the best transfructosylation reaction. The concentration of fructooligosaccharides (FOS) reached a maximum in 72 h with 25% (w/v) sucrose. The FOS were purified and the main products were kestose and nystose. Inulinase hydrolysed inulin in an exofashion and released mainly fructose.     

Production of β-glycosidases (linamarase and amygdalase) and pectolytic enzymes by Penicillium spp.

Fifty-eight strains, representing 31 species of Penicillium, were screened for extracellular -glycosidase (amygdalase/linamarase) and pectolytic (polygalacturonase, pectin lyase) enzymes. One strain each of P. turbatum, P. piceum and P. paxilli showed very high -glycosidase activity and slightly lower activities were found in P. crustosum, P. expansum, P. oxalicum and P. aurantiogriseum. Generally, maximum -glycosidase activity showed reached during the stationary phase of growth. The seven species with highest -glycosidase activity showed different patterns of pectolytic activities, indicating that different species or combinations of species could be selected for different potential applications.L. Brimer is with the Department of Pharmacology and Pathobiology, Royal Veterinary & Agricultural University, 13 Bulowsvej, DK 1870 Frederiksberg C, Denmark; A.R. Cicalini and F. Federici are with the Dipartimento Agrobiologia e Agrochimica, University of Tuscia, Via S.C. de Lellis, I-01100 Viterbo, Italy. M. Petruccioli is with the Dipartimento di Biologia, Difesa e Biotecnologie Agro-Forestali, University of Basilicata, Via N. Sauro, 85, I-85100 Potenza, Italy.     

Construction of a cellulose-metabolizing Komagataella phaffii (Pichia pastoris) by co-expressing glucanases and β-glucosidase

Applied Microbiology and Biotechnology - Cellulose is a highly available and renewable carbon source in nature. However, it cannot be directly metabolized by most microbes including Komagataella...     

Purification and characterization of an isoflavones conjugate hydrolyzing β-glucosidase (ICHG) from Cyamopsis tetragonoloba (guar)

A β-glucosidase with high specific activity towards isoflavone glycosidic conjugates was purified from seeds of Guar (Cyamopsis tetragonoloba) by ammonium sulphate precipitation followed by size exclusion and ion exchange chromatography. The pH and temperature optima of the purified Isoflavones conjugate hydrolyzing β-glucosidase (ICHG) were found to be pH 4.5 and 37 °C, respectively. The enzyme was relatively stable at higher temperatures. Effect of different divalent metal ions was studied and it was found that Cobalt and Mercury ions completely inhibited the enzyme activity. K_m and V_max of the purified isoflavones conjugates hydrolyzing β-glucosidases (ICHG) was 0.86 mM and 6.6 IU/mg respectively. The enzyme was most likely a trimer (approximate Mr 150 kDa) with potential subunits of 50 kDa. The purified enzyme showed activity against isoflavone conjugate glycosides viz daidzin and genistin but was inactive towards other flavonoid conjugates. The product conversion was confirmed by HPTLC and HRMS analysis. The MALDI-TOF analysis of the ICHG showed a score greater than 78 with 20 matches in MASCOT software. The five resultant peptides obtained had highest similarity in sequence with β-glucosidase from Cicer arietinum. The β-glucosidase from the C. arietinum has also been reported to exhibit the isoflavone conjugate hydrolyzing properties thus confirming the nature of the enzyme purified from the Guar seeds.