Small Amounts Of Glucose Research Articles

少量ブドウ糖投与による体液量測定25年間の臨床経験

1986年にわれわれはブドウ糖初期分布容量（IDVG）が糖代謝の影響を受けない体液量であることを発見した．それ以来，ICUで種々の病態におけるIDVGを検討してきた．その結果IDVGは血漿量および毛細血管において血管内と活発に交流している組織間液量を含む中心部細胞外液量を反映しており，体液管理に有用な指標であることが判明した．IDVGは心臓前負荷の指標と必ずしも一致しないが，心臓充満圧や胸郭内血液量よりも心拍出量と密接な関係にある．今回，25年間にわたる臨床研究と経験を基に本法を概説する．

128 CULTURE CONDITIONS AFFECT THE SEX RATIO OF IN VITRO PRODUCED BOVINE EMBRYOS

Most systems for producing bovine embryos in vitro use glucose as an energy source despite putative toxic effects. Glucose has a selective embryotoxicity towards female embryos, due to the higher expression of the X-linked glucose-6-phosphate dehydrogenase gene (Kimura et al. 2005 Mol. Reprod. Dev. 72, 201–207). Recently, the replacement of glucose with citrate and myo-inositol in SOF medium supplemented with 5% bovine serum (BS) increased the percentage of female embryos (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Serum also affects the sex ratio of in vitro-produced (IVP) bovine embryos, favoring the male gender (Gutierrez-Adan et al. 2001 Theriogenology 55, 1117–1126). The aim of this work was to evaluate the effect of glucose replacement with myo-inositol during in vitro culture, in the presence of either BS or BSA, on bovine embryo sex ratio. Abattoir-derived oocytes (n = 1164, over 4 replicates) were matured and fertilized in vitro as previously described (Rubessa et al. 2011). After 20 to 22 h of gametes co-incubation, zygotes were denuded and cultured for 7 days in SOF with: group A) 0.34 mM trisodium citrate + 2.77 mM myo-inositol + 5% BS (n = 287); group B) 0.34 mM tri-sodium citrate + 2.77 mM myo-inositol + 8 mg mL–1 BSA(n = 290); group C) 1.5 mM glucose + 5% BS (n = 302) and group D) 1.5 mM glucose + 8 mg mL–1 BSA (n = 285). Representative samples of blastocysts produced in each group (n = 96, 58, 99, and 70, respectively in groups A, B, C, and D) were sexed by PCR as previously described (Rubessa et al. 2011). Differences among groups in blastocyst yields were analyzed by ANOVA. The percentages of female embryos were analyzed by chi-square test. Blastocyst rates in group C were lower (28.1%) than those recorded in groups A, B, and D (35.9, 41.0 and 36.1%, respectively; P < 0.01). A higher (P < 0.05) percentage of female embryos was observed in group A (61.5%) compared to group C (45.5%), with intermediate values in groups B (51.7%) and D (60.0%). Therefore, the replacement of glucose with citrate and myo-inositol favored the development of female embryos in the presence of BS but was ineffective in the presence of BSA. Furthermore, when glucose was the energy source, a tendency to greater incidence of female embryos was observed when the medium was supplemented with BSA rather than BS (P = 0.06). As a small amount of glucose is present in the BS, we hypothesize an additional glucose-dependent toxic effect on female embryos in group C. However, we cannot rule out that other factors present in the BS may interact with the energy source, playing a role in determining the sex ratio. Furthermore, the shift in sex ratio in favor of males or females embryo can be due to a better development of embryo of one sex, or to the delayed development or degeneration of embryos of the other sex. In conclusion, these results suggest that manipulating the metabolic profile of the embryos during culture may have an impact on both blastocyst production and sex ratio.

Dialkylimidazolium Ionic Liquids Hydrolyze Cellulose Under Mild Conditions

The average molecular weight of cellulose derived from filter paper, poplar, and Avicel decreases by up to two orders of magnitude during typical mild dissolution protocols using ionic liquids (ILs). About an order of magnitude greater cellulose depolymerization rate during ionic liquid dissolution occurs in 1-butyl-3-methylimidazolium chloride (BmimCl) and 1-ethyl-3-methylimidazolium chloride (EmimCl) compared to 1-ethyl-3-methylimidazolium acetate (EmimOAc), and, unintuitively, greater IL purity results in greater cellulose depolymerization. The following data support the mechanism of cellulose hydrolysis to be acid-catalyzed: (i) increase in number of reducing ends following cellulose dissolution in IL; (ii) addition of N-methylimidazolium base suppresses cellulose depolymerization during dissolution in IL; (iii) small amounts of glucose and traces of hydroxymethyl furfural are present following cellulose dissolution in IL. The acid is presumably synthesized via IL decomposition to generate a carbene and proton, consistent with hypothesis derived from molecular modeling. Titration experiments conducted here measure the amount of acid synthesized to be in the 4000 ppm range for high-purity BmimCl IL during mild processing conditions for cellulose dissolution. This data is relevant for understanding the extent of IL decomposition during biomass dissolution.

The ability of the rumen ciliate protozoan Diploplastron affine to digest and ferment starch

The ciliate Diploplastron affine is known as a common species of the rumen fauna in cattle and sheep. This protozoon is able to digest cellulose, whereas its amylolytic activity is not well known. The objective of the reported studies was to examine the ability of D. affine to digest starch and to use this polysaccharide to cover the requirement for energy. The enzymatic studies showed that the protozoal cell extract degraded starch to reducing products with the rate being equivalent to 2.4 ± 0.47 μmol/L glucose per mg protein per min. Maltose, maltotriose and a small quantity of glucose were the end products of starch degradation. The degradation rate of maltose was only 0.05 μmol/L glucose per mg protein per min. Two peaks in α-amylase and a single peak in maltase activity were found following molecular filtration of ciliate cell extract, whereas three starch-degrading enzymes were identified by a zymographic technique. Incubation of the bacteria-free ciliates with starch in the presence of antibiotics resulted in a release of volatile fatty acids with the net rate of 25 pmol per protozoan per h. Acetic acid followed by butyric acid was the main product of starch fermentation. The results confirmed the ability of D. affine to utilize starch in energy-yielding processes.

Modification of Glucose Oxides Sensors Using Colloidal Gold Nanoparticles

Glucose oxidase sensor is one of the best methods for measuring small amounts of glucose; this sensor can be modified using colloidal gold nanoparticles as complementary substance in the electrode structure with the aim of increasing efficiency. In this article, the colloidal gold nanoparticles (24 nm) were used to construct the two electrodes. The first electrode (Au/CP) was constructed of 100 mg carbon graphite powder, 36 µl paraffin oil and 300 µl colloidal gold nanoparticles. The second electrode (Au/CILE) was constructed of 100 mg carbon graphite powder, 36 µl paraffin oil, 300 µl colloidal gold and 50 mg ionic liquid oppf6. To evaluate the performance of each electrode and to prepare of bio sensor, these were covered by solution of 10 mg glucose oxidase and 1 ml phosphate buffer. The bio sensors were test with 0.8 mM glucose solution. By comparing the amount of AMP and the transfer time for both, the according results, the effect of colloidal gold nanoparticles on the increasing conductivity, sensitivity and stability biosensor, was determined.

Behavioral Evidence for a Glucose Polymer Taste Receptor That Is Independent of the T1R2+3 Heterodimer in a Mouse Model

Although it is clear that the heterodimer formed by the T1R2 and T1R3 proteins serves as the primary taste receptor for sweeteners, there is growing evidence that responses to glucose polymers may be mediated by a different taste receptor. Here we report that although T1R2 knock-out (KO) and T1R3 KO mice displayed severely impaired responding to glucose, maltose, and maltotriose in an initial session of a brief-access taste test (5 s trials, 25 min sessions) relative to wild-type (WT) mice, they subsequently increased their licking as a function of concentration for maltose and maltotriose with continued testing, presumably due to associating weak oral cues with positive post-ingestive consequences. Interestingly, these KO mice displayed relatively normal concentration-dependent licking to Polycose, a mixture of glucose polymers, even in the first session. Importantly, the experience-dependent increase in responsiveness to the sugars observed with the T1R2 and T1R3 single KO mice was not statistically significant in the T1R2/3 double KO mice. The double KO mice, however, still displayed significant concentration-dependent responding to Polycose in the first test session, albeit lick rates were slightly lower than those seen for WT mice, perhaps because small amounts of glucose, maltose, and maltotriose found in Polycose were enhancing the signal in WT mice or because T1R2 or T1R3 can possibly heteromerize with another protein to form a fully functional glucose polymer receptor. These findings provide behavioral evidence that glucose polymers, with an optimal chain length greater than three glucose moieties, stimulate a taste receptor independent of the T1R2+3 heterodimer.

Characteristics of raw starch degrading α‐amylase from Bacillus aquimaris MKSC 6.2 associated with soft coral Sinularia sp.

AbstractPartially purified α‐amylase from Bacillus aquimaris MKSC 6.2, a bacterium isolated from a soft coral Sinularia sp., Merak Kecil Island, West Java, Indonesia, showed an ability to degrade raw corn, rice, sago, cassava, and potato starches with adsorption percentage in the range of 65–93%. Corn has the highest degree of hydrolysis followed by cassaca, sago potato and rice, consecutively. The end products of starch hydrolysis were a mixture of maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and small amount of glucose.

Anticoagulant and anti-platelet activity of polyphenolic-polysaccharide preparation isolated from the medicinal plant Erigeron canadensis L.

The polyphenolic-polysaccharide preparation from Erigeron canadensis L. was isolated by multi-step process, characterized by chromatographic and spectroscopic methods, and was subjected to anion-exchange chromatography. The whole preparation demonstrated in vivo anticoagulant activity, and the effect was neutralized by protamine sulfate. It had also anti-platelet activity, limited to the cyclooxygenase pathway, induced by arachidonic acid. The plant preparation was fractionated to receive the fraction of the highest anticoagulant activity - 7-9 IU/mg of heparin standard, expressed in aPTT. The influences of the plant preparation as well as its the most active fraction on thrombin and factor Xa inactivation by antithrombin, and on thrombin inhibition by heparin cofactor II, were compared. The both tested plant preparations inhibited thrombin as well as factor Xa amidolytic activities in the presence of antithrombin, but much higher concentrations were required to obtain the same effects like for unfractionated heparin. The mechanisms of anticoagulant activity in the case of the plant preparation are based on interactions with heparin cofactor II, to inactivate thrombin. Chromatographic and spectroscopic methods revealed its macromolecular polyanionic non-sulfated polyphenolic-polysaccharide conjugate, with carboxylic groups. The polysaccharide part constituted 32% of the total mass and was homogenous, with molecular mass 38 kDa, containing mainly hexuronic acids, and much smaller amounts of glucose, arabinose, galactose, as well as some traces of mannose, xylose and rhamnose. Polyphenolic part, with molecular mass > 12.5 kDa, was rich in hydroxylic rests as well as in carboxylic groups, free and esterified. The polyphenolic-polysaccharide preparation from E. canadensis may become a new source of anticoagulant compound potentially useful in anticoagulant and anti-platelet therapy.

Pretreatment of partially delignified hybrid poplar for biofuels production: Characterization of organosolv hemicelluloses

In this study, extraction of hemicelluloses from the carbohydrate-enriched residues was successfully carried out with organic solvent and the residue was used for bio-based energy production. The chemical composition and physico-chemical properties of six hemicelluloses released were elucidated by a combination of sugar analysis, molecular determination, Fourier transform infrared, and 1H, 13C and 2D-HSQC NMR spectroscopy. The results showed that the successful treatments resulted in a fractionation of the native hemicelluloses. The sugar analysis indicated that xylose (47.14–56.91%) was found to be the major sugar components and small amounts of glucose (14.1–19.06%) and mannose (12.41–18.09%) were also observed in these hemicellulosic fractions. Further studies by NMR spectroscopy exhibited that the acetylated hemicellulosic fraction had a main structure of (1→4)-linked β-d-xylopyranosyl backbone with 4-O-methyl-α-d-glucuronic acid as a side chain and a minor structure of linear β-(1→4)-linked glucomannans. Furthermore, these hemicelluloses possessed a low substituted degree which was beneficial for enzymatic saccharification.

125 EFFECT OF GLYCERALDEHYDE-3-PHOSPHATE DURING BOVINE IN VITRO EMBRYO CULTURE

Most systems for producing mammalian embryos in vitro use glucose as an energy source in the media despite putative toxic effects (Schini and Bavister 1988 Biol. Reprod. 39, 1183–1192; Takahashi and First 1992 Theriogenology 37, 963–978). Currently there is a tendency to identify other suitable energy sources in an attempt to replace glucose from culture media. Glyceraldehyde-3-phosphate (G3P), a glucose-derived high-energy compound, is the end product of the energy-consuming phase of glycolysis that enters the pay-off phase of the pathway characterised by a net gain of energy. The aim of this study was to determine whether G3P is a valid energy source for supporting in vitro embryo development in cattle. Abattoir-derived oocytes (n = 832, over 4 replicates) were matured in vitro in TCM-199 with 15% bovine serum (BS), 0.5 μg mL–1 FSH, 5 μg mL–1 LH, 0.8 mM L-glutamine, and 50 mg mL–1 gentamicin. Mature COC were fertilized in Tyrode’s modified medium, with 30 mg mL–1 heparin, 30 mM penicillamine, 15 mM hypotaurine, 0.15 mM epinephrine, and 1% BS. Both IVM and IVF were carried out at 39°C and 5% CO2 in air. After 20 to 22 h of gamete co-incubation, presumptive zygotes were denuded and cultured in SOF containing either 1.5 mM glucose (control group) or G3P at 3 different concentrations (0.125, 0.5, and 1.5 mM). It is worth specifying that in the 3 G3P-supplemented groups small amounts of glucose were left (0.15 mM) because it is known that a complete removal would affect embryo development by interfering with ribose synthesis through the pentose–phosphate pathway. In vitro culture was carried out at 39°C under humidified air with 5% CO2, 7% O2, and 88% N2 in air for 7 days, when the percentages of tight morulae-blastocysts (TMBL) and superior quality blastocysts (BL) were recorded. Differences in embryo yields among groups were analysed by chi-square test. Supplementation of IVC medium with 1.5 mM G3P reduced (P < 0.01) TMBL (5.0%) and BL (5.0%) rates compared with all other groups, indicating a toxic effect. However, when G3P was added at lower concentrations, no differences in TMBL (37.3 and 26.1, respectively, with 0.125 and 0.5 mM G3P) and in BL rates (35.3 and 25.5%, respectively, with 0.125 and 0.5 mM G3P) were observed compared with the control (32.7% TMBL and 31.4% BL, respectively). Within G3P-treated groups, the higher embryo yields were recorded with 0.125 mM compared with 0.5 mM (P < 0.05) and 1.5 mM (P < 0.01). Interestingly, embryos produced with G3P at the lower concentrations (0.125 and 0.5 mM) seemed to show a faster development compared with the control. In conclusion, these results demonstrated that G3P is a valid energy source for bovine preimplantation embryos and, hence, that G3P supplementation of IVC medium may be a suitable option for reducing glucose concentration in the media. However, further studies are needed to investigate lower concentrations of G3P and to better evaluate embryo viability.

Kinetic characterization of a glycoside hydrolase family 44 xyloglucanase/endoglucanase from Ruminococcus flavefaciens FD-1

Two forms of Ruminococcus flavefaciens FD-1 endoglucanase B, a member of glycoside hydrolase family 44, one with only a catalytic domain and the other with a catalytic domain and a carbohydrate binding domain (CBM), were produced. Both forms hydrolyzed cellotetraose, cellopentaose, cellohexaose, carboxymethylcellulose (CMC), birchwood and larchwood xylan, xyloglucan, lichenan, and Avicel but not cellobiose, cellotriose, mannan, or pullulan. Addition of the CBM increased catalytic efficiencies on both CMC and birchwood xylan but not on xyloglucan, and it decreased rates of cellopentaose and cellohexaose hydrolysis. Catalytic efficiencies were much higher on xyloglucan than on other polysaccharides. Hydrolysis rates increased with increasing cellooligosaccharide chain length. Cellotetraose hydrolysis yielded only cellotriose and glucose. Hydrolysis of cellopentaose gave large amounts of cellotetraose and glucose, somewhat more of the former than of the latter, and much smaller amounts of cellobiose and cellotriose. Cellohexaose hydrolysis yielded much more cellotetraose than cellobiose and small amounts of glucose and cellotriose, along with a low and transient amount of cellopentaose.

Evaluation of carbohydrates in natural and cultured Cordyceps by pressurized liquid extraction and gas chromatography coupled with mass spectrometry.

Free and polymeric carbohydrates in Cordyceps, a valued edible mushroom and well-known traditional Chinese medicine, were determined using stepwise pressurized liquid extraction (PLE) extraction and GC-MS. Based on the optimized PLE conditions, acid hydrolysis and derivatization, ten monosaccharides, namely rhamnose, ribose, arabinose, xylose, mannose, glucose, galactose, mannitol, fructose and sorbose in 13 samples of natural and cultured Cordyceps were qualitatively and quantitatively analyzed and compared with myo-inositol hexaacetate as internal standard. The results showed that natural C. sinensis contained more than 7.99% free mannitol and a small amount of glucose, while its polysaccharides were usually composed of mannose, glucose and galactose with a molar ratio of 1.00:16.61~3.82:1.60~1.28. However, mannitol in cultured C. sinensis and cultured C. militaris were less than 5.83%, and free glucose was only detected in a few samples, while their polysaccharides were mainly composed of mannose, glucose and galactose with molar ratios of 1.00:3.01~1.09:3.30~1.05 and 1.00:2.86~1.28:1.07~0.78, respectively. Natural and cultured Cordyceps could be discriminated by hierarchical clustering analysis based on its free carbohydrate contents.

Bioconversion of rapeseed meal for the production of a generic microbial feedstock

Rapeseed meal, a major byproduct from biodiesel production, has been used as a low-cost raw material for the production of a generic microbial feedstock through a consolidated bioconversion process. Solid state fermentation by Aspergillus oryzae led to the production of hydrolytic enzymes that could release free amino nitrogen (FAN), inorganic phosphorus (IP), small amount of glucose, and possibly many other microbial nutrients from rapeseed meal. Suspending the fermented solids in water at elevated temperature resulted in further hydrolysis of the remaining meal components for the production of a feedstock containing 2061.2 mg l −1 FAN, 304 mg l h −1 IP, and 1.8 g l −1 glucose. A three-fold dilution of this feedstock provided all essential nutrients except sufficient carbon source to support the production of 6.85 g l −1 dry Saccharomyces cerevisiae cells in aerobic incubation, while consuming 80.6 g l −1 of the glucose supplement. Comparative yeast incubation confirmed the nutritional similarity between the feedstock and a mixture of commercial peptone and yeast extract.

D‐Lactic Acidosis: “Right‐Left Disorientation” in Laboratory Testing: Acute Encephalopathy in a Child With Carbohydrate Malabsorption Syndrome

106 an occur as a rare and s D -Lactic acidosis c evere complication in patients with short bowel syndrome. In healthy individuals, relatively small amounts of glucose and starch reach the colon because of extensive absorption in the small intestine. In patients with short bowel syndrome, delivery of these substrates to the colon is significantly increased. Due to an overgrowth of Gram-positive anaerobic rods, such as Lactobacillus, glucose and starch are metabolized in the colon to D-lactic acid, which is then absorbed into the systemic circulation leading to metabolic acidosis. Because D-lactate is neurotoxic (1), the clinical presentation is characterized by episodes of encephalopathy with neurological symptoms such as altered mental status, confusion, slurred speech, ataxia, hallucinations, and amnesia (2,3). D-Lactic acid is not detected in routine laboratory tests using L-lactate dehydrogenase.

Isomaltulose production by free cells of Serratia plymuthica in a batch process

Free cells of Serratia plymuthica were used to convert sucrose into isomaltulose and trehalulose reducing sugars. The effects of substrate concentration and temperature were observed in a batch process with flasks shaken at 150 rpm. The experimental design and response surface methodology analysis indicated that the conversion parameters had significant influence ( p < 0.05) on sucrose conversion, and that a valid model was obtained after an analysis of variance ( F model = 10.48 > F charted = 5.79) to obtain a response surface and isocurve. Conversion was favoured when a 30% sucrose solution and temperature of 25 °C were used, which resulted in a high conversion into isomaltulose – over 70% – and 7–8% trehalulose. Small amounts of glucose (5–7%) and fructose (5–8%) were formed in the reaction medium.

Production of xylooligosaccharides by controlled acid hydrolysis of lignocellulosic materials

Different agricultural wastes, namely tobacco stalk (TS), cotton stalk (CS), sunflower stalk (SS), and wheat straw (WS), were used for the production of xylooligosaccharide (XO). XO production was performed by acid hydrolysis of xylan, which was obtained by alkali extraction from these agricultural wastes. The major component of these agricultural wastes was determined as cellulose (30–42%), followed by xylan (20%) and lignin (20–27%). Xylans from these wastes had mainly xylose (85–96%) with small amount of glucose, while wheat straw xylan contained also arabinose. The best xylan conversion into XOs was achieved with 0.25 M H 2SO 4 with 30-min reaction time. Under these conditions, the XO yield was between 8% and 13%. The yield of XOs depends on both acid concentration and hydrolysis time, but the yield of monosaccharide depends on the structure and composition of xylan besides acid concentration and the time. The more branched xylan, WSX, gave the highest monosaccharide (∼16%) and furfural (∼49 mg/100 g xylan) yield. This research showed that all xylans from selected agricultural wastes generated XOs with similar profiles, and these oligosaccharides could be used as functional food ingredients or soluble substrates for xylanases.

Enzymatic production of Xylooligosaccharide from selected agricultural wastes

Four different agricultural wastes, namely tobacco stalk (TS), cotton stalk (CS), sunflower stalk (SS) and wheat straw (WS) were tested for the production of Xylooligosaccharide (XO). XO production was performed by enzymatic hydrolysis of xylans which were obtained by alkali extraction from the agricultural wastes. Depending on the source, it was found that these four agricultural wastes contained different amount of xylan, cellulose and lignin and the xylan obtained from these source contained different amount of sugar and uronic acid. The highest amount of arabinose was in xylan from WS while the other xylans mainly had xylose and small amount of glucose. Different xylanase preparations were evaluated for production XO from these xylan sources. Aspergillus niger xylanase produced lower amount of XO from wheat straw xylan (WSX) than cotton stalk xylan (CSX), sun flower xylan (SSX) and tobacco stalk xylan (TSX) while Trichoderma longibrachiatum xylanase hydrolyzed highly branched WSX better. The HPLC analysis of the hydrolysis products indicated that depending on structure and composition of xylan, A. niger xylanase produced less amount of xylose than T. longibrachiatum xylanase, and the hyrolysis product of A. niger xylanase contained different amount of oligosaccharides (X2 > X3 > X4 > X5 > X6, >X6). Regardless of the structural differences of the xylan types presented in this paper, all xylans generated XO with different degree of polymerization (DP), but the DP of XO depended on the enzyme specificity and the structure of substrate.

Isolation and purification of an anticoagulant from fermented red seaweed Lomentaria catenata

We attempted to isolate an anticoagulant polysaccharide from marine algae by fermentation of freeze-dried seaweed with nonselective microorganisms present in the seaweed itself. An anticoagulant compound was purified from red algae Lomentaria catenata and the molecular mass of the purified polysaccharide ranged from 100 to 500 kDa. The purified anticoagulant polysaccharide was mainly composed of galactose with small amounts of glucose and it is highly sulfated (21.76% as SO 4 2−). In addition, 9.42% of protein content proved the compound to be a proteoglycan. The anticoagulant activity of the purified compound was assayed by the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) assays and compared with the classical anticoagulant heparin. It demonstrated >1000 s of APTT activity at 40 μg/mL and the activity is greater than heparin (183 IU/mg, >1000 s of APTT activity at 62.5 μg/mL). The anticoagulant compound showed prolonged activity towards APTT and TT assays but low or no activity for PT. Therefore, the isolated compound may act on the intrinsic and/or common pathways of the blood coagulation system.

A novel thermostable endoglucanase from the wood-decaying fungus Daldinia eschscholzii (Ehrenb.:Fr.) Rehm

A thermostable endoglucanase was purified to homogeneity from culture supernatants of the wood-decaying fungus Daldinia eschscholzii (Ehrenb.:Fr.) Rehm grown on 1.0% (w/v) carboxymethyl-cellulose using ammonium sulfate precipitation, ion-exchange, hydrophobic interaction, and gel filtration chromatography. The molecular weight of the enzyme was 46.4 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the enzyme was at pH 4.9. The temperature for maximum activity was 70 °C, with 85% of its maximum activity retained after 150 min of incubation at 50 °C, but was rapidly inactivated at 70 °C. The pH optimum of the enzyme activity was 6.0, and it was stable over a pH range of 4.0–7.0 at 50 °C. The enzyme was significantly inhibited by Hg 2+, Cu 2+, and Fe 2+, and stimulated by Ca 2+, Co 2+, Mg 2+, Mn 2+, glycerol, DMSO, DTT, and EDTA. The enzyme also hydrolyzed filter paper, and Avicel ® PH-101 at rates of 25.8%, and 7.3%, respectively when compared with carboxymethyl-cellulose. The enzyme did not hydrolyze soluble starch, oat spelt xylan, birch wood xylan, or locust bean gum. The enzyme catalyzed the hydrolysis of carboxymethyl-cellulose with a K m of 1.74 mg/ml and a V max of 0.63 U/min/mg protein. This enzyme was competitively inhibited by glucose and cellobiose with K i values of 0.67 and 0.45 M, respectively. TLC showed that the endoglucanase produces cellotetraose, cellotriose, cellobiose, and a small amount of glucose. The deduced internal amino acid sequences of the D. eschscholzii endoglucanase showed similarity to the sequences of the glucosyl hydrolase family 5.

Kombucha fermentation on raw extracts of different cultivars of Jerusalem artichoke

Kombucha is a symbiosis between yeasts and acetic bacteria. It usually grows on sweetened black tea, but cultivation is possible on many other substrates. Jerusalem artichoke tubers extract is one of them. Tubers are suitable for the dietetic nutrition because of the low monosaccharide content and presence of some polyfructan ingredients which act as prebiotic. Five different cultivars of Jerusalem artichoke were used for the preparation of substrates for kombucha fermentation. The aim of this paper was the investigation of the influence of different Jerusalem artichoke cultivars on metabolic activity of kombucha. Composition of carbohydrates was followed using thin-layer chromatography and pH, reducing sugars content and yield of biomass were measured. Most of the samples with Jerusalem artichoke tubers extract contained fructose, probably small amount of glucose, fructo-oligosaccharides with different degree of polymerization and, inulin. Considering TLC chromatograms, Jerusalem artichoke cultivar did not affect significantly the composition of oligosaccharides in the fermentative liquid, as only minor differences were observed.