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Fabricating of hydrogels based upon polymers and inorganic matter is an innovative replacement for the generation of adaptable matrices.In this study,the poly（vinyl alcohol）（PVA）/chitosan（CS）/soluble starch（SS）composite hydrogel was prepared by the solution blending method,in which SS was used as a cross-linking agent to cross-link with PVA in order to improve the stability of PVA in the tissue fluid.The composition and the thermal stability of hydrogels were characterized by Fourier transform infrared（FTIR） spectroscopy and thermo gravimetric analysis（TGA）.The result shows that the PVA/CS/SS composite hydrogel possesses potentially morphological and thermal stability and can be used for tissue engineering. [ABSTRACT FROM AUTHOR]

Aims: This present study focused on purification of fungal β-mannanase produced by Aspergillus niger USM F4 and also physicochemical characterisation of the purified enzyme Methodology and results: The purified β-mannanase with a molecular mass of ~47.4 kDa was demonstrated on SDSPAGE gel. The enzyme signified a purification degree of 4-fold, with final specific activity of 196.42 U/mg. It reached an optimum catalytic activity at pH 4.0 and 60 °C. The thermal stability of the enzyme was up to 70 °C and maintained the 50% activity after 30 min at 80 °C. Meanwhile, the pH stability was in the range of pH 3.0-9.0 and a 30 min half-life at pH 10.0. All chemical substances manifested an inhibitory effect on purified β-mannanase, with SDS (28.16 ± 0.05% residual activity) as the strongest inhibitor, followed by cupric ion (Cu2+) (49.51 ± 0.09% residual activity). As a whole, the enzyme displayed a substrate specificity in the order of locust bean gum (LBG) > carboxymethylcellulose > soluble starch > xylan from oat spelt > α-cellulose. Its preference for LBG has generated the Km and Vmax values of 0.20 mg/mL and 9.82 U/mL, respectively Conclusion, significance and impact of study: The outcomes of our study offer potential for use at industrial scales, particularly in the oligosaccharides production that involve acid-related activity, wide-ranging temperature and pH stability. [ABSTRACT FROM AUTHOR]

Pierre Jacques Antoine Béchamp (1816-1908) was a French chemist and physician who studied the preparation, properties, and derivatives of collodion, and found that its behavior was similar to that of ethyl nitrate. He developed a very fast and efficient method for reducing nitrobenzene to aniline and naphthylamine with ferrous salts with ferrous salts and acetic acid, or acetic acid and iron filings. The reaction was probably done by nascent hydrogen (a prelude of the modern process of catalytic hydrogenation of nitrobenzene). This discovery led to a better and more economical method for manufacturing aniline violet, fuchsine, and paminophenylarsonic acid (arsanylic acid). The synthesis of the latter opened the door for the preparation of many medicines based on arsenic. He also discovered the ability of sodium ethylate to reduce nitrobenzene. His study of the action of mineral acids, glacial acetic acid, zinc chloride, and caustic alkalis, on starch led to the synthesis of modified starches, soluble in water and different from dextrin. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract In this study silver nanoparticles were synthesized by microwave irradiation method using soluble starch as a green capping and reducing agent. The as-prepared soluble starch coated silver nanoparticles (S-Ag NPs) were incorporated in polyvinyl alcohol (PVA) matrix to fabricate nanofibers through electrospinning process. Two different types of crosslinking treatments were used to make the nanofiber mats insoluble in physiological environments. Experimental studies revealed that the choice of the crosslinking treatment led to affect the silver ion release. The nanofiber mats crosslinked with glutaraldehyde have superior silver ion release and stability in simulated body fluid (SBF). The released amounts of silver ions were lower than the toxic level of silver ions for HaCat keratinocytes and human epidermal keratinocytes. After proving antibacterial properties of the glutaraldehyde crosslinked S-Ag NPs loaded PVA nanofiber mats against E. coli and S. aureus it was thought that the nanofibrous mats fabricated in this study can be good candidates as antibacterial scaffolds for wound dressing applications. [ABSTRACT FROM AUTHOR]

Based on soluble starch and acrylamide by performing graft polymerization in aqueous solution and hydrolysis step, a low-cost ion exchange resin has been synthesized to remove the heavy metal ions of Cr3+ and Ni2+. The hydrolysis progresses by adding NaOH to convert -CONH2 to -COONa, and the adsorption experiments confirmed that the functional group to adsorb heavy metals is -COO−, rather than -CONH2. During the determination of heavy metal adsorption, the Na+ concentration diffused by SR-16 into the solution was also analysed to investigate the ion exchange process. The composition and morphology of SR-16 was characterized by FT-IR, SEM, elemental analyser and EDS, and the results showed that SR-16 has an excellent adsorption capacity to the removal of heavy metal pollution; the adsorption mechanism of SR-16 could be explained by ion exchange progress with -COONa attached on the network structure. [ABSTRACT FROM AUTHOR]

In this paper, soluble starch was studied as a depressant of hematite during flotation separation of apatite using sodium oleate as a collector. Surface charge measurement, soluble starch adsorptions, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to understand the interaction mechanisms between minerals (hematite and apatite) and soluble starch. The results indicated that chemical interaction between hematite and soluble starch was present, and supported the bonding of hydroxyl, while physical adsorption of soluble starch molecules with apatite occurred. Results of micro-flotation studies suggested that soluble starch was considered as a selective depressant for hematite. The maximum recovery difference between hematite and apatite of 77.5% was obtained with 40 mg/dm3 soluble starch. The flotation experiment results of natural iron ore showed that flotation indexes with 59.73% Fe, iron recovery of 81.5% and 75.68% of dephosphorization ratio were achieved at a soluble starch dosage of 60 mg/dm3. However, a higher dosage of soluble starch addition caused the difficulty for flotation separation of apatite from hematite. Our results provided theoretical basis for the flotation separation of apatite from iron oxide ores. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel nano-biosorbent based on modified dextrin was fabricated. • Nano-biosorbent can be used to remove Pb(II) and methylene blue from water. • The new nanochelating adsorbent was characterized using different techniques. • Kinetic, isotherm and thermodynamic of adsorption was investigated. Abstract Novel nano-biosorbent was successfully prepared based on dextrin-g-poly m-phenylenediamine (DgPmPDA) and graphene oxide (GO) by using the solution blending technique and was found to be an effective adsorbent for Pb(II) and methylene blue (MB) dye. The nano-biosorbent was characterized by FTIR, CHN, XRD, SEM, AFM and TGA. The adsorption process depended on the pH of solution, adsorbent dosage, contact time, initial concentration of Pb(II) and MB, and temperature. Experimental results were in good agreement with Langmuir isotherm model for both Pb(II) and MB adsorption. The maximum adsorption capacity (Q max) of Pb(II) and MB was found to be 80 mg/g and 76.33 mg/g, respectively, at optimum conditions. Results showed that the kinetics of Pb(II) and MB onto the DgPmPDA@GO nano-biosorbent followed the pseudo-first-order and pseudo-second-order models, respectively. Thermodynamic parameters exhibited the endothermic and spontaneous nature of the sorption process. A possible mechanism of adsorption was suggested where π–π stacking interactions, H-bonding interaction and electrostatic attraction controlled the MB adsorption and chelation and electrostatic attraction controlled the Pb(II) adsorption. [ABSTRACT FROM AUTHOR]

Thermophilic fungus Myceliophthora thermophila has great capacity for biomass degradation and is an attractive option for use as cell factory to produce chemicals directly from renewable polysaccharides, such as starch, rather than monomer glucose. To date, there has been no transcriptomic analysis of this thermophilic fungus on starch. This study determined the transcriptomic profile of M. thermophila responding to soluble starch and a 342-gene set was identified as a “starch regulon”, including the major amylolytic enzyme (Mycth_72393). Its overexpression led to increased amylase activities on starch by 35%. Furthermore, overexpressing the key amylolytic enzyme regulator AmyR in M. thermophila significantly increased amylase activity by 30%. Deletion of amyR by the CRISPR/Cas9 system led to the relief of carbon catabolite repression and 3-fold increased lignocellulase activities on cellulose. This study will accelerate rational fungal strain engineering for biochemical production from biomass substrates such as raw corn starch and even crop straw. [ABSTRACT FROM AUTHOR]

Maximum production of industrially important enzymes such as chitosanases through media optimization still holds foremost interest. The present study was conducted to improve chitosanase activity of an indigenous strain identified as Bacillus mojavensis. Initially, carbon and nitrogen sources were optimized by one‐variable‐at‐a‐time approach. Further, fermentation medium was optimized using Plackett‐Burman (PB) and central composite designs (CCD). PB verified soluble starch (SS), colloidal chitosan (CC) peptone, and NaCl as most significant variables affecting chitosanase production. CCD results predicted the optimum concentrations of SS, CC, peptone, and NaCl as 7.8, 7.0, 6.5, and 2.7 g L−1, respectively to achieve maximum chitosanase activity (21.1 U ml−1). Discovery of the novel optimal medium has improved chitosanase production by B. mojavensis up‐to 9.5 folds. Lastly, 18.6 U ml−1 chitosanase activity was achieved in stirred tank bioreactor using optimal medium, which is quite satisfactory to proclaim this strain as a potential candidate to provide commercial chitosanase. [ABSTRACT FROM AUTHOR]

The gene encoding the novel amylolytic enzyme designated CoMA was cloned from Corallococcus sp. strain EGB. The deduced amino acid sequence contained a predicted lipoprotein signal peptide (residues 1 to 18) and a conserved glycoside hydrolase family 13 (GH13) module. The amino acid sequence of CoMA exhibits low sequence identity (10 to 19%) with cyclodextrin-hydrolyzing enzymes (GH13_20) and is assigned to GH13_36. The most outstanding feature of CoMA is its ability to catalyze the conversion of maltooligosaccharides (≥G3) and soluble starch to maltose as the sole hydrolysate. Moreover, it can hydrolyze γ-cyclodextrin and starch to maltose and hydrolyze pullulan exclusively to panose with relative activities of 0.2, 1, and 0.14, respectively. CoMA showed both hydrolysis and transglycosylation activities toward α.-1,4-glycosidic bonds but not to α.-1,6-linkages. Moreover, glucosyl transfer was postulated to be the major transglycosidation reaction for producing a high level of maltose without the attendant production of glucose. These results indicated that CoMA possesses some unusual properties that distinguish it from maltogenic amylases and typical a.-amylases. Its physicochemical properties suggested that it has potential for commercial development. IMPORTANCE The α.-amylase from Corallococcus sp. EGB, which was classified to the GH13_36 subfamily, can catalyze the conversion of maltooligosaccharides (2≤G3) and soluble starch to maltose as the sole hydrolysate. An action mechanism for producing a high level of maltose without the attendant production of glucose has been proposed. Moreover, it also can hydrolyze γ-cyclodextrin and pullulan. Its biochemical characterization suggested that CoMA may be involved the accumulation of maltose in Corallococcus media. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Amylodextrins from cassava starch were obtained by acid hydrolysis, and their structural, thermal and morphological characteristics were evaluated and compared to those from potato and corn amylodextrins. RESULTS: Cassava starch was the most susceptible to hydrolysis due to imperfections in its crystalline structure. The crystalline patterns of amylodextrins remained unchanged, and crystallinity and peak temperature increased with hydrolysis time, whereas thermal degradation temperature decreased, independent of treatment time and starch source. Cassava amylodextrins had similar structural and morphological characteristics to those from corn amylodextrins due to their A‐type crystalline arrangements. A‐amylodextrins were structurally and thermally more stable than potato amylodextrins (B‐type). Starch nanocrystals (SNC) were observed by transmission electron microscopy from the third day of hydrolysis in cassava amylodextrins, whereas potato and corn amylodextrins displayed SNC only on the fifth day. A‐SNC displayed platelet shapes, whereas B‐SNC were rounded. The SNC shape was related to the packing form and geometry of unit cells of allomorphs A and B. CONCLUSION: Microstructures (agglomerated crystalline particles) and nanostructures (double helix organization) were observed for amylodextrins. Cassava starch was shown to be a promising material for SNC production, since it requires less hydrolysis time to obtaining more stable crystals. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Monascus spp. have been used for thousands of years as a traditional food additive in China. This mold can produce many different types of commercially valuable secondary metabolites of biological activity. Soluble starch and glycerol are the two principal carbon sources universally utilized by Monascus for the production of beneficial metabolites. In this study, the effects and regulation mechanisms of soluble starch and glycerol for M. purpureus FAFU618 on Monascus azaphilone pigments (MonAzPs) were investigated through ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF-MS/MS), comparative proteomics and quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR). The production of intracellular and extracellular pigments was significantly different between the soluble starch group (SSG) and glycerol group (GCG). Additionally, the components of intracellular pigments revealed by UPLC-QTOF-MS/MS showed that Monascin and Ankaflavin increased significantly in the GCG, while Rubropunctatin and Monascorubrin increased in the SSG. Differentially expressed proteins of mycelia between SSG and GCG were analyzed by two-dimensional gel electrophoresis (2-DE) and MALDI-TOF/TOF MS. We identified 27 proteins with statistically altered expression, of which 18 proteins associated with the EMP (glycolytic pathway), translation, energy generation, proteolysis, etc. were up-regulated, and 9 proteins, including ribosomal proteins, heat shock proteins (HSPs) and others, were down-regulated in GCG. Meanwhile, the expression levels of MonAzP biosynthetic genes were also analyzed by RT-qPCR, and the results showed that mppA , mppC , mppR1 and mppR2 were down-regulated, whereas genes MpPKS5 , MpFasA2 , MpFasB2 , mppB , mppD and mppE were up-regulated. Collectively, these findings illustrate that the regulation of MonAzPs is not only closely related to the expression levels of certain proteins in the polyketide synthesis pathway but also closely related to the concentration of primary metabolism-generated molecules that are used as substrates for polyketide synthesis. The present study provides insights into the regulation of different carbon sources on the metabolism of MonAzPs in M. purpureus FAFU618. These results may promote further development of functional foods or medicines from Monascus spp. fermented products. [ABSTRACT FROM AUTHOR]

[Objectives] To study the effect of different culture conditions on the growth of wild I. cicadae Miq. liquid strain. [Methods] The I. cicadae Miq. strain was inoculated into the liquid culture medium with different carbon sources, nitrogen sources, micronutrients ad pH, cultured in the constant temperature shaking incubator with rotating speed of 120 r/min at 19°C, and the mycelium pellet diameter, density and weight were compared between different treatments. [Results] The results showed that the optimum components of L. ciadae Miq. strain liquid included soluble starch, milk powder ad vitamin B12, and the optimum pH was 5.0-6.0. [Conclusions] Soluble starch was the most suitable carbon source for the culture medium of L cicadae Miq. liquid strain; milk powder was the most suitable nitrogen source for the culture medium of L cicadae Miq. liquid strain ;the most suitable pH was 5.0-9.0 for the mycelial growth of L cicadae Miq.; the formula and mixture ratio of the optimum culture medium for the growth of liquid strain were determined. [ABSTRACT FROM AUTHOR]

AmyJ33, an α-amylase isolated from Bacillus amyloliquefaciens JJC33M, has been characterized as a non-metalloenzyme that hydrolyzes raw starch. In this work, the gene that codifies for AmyJ33 was isolated and cloned. The recombinant α-amylase (AmyJ33r) produced had a molecular weight of 72 kDa, 25 kDa higher than the native α-amylase (AmyJ33). Our results suggest that the C-terminal was processed in a different way in the native and the recombinant enzyme causing the difference observed in the molecular weight. Additionally, the enzyme activity, specificity and biochemical behavior were affected by this larger C-terminal extra region in AmyJ33r, since the enzyme lost the ability to hydrolyze raw starch compared to the native but increased its thermal stability and pH stability, and modified the profile of activity toward alkaline pH. It is suggested that the catalytic domain in recombinant enzyme, AmyJ33r, could be interfered or blocked by the amino acids involved in the C-terminal additional region producing changes in the enzyme properties. [ABSTRACT FROM AUTHOR]

Background: Amylases are used in various industrial processes and a key requirement for the efficiency of these processes is the use of enzymes with high catalytic activity at ambient temperature. Unfortunately, most amylases isolated from bacteria and filamentous fungi have optimal activity above 45 °C and low pH. For example, the most commonly used industrial glucoamylases, a type of amylase that degrades starch to glucose, are produced by Aspergillus strains displaying optimal activities at 45-60 °C. Thus, isolating new amylases with optimal activity at ambient temperature is essential for improving industrial processes. In this report, a glucoamylase secreted by the cold-adapted yeast Tetracladium sp. was isolated and biochemically characterized. Results: The effects of physicochemical parameters on enzyme activity were analyzed, and pH and temperature were found to be key factors modulating the glucoamylase activity. The optimal conditions for enzyme activity were 30 °C and pH 6.0, and the Km and kcat using soluble starch as substrate were 4.5 g/L and 45 min-1, respectively. Possible amylase or glucoamylase encoding genes were identified, and their transcript levels using glucose or soluble starch as the sole carbon source were analyzed. Transcription levels were highest in medium supplemented with soluble starch for the potential glucoamylase encoding gene. Comparison of the structural model of the identified Tetracladium sp. glucoamylase with the solved structure of the Hypocrea jecorina glucoamylase revealed unique structural features that may explain the thermal lability of the glucoamylase from Tetracladium sp. Conclusion: The glucoamylase secreted by Tetracladium sp. is a novel cold-adapted enzyme and its properties should render this enzyme suitable for use in industrial processes that require cold-active amylases, such as biofuel production. [ABSTRACT FROM AUTHOR]

Cold-induced sweetening (CIS) in potato is detrimental to the quality of processed products. Conversion of starch to reducing sugars (RS) by amylases is considered one of the main pathways in CIS but is not well studied. The amylase genes StAmy23, StBAM1 and StBAM9 were studied for their functions in potato CIS. StAmy23 is localized in the cytoplasm, whereas StBAM1 and StBAM9 are targeted to the plastid stroma and starch granules, respectively. Genetic transformation of these amylases in potatoes by RNA interference showed that β-amylase activity could be decreased in cold-stored tubers by silencing of StBAM1 and collective silencing of StBAM1 and StBAM9. However, StBAM9 silencing did not decrease β-amylase activity. Silencing StBAM1 and StBAM9 caused starch accumulation and lower RS, which was more evident in simultaneously silenced lines, suggesting functional redundancy. Soluble starch content increased in RNAi-StBAM1 lines but decreased in RNAi-StBAM9 lines, suggesting that StBAM1 may regulate CIS by hydrolysing soluble starch and StBAM9 by directly acting on starch granules. Moreover, StBAM9 interacted with StBAM1 on the starch granules. StAmy23 silencing resulted in higher phytoglycogen and lower RS accumulation in cold-stored tubers, implying that StAmy23 regulates CIS by degrading cytosolic phytoglycogen. Our findings suggest that StAmy23, StBAM1 and StBAM9 function in potato CIS with varying levels of impact. [ABSTRACT FROM AUTHOR]

Bacillus subtilis SB-MYP-1 isolated from Thai Thua-nao fermentation has already been demonstrated as a potential starter culture. The aim of this work was to reveal the efficiency order of soy protein isolate (SPI), soluble starch (ST), maltodextrin (MD), and Doikham soybean flour (SBF) for protecting B. subtilis SB-MYP-1 cells under sub-lethal stress of freeze-dried encapsulation. The combination criteria, including the survival rate, low water activity, and moisture content of freeze-dried cells with SBF, were approximately 63.72% (1.30 × 10 8 CFU/g as cell viability), 0.285, and 2.31% wet basis, respectively, which were relative to the standard quality of powdered starter culture. In addition, the cell membrane fluidity, metabolic retardation, activities of three intracellular enzymes (glutamate dehydrogenase, GDH; 2-oxoglutarate aminotransferase, GOGAT; and glutamine synthetase, GS), and pgsB gene expression of freeze-dried cells were maintained by SBF protection. Surprisingly, the mode of action of SBF could preserve the protein stabilization, phospholipid bilayer, and peptidoglycan surface in freeze-dried cells, whereas the partial cell surface and lipid bilayer of cells with SPI, ST and MD were destroyed after sub-lethal freeze drying. This study revealed the novel application of SBF as a cryoprotective agent for further freeze-dried B. subtilis SB-MYP-1 preservation. [ABSTRACT FROM AUTHOR]

An inexpensive and facile direct method to synthesis ultrafine WC-Co composite powders was proposed employing soluble starch as an in situ carbon source in a H2 atmosphere via a one-step reduction-carbonization process. Influences of processing factors, such as temperature, H2 flow rate, and reaction time have been investigated. The results revealed that the system of synthesis process was dynamic in nature where temperature, H2 flow rate, and reaction time had a suitable value to achieve the desired product phase. Mainly due to the gas reaction and homogeneous in situ carbon, the synthesizing temperature and reaction time were greatly lower than the conventional method. Lowering the reaction temperature and increasing the reaction rate would lead to finer WC-Co composite powders. Ultrafine WC-Co composite powders with almost no unwanted phases were obtained under the H2 flow rate of 0.75 m3/h at 950°C for 0.5 hour and the average particle size was 155 nm with good dispersion. Furthermore, the mechanism for the phase transformation was discussed in this study as well. [ABSTRACT FROM AUTHOR]

Hierarchically structured Bi 24 O 31 Br 10 photocatalysts were synthesized by a facile solvothermal method with the help of soluble starch. As-prepared samples were characterized by XRD, SEM, EDS, TEM, FTIR and N 2 adsorption. It was found that starch played a key role in shaping morphology of Bi 24 O 31 Br 10, and especially a novel grain-like Bi 24 O 31 Br 10 hierarchical architecture could be obtained by adding the right amount of starch. The forming mechanisms of different microstructures were proposed. The photocatalytic performances of the obtained samples were also investigated by degradation of Rhodamine B (RhB) under visible light illumination. Starch-modulated Bi 24 O 31 Br 10 photocatalysts exhibited obviously enhanced photocatalytic activity, whose mechanism was discussed. The present work demonstrated a novel strategy to modulate the structures, morphologies and properties of materials, which can be extended to other photocatalysts. [ABSTRACT FROM AUTHOR]

Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25 °C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions. [ABSTRACT FROM AUTHOR]

Platensimycin (PTM) and platencin (PTN), isolated from several strains of Streptomyces platensis are potent antibiotics against multi-drug resistant bacteria. PTM was also shown to have antidiabetic and antisteatotic activities in mouse models. Through a novel genome-mining method, we have recently identified six PTM and PTN dual-producing strains, and generated several mutants with improved production of PTM or PTN by inactivating the pathway-specific transcriptional repressor gene ptmR1. Among them, S. platensis SB12026 gave the highest titer of 310 mg/L for PTM. In this study, we now report titer improvement by medium and fermentation optimization and pilot-scale production and isolation of PTM from SB12026. The fermentation medium optimization was achieved by manipulating the carbon and nitrogen sources, as well as the inorganic salts. The highest titer of 1560 mg/L PTM was obtained in 15-L fermentors, using a formulated medium mainly containing soluble starch, soybean flour, morpholinepropanesulfonic acid sodium salt and CaCO. In addition, a polyamide chromatographic step was applied to facilitate the purification and 45.14 g of PTM was successfully obtained from a 60 L scale fermentation. These results would speed up the future development of PTM as human medicine. [ABSTRACT FROM AUTHOR]

An efficient thermotolerant alkaline protease producer, strain Brevibacillus brevis BT2 was isolated from waste water effluents from textile dyeing industry. Effect of variables, i.e. soybean meal, soluble starch, inoculums, temperature and pH and their mutual interaction were analyzed by Box-Behnken design (BBD) for optimizing their levels in the medium and effect of their mutual interaction on thermotolerant alkaline protease production. All the above variables were found significantly influencing protease activity individually and also in interaction with other variables. The model predicted maximal protease production of 121.1 (U ml − 1 ) at the soybean meal 7.46 (gL −1 ), soluble starch 10.00 (gL −1 ), inoculums 1.76%, temperature 49.3 °C, and pH 9.1. The maximum protease production obtained experimentally was found to be 128.5 U/ml. The result was coincident with the predicted value and the model was proven to be adequate. [ABSTRACT FROM AUTHOR]

Starch nanoparticle loaded with curcumin was fabricated using a facile solution mixing method. Curcumin was encapsulated at various weight ratio and the results showed that 3 wt% loading achieved the highest encapsulation ability, encapsulation efficiency as well as storage ability. The obtained curcumin loaded starch (cur@star) was yellowish colored and well dispersed in water. Morphological properties were observed via transmission electron microscopy which revealed that the particles were spherical and unified distributed with diameter around 100 nm. Differential scanning calorimetry and X-ray diffraction were preformed to confirm that curcumin exists in the starch matrix in amorphous state. Moreover, Fourier transform infrared spectroscopy spectra indicate that hydrogen bonding may be responsible for the interaction between curcumin and starch. Cur@star increased the stability of curcumin against UV irradiation and retained its antioxidant ability. Due to the simple preparation procedures and low-priced material used, curcumin soluble starch nanocomposite reported here is promising to widen applications of curcumin in the food industry. [ABSTRACT FROM AUTHOR]

Starch ethyl carbonates were synthesized applying novel paths including chlorocarbonic acid ethyl ester and ethyl 1H-imidazole-1-carboxylate as reagent. The influence of starch, reaction medium, and base on the degree of substitution (DS) was investigated. The conversion of starch with chlorocarbonic acid ethyl ester in N,N-dimethyl formamide (DMF)/LiCl leads to a preferred substitution of position 6 of the anhydroglucose unit (AGU), on one hand. On the other, the reaction of starch with 1H-imidazole-1-carboxylate in dimethyl sulfoxide (DMSO) or DMF/LiCl results in a preferred functionalization of position 2. The products obtained were well soluble in polar aprotic solvents and in water depending on starch and DS. Intermolecular cross-linking or intramolecular cyclic carbonate formation could not be observed. A detailed structure characterization was carried out by one- and two-dimensional NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Biohydrogen is a clean source of energy that produces no harmful byproducts during combustion, being a potential sustainable energy carrier for the future. Therefore, biohydrogen produced by anaerobic bacteria via dark fermentation has attracted attention worldwide as a renewable energy source. However, the hydrogen production capability of these bacteria depends on major factors such as substrate, iron-containing hydrogenase, reduction agent, pH, and temperature. In this study, the response surface methodology (RSM) with central composite design (CCD) was employed to improve the hydrogen production by an anaerobic bacterial strain isolated from animal waste in Phu Linh, Soc Son, Vietnam (PL strain). The hydrogen production process was investigated as a function of three critical factors: soluble starch concentration (8 g L to 12 g L), ferrous iron concentration (100 mg L to 200 mg L), and l-cysteine concentration (300 mg L to 500 mg L). RSM analysis showed that all three factors significantly influenced hydrogen production. Among them, the ferrous iron concentration presented the greatest influence. The optimum hydrogen concentration of 1030 mL L medium was obtained with 10 g L soluble starch, 150 mg L ferrous iron, and 400 mg L l-cysteine after 48 h of anaerobic fermentation. The hydrogen concentration produced by the PL strain was doubled after using RSM. The obtained results indicate that RSM with CCD can be used as a technique to optimize culture conditions for enhancement of hydrogen production by the selected anaerobic bacterial strain. Hydrogen production from low-cost organic substrates such as soluble starch using anaerobic fermentation methods may be one of the most promising approaches. [ABSTRACT FROM AUTHOR]

Cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) production using new alkaliphile Microbacterium terrae KNR 9 was investigated by submerged fermentation. Statistical screening for components belonging to different categories, namely, soluble and raw starches as carbon sources, complex organic and inorganic nitrogen sources, minerals, a buffering agent, and a surfactant, has been carried out for CGTase production using Plackett-Burman factorial design. To screen out k (19), number of variables, k+1 (20), number of experiments, were performed. Among the fourteen components screened, four components, namely, soluble starch, corn flour, yeast extract, and K2HPO4, were identified as significant with reference to their concentration effect and corresponding p value. Although soluble starch showed highest significance, comparable significance was also observed with corn flour and hence it was selected as a sole carbon source along with yeast extract and K2HPO4 for further media optimization studies. Using screened components, CGTase production was increased to 45% and 87% at shake flask level and laboratory scale fermenter, respectively, as compared to basal media. [ABSTRACT FROM AUTHOR]

ZSM-5 zeolite with intracrystal mesopores was synthesized via soluble starch as in-situ template. The pore structure of the samples is demonstrated by N 2 adsorption, XRD, SEM and TEM techniques. The results show that the intracrystal mesopores are ascribed to the carbonized starch encapsulated in the ZSM-5 mesophase. The carbonized starch was removed through calcination, and then unordered mesopores are exposed. While the mesopores are unordered and the mesopore diameter is not uniform due to the different size of the assembling carbonized starch among ZSM-5 mesophase. Of note is that the mesopores exhibit good thermal and hydrothermal stability. The mesopore volume of the ZSM-5 treated at 800 °C with flow of stream is almost unchanged compared to the untreated samples. [ABSTRACT FROM AUTHOR]

Preparation and investigation of the resistant starch-soluble dietary fiber conjugates are very important, considering the different and meaningful physiological properties of resistant starch and soluble dietary fiber. In this study, the different starch-soluble dietary fiber conjugates were obtained by crosslinking using sodium trimetaphosphate, under the different treatments of conventional heat moisture and microwave heat moisture. The starch-soluble dietary fiber conjugates prepared under the treatment of conventional heat moisture almost completely resisted the hydrolysis of the amylolytic enzymes. However, the hydrolysis of the starch-soluble dietary fiber conjugates treated by microwave heat moisture was obvious. In the treatment of conventional heat moisture, soluble dietary fiber was combined into outer layer of the overall starch granule by the linking with 2-, 3-, or 6-OH of glucose in the amorphous region. This combination showed a large protective effect on the resistance to enzymatic hydrolysis of the whole starch granules. Whereas, in the treatment of microwave heat moisture, soluble dietary fiber was linked into the amorphous part of starch blocks derived from destructive starch granule, resulting in the conjugates with high homogeneity. Therefore, the as-prepared resistant starch-soluble dietary fiber conjugates under the treatment of conventional heat moisture have a potential to be used as new dietary supplement in the food industry. [ABSTRACT FROM PUBLISHER]

Clostridium tyrobutyricum does not have the enzymes needed for using maltose or starch. Two extracellular α-glucosidases encoded by agluI and agluII from Clostridium acetobutylicum ATCC 824 catalyzing the hydrolysis of α-1,4-glycosidic bonds in maltose and starch from the non-reducing end were cloned and expressed in C. tyrobutyricum (Δ ack, adhE2), and their effects on n-butanol production from maltose and soluble starch in batch fermentations were studied. Compared to the parental strain grown on glucose, mutants expressing agluI showed robust activity in breaking down maltose and produced more butanol (17.2 vs. 9.5 g/L) with a higher butanol yield (0.20 vs. 0.10 g/g) and productivity (0.29 vs. 0.16 g/L h). The mutant was also able to use soluble starch as substrate, although at a slower rate compared to maltose. Compared to C. acetobutylicum ATCC 824, the mutant produced more butanol from maltose (17.2 vs. 11.2 g/L) and soluble starch (16.2 vs. 8.8 g/L) in batch fermentations. The mutant was stable in batch fermentation without adding antibiotics, achieving a high butanol productivity of 0.40 g/L h. This mutant strain thus can be used in industrial production of n-butanol from maltose and soluble starch. [ABSTRACT FROM AUTHOR]

A maltotriose-producing α-amylase, AmyA, from a newly isolated bacterial strain Microbulbifer thermotolerans DAU221 was purified and characterized in the heterologous host, Escherichia coli, using the pCold I vector. The amyA gene encoded a 761-residue protein composed of a 33 amino acid secretion signal peptide. The purified α-amylase with a molecular mass of 80 kDa, approximately, shared a sequence motif characteristic of the glycoside hydrolase family 13. The enzyme was optimally active, at 50 °C in sodium phosphate buffer (pH 6.0), by the traditional one factor-at-a-time method. But the optimal conditions of time, temperature, and pH for production of maltotriose from soluble starch were 1.76 h, 44.95 °C, and pH 6.35 by response surface methodology, respectively. Maltotriose, as the major enzyme reaction product, was analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The enzyme was found to be inhibited by the addition of 10 mM Cu, Fe, Hg, Zn, and EDTA, but exhibited extreme stability toward hexane. The K and V values for the hydrolysis of soluble starch were 1.08 mg/mL and 1.736 mmol maltotriose/mg protein/min, respectively. [ABSTRACT FROM AUTHOR]

Condensed distillers solubles (CDS) is a viscous, syrupy co-product of ethanol production from corn or other starchy grains; CDS exhibits strong recalcitrance to drying due to its chemical composition, which includes a substantial amount of glycerol. The objectives of this study were to determine the drum drying performance of CDS and to compare it to that of a physically modified CDS (MCDS) having a reduced glycerol level. Material type (CDS vs. MCDS), dwell time, drum internal steam temperature, and gap width were evaluated for their effects on the final moisture content, water activity, and color of the dried product. While both CDS and MCDS could be dried to a range of endpoint moisture contents, dried CDS exhibited a narrow range of water activity compared to that of MCDS. Gap width was found to be the predominant factor affecting dried product color. This work demonstrates that drum drying can effectively reduce the moisture content of CDS, even though the water activity of the dried product cannot be reduced beyond ~0.45. In contrast, MCDS can be readily drum-dried into a shelf-stable, flaked product with a pleasing appearance. [ABSTRACT FROM AUTHOR]

Plant carbohydrates are of increasing interest as renewable feedstocks to replace petrochemicals in the generation of fuels and production of high-value chemicals. Greater understanding of the genetic control of diversity in fructan synthesis and accumulation would facilitate more directed channelling of feedstock to process in a ryegrass biorefinery. Divergent populations produced by phenotypic selection for water-soluble carbohydrate content have been used to investigate relationships between traits, and to identify patterns of genetic differentiation which indicate genomic regions under high and low selection pressure. Selection for high water-soluble carbohydrate content was associated with increased synthesis of large fructan polymers and increased accumulation of above-ground plant biomass, particularly during spring. Three rounds of selection and two rounds of recombination resulted in widespread genetic differentiation across the whole genome, causing reduced allelic richness and increasing homozygosity at some loci. A smaller number of loci were shown to be subject to high selection pressure. Breeding material subjected to many years of selection for water-soluble carbohydrate also showed allelic differences which may reflect the consequences of high selection pressure at some of these same loci. However, some of the loci unaffected in the divergent selection experiment showed similar effects. This might arise from differences in linkage disequilibrium in these two sets of plant materials, but more likely from the different genetic background of the germplasm. This illustrates the complex nature of the water-soluble carbohydrate trait in perennial ryegrass. [ABSTRACT FROM AUTHOR]

Gowé is a traditional Beninese fermented red sorghum beverage made from a blend of malted and precooked nonmalted flour. The main objective of this work was to evaluate the degradation of starch during the production of gowé and to characterise the organic acid and sugar profiles of the product obtained using starter cultures. Inoculation was performed with strains of Lactobacillus fermentum or Weissella confusa and of Kluyveromyces marxianus or Pichia anomala used singly or in combination. Size exclusion chromatography revealed that starch was hydrolysed into high molecular weight dextrins ( DP over 35), oligosaccharides and glucose, mainly due to the malting and precooking steps. Glucose was the main free sugar, and lactic acid was the main organic acid. The choice of the inoculation strain directly influenced the acidity but also indirectly the sugar content of the resulting gowé and will thus affect consumer acceptability. [ABSTRACT FROM AUTHOR]

The α-glucosidase from sugar beet (SBG) is an exo-type glycosidase. The enzyme has a pocket-shaped active site, but efficiently hydrolyzes longer maltooligosaccharides and soluble starch due to lower Km and higher kcat/Km for such substrates. To obtain structural insights into the mechanism governing its unique substrate specificity, a series of acarviosyl-maltooligosaccharides was employed for steady-state kinetic and structural analyses. The acarviosyl-maltooligosaccharides have a longer maltooligosaccharide moiety compared with the maltose moiety of acarbose, which is known to be the transition state analog of α-glycosidases. The clear correlation obtained between log Ki of the acarviosyl-maltooligosaccharides and log(Km/kcat) for hydrolysis of maltooligosaccharides suggests that the acarviosyl-maltooligosaccharides are transition state mimics. The crystal structure of the enzyme bound with acarviosyl-maltohexaose reveals that substrate binding at a distance from the active site is maintained largely by van der Waals interactions, with the four glucose residues at the reducing terminus of acarviosyl-maltohexaose retaining a left-handed single-helical conformation, as also observed in cycloamyloses and single helical V-amyloses. The kinetic behavior and structural features suggest that the subsite structure suitable for the stable conformation of amylose lowers the Km for long-chain substrates, which in turn is responsible for higher specificity of the longer substrates. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effect of soybean meal (SM) and soluble starch (SS) on biogenic amine production and microbial diversity using in vitro ruminal fermentation. Treatments comprised of incubation of 2 g of mixture (expressed as 10 parts) containing different ratios of SM to SS as: 0:0, 10:0, 7:3, 5:5, 3:7, or 0:10. In vitro ruminal fermentation parameters were determined at 0, 12, 24, and 48 h of incubation while the biogenic amine and microbial diversity were determined at 48 h of incubation. Treatment with highest proportion of SM had higher (p<0.05) gas production than those with higher proportions of SS. Samples with higher proportion of SS resulted in lower pH than those with higher proportion of SM after 48 h of incubation. The largest change in NH3-N concentration from 0 to 48 h was observed on all SM while the smallest was observed on exclusive SS. Similarly, exclusive SS had the lowest NH3-N concentration among all groups after 24 h of incubation. Increasing methane (CH4) concentrations were observed with time, and CH4 concentrations were higher (p<0.05) with greater proportions of SM than SS. Balanced proportion of SM and SS had the highest (p<0.05) total volatile fatty acid (TVFA) while propionate was found highest in higher proportion of SS. Moreover, biogenic amine (BA) was higher (p<0.05) in samples containing greater proportions of SM. Histamines, amine index and total amines were highest in exclusive SM followed in sequence mixtures with increasing proportion of SS (and lowered proportion of SM) at 48 h of incubation. Nine dominant bands were identified by denaturing gradient gel electrophoresis (DGGE) and their identity ranged from 87% to 100% which were mostly isolated from rumen and feces. Bands R2 (uncultured bacterium clone RB-5E1) and R4 (uncultured rumen bacterium clone L7A_C10) bands were found in samples with higher proportions of SM while R3 (uncultured Firmicutes bacterium clone NI_52), R7 (Selenomonas sp. MCB2), R8 (Selenomonas ruminantium gene) and R9 (Selenomonas ruminantium strain LongY6) were found in samples with higher proportions of SS. Different feed ratios affect rumen fermentation in terms of pH, NH3-N, CH4, BA, volatile fatty acid and other metabolite concentrations and microbial diversity. Balanced protein and carbohydrate ratios are needed for rumen fermentation. [ABSTRACT FROM AUTHOR]

Candida utilis represents a promising expression host, generating relatively high levels of recombinant proteins. The current study presents preliminary characterization of the upstream regulatory regions controlling the carbon source-dependent expression of the C. utilis maltase gene. Cellobiose and soluble starch were recognised as inducers of maltase promoter, besides maltose. We successfully applied the Cre- loxP system to acquire a null mutant strain with disrupted maltase gene and promoter in polyploid yeast C. utilis . Furthermore, the strength and minimal functional region of the promoter was evaluated by measuring β-galactosidase activity. Our results suggest, the qPCR was shown itself a very smart method for relatively easy characterization of the transformants and correlation of the expression levels with gene dosage. [ABSTRACT FROM AUTHOR]

The influence of the cold‐water‐soluble fraction on gelatinization and pasting properties of rice flour was investigated. The cold‐water‐soluble fraction was removed by water extraction under room temperature. The gelatinization properties of untreated and treated flour were analyzed with a differential scanning calorimeter, and pasting profiles were measured with a rapid viscosity analyzer. The removal of the cold‐water‐soluble fraction resulted in the formation of a loosened starch granule structure, a morphological alteration of protein bodies, a markedly lower gelatinization temperature, and a significantly higher pasting enthalpy. The impact on paste viscosity followed different trends. In some cultivars that had lower endogenous amylase activity, the paste viscosity was greatly reduced by the removal of the cold‐water‐soluble fraction. In others, the higher level of endogenous amylase activity led to more soluble saccharides being released through starch hydrolysis. Removing the soluble fraction caused a remarkable increase in peak viscosity. The overall effect on paste viscosity of removing the cold‐water‐soluble fraction was attributed to multiple factors, involving loosening of the starch granule structure, alteration of morphology of protein bodies, and the release of saccharides by endogenous amylase activity. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop with thermoplastic extrusion amaranth starch derivatives and to characterize and evaluate their functionality as encapsulating agents of Bifidobacterium breve ATCC 15700 and Lactobacillus casei ATCC 334 during spray drying. The survival of both probiotics during storage at different water activities and at two storage temperatures, their viability in a food model system, and their tolerance to a simulated gastrointestinal tract were determined. Native amaranth starch was chemically modified to obtain phosphorylated, acetylated, and succinylated starch. Starch derivatives were reduced in viscosity, and the solubility in water was increased. In general, the modified amaranth starches and control corn starch did not provide good protection to both probiotics during storage at 25°C. However, there was excellent viability during storage at 4°C for both probiotics. Microcapsules showed a uniform coverage of the cells. Storage for 35 days at 25°C of blends of oat with succinylated amaranth microcapsules with probiotics had a lower reduction. Also, this succinylated amaranth starch containing probiotics showed a higher resistance to simulated gastrointestinal conditions. The results with food model systems supported the applicability of the modified starches. [ABSTRACT FROM AUTHOR]

Detection of low numbers ofSalmonellain complex food matrices such as ground beef by polymerase chain reaction (PCR) without enrichment is particularly difficult because of the presence of PCR inhibitors and fat. This study used soluble starch for the removal of fat in ground beef followed by the use of activated carbon coated with milk proteins for the removal of PCR inhibitors prior to conventional PCR and RealTime qPCR. This methodology without pre-enrichment allowed detection with conventional PCR of 5 CFU/g and 1 CFU/g with the real-time qPCR in ground beef containing 7%, 15%, and 27% fat. The total assay time was 5 h from the seeding of a 25 g sample of ground beef to agarose gel detection of amplicons of a 284 bpinvAgene fragment specific forSalmonellaand 4.5 h for real-time qPCR detection. [ABSTRACT FROM PUBLISHER]

In this article, the processing and microstructures of porous mullite bodies prepared by modifying the conventional route of the starch consolidation casting method were studied. The proposed route, called the 'soluble route', involves the use of native starches (i.e., potato, cassava, and corn starches) and a synthesized granular cold-water-soluble ( GCWS) starch. Stable aqueous mullite-starch suspensions (0.25 starch volume fraction of 40 vol% total solids) were prepared by mixing. The total starch content was a mixture of ungelatinized native starch and GCWS starch with a 1:10 ratio of GCWS starch to total starch. Steady-state shear flow properties of the suspensions were analyzed by measuring viscosity. The addition of CGWS starch increased the starting suspension viscosity and thus prevented the particle segregation. Porous mullite bodies were obtained by heating (80°C, 2 h) the suspensions in metallic molds and by drying (40°C, 24 h) and sintering (1650°C, 2 h) the green disks after burning out the starch (650°C, 2 h). Green bodies obtained before and after the burning-out process, and the sintered disks were characterized with density and porosity measurements (Archimedes method) and microstructural analysis by scanning electron microscopy. The phases generated after the sintering process were determined by X-ray diffraction analysis, and pore size distributions were studied by Hg-porosimetry. The obtained results showed that the use of the GCWS starch made the shaping of homogeneous mullite bodies without cracks or deformations possible along with the development of controlled porous microstructures. [ABSTRACT FROM AUTHOR]

Highlights: [•] A starch binding domain (SBD) was identified in the α-amylase (AmyP) of glycoside hydrolase subfamily GH13_37. [•] SBD and its homologues form a novel carbohydrate-binding module family (CBM69). [•] SBD provides new clues of biodiversity and evolution of SBD in the ocean. [•] SBD exhibits a binding preference toward raw rice starch. [•] SBD has a stronger effect on soluble starch hydrolysis than raw starch hydrolysis. [ABSTRACT FROM AUTHOR]

Organic waste generated from industrial sweet potato canning is estimated to be 30% of incoming raw material with significant residual carbohydrate content. The purpose of this study was to evaluate the potential of waste generated from sweet potato processing material to support the growth of lactic acid bacteria and the production of lactic acid. The waste was comprised of 16.5% solids consisting of 18.5% ash, 4.4% protein, 20.5% simple sugars and 19% soluble starch. Following a screening of three lactic acid bacteria strains, Lactobacillus rhamnosus was deemed the best candidate for lactic acid production. The potential of various dilutions of the enzyme-hydrolysed waste, with and without pH control, as a fermentation substrate was evaluated. Lactic acid production was highest in hydrolysed waste (without dilution) at pH set point 5.0, yielding 10 g L−1 in 72 h. Thus, lactic acid, a valuable organic compound, can be generated from sweet potato waste. [ABSTRACT FROM AUTHOR]

The impact of raw material variability on the prediction ability of a near-infrared calibration model was studied. Calibrations, developed from a quaternary mixture design comprising theophylline anhydrous, lactose monohydrate, microcrystalline cellulose, and soluble starch, were challenged by intentional variation of raw material properties. A design with two theophylline physical forms, three lactose particle sizes, and two starch manufacturers was created to test model robustness. Further challenges to the models were accomplished through environmental conditions. Along with full-spectrum partial least squares ( PLS) modeling, variable selection by dynamic backward PLS and genetic algorithms was utilized in an effort to mitigate the effects of raw material variability. In addition to evaluating models based on their prediction statistics, prediction residuals were analyzed by analyses of variance and model diagnostics ( Hotelling's T2 and Q residuals). Full-spectrum models were significantly affected by lactose particle size. Models developed by selecting variables gave lower prediction errors and proved to be a good approach to limit the effect of changing raw material characteristics. Hotelling's T2 and Q residuals provided valuable information that was not detectable when studying only prediction trends. Diagnostic statistics were demonstrated to be critical in the appropriate interpretation of the prediction of quality parameters. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:545-556, 2014 [ABSTRACT FROM AUTHOR]

In this study, porous poly(lactide- co-glycolide) (PLGA) microparticles with low mass density and large particle size were developed for chronic obstructive pulmonary disease treatment using anticholinergic drug (tiotropium). The porous PLGA microparticles were prepared by the water-in-oil-in-water (W1/O/W2) multi-emulsion method using PLGA polymer and ammonium bicarbonate (as a porogen). Herein, soluble starch was incorporated in porous PLGA microparticles for long-term tiotropium release. In vitro drug release studies determined that the rapid release of tiotropium from porous PLGA microparticles was reduced because of the high viscosity of the incorporated starch. Tiotropium release from porous PLGA microparticles continued up to 3 days. Furthermore, the inhaled microparticles showed longer drug residence in in vivo lung epithelium. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Soluble carbohydrates play a key role as osmolytes and significantly contribute in salt defence mechanism, especially in halophyte species. The objective of this study is to investigate the transcriptional expression of starch-related genes, sugar profile and physiological performances of two contrasting rice genotypes, Pokkali (salt tolerant) and IR29 (salt sensitive), in response to salt stress. Total soluble sugars, glucose and fructose levels in the flag leaf of salt-stressed Pokkali rice were enhanced relative to soluble starch accumulation in plants exposed to EC = 13.25 dS m (salt stress) for 3 days. In Pokkali, the net photosynthetic rate and starch metabolism may play a key role as energy resources under salt stress. In contrast, photosynthetic performance, indicated by photosynthetic pigment levels and chlorophyll fluorescence parameters, in salt-stressed IR29 was significantly reduced, leading to delayed starch biosynthesis. The reduction in photosynthetic ability and lack of defence mechanisms in IR29 caused growth inhibition and yield loss. Soluble starch and soluble sugar enrichment in Pokkali rice may function alternatively as osmotic adjustment in salt defence mechanism and strengthen carbon energy reserves, greater survival prospects under salt stress and enhanced productivity. [ABSTRACT FROM AUTHOR]

Oligopeptidases impose a size limitation on their substrates, themechanismof which has long been under debate. Herewepresent the structure of a hexameric serine protease, an oligopeptidase from Pyrococcus horikoshii (PhAAP), revealing a complex, selfcompartmentalized inner space, where substrates may access the monomer active sites passing through a double-gated "check-in" system, first passing through a pore on the hexamer surface and then turning to enter through an even smaller opening at the monomers' domain interface. This substrate screening strategy is unique within the family.Wefound that among oligopeptidases, a residue of the catalytic apparatus is positioned near an amylogenic β-edge,whichneeds tobeprotected to prevent aggregation,andwe found that different oligopeptidases use different strategies to achieve such an end. We propose that self-assembly within the family results in characteristically different substrate selection mechanisms coupled to different multimerization states. [ABSTRACT FROM AUTHOR]

In this study, we achieved the efficient synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) from soluble starch by fusing a carbohydrate-binding module (CBM) from Alkalimonas amylolytica α-amylase (CBMAmy) to cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans. One fusion enzyme, CGT-CBMAmy, was constructed by fusing the CBMAmy to the C-terminal region of CGTase, and the other fusion enzyme, CGT▵ E-CBMAmy, was obtained by replacing the E domain of CGTase with CBMAmy. The two fusion enzymes were then used to synthesize AA-2G from soluble starch as a cheap and easily soluble glycosyl donor. Under the optimal conditions, the AA-2G yields produced using CGT▵ E-CBMAmy and CGT-CBMAmy were 2.01 g/liter and 3.03 g/liter, respectively, which were 3.94- and 5.94-fold of the yield from the wild-type CGTase (0.51 g/liter). The reaction kinetics of the two fusion enzymes were analyzed and modeled to confirm the enhanced specificity toward soluble starch. It was also found that, compared to the wild-type CGTase, the two fusion enzymes had relatively high hydrolysis and disproportionation activities, factors that favor AA-2G synthesis. Finally, it was speculated that the enhancement of soluble starch specificity may be related to the changes of substrate binding ability and the substrate binding sites between the CBM and the starch granule. [ABSTRACT FROM AUTHOR]

The gene encoding the cyclodextrin glucanotransferase (CGTase, EC2.4.1.19) of Paenibacillus illinoisensis was isolated, cloned, sequenced and expressed in Escherichia coli. Sequence analysis showed that the mature enzyme (684 amino acids) was preceded by a signal peptide of 34-residues. The deduced amino acid sequence of the CGTase from P. illinoisensis ZY-08 exhibited highest identity (99 %) to the CGTase sequence from Bacillus licheniformis (P14014). The four consensus regions of carbohydrate converting domain and Ca binding domain could be identified in the sequence. The CGTase was purified by using cold expression vector, pCold I, and His-tag affinity chromatography. The molecular weight of the purified enzyme was about 74 kDa. The optimum temperature and pH of the enzyme were 40 °C and pH 7.4, respectively. The enzyme activity was increased by the addition of Ca and inhibited by Ba, Cu, and Hg. The K and V values calculated were 0.48 mg/ml and 51.38 mg of β-cyclodextrin/ml/min. The ZY-08 and recombinant readily converted soluble starch to β-cyclodextrin but ZY-08 did not convert king oyster mushroom powder and enoki mushroom powder. However the recombinant CGTase converted king oyster mushroom powder and enoki mushroom powder to β-cyclodextrin. [ABSTRACT FROM AUTHOR]