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Manish Salgaonkar, Shamraja S Nadar, Virendra K Rathod
The multi-enzyme biocatalyst allows to run in vitro multi-step cascade reactions in a single pot. An efficient combi-metal organic frameworks (combi-MOF) of α-amylase and glucoamylase for one pot starch hydrolysis was constructed by mixing zinc acetate and 2‑methylimmidazole with enzyme mixture in one pot under biocompatible conditions. The prepared combi-MOF was characterized and analyzed by powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM)...
February 16, 2018: International Journal of Biological Macromolecules
Deepali Jain, Priya Katyal
Fungal gluco-amylase is required for the production of sugars from starchy substrates. Commercially available fungal gluco-amylase is quite costly which makes the process uneconomical. This study was undertaken to standardize physico-chemical parameters for optimum production of gluco-amylases from Aspergillus spp. Two fungal cultures, i.e., Aspergillus niger and Aspergillus terreus, were compared for gluco-amylase activity both under stationary and shake flask conditions. Among two fungal cultures, maximum gluco-amylase activity was shown by A...
February 2018: 3 Biotech
Madiha Kazmi, Sumera Zaib, Aliya Ibrar, Sayyeda Tayyeba Amjad, Zainab Shafique, Saifullah Mehsud, Aamer Saeed, Jamshed Iqbal, Imtiaz Khan
Diabetes mellitus (DM), a chronic multifarious metabolic disorder resulting from impaired glucose homeostasis has become one of the most challenging diseases with severe life threat to public health. The inhibition of α-glucosidase, a key carbohydrate hydrolyzing enzyme, could serve as one of the effective methodology in both preventing and treating diabetes through controlling the postprandial glucose levels and suppressing postprandial hyperglycemia. In this context, three series of diamine-bridged bis-coumarinyl oxadiazole conjugates were designed and synthesized by one-pot multi-component methodology...
January 16, 2018: Bioorganic Chemistry
Daniel Rosas-Ramírez, Sonia Escandón-Rivera, Rogelio Pereda-Miranda
Twenty-seven individual resin glycosides from the morning glory family (Convolvulaceae) were evaluated for their α-glucosidase inhibitory potential. Four of these compounds displayed an inhibitory activity comparable to acarbose, which was used as a positive control. Molecular modeling studies performed by docking analysis were accomplished to predict that the active compounds and acarbose bind to the α-1,4-glucosidase enzyme catalytic site of MAL12 from the yeast Saccharomyces cerevisiae through stable hydrogen bonds primarily with the amino acid residues HIS279 and GLN322...
February 1, 2018: Phytochemistry
Tsz Him Kwan, Khai Lun Ong, Md Ariful Haque, Wing Hei Kwan, Sandeep Kulkarni, Carol Sze Ki Lin
Valorisation of mixed food and beverage (F&B) waste was studied for the recovery of sugars via saccharification. Glucoamylase and sucrase were employed to hydrolyse the starch and sucrose present in the mixed F&B waste because of the high cost-effectiveness for such recovery. The Michaelis-Menten kinetics model suggests that preservatives and additives in beverages did not inhibit glucoamylase and sucrase during saccharification. High levels of glucose (228.1 g L-1) and fructose (55.7 g L-1) were efficiently produced within 12 h at a solid-to-liquid ratio of 37...
January 31, 2018: Bioresource Technology
Yacheng Hao, Yun Chen, Qian Li, Qunyu Gao
A comparative experiment about the production of starch nanocrystals (SNCs) with/without glucoamylase enzymatic pretreatment by sulfate acid hydrolysis from waxy potato starch (WPS) was employed in the present study. The research focused on the enhancement of the preparation efficiency while improving the dispersion of SNCs at the same time. The enzymatic pretreatment resulted in the decrease of acid hydrolysis duration. The minimum size and best dispersibility of nanocrystals was obtained after 5 days of hydrolysis...
March 15, 2018: Carbohydrate Polymers
Lei Han, Bo Liang, Jianxia Song
As an important cofactor, NADH is essential for most redox reactions and biofuel cells. However, supply of exogenous NADH is challenged, due to the low production efficiency and high cost of NADH regeneration system, as well as low stability of NADH. Here, we constructed a novel cell surface multi-enzyme co-display system with ratio- and space-controllable manner as exogenous NADH regeneration system for the sustainable NADH production from low-cost biomass. Dockerin-fused glucoamylase (GA) and glucose dehydrogenase (GDH) were expressed and assembled on the engineered bacterial surfaces, which displayed protein scaffolds with various combinations of different cohesins...
January 10, 2018: Journal of Industrial Microbiology & Biotechnology
Morgann C Reilly, Joonhoon Kim, Jed Lynn, Blake A Simmons, John M Gladden, Jon K Magnuson, Scott E Baker
Plant biomass, once reduced to its composite sugars, can be converted to fuel substitutes. One means of overcoming the recalcitrance of lignocellulose is pretreatment followed by enzymatic hydrolysis. However, currently available commercial enzyme cocktails are inhibited in the presence of residual pretreatment chemicals. Recent studies have identified a number of cellulolytic enzymes from bacteria that are tolerant to pretreatment chemicals such as ionic liquids. The challenge now is generation of these enzymes in copious amounts, an arena where fungal organisms such as Aspergillus niger have proven efficient...
January 6, 2018: Applied Microbiology and Biotechnology
Na Ji, Chengzhen Liu, Man Li, Qingjie Sun, Liu Xiong
The aim of this work was to evaluate the effects of cellulose nanocrystals (CNCs) on amylolytic enzyme activity and starch digestibility. For the first time, we investigated the interaction between α-amylase or glucoamylase and CNCs using ultraviolet visible (UV-Vis) absorption spectroscopy, fluorescence quenching method, Fourier transform infrared (FTIR) spectroscopy, and circular dichroism (CD). The results of UV and fluorescence spectra suggested that CNCs interacted with α-amylase and glucoamylase. Increasing the concentration of CNCs caused a reduction of α-amylase and glucoamylase activities...
April 15, 2018: Food Chemistry
Toshihiro Kojo, Chihiro Kadooka, Marisa Komohara, Shiori Onitsuka, Miya Tanimura, Yukiko Muroi, Shugo Kurazono, Yohei Shiraishi, Ken Oda, Kazuhiro Iwashita, Masahira Onoue, Kayu Okutsu, Yumiko Yoshizaki, Kazunori Takamine, Taiki Futagami, Kazuki Mori, Hisanori Tamaki
Aspergillus luchuensis is a kuro (black) koji fungus that has been used as a starch degrader for the awamori- and shochu-making industries in Japan. In this study, we investigated the effect of ion beam irradiation on A. luchuensis RIB2601 and obtained a high starch-degrading mutant strain U1. Strain U1 showed reduced growth rate, whereas it showed higher α-amylase, glucoamylase, and α-glucosidase activities on a mycelial mass basis than the wild type (wt) strain both on agar plates and in rice koji. In addition, strain U1 showed higher N-acetylglucosamine content in the cell wall and higher sensitivity to calcofluor white, suggesting a deficiency in cell wall composition...
October 17, 2017: Journal of General and Applied Microbiology
Lagzouli Mohamed, Youssfi El Kettani, Aitounejjar Ali, Elyachioui Mohamed, Jadal Mohamed
OBJECTIVE: Glucoamylase is among the most important enzymes in biotechnology. The present study aims to determine better conditions for growth and glucoamylase production by Candida guilliermondii and to reduce the overall cost of the medium using Box-Behnken design with one central point and response surface methodology. METHODOLOGY: Box-Behnken factorial design based on three levels was carried out to obtain optimal medium combination of five independent variables such as initial pH, soluble starch, CH4N2O, yeast extract and MgSO4...
2017: Pakistan Journal of Biological Sciences: PJBS
Mahdi Amiri, Hassan Y Naim
In this study, we used a brush border membrane (BBM) preparation from human small intestine to analyze the proportion and the activity of major intestinal disaccharidases, including sucrase-isomaltase (SI), maltase-glucoamylase (MGAM) and lactase-phlorizin hydrolase (LPH). SI, MGAM and LPH respectively constituted 8.2%, 2.7% and 1.4% of total BBM protein. The activity of SI and LPH decreased threefold after purification from the brush border membrane, which highlights the effect of membrane microdomains on the functional capacity of these enzymes...
October 10, 2017: Nutrients
Yousuke Suyama, Norifumi Muraki, Masami Kusunoki, Hideo Miyake
Glucoamylases are widely used commercially to produce glucose syrup from starch. The starch-binding domain (SBD) of glucoamylase from Aspergillus niger is a small globular protein containing a disulfide bond. The structure of A. niger SBD has been determined by NMR, but the conformation surrounding the disulfide bond was unclear. Therefore, X-ray crystal structural analysis was used to attempt to clarify the conformation of this region. The SBD was purified from an Escherichia coli-based expression system and crystallized at 293 K...
October 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
Jingjing Liu, Jianghua Li, Hyun-Dong Shin, Guocheng Du, Jian Chen, Long Liu
l-Malate, an important chemical building block, has been widely applied in the food, pharmaceutical, and bio-based materials industries. In previous work, we engineered Aspergillus oryzae by rewiring the reductive tricarboxylic acid pathway to produce l-malate from glucose. To decrease the production cost, here, we further engineered A. oryzae to efficiently produce l-malate directly from corn starch with simultaneous liquefaction-saccharification and fermentation. First, a promoter PN5 was constructed by quintuple tandem of the 97-bp fragment containing the cis-element of the glucoamylase gene promoter (PglaA), and with the promoter PN5, the transcriptional level of glaA gene increased by 25-45%...
September 28, 2017: Journal of Biotechnology
Liang Xian, Jia-Xun Feng
Glucoamylase, cleaving the nonreducing end of starch releasing glucose, is an important enzyme in starch processing. The optimal temperature for industrial glucoamylase activity is 60-70°C, which is not compatible with the optimal growth temperature for Saccharomyces cerevisiae. In this study, 26 fungal strains producing amylolytic activities that were more active at 30°C than at 60°C were isolated from 151 environmental samples. Fungal strain WZ99, produced extracellular amylolytic activities with the lowest optimal temperature at 40°C, was identified as Aspergillus tritici by analysis of morphological and molecular data...
September 23, 2017: International Journal of Biological Macromolecules
Zhibin Liu, Zhiyao Wang, Xucong Lv, Xiaoping Zhu, Liling Chen, Li Ni
Hong Qu, which mainly contains Monascus sp. and other microorganisms, as well as numerous microbial metabolites, is used as the fermentation starter of Hong Qu glutinous rice wine, a traditional alcoholic beverage. Two widely-used types of Hong Qu, namely Wuyi Qu (WYQ) and Gutian Qu (GTQ), were thoroughly compared for their fermentation properties, volatile profiles, and microbiota structures in this study. Significantly higher color value, glucoamylase and α-amylase activities were discovered in WYQ. And substantial variation in volatile components and microbial communities were also observed between them...
February 2018: Food Microbiology
Danli Wang, Xiaobin Ma, Lufeng Yan, Thunthacha Chantapakul, Wenjun Wang, Tian Ding, Xingqan Ye, Donghong Liu
The present work investigates the synergistic impact of glucoamylase and ultrasound on starch hydrolysis. The extent of starch hydrolysis at different reaction parameters (ultrasonic intensity, temperature, reaction time) was analyzed. The hydrolysis extent increased with the reaction time and reached a maximum value under ultrasonic intensity of 7.20W/mL at 10min. Ultrasound did not alter the optimum enzymatic temperature but speeded up the thermal inactivation of glucoamylase. The evaluation of enzymatic kinetics and starch degradation kinetics indicated a promotion of the reaction rate and enzyme-substrate affinity...
November 1, 2017: Carbohydrate Polymers
Qingwang Xue, Yancong Kong, Huaisheng Wang, Wei Jiang
Development of reliable and affordable quantitative methods for miRNAs with high specificity and sensitivity is a central challenge to make miRNA testing a routine part of medical care with respect to cancer. Herein, we propose a strategy for glucoamylase-encapsulated liposome-encoded magnetic beads initiated by padlock exponential rolling circle amplification (P-ERCA) for portable and accurate quantification of miRNA by using a glucometer readout.
September 28, 2017: Chemical Communications: Chem Comm
Bo-Wei Zhang, Xia Li, Wen-Long Sun, Yan Xing, Zhi-Long Xiu, Chun-Lin Zhuang, Yue-Sheng Dong
The inhibition of porcine pancreatic α-amylase and mammalian α-glucosidase by 16 individual flavonoids was determined. The IC50 values for baicalein, (+)-catechin, quercetin, and luteolin were 74.1 ± 5.6, 175.1 ± 9.1, 281.2 ± 19.2, and 339.4 ± 16.3 μM, respectively, against α-glucosidase. The IC50 values for apigenin and baicalein were 146.8 ± 7.1 and 446.4 ± 23.9 μM, respectively, against α-amylase. The combination of baicalein, quercetin, or luteolin with acarbose showed synergistic inhibition, and the combination of (+)-catechin with acarbose showed antagonistic inhibition of α-glucosidase...
September 15, 2017: Journal of Agricultural and Food Chemistry
Denis Magaña-Ortíz, Francisco Fernández, Achim M Loske, Miguel A Gómez-Lim
Nucleoside hydrolase and sterol 24-c-methyltransferase, two antigenic proteins of Leishmania sp., were expressed in Aspergillus niger. Genetic transformation of conidia was achieved using underwater shock waves. scFv antibody addressed to DEC205, a receptor of dendritic cells, was fused to two proteins of Leishmania sp. Receptor 205 has a relevant role in the immune system in mammals; it can modulate T cell response to different antigens. Extracellular expression strategy of recombinant antibody was achieved using a fragment of native glucoamylase A (514 aa) as a carrier...
August 31, 2017: Current Microbiology
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