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Rémi Dulermo, François Brunel, Thierry Dulermo, Rodrigo Ledesma-Amaro, Jérémy Vion, Marion Trassaert, Stéphane Thomas, Jean-Marc Nicaud, Christophe Leplat
BACKGROUND: The yeast Yarrowia lipolytica is an increasingly common biofactory. To enhance protein expression, several promoters have been developed, including the constitutive TEF promoter, the inducible POX2 promotor, and the hybrid hp4d promoter. Recently, new hp4d-inspired promoters have been created that couple various numbers of UAS1 tandem elements with the minimal LEU2 promoter or the TEF promoter. Three different protein-secretion signaling sequences can be used: preLip2, preXpr2, and preSuc2...
February 17, 2017: Microbial Cell Factories
Xudong Zhu, Bessembayev Arman, Ju Chu, Yonghong Wang, Yingping Zhuang
OBJECTIVES: To develop an efficient cost-effective screening process to improve production of glucoamylase in Aspergillus niger. RESULTS: The cultivation of A. niger was achieved with well-dispersed morphology in 48-deep-well microtiter plates, which increased the throughput of the samples compared to traditional flask cultivation. There was a close negative correlation between glucoamylase and its pH of the fermentation broth. A novel high-throughput analysis method using Methyl Orange was developed...
January 30, 2017: Biotechnology Letters
Minhal Abidi, Afshin Iram, Mohammad Furkan, Aabgeena Naeem
Glucoamylase (EC from Aspergillus niger possesses 31% α-helix, 36% β structure and rest aperiodic structure. A transition of glucoamylase structure in the presence of varying concentrations of glyoxal (GO) and trifluoroethanol (TFE) was studied by using multi-methodological approaches. At 20% GO, glucoamylase exists as molten globule state as evident by high tryptophan and ANS fluorescence, retention of secondary structure and loss of native tertiary structure. This state precedes the onset of the aggregation process and maximum is achieved at the highest concentration i...
January 27, 2017: International Journal of Biological Macromolecules
Alexander G Bulakhov, Pavel V Volkov, Aleksandra M Rozhkova, Alexander V Gusakov, Vitaly A Nemashkalov, Aidar D Satrutdinov, Arkady P Sinitsyn
BACKGROUND: Penicillium verruculosum is an efficient producer of highly active cellulase multienzyme system. One of the approaches for enhancing cellulase performance in hydrolysis of cellulosic substrates is to enrich the reaction system with β -glucosidase and/or accessory enzymes, such as lytic polysaccharide monooxygenases (LPMO) displaying a synergism with cellulases. RESULTS: Genes bglI, encoding β-glucosidase from Aspergillus niger (AnBGL), and eglIV, encoding LPMO (formerly endoglucanase IV) from Trichoderma reesei (TrLPMO), were cloned and expressed by P...
2017: PloS One
Haiyan Sun, Ming Peng
OBJECTIVES: To investigate the role of maltose stearic acid ester (MSAE) for improving raw-starch-digesting glucoamylase (RSDG) production by Aspergillus niger F-01 and its regulatory mechanism. RESULTS: RSDG activity was enhanced 8.3-fold by adding 5 g MSAE to 1 l basal medium at the beginning of the culture. RSDG biosynthesis nearly ceased by adding 100 μg actinomycin D/ml or 50 μg cycloheximide/ml in a 48 h culture in the basal medium. RSDG biosynthesis was restarted by adding MSAE in the culture repressed by actinomycin D...
January 2, 2017: Biotechnology Letters
Masayoshi Sakaguchi, Yudai Matsushima, Yusuke Nagamine, Tomoki Matsuhashi, Shotaro Honda, Shoi Okuda, Misa Ohno, Yasusato Sugahara, Yongchol Shin, Fumitaka Oyama, Masao Kawakita
Clostridium sp. G0005 glucoamylase (CGA) is composed of a β-sandwich domain (BD), a linker, and a catalytic domain (CD). In the present study, CGA was expressed in Escherichia coli as inclusion bodies when the N-terminal region (39 amino acid residues) of the BD was truncated. To further elucidate the role of the N-terminal region of the BD, we constructed N-terminally truncated proteins (Δ19, Δ24, Δ29, and Δ34) and assessed their solubility and activity. Although all evaluated proteins were soluble, their hydrolytic activities toward maltotriose as a substrate varied: Δ19 and Δ24 were almost as active as CGA, but the activity of Δ29 was substantially lower, and Δ34 exhibited little hydrolytic activity...
December 9, 2016: Applied Microbiology and Biotechnology
Wei Han, Yingting Yan, Yiwen Shi, Jingjing Gu, Junhong Tang, Hongting Zhao
In this study, the feasibility of biohydrogen production from enzymatic hydrolysis of food waste was investigated. Food waste (solid-to-liquid ratio of 10%, w/v) was first hydrolyzed by commercial glucoamylase to release glucose (24.35 g/L) in the food waste hydrolysate. Then, the obtained food waste hydrolysate was used as substrate for biohydrogen production in the batch and continuous (continuous stirred tank reactor, CSTR) systems. It was observed that the maximum cumulative hydrogen production of 5850 mL was achieved with a yield of 245...
December 2, 2016: Scientific Reports
Shamraja S Nadar, Virendra K Rathod
The self-assembled glucoamylase metal-organic framework (glucoamylase-MOF) was synthesized by facile one-step method within 20min by simply mixing aqueous solution of 2-methylimidazole (160mM), glucoamylase (5mg/mL) and zinc acetate (40mM) at room temperature (28±2°C). The prepared glucoamylase-MOF was characterized by using FT-IR, confocal scanning laser microscopy, XRD and SEM. The robustness and thermal stability of glucoamylase embedded MOF was evaluated in terms of half-life (in the range of 60-80°C) which showed 6 folds increment as against free form...
February 2017: International Journal of Biological Macromolecules
Deepak Kumar, Vijay Singh
BACKGROUND: Conventional corn dry-grind ethanol production process requires exogenous alpha and glucoamylases enzymes to breakdown starch into glucose, which is fermented to ethanol by yeast. This study evaluates the potential use of new genetically engineered corn and yeast, which can eliminate or minimize the use of these external enzymes, improve the economics and process efficiencies, and simplify the process. An approach of in situ ethanol removal during fermentation was also investigated for its potential to improve the efficiency of high-solid fermentation, which can significantly reduce the downstream ethanol and co-product recovery cost...
2016: Biotechnology for Biofuels
Jyotiranjan Bal, Suk-Hyun Yun, Jeesun Chun, Beom-Tae Kim, Dae-Hyuk Kim
The most economically important species used in a wide range of fermentation industries throughout Asia belong to Aspergillus section Flavi, which are morphologically and phylogenetically indistinguishable, with a few being toxigenic and therefore a major concern. They are frequently isolated from Korean fermentation starters, such as nuruk and meju. The growing popularity of traditional Korean alcoholic beverages has led to a demand for their quality enhancement, therefore requiring selection of efficient non-toxigenic strains to assist effective fermentation...
September 2016: Mycobiology
Qiang-Sheng Xu, Yu-Si Yan, Jia-Xun Feng
BACKGROUND: Starch is a very abundant and renewable carbohydrate and is an important feedstock for industrial applications. The conventional starch liquefaction and saccharification processes are energy-intensive, complicated, and not environmentally friendly. Raw starch-digesting glucoamylases are capable of directly hydrolyzing raw starch to glucose at low temperatures, which significantly simplifies processing and reduces the cost of producing starch-based products. RESULTS: A novel raw starch-digesting glucoamylase PoGA15A with high enzymatic activity was purified from Penicillium oxalicum GXU20 and biochemically characterized...
2016: Biotechnology for Biofuels
J Suriya, S Bharathiraja, M Krishnan, P Manivasagan, S-K Kim
Amylases are crucial enzymes which hydrolyze internal glycosidic linkages in starch and produce as primary products dextrins and oligosaccharides. Amylases are classified into α-amylase, β-amylase, and glucoamylase based on their three-dimensional structures, reaction mechanisms, and amino acid sequences. Amylases have innumerable applications in clinical, medical, and analytical chemistries as well as in food, detergent, textile, brewing, and distilling industries. Amylases can be produced from plants, animals, and microbial sources...
2016: Advances in Food and Nutrition Research
Hongzhong Lu, Weiqiang Cao, Liming Ouyang, Jianye Xia, Mingzhi Huang, Ju Chu, Yingping Zhuang, Siliang Zhang, Henk Noorman
Aspergillus niger is one of the most important cell factories for industrial enzymes and organic acids production. A comprehensive genome-scale metabolic network model (GSMM) with high quality is crucial for efficient strain improvement and process optimization. The lack of accurate reaction equations and gene-protein-reaction associations (GPRs) in the current best model of A. niger named GSMM iMA871, however, limits its application scope. To overcome these limitations, we updated the A. niger GSMM by combining the latest genome annotation and literature mining technology...
October 3, 2016: Biotechnology and Bioengineering
Mahkameh Amirbandeh, Asghar Taheri-Kafrani
Immobilization of an enzyme can enhance its catalytic activity, depending on the properties of the enzyme and the matrix. Graphene oxide is a nontoxic material and selective modulator for enzyme activity and is also a thermostable molecule that is important in large-scale nanostructure sheet applications. Herein, we have successfully developed a strategy for preparing a nanocomposite for enzyme immobilization model with high loading capacity. Nanostructures of hybrid graphene oxide-Fe3O4-cyanuric chloride (GO/MNP-CC) have adjustable surface chemistry that is an excellent candidate for covalent immobilization of enzymes...
December 2016: International Journal of Biological Macromolecules
Wei Han, Yunyi Hu, Shiyi Li, Qiulin Nie, Hongting Zhao, Junhong Tang
Waste pastry (6%, w/v) was hydrolyzed by the produced glucoamylase and protease to obtain the glucose (19.8g/L) and free amino nitrogen (179mg/L) solution. Then, the effect of organic loading rate (OLR) (8-40kgCOD/(m(3)d)) on dark fermentative hydrogen production in the continuous stirred tank reactor (CSTR) and continuous mixed immobilized sludge reactor (CMISR) from waste pastry hydrolysate was investigated and compared. The maximum hydrogen production rate of CSTR (277.76mL/(hL)) and CMISR (320.2mL/(hL)) were achieved at OLR of 24kgCOD/(m(3)d) and 32kgCOD/(m(3)d), respectively...
December 2016: Waste Management
Janice L Daniels, Richard J Bloomer, Marie van der Merwe, Samantha L Davis, Karyl K Buddington, Randal K Buddington
BACKGROUND: Endurance athletes search for diet regimens that will improve performance and decrease gastrointestinal disturbances during training and events. Although the intestine can adapt to changes in the amount and composition of dietary inputs, the responses to the combination of endurance exercise and diet are poorly understood. METHODS: We evaluated small intestinal dimensions and mucosal architecture and calculated the capacities of the entire small intestine to digest maltose and maltodextrin and absorb glucose in response to two different diet types; a western human diet and the Daniel Fast, a vegan style diet, and with moderate intensity endurance training or a no-exercise sedentary lifestyle for a 13 week period (n = 7 per group)...
2016: Journal of the International Society of Sports Nutrition
Ya Xu, Cheng-Heng Liao, Li-Li Yao, Xu Ye, Bang-Ce Ye
Starch-degrading enzymes hydrolyze starch- and starch-derived oligosaccharides to yield glucose. We investigated the transcriptional regulation of genes encoding starch-degrading enzymes in the industrial actinobacteria Saccharopolyspora erythraea We observed that most genes encoding amylolytic enzymes (one α-amylase, one glucoamylase and four α-glucosidases) were regulated by GlnR and PhoP, which are global regulators of nitrogen and phosphate metabolism, respectively. Electrophoretic mobility shift assays and RT-PCR analyses demonstrated that GlnR and PhoP directly interact with their promoter regions, and collaboratively or competitively activate their transcription...
September 16, 2016: Applied and Environmental Microbiology
Qin-Qing Wang, Yi Lu, Zi-Yan Ren, Zhe Chi, Guang-Lei Liu, Zhen-Ming Chi
Aureobasidium melanogenum P16 is a high pullulan-producing yeast. However, glucose repression on its pullulan biosynthesis must be relieved. After the gene encoding a glucose repressor was cloned, characterized and analyzed, it was found that the repressor belonged to one member of the CreA in filamentous fungi, not to one member of the Mig1 in yeasts. After the CREA gene was fully removed from the yeast strain P16, the glucose repression in the disruptant DG41 was relieved. At the same time, the pullulan production by the disruptant DG41 was enhanced compared to that by its wild-type strain P16, and the transcriptional levels of the gene encoding a glucosyltransferase, three genes encoding glucose transporters, the gene encoding a 6-P-glucose kinase and the genes encoding α-amylase, glucoamylase and pullulanase in the disruptant DG41 were also promoted...
September 15, 2016: Current Genetics
Youna Zhang, Qingwang Xue, Jifeng Liu, Huaisheng Wang
DNA methyltransferase (MTase) plays a critical role in maintaining genome methylation patterns, which has a close relationship to cancer and bacterial diseases. This encouraged the need to develop highly sensitive, simple, and robust assays for DNA MTase detection and inhibitor screening. Herein, a simple, sensitive, and specific DNA MTase activity assay was developed based on magnetic beads-liposome hybrids combined with personal glucose meter (PGM) for quantitative detection of DNA MTase and inhibitor screening...
January 15, 2017: Biosensors & Bioelectronics
Osato Miyawaki, Tsukasa Kanazawa, Chika Maruyama, Michiko Dozen
The static half-life of an enzyme is the half-life of a free enzyme not working without substrate and the dynamic half-life is that of an active enzyme working with plenty amount of substrate. These two half-lives were measured and compared for glucoamylase (GA) and β-galactosidase (BG). The dynamic half-life was much longer than the static half-life by one to three orders of magnitude for both enzymes. For BG, the half-life of the enzyme physically entrapped in a membrane reactor was also measured. In this case also, the half-life of BG in the membrane reactor was much longer than the free enzyme without substrate...
January 2017: Journal of Bioscience and Bioengineering
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