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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...
September 28, 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...
September 20, 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...
August 30, 2016: 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...
September 3, 2016: Journal of Bioscience and Bioengineering
Laura Nekiunaite, Magnus Ø Arntzen, Birte Svensson, Gustav Vaaje-Kolstad, Maher Abou Hachem
BACKGROUND: Starch is the second most abundant plant-derived biomass and a major feedstock in non-food industrial applications and first generation biofuel production. In contrast to lignocellulose, detailed insight into fungal degradation of starch is currently lacking. This study explores the secretomes of Aspergillus nidulans grown on cereal starches from wheat and high-amylose (HA) maize, as well as legume starch from pea for 5 days. RESULTS: Aspergillus nidulans grew efficiently on cereal starches, whereas growth on pea starch was poor...
2016: Biotechnology for Biofuels
Pan Li, Weifeng Lin, Xiong Liu, Xiaowen Wang, Lixin Luo
In this study, we investigated the microbiota dynamics during two industrial-scale traditional solid-state fermentation (SSF) processes of Daqu starters. Similar evolution profiles of environmental parameters, enzymatic activities, microbial amounts, and communities were observed during the medium temperature SSF (MTSSF) and low temperature SSF (LTSSF) processes. Orders of Rickettsiales and Streptophyta only dominated the initial 2 days, and Eurotiales only predominated from days 10 to 24, however, phylotypes of Enterobacteriales, Lactobacillales, Bacillales, Saccharomycetales, and Mucorales both prevailed throughout the MTSSF and LTSSF processes...
2016: Frontiers in Microbiology
Aihua Liu, Qiaolin Lang, Bo Liang, Jianguo Shi
Glucoamylase-displayed bacteria (GA-bacteria) and glucose dehydrogenase-displayed bacteria (GDH-bacteria) were co-immobilized on multi-walled carbon nanotubes (MWNTs) modified glassy carbon electrode (GCE) to construct GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor. The biosensor was developed by optimizing the loading amount and the ratio of GA-bacteria to GDH-bacteria. The as-prepared biosensor exhibited a wide dynamic range of 0.2-10mM and a low detection limit of 0.1mM maltose (S/N=3). The biosensor also had a linear response to glucose in the range of 0...
July 15, 2016: Biosensors & Bioelectronics
Kazi Muhammad Rezaul Karim, Ahmad Husaini, Md Anowar Hossain, Ngieng Ngui Sing, Fazia Mohd Sinang, Mohd Hasnain Md Hussain, Hairul Azman Roslan
A novel thermostable glucoamylase cDNA without starch binding domain (SBD) of Aspergillus flavus NSH9 was successfully identified, isolated, and overexpressed in Pichia pastoris GS115. The complete open reading frame of glucoamylase from Aspergillus flavus NSH9 was identified by employing PCR that encodes 493 amino acids lacking in the SBD. The first 17 amino acids were presumed to be a signal peptide. The cDNA was cloned into Pichia pastoris and the highest expression of recombinant glucoamylase (rGA) was observed after 8 days of incubation period with 1% methanol...
2016: BioMed Research International
Wei Han, Yunyi Hu, Shiyi Li, Feifei Li, Junhong Tang
Waste pastry was hydrolyzed by glucoamylase and protease which were obtained from solid state fermentation of Aspergillus awamori and Aspergillus oryzae to produce waste pastry hydrolysate. Then, the effects of hydraulic retention times (HRTs) (4-12h) on hydrogen production rate (HPR) in the suspended microbial growth system (continuous stirred tank reactor, CSTR) and attached microbial growth system (continuous mixed immobilized sludge reactor, CMISR) from waste pastry hydrolysate were investigated. The maximum HPRs of CSTR (201...
October 2016: Bioresource Technology
Fatima Syed, Khurshid Ali, Muhammad Javaid Asad, Muhammad Gul Fraz, Zahid Khan, Muhammad Imran, Raheela Taj, Aftab Ahmad
The preparation of green nano supports for the covalent immobilization of enzymes is of special interest both from the economic and environmental point of view. In this contribution, we report on the synthesis of phytochemicals coated silver nanoparticles, which were used as a novel green support for the covalent immobilization of glucoamylase isolated from Neurospora sitophila. The aqueous extract of Fagonia indica was used as a source of reducing and capping agents for the reduction of silver ions into silver nanoparticles...
September 2016: Journal of Photochemistry and Photobiology. B, Biology
Shamraja S Nadar, Sarita D Gawas, Virendra K Rathod
An organic-inorganic hybrid glucoamylase nanoflower was prepared in single pot by simple, facile and highly efficient method. The stepwise formation of enzyme-embedded hybrid nanoflowers and influence of experimental parameters viz. pH of solution mixture, enzyme and copper ion concentration on the activity of prepared hybrid nanoflowers were systematically investigated. The self-assembled hybrid glucoamylase nanoflowers were synthesized by mixing aqueous solution of copper sulphate (200mM) with PBS (pH 7.5, 5mM) containing glucoamylase (1mg/mL) in 24h at room temperature...
June 22, 2016: International Journal of Biological Macromolecules
Yan-Fang Wang, Li Tan, Ting Wang, Zhao-Yong Sun, Yue-Qin Tang, Kenji Kida
Kitchen waste is rich in carbohydrates and can potentially serve as feedstock for ethanol production. Starch was the primary carbohydrate in kitchen waste obtained from the canteen in Sichuan University, which was used to evaluate long-term ethanol fermentation performance in this study. The optimal conditions for liquefaction and saccharification of the kitchen waste were as follows: adding α-amylase at 0.3 μL/g glucan for liquefaction at 90°C for 30 min, and adding glucoamylase at 4 μL/g glucan for saccharification at 50°C...
May 31, 2016: Environmental Technology
Md Ariful Haque, Vasiliki Kachrimanidou, Apostolis Koutinas, Carol Sze Ki Lin
A concept of utilizing bakery waste as a nutrient source for the fermentative production of bio-colorant by Monasucus purpureus has been developed. The proposed ideas provide an innovative approach to establish a system or method to reduce the bakery waste problem encountered by Hong Kong or other countries. Bakery waste collected from bakery store was used in submerged and solid-state fermentation of Monascus purpureus to produce bio-colorant, which could potentially be applied in food and textile industries...
August 10, 2016: Journal of Biotechnology
Sergi Maicas, Antonio Caminero, José Pedro Martínez, Rafael Sentandreu, Eulogio Valentín
Candida albicans Gca1p is a putative glucoamylase enzyme which contains 946 amino acids, 11 putative sites for N-glycosylation and 9 for O-glycosylation. Gca1p was identified in β-mercaptoethanol extracts from isolated cell walls of strain C. albicans SC5314 and it is involved in carbohydrate metabolism. The significance and the role of this protein within the cell wall structure were studied in the corresponding mutants. The homozygous mutant showed that GCA1 was not an essential gene for cell viability. Subsequent phenotypic analysis performed in the mutants obtained did not show significant difference in the behavior of mutant when compared with the wild strain SC5314...
June 2016: FEMS Yeast Research
Kentaro Inokuma, Takahiro Bamba, Jun Ishii, Yoichiro Ito, Tomohisa Hasunuma, Akihiko Kondo
Recombinant yeast strains displaying aheterologous cellulolytic enzymes on their cell surfaces using a glycosylphosphatidylinositol (GPI) anchoring system are a promising strategy for bioethanol production from lignocellulosic materials. A crucial step for cell wall localization of the enzymes is the intracellular transport of proteins in yeast cells. Therefore, the addition of a highly efficient secretion signal sequence is important to increase the amount of the enzymes on the yeast cell surface. In this study, we demonstrated the effectiveness of a novel signal peptide (SP) sequence derived from the Saccharomyces cerevisiae SED1 gene for cell-surface display and secretory production of cellulolytic enzymes...
November 2016: Biotechnology and Bioengineering
Chiaki Ota, Masamichi Ikeguchi, Akiyoshi Tanaka, Daizo Hamada
Protein folding is a thermodynamic process driven by energy gaps between the native and unfolded states. Although a wealth of information is available on the structure of folded species, there is a paucity of data on unfolded species. Here, we analyzed the structural properties of the unfolded state of the starch-binding domain of glucoamylase from Aspergillus niger (SBD) formed in the presence of guanidinium hydrochloride (GuHCl). Although far-UV CD and intrinsic tryptophan fluorescence spectra as well as small angle X-ray scattering suggested that SBD assumes highly unfolded structures in the presence of GuHCl, near-UV circular dichroism of wild-type SBD suggested the presence of residual structures in the unfolded state...
October 2016: Biochimica et Biophysica Acta
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