Abstract：
:Lactulose and galacto-oligosaccharides (GOS) are well recognized prebiotics derived from lactose. In the synthesis of lactulose with β-galactosidases GOS are also produced, but the ratio of lactulose and GOS in the product can be tuned at will, depending on the operation conditions, so to obtain an optimal product distribution in terms of prebiotic potential. The selectivity of fermentation of each carbohydrate alone as well as mixtures of both was determined using pH-controlled anaerobic batch cultures with faecal inoculum. Within the experimental range considered, lactulose/GOS molar ratio of 4 resulted in the highest selectivity for Bifidobacterium and Lactobacillus/Enterococcus, so this ratio was selected as the target for the synthesis of lactulose from fructose and lactose with Aspergillus oryzae β-galactosidase. Synthesis was optimized using response surface methodology, considering temperature, initial concentrations of acceptor sugars and fructose/lactose molar ratio as key variables, with the aim of maximizing lactulose yield at the optimal product distribution in terms of prebiotic potential (lactulose/GOS molar ratio of 4). Under optimal conditions (50°C, 50%w/w total initial concentrations of sugars and fructose/lactose molar ratio of 6.44), lactulose yield of 0.26g of lactulose produced per g of initial lactose was obtained at the optimal product distribution.
journal_name
J Biotechnoljournal_title
Journal of biotechnologyauthors
Guerrero C,Vera C,Acevedo F,Illanes Adoi
10.1016/j.jbiotec.2015.06.394subject
Has Abstractpub_date
2015-09-10 00:00:00pages
31-40eissn
0168-1656issn
1873-4863pii
S0168-1656(15)30015-8journal_volume
209pub_type
杂志文章abstract：:Production of heterologous proteins in bacteria is one of the main applications of biotechnology. Although several high-efficiency expression systems have been developed, different steps in protein production may become rate-limiting depending on the production system and the protein being produced. One bottle neck ca...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2006.10.010
更新日期：2007-02-01 00:00:00
abstract：:The use of the fungus Aspergillus niger for the bioleaching of heavy metals from spent catalyst was investigated, with fluid catalytic cracking (FCC) catalyst as a model. Bioleaching was examined in batch cultures with the spent catalysts at various pulp densities (1-12%). Chemical leaching was also performed using mi...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2004.10.008
更新日期：2005-03-16 00:00:00
abstract：:The genome of the biotechnologically important solventogenic Clostridium saccharobutylicum NCP 262 contains two operons coding for genes of presumed type I RM systems belonging to the families A and C. They represent a limiting factor for the development of transformation and conjugation protocols. We established an e...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2014.07.005
更新日期：2014-10-20 00:00:00
abstract：:Steady state studies in a chemostat enable the control of microbial growth rate at defined reaction conditions. The effects of bacteriophage M13 infection on maximum growth rate of Escherichia coli JM109 were studied in parallel operated chemostats on a milliliter-scale to analyze the steady state kinetics of phage pr...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2017.06.409
更新日期：2017-09-20 00:00:00
abstract：:Bacillus methylotrophicus JJ-D34 showing good proteolytic and antipathogenic activities was isolated from doenjang, a Korean traditional fermented soybean paste. Here, we report the complete genome sequence of strain JJ-D34 harboring a 4,105,955 bp circular chromosome encoding 4044 genes with a 46.24% G+C content, whi...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2015.12.030
更新日期：2016-02-10 00:00:00
abstract：:This work explores the role of one of the factors explaining lipase/esterase activity: the contribution of electrostatic interactions to lipase/esterase activity. The electrostatic potential distribution on the molecular surface of an enzyme as a function of pH determines, to a large extent, the enzyme's pH activity p...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/s0168-1656(00)00360-6
更新日期：2001-02-13 00:00:00
abstract：:Recombinant Escherichia coli clones encoding between 0 and 6 copies of the mammalian cytochrome b5 gene were subjected to pyrolysis mass spectrometry (PyMS). To deconvolute the pyrolysis mass spectra so as to obtain quantitative information on the amount of cytochrome b5 produced fully-interconnected feedforward artif...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/0168-1656(94)90088-4
更新日期：1994-05-15 00:00:00
abstract：:Medium composition and cultivation conditions were constructed for the optimum production of leupeptin by Streptomyces exfoliatus SMF13. The production of leupeptin was related to mycelial growth, being optimum in the cultivation with glucose-excess, phosphate-limited, and casamino acids medium. However, leupeptin-ina...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/0168-1656(95)00061-t
更新日期：1995-08-15 00:00:00
abstract：:Consumers prefer biotechnological food products with high nutritional values and good flavors. Solid-state fermentation is a commonly used technique with a long history. In the present study, Myroides sp. ZB35 was used in solid-state fermentative production of aroma volatiles on a rice medium. Using the headspace soli...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2017.02.003
更新日期：2017-03-10 00:00:00
abstract：:A novel methodology based on analysis of mtDNA-cytb diagnostic sites was performed to discriminate four closely related species of Thunnus (Thunnus alalunga, Thunnus albacares, Thunnus obesus and Thunnus thynnus) and one species of Euthynnus (Katsuwonus pelamis) genus in raw and canned tuna. The primers used in the pr...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2007.01.032
更新日期：2007-05-01 00:00:00
abstract：:To meet the food demand of growing population, agricultural productivity needs to be increased by employing safe strategies without harming ecosystem. Silver nanoparticle (AgNP) using a green approach has become a promising substitute to the synthetic pesticides to overcome pest menace. In this study, AgNPs were synth...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2019.12.009
更新日期：2020-02-10 00:00:00
abstract：:Halophilic and freshwater strains of cyanobacteria representing the Oscillatoriales, Nostocales, Chroococcales, and Synechococcales orders of Cyanophyta were examined to determine (i) the resistance of their cultures when suppressed by the presence of exogenous methoxylated and methylated derivatives of 2'-hydroxychal...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2019.01.005
更新日期：2019-03-10 00:00:00
abstract：:A highly active and stable cross-linked enzyme aggregates (CLEAs) of epoxide hydrolases (EHs) from Mung bean, which plays a crucial role in synthesis of valuable enantiopure diols, were successfully prepared and characterized. Under the optimum preparation conditions, the activity recovery of CLEAs recorded 92%. The C...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2013.04.015
更新日期：2013-06-20 00:00:00
abstract：:Six bacterial strains with the capability of degrading textile dyes were isolated from sludge samples and mud lakes. Aeromonas hydrophila was selected and identified because it exhibited the greatest color removal from various dyes. Although A. hydrophila displayed good growth in aerobic or agitation culture (AGI cult...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/s0168-1656(02)00303-6
更新日期：2003-02-27 00:00:00
abstract：:CRISPR-Cpf1 is a type V CRISPR system that has recently been exploited for genome engineering purposes. Compared to the well-known Streptococcus pyogenes CRISPR-Cas9 system, the effector protein Cpf1 recognizes T-rich protospacer-adjacent motif (PAM) instead of G-rich PAM (used by CRISPR-Cas9), which could offer a sub...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2018.07.040
更新日期：2018-10-20 00:00:00
abstract：:Recently, some research in the field of enhanced biological phosphorus removal (EBPR) has been focused on studying systems where the electron donor (substrate) and the electron acceptor (nitrate or oxygen) are present simultaneously. This can occur, for example, in a full scale wastewater treatment plant during heavy ...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2005.10.018
更新日期：2006-05-03 00:00:00
abstract：:The alpha-amylase (1, 4-alpha-d-glucanohydrolase; EC 3.2.1.1) and alpha-glucosidase (alpha-d-glucoside glucohydrolase; EC 3.2.1.20) secreted by Geobacillus thermodenitrificans HRO10 were purified to homogeneity (13.6-fold; 11.5% yield and 25.4-fold; 32.0% yield, respectively) through a series of steps. The molecular w...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2006.02.006
更新日期：2006-08-20 00:00:00
abstract：:Enzyme engineering by molecular modelling and site-directed mutagenesis can be remarkably efficient. Directed enzyme evolution appears as a more general strategy for the isolation of catalysts as it can be applied to most chemical reactions in aqueous solutions. Selections, as opposed to screening, allow the simultane...
journal_title：Journal of biotechnology
pub_type： 杂志文章,评审
doi：10.1016/j.jbiotec.2004.03.032
更新日期：2004-09-30 00:00:00
abstract：:The Semliki Forest virus (SFV) viral vector has been widely used for transient protein expression. This study aimed to analyze comprehensively the capacity of SFV vector to express rabies lyssavirus glycoprotein (RVGP) in mammalian cells. The assessed parameters were transfection strategy, multiplicity of infection (M...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2019.08.012
更新日期：2019-10-10 00:00:00
abstract：:Cutinase from Fusarium solani pisi was genetically modified near the active site, by site-directed mutagenesis, to enhance its activity towards polyethylene terephthalate (PET) and polyamide 6,6 (PA 6,6) fibers. The mutations L81A, N84A, L182A, V184A and L189A were done to enlarge the active site in order to better fi...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2006.12.028
更新日期：2007-03-10 00:00:00
abstract：:A system has been developed for the release of heterologous proteins from Saccharomyces cerevisiae, based on the use of thermosensitive osmotic-remedial mutants, deficient in cell integrity, that lyse at the non-permissive temperature, thus releasing the bulk of intracellular proteins and leaving behind cell ghosts an...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/0168-1656(94)90149-x
更新日期：1994-11-30 00:00:00
abstract：:Papain-catalyzed polymerization of L-tyrosine ethyl ester in aqueous media was efficient for synthesis of oligo-tyrosine peptides having angiotensin I-converting enzyme inhibitory activity. Di-, tri-, and tetra-tyrosine accumulated in the soluble fraction of reaction mixture. On the other hand, the peptide products wi...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2010.09.931
更新日期：2010-11-01 00:00:00
abstract：:Peptide synthesis was carried out in a variety of organic solvents with low contents of water. The enzyme was deposited on the support material, celite, from an aqueous buffer solution. After evaporation of the water the biocatalyst was suspended in the reaction mixtures. The chymotrypsin-catalyzed reaction between Z-...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/0168-1656(90)90090-x
更新日期：1990-09-01 00:00:00
abstract：:Batch bioreactor cultivations using Saccharomyces cerevisiae at high (190-305 gl(-1) glucose) or low (21-25 gl(-1) glucose) gravity conditions were monitored on-line using multi-wavelength fluorescence (MWF) and standard monitoring sensors. Partial least squares models were calibrated for the prediction of cell dry we...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2009.08.018
更新日期：2009-10-26 00:00:00
abstract：:Often, degradability under anaerobic conditions is desirable for plastics claimed to be biodegradable, e.g. in anaerobic biowaste treatment plants, landfills and in natural anaerobic sediments. The biodegradation of the natural polyesters poly(beta-hydroxybutyrate) (PHB), poly(beta-hydroxybutyrate-co-11.6%-beta-hydrox...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/s0168-1656(00)00406-5
更新日期：2001-03-30 00:00:00
abstract：:Acinetobacter baumannii has turned into an important threat in nosocomial outbreak infections and multidrug resistance leading to high mortality rates in the 21st century. In recent years its mortality has increased by 15% which in part could be due to lack of a rapid and sensitive diagnostic test. In this work we int...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2016.05.024
更新日期：2016-08-10 00:00:00
abstract：:The filamentous ascomycete fungus Cryphonectria parasitica naturally secretes endothiapepsin, an aspartic proteinase. It is cultured on a commercial scale as a source of the milk-clotting enzyme for cheese making. Our objective was to increase enzyme production of an industrial C. parasitica strain by a new technique ...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/0168-1656(95)00036-p
更新日期：1995-06-01 00:00:00
abstract：:Dynamic miniaturized human multi-micro-organ bioreactor systems are envisaged as a possible solution for the embarrassing gap of predictive substance testing prior to human exposure. A rational approach was applied to simulate and design dynamic long-term cultures of the smallest possible functional human organ units,...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2010.02.001
更新日期：2010-07-01 00:00:00
abstract：:Oxygen tension regulates the biological characteristics of hematopoietic stem and progenitor cells (HSPCs) by modulating intracellular reactive oxygen species (ROS). To better understand oxygen tension mechanism on HSPCs culture, gene expression analysis of human CD34(+)CD38(-) HSPCs was performed using microarrays. T...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2012.01.017
更新日期：2012-04-15 00:00:00
abstract：:The development and optimization of a purification process of monoclonal antibodies based on two continuous chromatography steps for capture and intermediate purification are presented. The two chromatography steps were individually optimized using either batch chromatography or sequential multicolumn chromatography (...
journal_title：Journal of biotechnology
pub_type： 杂志文章
doi：10.1016/j.jbiotec.2015.04.026
更新日期：2015-11-10 00:00:00
