Abstract:
:In the important industrial yeast Saccharomyces cerevisiae, galactose metabolism requires energy production by respiration; therefore, this yeast cannot metabolize galactose under strict anaerobic conditions. While the respiratory dependence of galactose metabolism provides benefits in terms of cell growth and population stability, it is not advantageous for producing fuels and chemicals since a substantial fraction of consumed galactose is converted to carbon dioxide. In order to force S. cerevisiae to use galactose without respiration, a subunit (COX9) of a respiratory enzyme was deleted, but the resulting deletion mutant (Δcox9) was impaired in terms of galactose assimilation. Interestingly, after serial sub-cultures on galactose, the mutant evolved rapidly and was able to use galactose via fermentation only. The evolved strain (JQ-G1) produced ethanol from galactose with a 94% increase in yield and 6.9-fold improvement in specific productivity as compared to the wild-type strain. (13)C-metabolic flux analysis demonstrated a three-fold reduction in carbon flux through the TCA cycle of the evolved mutant with redirection of flux toward the fermentation pathway. Genome sequencing of the JQ-G1 strain revealed a loss of function mutation in a master negative regulator of the Leloir pathway (Gal80p). The mutation (Glu348*) in Gal80p was found to act synergistically with deletion of COX9 for efficient galactose fermentation, and thus the double deletion mutant Δcox9Δgal80 produced ethanol 2.4 times faster and with 35% higher yield than a single knockout mutant with deletion of GAL80 alone. When we introduced a functional COX9 cassette back into the JQ-G1 strain, the JQ-G1-COX9 strain showed a 33% reduction in specific galactose uptake rate and a 49% reduction in specific ethanol production rate as compared to JQ-G1. The wild-type strain was also subjected to serial sub-cultures on galactose but we failed to isolate a mutant capable of utilizing galactose without respiration. We concluded that the metabolic "death valley" (i.e. no galactose utilization by the Δcox9 mutant) is a necessary intermediate phenotype to facilitate galactose utilization without respiration in yeast. The results in this study demonstrate a promising approach for directing adaptive evolution toward fermentative metabolism and for generating evolved yeast strains with improved phenotypes under anaerobic conditions.
journal_name
J Biotechnoljournal_title
Journal of biotechnologyauthors
Quarterman J,Skerker JM,Feng X,Liu IY,Zhao H,Arkin AP,Jin YSdoi
10.1016/j.jbiotec.2016.04.041subject
Has Abstractpub_date
2016-07-10 00:00:00pages
13-21eissn
0168-1656issn
1873-4863pii
S0168-1656(16)30236-Xjournal_volume
229pub_type
杂志文章abstract::Biosurfactants are surface-active agents produced by microorganisms and show increasing significance in various industrial applications. A great variety of these secondary metabolites are described to occur within actinomycetes, amongst trehalose lipids and oligosaccharide lipids produced by the family Tsukamurellacea...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2015.06.424
更新日期:2015-10-10 00:00:00
abstract::The effect of an additional carbon source, lactate, on Penicillium camembertii growth on glutamate as both carbon and nitrogen sources was examined. Glutamate (and lactate) was present in excess in both media. Throughout the whole culture, similar growth time-courses were recorded on both media, indicating the absence...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2004.07.007
更新日期:2004-11-09 00:00:00
abstract::Harbour sediments are periodically subjected to dredging operations and their management is mainly based on the assessment of the chemical contamination levels, but the potential risks posed by the presence of pathogenic microorganisms have been largely neglected. Here we first developed new molecular protocols based ...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2011.07.033
更新日期:2012-02-20 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::Protein expression of Spodoptera frugiperda (Sf9) insect cells was characterized upon exposure to environmental stresses typically present in bioreactors including heat shock, oxygen deprivation, shear stress, change of pH, and salinity or ethanol shock. This study fills the void in knowledge as to how bioreactor hydr...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2005.05.009
更新日期:2005-08-22 00:00:00
abstract::Nontypeable Haemophilus influenzae (NTHi) is a gram-negative coccobacillus that is one of the bacteria that form the commensal flora of the upper respiratory tract in humans. This bacterium is an important human pathogen causing a broad spectrum of disease in both adults and children, including invasive and localised ...
journal_title:Journal of biotechnology
pub_type: 杂志文章,评审
doi:10.1016/s0168-1656(99)00113-3
更新日期:1999-08-20 00:00:00
abstract::The action of three glycoside hydrolase family GH51 and one GH54 α-arabinofuranosidases (ABFs) was studied on polymeric arabinoxylan and arabinoxylooligosaccharides. The substrates covered all possible arabinofuranosyl (Araf) substituents, i.e., terminal and internal α(1→2) and α(1→3)-linked Araf monosubstitutions and...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2016.04.050
更新日期:2016-07-10 00:00:00
abstract::The fed-batch process for commercial production of riboflavin (vitamin B2) was optimized on-line using model-predictive control based on artificial neural networks (ANNs). The information required for process models was extracted from both historical data and heuristic rules. After each cultivation the process model w...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/s0168-1656(00)00211-x
更新日期:2000-04-14 00:00:00
abstract::Development of reagentless biosensors implies the tight and functional immobilisation of biological recognition elements on transducer surfaces. Specifically, in the case of amperometric enzyme electrodes, electron-transfer pathways between the immobilised redox protein and the electrode surface have to be established...
journal_title:Journal of biotechnology
pub_type: 杂志文章,评审
doi:10.1016/s1389-0352(01)00058-7
更新日期:2002-02-01 00:00:00
abstract::It has been well recognized that many key aspects of cell cycle regulation are encoded into the size distributions of growing budding yeast populations due to the tight coupling between cell growth and cell division present in this organism. Several attempts have been made to model the cell size distribution of growin...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2006.01.011
更新日期:2006-07-13 00:00:00
abstract::Selected phage clones expressing a peptide with high binding affinity for recombinant human lactoferrin or von Willebrand factor (vWF) were covalently coupled to macroporous poly(dimethylacrylamide) monolithic column. Large pore size (10-100 microm) of macroporous poly(dimethylacrylamide) makes it possible to couple l...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2007.06.021
更新日期:2007-09-15 00:00:00
abstract::Biodegradable scaffolds are of great value in tissue engineering. We have developed a method for fabricating patient-specific vascular scaffolds from a biocompatible and biodegradable polymer, poly(L-lactide-co-epsilon-caprolactone). This method's usefulness is due to flexibility in the choice of materials and vascula...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2007.08.017
更新日期:2008-01-20 00:00:00
abstract::This review is aimed at biochemists and molecular biologists, and covers the chemistry and key features involved in the solid-phase synthesis of a variety of the better known DNA and RNA analogues by the phosphoramidite and H-phosphonate methods. A wide spectrum of biological applications such as inhibition of gene ex...
journal_title:Journal of biotechnology
pub_type: 杂志文章,评审
doi:10.1016/0168-1656(95)00012-f
更新日期:1995-07-31 00:00:00
abstract::The addition of 5-40 mM L-glutamine to batch cultures of a murine hybridoma following the cessation of rapid growth significantly stimulated monoclonal antibody (mAb) synthesis and secretion per cell. Stimulation of mAb secretion following the cessation of rapid growth was also observed in response to addition of mito...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/0168-1656(92)90142-v
更新日期:1992-02-01 00:00:00
abstract::Recombinant FVIIa has been developed for treatment of bleedings in hemophilia patients with inhibitors, and has been found to induce hemostasis even during major surgery such as major orthopedic surgery. Recombinant FVIIa is being produced in BHK cell cultures and has been shown to be very similar to plasma-derived FV...
journal_title:Journal of biotechnology
pub_type: 杂志文章,评审
doi:10.1016/j.jbiotec.2006.03.042
更新日期:2006-08-05 00:00:00
abstract::New methods for an extended physiological characterization of yeast at a microtiter plate scale were applied to 27 deletion mutants of Saccharomyces cerevisiae cultivated on glucose and galactose as sole carbon sources. In this way, specific growth rates, specific rates of glucose consumption and ethanol production we...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2007.08.043
更新日期:2007-12-01 00:00:00
abstract::A newly developed flat panel airlift photobioreactor with a defined circulation path was tested for microalgal culture. The bioreactor exposed the cells to intermittent light to improve the efficiency of light utilization through the flashing-light effect. During batch cultures in the new photobioreactor, the biomass ...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/s0168-1656(01)00350-9
更新日期:2001-12-28 00:00:00
abstract::A model for transport of ammonia and ammonium ions across cell membranes is presented. The model suggests that ammonium ions compete with potassium ions for inward transport, over the cytoplasmic membrane, via potassium transport proteins like the Na+/K(+)-ATPase and the Na+K+2Cl(-)-cotransporter. It also explains the...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/0168-1656(93)90148-g
更新日期:1993-09-01 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 pair of genes designated parA and parB are encoded by many low copy number plasmids and bacterial chromosomes. They work with one or more cis-acting sites termed centromere-like sequences to ensure better than random predivisional partitioning of the DNA molecule that encodes them. The centromere-like sequences nucl...
journal_title:Journal of biotechnology
pub_type: 杂志文章,评审
doi:10.1016/s0168-1656(01)00293-0
更新日期:2001-09-13 00:00:00
abstract::A new current amplified immunosensor for the determination of carcinoembryonic antigen (CEA) was demonstrated in this work. The electrode architecture was fabricated by positively charged toluidine blue (TB) coated on negatively charged poly-sulfanilic acid (PSAA) modified glassy carbon electrode (GCE) surface through...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2005.11.023
更新日期:2006-05-29 00:00:00
abstract::To monitor the colonization of wheat roots by Azospirillum brasilense, we constructed several plasmids based on the pBBR1 replicon expressing the gfp and gusA genes constitutively. Both genes were placed under control of the gentamycin resistance gene promoter resulting in high levels of expression in Escherichia coli...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/s0168-1656(02)00108-6
更新日期:2002-08-28 00:00:00
abstract::A transgenic tobacco plant (Nicotiana tabacum L.) expressing a fungal pectin methylesterase (PME; EC 3.1.1.11) gene derived from a black filamentous fungus, Aspergillus niger was created. Fungal PME should have a wider range of adaptability to substrate pectin compared with plant PME. As expected, the proportion of me...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2004.04.015
更新日期:2004-08-05 00:00:00
abstract::Monitoring cell growth is crucial to the success of an animal cell culture process that can be accomplished by a variety of direct or indirect methodologies. Glucose is a major carbon and energy source for cultured mammalian cells in most cases, but glycolytic metabolism often results in the accumulation of lactate. G...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2005.05.016
更新日期:2005-08-22 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::Linoleate 13-hydratase from Lactobacillus acidophilus LMG 11470 converted linoleic acid to hydroxyl fatty acid, which was identified as 13S-hydroxy-9(Z)-octadecenoic acid (13-HOD) by GC-MS and NMR. The expression of linoleate 13-hydratase gene in Escherichia coli was maximized by using pACYC plasmid and super optimal ...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2015.05.006
更新日期:2015-08-20 00:00:00
abstract::We have carried out the adaptation of BHK-21 cells to two serum free (Ex Cell 520 and HyQ PF CHO) and three animal protein free media: Ex Cell 302, HyQ PF CHO MPS and Rencyte BHK. After a direct switch or a gradual adaptation, we have achieved BHK-21 cells growth in the following media: HyQ PF CHO, HyQ PF CHO MPS, Ren...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/s0168-1656(02)00009-3
更新日期:2002-05-23 00:00:00
abstract::Oral infection of insect larvae with baculovirus is an advantageous methodology for producing high levels of recombinant proteins and for achieving plague control. However, many recombinant baculoviruses express a foreign protein in lieu of the polyhedrin and hence do not form occlusion bodies (occ-), resulting in ext...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2009.10.015
更新日期:2010-01-15 00:00:00
abstract::Aptamers are single-stranded DNA or RNA oligonucleotides, which have been emerging as recognition elements in disease diagnostics and food control, including the detection of bacterial toxins. In this study, we employed the semi-automated just in time-selection to identify aptamers that bind to cholera toxin (CT) with...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/j.jbiotec.2018.01.012
更新日期:2018-03-10 00:00:00
abstract::A solid-phase method is described to create subclones, suitable for DNA sequencing, from lambda or cosmid libraries. The purified target DNA is sonicated and two linkers, with one oligonucleotide biotinylated in the 5'-end, are ligated to the ends of the fragments produced by sonication. After size separation, the fra...
journal_title:Journal of biotechnology
pub_type: 杂志文章
doi:10.1016/0168-1656(94)90038-8
更新日期:1994-06-30 00:00:00