scholarly journals Improvement of L-Arabinose Fermentation by Modifying the Metabolic Pathway and Transport inSaccharomyces cerevisiae

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Chengqiang Wang ◽  
Yu Shen ◽  
Yanyan Zhang ◽  
Fan Suo ◽  
Jin Hou ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Recombinant Strain ◽  
Consumption Rate ◽  
Specific Growth ◽  
Ethanol Yield ◽  
Maximum Specific Growth Rate ◽  
Dry Cell Weight ◽  
Utilization Pathway ◽  
Dry Cell ◽  
Arabinose Fermentation

The L-arabinose utilization pathway was established inSaccharomyces cerevisiae, by expressing the codon-optimizedaraA,araB, andaraDgenes ofLactobacillus plantarum. After overexpressing theTAL1,TKL1,RPE1,RKI1, andGAL2genes and adaptive evolution, the L-arabinose utilization of the recombinant strain became efficient. The resulting strain displayed a maximum specific growth rate of 0.075 h−1, a maximum specific L-arabinose consumption rate of 0.61 g h−1 g−1dry cell weight, and a promising ethanol yield of 0.43 g g−1from L-arabinose fermentation.

scholarly journals Anaplerotic reactions active during growth of Saccharomyces cerevisiae on glycerol

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Joeline Xiberras ◽  
Mathias Klein ◽  
Celina Prosch ◽  
Zahabiya Malubhoy ◽  
Elke Nevoigt
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Pyruvate Carboxylase ◽  
Reference Strain ◽  
Specific Growth ◽  
Glyoxylate Cycle ◽  
Maximum Specific Growth Rate ◽  
The Glyoxylate Cycle ◽  
Anaplerotic Reactions

ABSTRACT Anaplerotic reactions replenish TCA cycle intermediates during growth. In Saccharomyces cerevisiae, pyruvate carboxylase and the glyoxylate cycle have been experimentally identified to be the main anaplerotic routes during growth on glucose (C6) and ethanol (C2), respectively. The current study investigates the importance of the two isoenzymes of pyruvate carboxylase (PYC1 and PYC2) and one of the key enzymes of the glyoxylate cycle (ICL1) for growth on glycerol (C3) as a sole carbon source. As the wild-type strains of the CEN.PK family are unable to grow in pure synthetic glycerol medium, a reverse engineered derivative showing a maximum specific growth rate of 0.14 h−1 was used as the reference strain. While the deletion of PYC1 reduced the maximum specific growth rate by about 38%, the deletion of PYC2 had no significant impact, neither in the reference strain nor in the pyc1Δ mutant. The deletion of ICL1 only marginally reduced growth of the reference strain but further decreased the growth rate of the pyc1 deletion strain by 20%. Interestingly, the triple deletion (pyc1Δ pyc2Δ icl1Δ) did not show any growth. Therefore, both the pyruvate carboxylase and the glyoxylate cycle are involved in anaplerosis during growth on glycerol.

scholarly journals Functional Analysis of Two l-Arabinose Transporters from Filamentous Fungi Reveals Promising Characteristics for Improved Pentose Utilization in Saccharomyces cerevisiae

2015 ◽  
Vol 81 (12) ◽  
pp. 4062-4070 ◽  
Author(s):  
Jingen Li ◽  
Jing Xu ◽  
Pengli Cai ◽  
Bang Wang ◽  
Yanhe Ma ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sugar Transport ◽  
Biomass Accumulation ◽  
Kinetic Properties ◽  
High Identity ◽  
Content Type ◽  
Substrate Specificities ◽  
Dry Cell Weight ◽  
Dry Cell

ABSTRACTLimited uptake is one of the bottlenecks forl-arabinose fermentation from lignocellulosic hydrolysates in engineeredSaccharomyces cerevisiae. This study characterized two novell-arabinose transporters, LAT-1 fromNeurospora crassaand MtLAT-1 fromMyceliophthora thermophila. Although the two proteins share high identity (about 83%), they display different substrate specificities. Sugar transport assays using theS. cerevisiaestrain EBY.VW4000 indicated that LAT-1 accepts a broad substrate spectrum. In contrast, MtLAT-1 appeared much more specific forl-arabinose. Determination of the kinetic properties of both transporters revealed that theKmvalues of LAT-1 and MtLAT-1 forl-arabinose were 58.12 ± 4.06 mM and 29.39 ± 3.60 mM, respectively, with correspondingVmaxvalues of 116.7 ± 3.0 mmol/h/g dry cell weight (DCW) and 10.29 ± 0.35 mmol/h/g DCW, respectively. In addition, both transporters were found to use a proton-coupled symport mechanism and showed only partial inhibition byd-glucose duringl-arabinose uptake. Moreover, LAT-1 and MtLAT-1 were expressed in theS. cerevisiaestrain BSW2AP containing anl-arabinose metabolic pathway. Both recombinant strains exhibited much fasterl-arabinose utilization, greater biomass accumulation, and higher ethanol production than the control strain. In conclusion, because of higher maximum velocities and reduced inhibition byd-glucose, the genes for the two characterized transporters are promising targets for improvedl-arabinose utilization and fermentation inS. cerevisiae.

scholarly journals Photosynthetic Co-production of Succinate and Ethylene in a Fast-Growing Cyanobacterium, Synechococcus elongatus PCC 11801

Metabolites ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 250 ◽  
Author(s):  
Annesha Sengupta ◽  
Prem Pritam ◽  
Damini Jaiswal ◽  
Anindita Bandyopadhyay ◽  
Himadri B. Pakrasi ◽  
...  
Keyword(s):  
Recombinant Strain ◽  
Single Copy ◽  
Gaseous Product ◽  
Synechococcus Elongatus ◽  
Fast Growing ◽  
Dry Cell Weight ◽  
Photosynthetic Production ◽  
Product Separation ◽  
Metabolome Profiling ◽  
Dry Cell

Cyanobacteria are emerging as hosts for photoautotrophic production of chemicals. Recent studies have attempted to stretch the limits of photosynthetic production, typically focusing on one product at a time, possibly to minimise the additional burden of product separation. Here, we explore the simultaneous production of two products that can be easily separated: ethylene, a gaseous product, and succinate, an organic acid that accumulates in the culture medium. This was achieved by expressing a single copy of the ethylene forming enzyme (efe) under the control of PcpcB, the inducer-free super-strong promoter of phycocyanin β subunit. We chose the recently reported, fast-growing and robust cyanobacterium, Synechococcus elongatus PCC 11801, as the host strain. A stable recombinant strain was constructed using CRISPR-Cpf1 in a first report of markerless genome editing of this cyanobacterium. Under photoautotrophic conditions, the recombinant strain shows specific productivities of 338.26 and 1044.18 μmole/g dry cell weight/h for ethylene and succinate, respectively. These results compare favourably with the reported productivities for individual products in cyanobacteria that are highly engineered. Metabolome profiling and 13C labelling studies indicate carbon flux redistribution and suggest avenues for further improvement. Our results show that S. elongatus PCC 11801 is a promising candidate for metabolic engineering.

Genetic Control of some Metabolic Modifications during the Sporulation of Saccharomyces cerevisiae Hansen

Microbiology ◽  
2000 ◽  
Vol 81 (2) ◽  
pp. 373-382 ◽  
Author(s):  
FRANCOISE VEZINHET ◽  
M. ROGER ◽  
MONIQUE PELLECUER ◽  
P. GALZY
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Control ◽  
Sporulation Medium ◽  
Lipid Contents ◽  
Yeast Strains ◽  
Dry Cell Weight ◽  
Mating Type Gene ◽  
Weight Protein ◽  
Type Gene ◽  
Dry Cell

Summary: The biochemical modifications of two yeast strains, a/α and α/α, have been studied during incubation in a sporulation medium. The increases in dry cell weight, protein, carbohydrate and lipid contents, as well as the variation in respiration rate are quite similar for the two strains. Mating type gene control of sporulation is discussed.

scholarly journals Bioethanol production from intermediate products of sugar beet processing with different types of Saccharomyces cerevisiae

2009 ◽  
Vol 15 (1) ◽  
pp. 13-16 ◽  
Author(s):  
Jovana Rankovic ◽  
Jelena Dodic ◽  
Sinisa Dodic ◽  
Stevan Popov
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fossil Fuels ◽  
Specific Growth ◽  
Culture Media ◽  
Ethanol Yield ◽  
Sugar Utilization ◽  
Yeast Strains ◽  
Different Types ◽  
Thick Juice ◽  
Different Strains

The use of biofuels as an alternative to fossil fuels has expanded in the last few decades. The aim of this study was to examine the application of different strains and forms of Saccharomyces cerevisiae for raw, thin and thick juice fermentation in order to produce bioethanol. According to the obtained results the strain applied in the form of pressed blocks with 70 % w/w moisture, attained higher value of the specific growth rate and lower value of ethanol yield in comparison with strains applied in dried form. In all culture media attained efficiency of sugar utilization was at least from 98-99 % w/w. Maximum productivity was achieved around 30th hour of fermentation and amounted ?1.8 g l?? h?? for all applied yeast strains. Therefore, optimal duration of the process in technical and economic terms should be considered.

scholarly journals Enhanced Iron Uptake of Saccharomyces cerevisiae by Heterologous Expression of a Tadpole Ferritin Gene

2001 ◽  
Vol 67 (3) ◽  
pp. 1280-1283 ◽  
Author(s):  
Young-Mi Shin ◽  
Tae-Ho Kwon ◽  
Kyung-Suk Kim ◽  
Keon-Sang Chae ◽  
Dae-Hyuk Kim ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heterologous Expression ◽  
Heavy Chain ◽  
Blot Analysis ◽  
Blue Staining ◽  
Recombinant Yeast ◽  
Iron Storage ◽  
Cell Weight ◽  
Dry Cell Weight ◽  
Dry Cell

ABSTRACT We genetically engineered Saccharomyces cerevisiae to express ferritin, a ubiquitous iron storage protein, with the major heavy-chain subunit of tadpole ferritin. A 450-kDa ferritin complex can store up to 4,500 iron atoms in its central cavity. We cloned the tadpole ferritin heavy-chain gene (TFH) into the yeast shuttle vector YEp352 under the control of a hybrid alcohol dehydrogenase II and glyceraldehyde-3-phosphate dehydrogenase promoter. We confirmed transformation and expression by Northern blot analysis of the recombinant yeast, by Western blot analysis using an antibody against Escherichia coli-expressed TFH, and with Prussian blue staining that indicated that the yeast-expressed tadpole ferritin was assembled into a complex that could bind iron. The recombinant yeast was more iron tolerant in that 95% of transformed cells, but none of the recipient strain cells, could form colonies on plates containing 30 mM ferric citrate. The cell-associated concentration of iron was 500 μg per gram (dry cell weight) of the recombinant yeast but was 210 μg per gram (dry cell weight) in the wild type. These findings indicate that the iron-carrying capacity of yeast is improved by heterologous expression of tadpole ferritin and suggests that this approach may help relieve dietary iron deficiencies in domesticated animals by the use of the engineered yeast as a feed and food supplement.

scholarly journals Saccharomyces cerevisiae Fermentation of 28 Barley and 12 Oat Cultivars

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 59
Author(s):  
Timothy J. Tse ◽  
Daniel J. Wiens ◽  
Jianheng Shen ◽  
Aaron D. Beattie ◽  
Martin J. T. Reaney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Succinic Acid ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Cereal Crops ◽  
Fermentation Products ◽  
Barley Cultivars ◽  
Oat Cultivars

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.

scholarly journals Complete biosynthesis of a sulfated chondroitin in Escherichia coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Adeola Awofiranye ◽  
Payel Datta ◽  
Ke Xia ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Scale Up ◽  
Production Methods ◽  
E Coli ◽  
Microbial Cell Factories ◽  
Cell Factories ◽  
Microbial Product ◽  
Dry Cell Weight ◽  
One Step ◽  
Dry Cell

AbstractSulfated glycosaminoglycans (GAGs) are a class of important biologics that are currently manufactured by extraction from animal tissues. Although such methods are unsustainable and prone to contamination, animal-free production methods have not emerged as competitive alternatives due to complexities in scale-up, requirement for multiple stages and cost of co-factors and purification. Here, we demonstrate the development of single microbial cell factories capable of complete, one-step biosynthesis of chondroitin sulfate (CS), a type of GAG. We engineer E. coli to produce all three required components for CS production–chondroitin, sulfate donor and sulfotransferase. In this way, we achieve intracellular CS production of ~27 μg/g dry-cell-weight with about 96% of the disaccharides sulfated. We further explore four different factors that can affect the sulfation levels of this microbial product. Overall, this is a demonstration of simple, one-step microbial production of a sulfated GAG and marks an important step in the animal-free production of these molecules.

scholarly journals Optimisation of Recombinant Myrosinase Production in Pichia pastoris

2021 ◽  
Vol 22 (7) ◽  
pp. 3677
Author(s):  
Zuzana Rosenbergová ◽  
Kristína Kántorová ◽  
Martin Šimkovič ◽  
Albert Breier ◽  
Martin Rebroš
Keyword(s):  
Pichia Pastoris ◽  
Plant Defence ◽  
Plant Secondary Metabolites ◽  
Specific Productivity ◽  
Fermentation Conditions ◽  
Threefold Increase ◽  
Dry Cell Weight ◽  
First Time ◽  
Hydrolysis Of ◽  
Dry Cell

Myrosinase is a plant defence enzyme catalysing the hydrolysis of glucosinolates, a group of plant secondary metabolites, to a range of volatile compounds. One of the products, isothiocyanates, proved to have neuroprotective and chemo-preventive properties, making myrosinase a pharmaceutically interesting enzyme. In this work, extracellular expression of TGG1 myrosinase from Arabidopsis thaliana in the Pichia pastoris KM71H (MutS) strain was upscaled to a 3 L laboratory fermenter for the first time. Fermentation conditions (temperature and pH) were optimised, which resulted in a threefold increase in myrosinase productivity compared to unoptimised fermentation conditions. Dry cell weight increased 1.5-fold, reaching 100.5 g/L without additional glycerol feeding. Overall, a specific productivity of 4.1 U/Lmedium/h was achieved, which was 102.5-fold higher compared to flask cultivations.

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