scholarly journals Engineering of Cyclodextrin Glucanotransferase on the Cell Surface of Saccharomyces cerevisiae for Improved Cyclodextrin Production

2006 ◽  
Vol 72 (3) ◽  
pp. 1873-1877 ◽  
Author(s):  
Zhankun Wang ◽  
Qingsheng Qi ◽  
Peng George Wang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Immunofluorescence Microscopy ◽  
Coupling Reaction ◽  
The Other ◽  
Yeast Fermentation ◽  
Cyclodextrin Glucanotransferase ◽  
Regulated Expression ◽  
Cyclodextrin Production

ABSTRACT The cyclodextrin glucanotransferase (CGTase) gene (cgt) from Bacillus circulans 251 was cloned into plasmid pYD1, which allowed regulated expression, secretion, and detection. The expression of CGTase with a-agglutinin at the N-terminal end on the extracellular surface of Saccharomyces cerevisiae was confirmed by immunofluorescence microscopy. This surface-anchored CGTase gave the yeast the ability to directly utilize starch as a sole carbon source and the ability to produce the anticipated products, cyclodextrins, as well as glucose and maltose. The resulting glucose and maltose, which are efficient acceptors in the CGTase coupling reaction, could be consumed by yeast fermentation and thus facilitated cyclodextrin production. On the other hand, ethanol produced by the yeast may form a complex with cyclodextrin and shift the equilibrium in favor of cyclodextrin production. The yeast with immobilized CGTase produced 24.07 mg/ml cyclodextrins when it was incubated in yeast medium supplemented with 4% starch.

Isolation of alcohol oxidase and two other methanol regulatable genes from the yeast Pichia pastoris

1985 ◽  
Vol 5 (5) ◽  
pp. 1111-1121
Author(s):  
S B Ellis ◽  
P F Brust ◽  
P J Koutz ◽  
A F Waters ◽  
M M Harpold ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Alcohol Oxidase ◽  
Methylotrophic Yeasts ◽  
Sequence Analyses ◽  
Yeast Pichia Pastoris ◽  
Oxidation Of Methanol ◽  
Regulated Expression

The oxidation of methanol follows a well-defined pathway and is similar for several methylotrophic yeasts. The use of methanol as the sole carbon source for the growth of Pichia pastoris stimulates the expression of a family of genes. Three methanol-responsive genes have been isolated; cDNA copies have been made from mRNAs of these genes, and the protein products from in vitro translations have been examined. The identification of alcohol oxidase as one of the cloned, methanol-regulated genes has been made by enzymatic, immunological, and sequence analyses. Methanol-regulated expression of each of these three isolated genes can be demonstrated to occur at the level of transcription. Finally, DNA subfragments of two of the methanol-responsive genomic clones from P. pastoris have been isolated and tentatively identified as containing the control regions involved in methanol regulation.

scholarly journals Comparison of Conventional and Novel Pre-treatment Methods for Bioethanol Production from Fruit and Vegetable Wastes

2020 ◽  
Vol 33 (4) ◽  
pp. 471-483
Author(s):  
Tugba Keskin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
The Other ◽  
Yeast Fermentation ◽  
Bioethanol Production ◽  
Fruit And Vegetable ◽  
Bacterial Fermentation ◽  
Waste Gas ◽  
Clostridium Ljungdahlii ◽  
Vegetable Wastes ◽  
Pre Treatment

In this study, novel and conventional techniques for the production of bioethanol from fruit and vegetable wastes (FVWs) by yeast and bacterial fermentation were investigated experimentally. Different pretreatment techniques (acid, heat, acid/heat, and microwave) for yeast fermentation were compared. Maximum ethanol concentrations of 11.7 and 11.8 g L–1 were observed from acid/heat and microwave pretreatment, respectively, by using Saccharomyces cerevisiae. On the other hand, biochar production from FVWs and syngas fermentation from the waste gas of this process were integrated. From waste gas with 12 % CO content, 5.5 g L–1 and 2.5 g L–1 ethanol production was observed by using anaerobic mixed culture and Clostridium ljungdahlii, respectively. The overall results emphasize the potential of bioethanol production from FVWs by economically feasible and environmentally friendly methods.

Lag, adaptation and ageing in a micro-organism ( Bact. lactis aerogenes )

1961 ◽  
Vol 155 (959) ◽  
pp. 195-201 ◽  
Keyword(s):  
Carbon Source ◽  
Generation Time ◽  
Sole Carbon Source ◽  
The Other ◽  
Lag Phase ◽  
Glucose Medium ◽  
Galactosidase Activity ◽  
Aerobacter Aerogenes ◽  
Isomerase Activity

The lag preceding growth of Bact. lactis aerogenes (Aerobacter aerogenes) after a first transfer to a medium containing D-arabinose as sole carbon source increases with the age and decreases with the size of the inoculum. During the long lag phase the β -galactosidase activity declines steeply. In contrast with this (and with a control ageing in a glucose medium) the D-ribulose isomerase activity is maintained, although no detectable consumption of D-arabinose occurs. If the long lag of unadapted cells in D-arabinose is divided into parts by intermediate passages in glucose or lactose media, the sum of the partial lags is nearly constant and equal to that observed when there is no interruption. But the periodic passages in the other media increase the rate at which growth eventually occurs in the D-arabinose. It is concluded that during the lag a decay of the enzymes in general occurs concomitantly with the development of the specific mechanisms concerned in the utilization of the new substrate. The balance of these processes (together with varying loss or retention of diffusible metabolites) is largely responsible for the observed variations in lag and mean generation time.

scholarly journals N-Acetylglucosamine Utilization by Saccharomyces cerevisiae Based on Expression of Candida albicans NAG Genes

2009 ◽  
Vol 75 (18) ◽  
pp. 5840-5845 ◽  
Author(s):  
Jürgen Wendland ◽  
Yvonne Schaub ◽  
Andrea Walther
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
De Novo ◽  
Biofuel Production ◽  
Bioethanol Production ◽  
Catabolic Pathway ◽  
Cellular Functions ◽  
Kinase A

ABSTRACT Synthesis of chitin de novo from glucose involves a linear pathway in Saccharomyces cerevisiae. Several of the pathway genes, including GNA1, are essential. Genes for chitin catabolism are absent in S. cerevisiae. Therefore, S. cerevisiae cannot use chitin as a carbon source. Chitin is the second most abundant polysaccharide after cellulose and consists of N-acetylglucosamine (GlcNAc) moieties. Here, we have generated S. cerevisiae strains that are able to use GlcNAc as a carbon source by expressing four Candida albicans genes (NAG3 or its NAG4 paralog, NAG5, NAG2, and NAG1) encoding a GlcNAc permease, a GlcNAc kinase, a GlcNAc-6-phosphate deacetylase, and a glucosamine-6-phosphate deaminase, respectively. Expression of NAG3 and NAG5 or NAG4 and NAG5 in S. cerevisiae resulted in strains in which the otherwise-essential ScGNA1 could be deleted. These strains required the presence of GlcNAc in the medium, indicating that uptake of GlcNAc and its phosphorylation were achieved. Expression of all four NAG genes produced strains that could use GlcNAc as the sole carbon source for growth. Utilization of a GlcNAc catabolic pathway for bioethanol production using these strains was tested. However, fermentation was slow and yielded only minor amounts of ethanol (approximately 3.0 g/liter), suggesting that fructose-6-phosphate produced from GlcNAc under these conditions is largely consumed to maintain cellular functions and promote growth. Our results present the first step toward tapping a novel, renewable carbon source for biofuel production.

scholarly journals Bacterial Oxidation of Dibromomethane and Methyl Bromide in Natural Waters and Enrichment Cultures

1998 ◽  
Vol 64 (12) ◽  
pp. 4629-4636 ◽  
Author(s):  
K. D. Goodwin ◽  
J. K. Schaefer ◽  
R. S. Oremland
Keyword(s):  
Carbon Source ◽  
Methane Oxidation ◽  
Methyl Bromide ◽  
Half Life ◽  
Sole Carbon Source ◽  
Natural Waters ◽  
The Other ◽  
Bacterial Oxidation ◽  
Enrichment Cultures ◽  
Saline Waters

ABSTRACT Bacterial oxidation of14CH2Br2 and14CH3Br was measured in freshwater, estuarine, seawater, and hypersaline-alkaline samples. In general, bacteria from the various sites oxidized similar amounts of14CH2Br2 and comparatively less 14CH3Br. Bacterial oxidation of14CH3Br was rapid in freshwater samples compared to bacterial oxidation of 14CH3Br in more saline waters. Freshwater was also the only site in which methyl fluoride-sensitive bacteria (e.g., methanotrophs or nitrifiers) governed brominated methane oxidation. Half-life calculations indicated that bacterial oxidation of CH2Br2 was potentially significant in all of the waters tested. In contrast, only in freshwater was bacterial oxidation of CH3Br as fast as chemical removal. The values calculated for more saline sites suggested that bacterial oxidation of CH3Br was relatively slow compared to chemical and physical loss mechanisms. However, enrichment cultures demonstrated that bacteria in seawater can rapidly oxidize brominated methanes. Two distinct cultures of nonmethanotrophic methylotrophs were recovered; one of these cultures was able to utilize CH2Br2 as a sole carbon source, and the other was able to utilize CH3Br as a sole carbon source.

scholarly journals Engineered Pentafunctional Minicellulosome for Simultaneous Saccharification and Ethanol Fermentation in Saccharomyces cerevisiae

2014 ◽  
Vol 80 (21) ◽  
pp. 6677-6684 ◽  
Author(s):  
Youyun Liang ◽  
Tong Si ◽  
Ee Lui Ang ◽  
Huimin Zhao
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Phosphoric Acid ◽  
Sole Carbon Source ◽  
Consolidated Bioprocessing ◽  
Content Type ◽  
Yeast Strains ◽  
Recombinant Yeast Strain ◽  
Polysaccharide Monooxygenases ◽  
Simultaneous Saccharification

ABSTRACTSeveral yeast strains have been engineered to express different cellulases to achieve simultaneous saccharification and fermentation of lignocellulosic materials. However, successes in these endeavors were modest, as demonstrated by the relatively low ethanol titers and the limited ability of the engineered yeast strains to grow using cellulosic materials as the sole carbon source. Recently, substantial enhancements to the breakdown of cellulosic substrates have been observed when lytic polysaccharide monooxygenases (LPMOs) were added to traditional cellulase cocktails. LPMOs are reported to cleave cellulose oxidatively in the presence of enzymatic electron donors such as cellobiose dehydrogenases. In this study, we coexpressed LPMOs and cellobiose dehydrogenases with cellobiohydrolases, endoglucanases, and β-glucosidases inSaccharomyces cerevisiae. These enzymes were secreted and docked onto surface-displayed miniscaffoldins through cohesin-dockerin interaction to generate pentafunctional minicellulosomes. The enzymes on the miniscaffoldins acted synergistically to boost the degradation of phosphoric acid swollen cellulose and increased the ethanol titers from our previously achieved levels of 1.8 to 2.7 g/liter. In addition, the newly developed recombinant yeast strain was also able to grow using phosphoric acid swollen cellulose as the sole carbon source. The results demonstrate the promise of the pentafunctional minicellulosomes for consolidated bioprocessing by yeast.

Control of catalase and peroxidase biosynthesis by carbon source and oxygen in the yeast Saccharomyces cerevisiae

1983 ◽  
Vol 29 (9) ◽  
pp. 1200-1204 ◽  
Author(s):  
E. Valdivia ◽  
J. Martinez ◽  
J. M. Ortega ◽  
E. Montoya
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Oxygen Tension ◽  
Aminolevulinic Acid ◽  
Inhibitory Effect ◽  
Enzymatic Activities ◽  
The Other ◽  
Prosthetic Group ◽  
Yeast Saccharomyces Cerevisiae ◽  
Direct Inhibitory Effect

The effect of carbon source and oxygen tension on catalase and peroxidase levels and on the intermediates of the biosynthesis of the prosthetic group of both enzymes has been studied. Oxygen produces an increase of both enzymatic activities, even in presence of glucose. On the other hand it seems probable that glucose does not have a direct inhibitory effect on the biosynthesis of 5-aminolevulinic acid (ALA) and porphyrins.

Evidence against the involvement of adenosine 3′,5′-cyclic monophosphate in glucose inhibition of β-galactosidase induction in Bacillus megaterium

1976 ◽  
Vol 54 (10) ◽  
pp. 854-865 ◽  
Author(s):  
Kwok-Him Yeung ◽  
Gillian Chaloner-Larssgn ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Bacillus Megaterium ◽  
Sole Carbon Source ◽  
The Other ◽  
Cyclic Monophosphate ◽  
Glucose Inhibition ◽  
Significant Rate ◽  
Phosphorylated Compounds ◽  
Grown Culture

When Bacillus megaterium cells are grown on D-galactose as the sole carbon source, the cells actively synthesize β-galactosidase (β-D-galactoside galactohydroIase, EC 3.2.1.23). However, D-galactose, when added to a glucose-grown culture, did not induce β-galactosidase, apparently because of the glucose inhibition of the transport of galactose. On the other hand, when glucose was added to a galactose-grown culture, the transport of galactose continued at a reduced but significant rate, whereas further synthesis of β-galactosidase was halted. Adenosine 3′,5′-cyclic monophosphate (cAMP) or guanosine 3′,5′-cyclic monophosphate (cGMP) did not relieve the glucose inhibition of β-galactosidase synthesis in the preinduced culture. A method which gave a reproducible assay of c[32P]AMP in Escherichia coli did not detect cAMP or cGMP in a B. megaterium culture undergoing β-galactosidase induction, but revealed the extracellular accumulation of two unknown phosphorylated compounds. Cell-free extracts prepared from galactose-grown cells did not catalyze the degradation of cAMP or cGMP.

scholarly journals Identification and analysis of a Saccharomyces cerevisiae copper homeostasis gene encoding a homeodomain protein.

1994 ◽  
Vol 14 (12) ◽  
pp. 7792-7804 ◽  
Author(s):  
S A Knight ◽  
K T Tamai ◽  
D J Kosman ◽  
D J Thiele
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Copper Resistance ◽  
Yeast Cells ◽  
Homeodomain Protein ◽  
Mrna Levels ◽  
Reading Frame ◽  
Cup1 Gene ◽  
Intracellular Copper

Yeast metallothionein, encoded by the CUP1 gene, and its copper-dependent transcriptional activator ACE1 play a key role in mediating copper resistance in Saccharomyces cerevisiae. Using an ethyl methanesulfonate mutant of a yeast strain in which CUP1 and ACE1 were deleted, we isolated a gene, designated CUP9, which permits yeast cells to grow at high concentrations of environmental copper, most notably when lactate is the sole carbon source. Disruption of CUP9, which is located on chromosome XVI, caused a loss of copper resistance in strains which possessed CUP1 and ACE1, as well as in the cup1 ace1 deletion strain. Measurement of intracellular copper levels of the wild-type and cup9-1 mutant demonstrated that total intracellular copper concentrations were unaffected by CUP9. CUP9 mRNA levels were, however, down regulated by copper when yeast cells were grown with glucose but not with lactate or glycerol-ethanol as the sole carbon source. This down regulation was independent of the copper metalloregulatory transcription factor ACE1. The DNA sequence of CUP9 predicts an open reading frame of 306 amino acids in which a 55-amino-acid sequence showed 47% identity with the homeobox domain of the human proto-oncogene PBX1, suggesting that CUP9 is a DNA-binding protein which regulates the expression of important copper homeostatic genes.

Saccharomyces cerevisiae glucose signalling regulator Mth1p regulates the organellar Na+/H+ exchanger Nhx1p

2010 ◽  
Vol 432 (2) ◽  
pp. 343-352 ◽  
Author(s):  
Keiji Mitsui ◽  
Masafumi Matsushita ◽  
Hiroshi Kanazawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Glucose Sensor ◽  
Ph Regulation ◽  
Gene Knockout ◽  
Carbon Sources ◽  
Acidic Ph ◽  
In Cells

Organelle-localized NHEs (Na+/H+ exchangers) are found in cells from yeast to humans and contribute to organellar pH regulation by exporting H+ from the lumen to the cytosol coupled to an H+ gradient established by vacuolar H+-ATPase. The mechanisms underlying the regulation of organellar NHEs are largely unknown. In the present study, a yeast two-hybrid assay identified Mth1p as a new binding protein for Nhx1p, an organellar NHE in Saccharomyces cerevisiae. It was shown by an in vitro pull-down assay that Mth1p bound to the hydrophilic C-terminal half of Nhx1p, especially to the central portion of this region. Mth1p is known to bind to the cytoplasmic domain of the glucose sensor Snf3p/Rgt2p and also functions as a negative transcriptional regulator. Mth1p was expressed in cells grown in a medium containing galactose, but was lost (possibly degraded) when cells were grown in medium containing glucose as the sole carbon source. Deletion of the MTH1 gene increased cell growth compared with the wild-type when cells were grown in a medium containing galactose and with hygromycin or at an acidic pH. This resistance to hygromycin or acidic conditions was not observed for cells grown with glucose as the sole carbon source. Gene knockout of NHX1 increased the sensitivity to hygromycin and acidic pH. The increased resistance to hygromycin was reproduced by truncation of the Mth1p-binding region in Nhx1p. These results implicate Mth1p as a novel regulator of Nhx1p that responds to specific extracellular carbon sources.

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