Biosynthesis of 1,3-propanediol from recombinant E. coli by optimization process using pure and crude glycerol as a sole carbon source under two-phase fermentation system

2013 ◽  
Vol 30 (4) ◽  
pp. 1359-1368 ◽  
Author(s):  
Rosarin Rujananon ◽  
Poonsuk Prasertsan ◽  
Amornrat Phongdara
2015 ◽  
Vol 192 ◽  
pp. 677-681 ◽  
Author(s):  
Mohan Ganesh ◽  
Arivazhagan Senthamarai ◽  
Santhanam Shanmughapriya ◽  
Kalimuthusamy Natarajaseenivasan

Metabolites ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 228
Author(s):  
R. Axayacatl Gonzalez-Garcia ◽  
Lars K. Nielsen ◽  
Esteban Marcellin

Polyketides are a remarkable class of natural products with diverse functional and structural diversity. The class includes many medicinally important molecules with antiviral, antimicrobial, antifungal and anticancer properties. Native bacterial, fungal and plant hosts are often difficult to cultivate and coax into producing the desired product. As a result, Escherichia coli has been used for the heterologous production of polyketides, with the production of 6-deoxyerythronolide B (6-dEB) being the first example. Current strategies for production in E. coli require feeding of exogenous propionate as a source for the precursors propionyl-CoA and S-methylmalonyl-CoA. Here, we show that heterologous polyketide production is possible from glucose as the sole carbon source. The heterologous expression of eight genes from the Wood-Werkman cycle found in Propionibacteria, in combination with expression of the 6-dEB synthases DEBS1, DEBS2 and DEBS3 resulted in 6-dEB formation from glucose as the sole carbon source. Our results show that the Wood-Werkman cycle provides the required propionyl-CoA and the extender unit S-methylmalonyl-CoA to produce up to 0.81 mg/L of 6-dEB in a chemically defined media.


2018 ◽  
Author(s):  
Sixto M. Leal ◽  
Elaine Newman ◽  
Kalai Mathee

ABSTRACTRegardless of the site of infectivity, all pathogens require high energetic influxes. This energy is required to counterattack the host immune system and in the absence the bacterial infections are easily cleared by the immune system. This study is an investigation into one highly bioenergetic pathway inPseudomonas aeruginosainvolving the amino acid L-serine and the enzyme L-serine deaminase (L-SD).P. aeruginosais an opportunistic pathogen causing infections in patients with compromised immune systems as well as patients with cystic fibrosis. L-SD has been linked directly to the pathogenicity of several organisms including but not limited toCampylobacter jejuni, Mycobacterium bovis,Streptococcus pyogenes, andYersinia pestis. We hypothesized thatP. aeruginosaL-SD is likely to be critical for its virulence. The genome sequence analysis revealed the presence of two L-SD homologs encoded bysdaAandsdaB.We analyzed the ability ofP. aeruginosato utilize serine and the role of SdaA and SdaB in serine deamination by comparing mutant strains ofsdaA(PAOsdaA) andsdaB(PAOsdaB) with their isogenic parentP. aeruginosaPAO1. We demonstrate thatP. aeruginosais unable to use serine as a sole carbon source. However, serine utilization is enhanced in the presence of glycine. Both SdaA and SdaB contribute to L-serine deamination, 34 % and 66 %, respectively. Glycine was also shown to increase the L-SD activity especially from SdaB. Glycine-dependent induction requires the inducer serine. The L-SD activity from both SdaA and SdaB is inhibited by the amino acid L-leucine. These results suggest thatP. aeruginosaL-SD is quite different from the characterizedE. coliL-SD that is glycine-independent but leucine-dependent for activation. Growth mutants able to use serine as sole carbon source were isolated. In addition, suicide vectors were constructed which allow for selective mutation of thesdaAandsdaBgenes on anyP. aeruginosastrain of interest. Future studies with a double mutant will reveal the importance of these genes for pathogenicity.


2021 ◽  
Vol 64 (1) ◽  
Author(s):  
Hyeon Jeong Seong ◽  
Yu-Sin Jang

AbstractEscherichia coli has been used as a host to construct the cell factory for biobased production of chemicals from renewable feedstocks. Because galactose is found in marine biomass as a major component, the strategy for galactose utilization in E. coli has been gained more attention. Although galactose and glucose co-fermentation has been reported using the engineered E. coli strain, few reports have covered fermentation supplemented with galactose as a sole carbon source in the mutant lacking the repressor-specific carbon catabolite repression (CCR). Here, we report the effects of the deregulation of the repressor-specific CCR (galR− and galS−) in fermentation supplemented with galactose as a sole carbon source, using the engineered E. coli strains. In the fermentation using the galR− and galS− double mutant (GR2 strain), an increase of rates in sugar consumption and cell growth was observed compared to the parent strain. In the glucose fermentation, wild-type W3110 and its mutant GR2 and GR2PZ (galR−, galS−, pfkA−, and zwf−) consumed sugar at a higher rate than those values obtained from galactose fermentation. However, the GR2P strain (galR−, galS−, and pfkA−) showed no difference between fermentations using glucose and galactose as a sole carbon source. This study provides essential information for galactose fermentation using the CCR-deregulated E. coli strains.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Walaa A. Eraqi ◽  
Aymen S. Yassin ◽  
Amal E. Ali ◽  
Magdy A. Amin

Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We have developed a process for the production of rhamnolipid biosurfactants using glycerol as the sole carbon source by a local Pseudomonas aeruginosa isolate that was obtained from an extensive screening program. A factorial design was applied with the goal of optimizing the rhamnolipid production. The highest production yield was obtained after 2 days when cells were grown in minimal salt media at pH 6, containing 1% (v/v) glycerol and 2% (w/v) sodium nitrate as nitrogen source, at 37°C and at 180 rpm, and reached 2.164 g/L after 54 hours (0.04 g/L h). Analysis of the produced rhamnolipids by TLC, HPLC, and FTIR confirmed the nature of the biosurfactant as monorhamnolipid. Glycerol can serve as a source for the production of rhamnolipid from microbial isolates providing a cheap and reliable substrate.


1999 ◽  
Vol 181 (12) ◽  
pp. 3837-3841 ◽  
Author(s):  
Min Huang ◽  
Fred Bernd Oppermann-Sanio ◽  
Alexander Steinbüchel

ABSTRACT A recent study indicated that Bacillus subtiliscatabolizes acetoin by enzymes encoded by the acu gene cluster (F. J. Grundy, D. A. Waters, T. Y. Takova, and T. M. Henkin, Mol. Microbiol. 10:259–271, 1993) that are completely different from those in the multicomponent acetoin dehydrogenase enzyme system (AoDH ES) encoded by aco gene clusters found before in all other bacteria capable of utilizing acetoin as the sole carbon source for growth. By hybridization with a DNA probe covering acoA and acoB of the AoDH ES from Clostridium magnum, genomic fragments from B. subtilis harboring acoA, acoB,acoC, acoL, and acoR homologous genes were identified, and some of them were functionally expressed inE. coli. Furthermore, acoA was inactivated inB. subtilis by disruptive mutagenesis; these mutants were impaired to express PPi-dependent AoDH E1 activity to remove acetoin from the medium and to grow with acetoin as the carbon source. Therefore, acetoin is catabolized in B. subtilis by the same mechanism as all other bacteria investigated so far, leaving the function of the previously described acu genes obscure.


2016 ◽  
Vol 182 (2) ◽  
pp. 495-510 ◽  
Author(s):  
Li-ping Liu ◽  
Yang Hu ◽  
Wen-yong Lou ◽  
Ning Li ◽  
Hong Wu ◽  
...  

2020 ◽  
Author(s):  
Hong Liang ◽  
Xiaoqiang Ma ◽  
Wenbo Ning ◽  
Yurou Liu ◽  
Anthony J. Sinskey ◽  
...  

AbstractEngineering microbes to utilize non-conventional substrates could create short and efficient pathways to convert substrate into product. In this study, we designed and constructed a two-step heterologous ethanol utilization pathway (EUP) in Escherichia coli by using acetaldehyde dehydrogenase (encoded by ada) from Dickeya zeae and alcohol dehydrogenase (encoded by adh2) from Saccharomyces cerevisiae. This EUP can convert ethanol into acetyl-CoA without ATP consumption, and generate two molecules of NADH per molecule of ethanol. We optimized the expression of these two genes and found that ethanol consumption could be improved by expressing them in a specific order (ada-adh2) with a constitutive promoter (PgyrA). The engineered E. coli strain with EUP consumed approximately 8 g/L of ethanol in 96 hours when it was used as sole carbon source. Subsequently, we combined EUP with the biosynthesis of polyhydroxybutyrate (PHB), a biodegradable polymer derived from acetyl-CoA. The engineered E. coli strain carrying EUP and PHB biosynthetic pathway produced 1.1 g/L of PHB from 10 g/L of ethanol and 1 g/L of aspartate family amino acids in 96 hours. We also engineered E. coli strain to produced 24 mg/L of prenol from 10 g/L of ethanol in 48 hours, supporting the feasibility of converting ethanol into different classes of acetyl-CoA derived compounds.HighlightsEngineered Escherichia coli strains to grow on ethanol as sole carbon sourceDemonstrated that ethanol was converted into acetyl-CoA (AcCoA) through two pathways (acetaldehyde-acetate-AcCoA and acetaldehyde-AcCoA)Converted ethanol into two acetyl-CoA derived products with low structural similarity (polyhydroxybutyrate and prenol)Discovered that supplementation of the aspartate family amino acids can substantially improve cell growth on ethanol


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