scholarly journals Metabolic Engineering of Zymomonas moblis for Ethylene Production

2019 ◽  
Author(s):  
Yan He ◽  
Bo Wu ◽  
Wei Xia ◽  
Kun-Yang Zhao ◽  
Qiong Tan ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Carbon Source ◽  
Ethylene Production ◽  
Sole Carbon Source ◽  
High Stress ◽  
Cellulosic Biomass ◽  
Corn Straw ◽  
Enzymatic Hydrolysate ◽  
Alternative Approach ◽  
Engineering Work

Abstract Background: Biological ethylene production via the ethylene-forming enzyme (EFE) can offer a promising sustainable alternative approach for fossil-based ethylene production. The high stress tolerance of Z. mobilis make it as promising bio-ethylene producer.Results: In this study, Heterologous expression of the efe gene in Z. mobilis successfully converted the non-ethylene producing strain into an ethylene producer. What’s more, we systematically performed the effect of knocking out the competitive metabolic pathway of pyruvate and the addition of nutrients to the medium to improve the ethylene production in Z. mobilis. These optimization pathways and different substrate supplies resulted in higher ethylene productivity (from 1.36 to 12.83 nmol/OD600/ml), which may guide future engineering work on ethylene production in other organisms to further improve ethylene productivity. Meanwhile, we obtained ethylene production of 5.8 nmol/OD600/ml in strain ZM532-efe by using enzymatic hydrolysate of corn straw as the sole carbon source. This is also the first report on the production of ethylene from cellulosic biomass.Conclusions: These results indicate that the engineered Z. mobilis show great potential for production of ethylene from cellulosic biomass in the future.

scholarly journals Host engineering for improved valerolactam production in Pseudomonas putida

2019 ◽  
Author(s):  
Mitchell G. Thompson ◽  
Luis E. Valencia ◽  
Jacquelyn M. Blake-Hedges ◽  
Pablo Cruz-Morales ◽  
Alexandria E. Velasquez ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Carbon Source ◽  
Pseudomonas Putida ◽  
Aromatic Compounds ◽  
Sole Carbon Source ◽  
Carbon Sources ◽  
Shotgun Proteomics ◽  
Rich Media ◽  
Amide Hydrolase

ABSTRACTPseudomonas putida is a promising bacterial chassis for metabolic engineering given its ability to metabolize a wide array of carbon sources, especially aromatic compounds derived from lignin. However, this omnivorous metabolism can also be a hindrance when it can naturally metabolize products produced from engineered pathways. Herein we show that P. putida is able to use valerolactam as a sole carbon source, as well as degrade caprolactam. Lactams represent important nylon precursors, and are produced in quantities exceeding one million tons per year[1]. To better understand this metabolism we use a combination of Random Barcode Transposon Sequencing (RB-TnSeq) and shotgun proteomics to identify the oplBA locus as the likely responsible amide hydrolase that initiates valerolactam catabolism. Deletion of the oplBA genes prevented P. putida from growing on valerolactam, prevented the degradation of valerolactam in rich media, and dramatically reduced caprolactam degradation under the same conditions. Deletion of oplBA, as well as pathways that compete for precursors L-lysine or 5-aminovalerate, increased the titer of valerolactam from undetectable after 48 hours of production to ~90 mg/L. This work may serve as a template to rapidly eliminate undesirable metabolism in non-model hosts in future metabolic engineering efforts.

scholarly journals A synthetic Calvin cycle enables autotrophic growth in yeast

2019 ◽  
Author(s):  
Thomas Gassler ◽  
Michael Sauer ◽  
Brigitte Gasser ◽  
Diethard Mattanovich ◽  
Matthias G. Steiger
Keyword(s):  
Metabolic Engineering ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Heterologous Protein ◽  
Calvin Cycle ◽  
Methylotrophic Yeast ◽  
Genes Encoding ◽  
Endogenous Genes ◽  
Multiple Cell ◽  
New Yeast

AbstractThe methylotrophic yeast Pichia pastoris is frequently used for heterologous protein production and it assimilates methanol efficiently via the xylulose-5-phosphate pathway. This pathway is entirely localized in the peroxisomes and has striking similarities to the Calvin-Benson-Bassham (CBB) cycle, which is used by a plethora of organisms like plants to assimilate CO2 and is likewise compartmentalized in chloroplasts. By metabolic engineering the methanol assimilation pathway of P. pastoris was re-wired to a CO2 fixation pathway resembling the CBB cycle. This new yeast strain efficiently assimilates CO2 into biomass and utilizes it as its sole carbon source, which changes the lifestyle from heterotrophic to autotrophic.In total eight genes, including genes encoding for RuBisCO and phosphoribulokinase, were integrated into the genome of P. pastoris, while three endogenous genes were deleted to block methanol assimilation. The enzymes necessary for the synthetic CBB cycle were targeted to the peroxisome. Methanol oxidation, which yields NADH, is employed for energy generation defining the lifestyle as chemoorganoautotrophic. This work demonstrates that the lifestyle of an organism can be changed from chemoorganoheterotrophic to chemoorganoautotrophic by metabolic engineering. The resulting strain can grow exponentially and perform multiple cell doublings on CO2 as sole carbon source with a µmax of 0.008 h−1.Graphical Abstract

Construction and Evaluation of Recombinant Strains for Ethanol Production from Lignocellulosic Hydrolysate

2011 ◽  
Vol 347-353 ◽  
pp. 48-51 ◽  
Author(s):  
Shao Lan Zou ◽  
Chao Zhang ◽  
Yuan Yuan Ma ◽  
Le You ◽  
Min Hua Zhang
Keyword(s):  
Carbon Source ◽  
Ethanol Production ◽  
Rapid Growth ◽  
Sole Carbon Source ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Corn Straw ◽  
Lignocellulosic Hydrolysate ◽  
Preliminary Results ◽  
Theoretical Yield

The recombinant Z.mobilis CX was constructed. Its ethanol concentration and ethanol yield from 2% xylose at 36 h were 6.73 g/L and 82.3% of theoretical yield, respectively. The recombinant S.cerevisiae YB was constructed and was showed to utilize cellobiose as the sole carbon source for rapid growth and ethanol production. The maximum ethanol concentration 7.493 g/L and ethanol yield 77.4% of theoretical yield from 2% cellobiose were obtained at 24 h. Further, the preliminary results of SSF of pretreated corn straw demonstrated the potential of improving ethanol production and reducing the costs of cellose enzymes used by co-fermentation of CX and YB.

Metabolic Engineering of E. coli for Xylose Production from Glucose as the Sole Carbon Source

2021 ◽  
Vol 10 (9) ◽  
pp. 2266-2275
Author(s):  
Wencheng Yin ◽  
Yujin Cao ◽  
Miaomiao Jin ◽  
Mo Xian ◽  
Wei Liu
Keyword(s):  
Metabolic Engineering ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
E Coli ◽  
Xylose Production

scholarly journals Pandrug-resistant Pseudomonas sp. expresses New Delhi metallo-β-lactamase-1 and consumes ampicillin as sole carbon source

2020 ◽  
Author(s):  
Vivek Kumar Ranjan ◽  
Shriparna Mukherjee ◽  
Subarna Thakur ◽  
Krutika Gupta ◽  
Ranadhir Chakraborty
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
New Delhi ◽  
Pseudomonas Sp

scholarly journals Study of a plugging microbial consortium using crude oil as sole carbon source

2008 ◽  
Vol 5 (4) ◽  
pp. 367-374 ◽  
Author(s):  
Jing Wang ◽  
Guiwen Yan ◽  
Mingquan An ◽  
Jieli Liu ◽  
Houming Zhang ◽  
...  
Keyword(s):  
Carbon Source ◽  
Crude Oil ◽  
Sole Carbon Source ◽  
Microbial Consortium

scholarly journals Mutants affecting histidine utilization inAspergillus nidulans

1975 ◽  
Vol 25 (2) ◽  
pp. 119-135 ◽  
Author(s):  
Meryl Polkinghorne ◽  
M. J. Hynes
Keyword(s):  
Carbon Source ◽  
Nitrogen Source ◽  
Sole Carbon Source ◽  
Nitrogen Sources ◽  
Limiting Factor ◽  
Sole Nitrogen Source ◽  
Wild Type ◽  
Exogenous Substrate ◽  
Growth Properties ◽  
Type Strains

SUMMARYWild-type strains ofAspergillus nidulansgrow poorly onL-histidine as a sole nitrogen source. The synthesis of the enzyme histidase (EC. 4.3.1.3) appears to be a limiting factor in the growth of the wild type, as strains carrying the mutantareA102 allele have elevated histidase levels and grow strongly on histidine as a sole nitrogen source.L-Histidine is an extremely weak sole carbon source for all strains.Ammonium repression has an important role in the regulation of histidase synthesis and the relief of ammonium repression is dependent on the availability of a good carbon source. The level of histidase synthesis does not respond to the addition of exogenous substrate.Mutants carrying lesions in thesarA orsarB loci (suppressor ofareA102) have been isolated. The growth properties of these mutants on histidine as a sole nitrogen source correlate with the levels of histidase synthesized. Mutation at thesarA andsarB loci also reduces the utilization of a number of other nitrogen sources. The data suggest that these two genes may code for regulatory products involved in nitrogen catabolism. No histidase structural gene mutants were identified and possible explanations of this are discussed.

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