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 ◽  
...  

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.

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Chengqiang Wang ◽  
Yu Shen ◽  
Yanyan Zhang ◽  
Fan Suo ◽  
Jin Hou ◽  
...  

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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Adeola Awofiranye ◽  
Payel Datta ◽  
Ke Xia ◽  
...  

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.


2021 ◽  
Vol 22 (7) ◽  
pp. 3677
Author(s):  
Zuzana Rosenbergová ◽  
Kristína Kántorová ◽  
Martin Šimkovič ◽  
Albert Breier ◽  
Martin Rebroš

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.


2021 ◽  
Vol 11 (20) ◽  
pp. 9573
Author(s):  
Natalia Kujawska ◽  
Szymon Talbierz ◽  
Marcin Dębowski ◽  
Joanna Kazimierowicz ◽  
Marcin Zieliński

The study aimed to determine the effectiveness of docosahexaenoic acid (DHA) production by Schizochytrium sp. biomass fed with waste glycerol depending on the concentration of extracellular polymeric substances (EPS) in the culture medium and medium aeration effectiveness. The microalgae from the genus Schizochytrium sp. were proved to be capable of producing EPS composed of glucose, galactose, mannose, fucose, and xylose. The highest EPS concentration, reaching 8.73 ± 0.09 g/dm3, was determined at the stationary growth phase. A high EPS concentration caused culture medium viscosity to increase, contributing to diminished oxygen availability for cells, lower culture effectiveness, and reduced waste glycerol conversion to DHA. The Schizochytrium sp. culture variant found optimal in terms of the obtained technological effects and operating costs was performed at the volumetric oxygen mass transfer coefficient of kLa = 600 1/h, which enabled obtaining dry cell weight (DCW) of 147.89 ± 4.77 g/dm3, lipid concentration of 69.44 ± 0.76 g/dm3, and DHA concentration in the biomass reaching 29.44 ± 0.36 g/dm3. The effectiveness of waste glycerol consumption in this variant reached 3.76 ± 0.31 g/dm3·h and 3.16 ± 0.22 g/gDCW.


Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 443 ◽  
Author(s):  
Mai-Lan Pham ◽  
Anh-Minh Tran ◽  
Suwapat Kittibunchakul ◽  
Tien-Thanh Nguyen ◽  
Geir Mathiesen ◽  
...  

Lysin motif (LysM) domains are found in many bacterial peptidoglycan hydrolases. They can bind non-covalently to peptidoglycan and have been employed to display heterologous proteins on the bacterial cell surface. In this study, we aimed to use a single LysM domain derived from a putative extracellular transglycosylase Lp_3014 of Lactobacillus plantarum WCFS1 to display two different lactobacillal β-galactosidases, the heterodimeric LacLM-type from Lactobacillus reuteri and the homodimeric LacZ-type from Lactobacillus delbrueckii subsp. bulgaricus, on the cell surface of different Lactobacillus spp. The β-galactosidases were fused with the LysM domain and the fusion proteins, LysM-LacLMLreu and LysM-LacZLbul, were successfully expressed in Escherichia coli and subsequently displayed on the cell surface of L. plantarum WCFS1. β-Galactosidase activities obtained for L. plantarum displaying cells were 179 and 1153 U per g dry cell weight, or the amounts of active surface-anchored β-galactosidase were 0.99 and 4.61 mg per g dry cell weight for LysM-LacLMLreu and LysM-LacZLbul, respectively. LysM-LacZLbul was also displayed on the cell surface of other Lactobacillus spp. including L. delbrueckii subsp. bulgaricus, L. casei and L. helveticus, however L. plantarum is shown to be the best among Lactobacillus spp. tested for surface display of fusion LysM-LacZLbul, both with respect to the immobilization yield as well as the amount of active surface-anchored enzyme. The immobilized fusion LysM-β-galactosidases are catalytically efficient and can be reused for several repeated rounds of lactose conversion. This approach, with the β-galactosidases being displayed on the cell surface of non-genetically modified food-grade organisms, shows potential for applications of these immobilized enzymes in the synthesis of prebiotic galacto-oligosaccharides.


2011 ◽  
Vol 343-344 ◽  
pp. 1023-1028 ◽  
Author(s):  
Xiong Chen ◽  
Zhi Wang ◽  
Yong Ze Wang ◽  
Fa Tang Jiang ◽  
Dong Sheng Li ◽  
...  

Yeast extract (YE) is a sole organic nitrogen source in a commonly medium 3G for Streptomyces albulus to produce poly-ε-lysine (ε-PL). In this study, five YEs from five commercial suppliers were used to evaluate their effects on the growth of Streptomyces albulus 213 and ε-PL production. YE from bakers’ yeast with the highest total nitrogen content (TN), α-amino nitrogen content (AN) or the ratio of AN/TN produced the highest yield of ε-PL, while YE from brewers’ yeast with the highest RNA content got the most dry cell weight (DCW). However, there was little correlation between TN, AN or AN/TN in YE and the yield of ε-PL. There was also weak correlation between RNA in YE and DCW. When 60% baker YE was mixed with 40% brewer YE, the yield of ε-PL reached 1.89 g/l and increased by 16% and 37% than those of baker YE and brewer YE, respectively. Furthermore, five kinds of vitamins and nine kinds of amino acids were screened to supplement baker YE. When 6 mg/l biotin, 5mg/l pantothenic acid, 0.7 g/l L-glutamine and 0.5 g/l L-arginine were mixed with baker YE in M3G, ε-PL reached maximum production respondent to 3.05 g/l that was 61.4% higher than control.


Biomolecules ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 198 ◽  
Author(s):  
Manoj K. Singh ◽  
Pradeep K. Rai ◽  
Anuradha Rai ◽  
Surendra Singh ◽  
Jay Shankar Singh

The production of poly-β-hydroxybutyrate (PHB) under varying environmental conditions (pH, temperature and carbon sources) was examined in the cyanobacterium Scytonema geitleri Bharadwaja isolated from the roof-top of a building. The S. geitleri produced PHB and the production of PHB was linear with the growth of cyanobacterium. The maximum PHB production (7.12% of dry cell weight) was recorded when the cells of S. geitleri were at their stationary growth phase. The production of PHB was optimum at pH 8.5 and 30 °C, and acetate (30 mM) was the preferred carbon source.


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