scholarly journals Enhanced Production of Ectoine From Methane Using Metabolically Engineered Methylomicrobium Alcaliphilum 20Z

Author(s):  
Sukhyeong Cho ◽  
Yun Seo Lee ◽  
Hanyu Chai ◽  
Sang eun Lim ◽  
Jeong Geol Na ◽  
...  

Abstract Background: Ectoine (1,3,4,5-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) is an attractive compatible solute because of its wide industrial applications. Previous studies on the microbial production of ectoine have focused on sugar fermentation. Alternatively, methane can be used as an inexpensive and abundant resource for ectoine production by using the halophilic methanotroph, Methylomicrobium alcaliphilum 20Z. However, there are some limitations, including the low production of ectoine from methane and the limited tools for the genetic manipulation of methanotrophs to facilitate their use as industrial strains.Results: We constructed a genetically tractable M. alcaliphilum 20Z with a high conjugation efficiency and stability of the episomal plasmid by the removal of its native plasmid. To improve the ectoine production in M. alcaliphilum 20Z from methane, the ectD (encoding ectoine hydroxylase) and ectR (transcription repressor of the ectABC-ask operon) were deleted to reduce the formation of by-products (such as hydroxyectoine) and induce ectoine production. When the double mutant was batch cultured with methane, ectoine production was enhanced 1.6-fold compared to that obtained with M. alcaliphilum 20ZDP (45.58 mg/L vs. 27.26 mg/L) without growth inhibition. Notably, the use of an optimized medium for ectoine production, containing 6% NaCl and 0.05 µM tungsten, gave ectoine yields of up to 142.32 mg/L without hydroxyectoine production. This result demonstrates the highest ectoine production from methane to date.Conclusions: Ectoine production was significantly enhanced by the disruption of the ectD and ectR genes in M. alcaliphilum 20Z under optimized conditions favoring ectoine accumulation. We demonstrated effective genetic engineering in a methanotrophic bacterium, with enhanced production of ectoine from methane as the sole carbon source. This study suggests a potentially transformational path to commercial sugar-based ectoine production.

2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Sukhyeong Cho ◽  
Yun Seo Lee ◽  
Hanyu Chai ◽  
Sang Eun Lim ◽  
Jeong Geol Na ◽  
...  

Abstract Background Ectoine (1,3,4,5-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) is an attractive compatible solute because of its wide industrial applications. Previous studies on the microbial production of ectoine have focused on sugar fermentation. Alternatively, methane can be used as an inexpensive and abundant resource for ectoine production by using the halophilic methanotroph, Methylomicrobium alcaliphilum 20Z. However, there are some limitations, including the low production of ectoine from methane and the limited tools for the genetic manipulation of methanotrophs to facilitate their use as industrial strains. Results We constructed M. alcaliphilum 20ZDP with a high conjugation efficiency and stability of the episomal plasmid by the removal of its native plasmid. To improve the ectoine production in M. alcaliphilum 20Z from methane, the ectD (encoding ectoine hydroxylase) and ectR (transcription repressor of the ectABC-ask operon) were deleted to reduce the formation of by-products (such as hydroxyectoine) and induce ectoine production. When the double mutant was batch cultured with methane, ectoine production was enhanced 1.6-fold compared to that obtained with M. alcaliphilum 20ZDP (45.58 mg/L vs. 27.26 mg/L) without growth inhibition. Notably, a maximum titer of 142.32 mg/L was reached by the use of an optimized medium for ectoine production containing 6% NaCl and 0.05 μM of tungsten without hydroxyectoine production. This result demonstrates the highest ectoine production from methane to date. Conclusions Ectoine production was significantly enhanced by the disruption of the ectD and ectR genes in M. alcaliphilum 20Z under optimized conditions favoring ectoine accumulation. We demonstrated effective genetic engineering in a methanotrophic bacterium, with enhanced production of ectoine from methane as the sole carbon source. This study suggests a potentially transformational path to commercial sugar-based ectoine production. Graphical Abstract


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 214
Author(s):  
YuJin Noh ◽  
Hwanhui Lee ◽  
Myeongsun Kim ◽  
Seong-Joo Hong ◽  
Hookeun Lee ◽  
...  

Synechocystis strains are cyanobacteria that can produce useful biomaterials for biofuel and pharmaceutical resources. In this study, the effects of exogenous glucose (5-mM) on cell growth, photosynthetic pigments, metabolites, and lipids in Synechocystis sp. PCC 7338 (referred to as Synechocystis 7338) were investigated. Exogenous glucose increased cell growth on days 9 and 18. The highest production (mg/L) of chlorophyll a (34.66), phycocyanin (84.94), allophycocyanin (34.28), and phycoerythrin (6.90) was observed on day 18 in Synechocystis 7338 culture under 5-mM glucose. Alterations in metabolic and lipidomic profiles under 5-mM glucose were investigated using gas chromatography-mass spectrometry (MS) and nanoelectrospray ionization-MS. The highest production (relative intensity/L) of aspartic acid, glutamic acid, glycerol-3-phosphate, linolenic acid, monogalactosyldiacylglycerol (MGDG) 16:0/18:1, MGDG 16:0/20:2, MGDG 18:1/18:2, neophytadiene, oleic acid, phosphatidylglycerol (PG) 16:0/16:0, and PG 16:0/17:2 was achieved on day 9. The highest production of pyroglutamic acid and sucrose was observed on day 18. We suggest that the addition of exogenous glucose to Synechocystis 7338 culture could be an efficient strategy for improving growth of cells and production of photosynthetic pigments, metabolites, and intact lipid species for industrial applications.


Author(s):  
Sara Díaz ◽  
Antonio N. Benítez ◽  
Sara Ramírez-Bolaños ◽  
Lidia Robaina ◽  
Zaida Ortega

AbstractThe aim of this work is the optimization of phenolic compound extraction from three by-products of banana crops (rachis, discarded banana, and banana’s pseudostem pulp), as a way to valorize them through a green extraction process. The influence of the temperature and aqueous ethanol concentration (Et-OH) on extract properties (total phenol content (TPC) and antioxidant activity) was firstly analyzed. 78 ℃ and ethanol concentrations close to 50% yielded the best results for the three materials. The equations obtained by the response surface methodology gave a satisfactory description of the experimental data, allowing optimizing the extraction conditions. Under optimized conditions, time influence was then assessed, although this parameter seemed not influence results. Among the three by-products, rachis extract (60% Et-OH, 78 ℃, and 30 min) presented the highest TPC (796 mg gallic acid/100 g of dried material) and antioxidant activity (6.51 mg Trolox equivalents/g of dried material), followed by discarded banana, and pseudostem pulp. Under the optimal conditions, experiments were performed at a larger scale, allowing to determine the extraction yields (EY) and to characterize the extracts. The highest EY was obtained for the rachis (26%), but the extract with the highest activity was obtained for discarded banana (50% Et-OH, 78 ℃, and 60 min), which presented a TPC of 27.26 mg/g extract corresponding to 54.59 mg Trolox equivalents/g extract. This study contributes to the valorization of banana crops residues as a source of polyphenolic compounds with bioactive functions that can be extracted under economic extraction conditions. Graphical abstract


Author(s):  
Girisha Malhotra ◽  
Shilpa S. Chapadgaonkar

Abstract Background Xylanase is one of the widely applied industrial enzymes with diverse applications. Thermostability and alkali tolerance are the two most desirable qualities for industrial applications of xylanase. In this paper, we reveal the statistical Taguchi optimization strategy for maximization of xylanase production. The important process parameters pH, temperature, concentration of wheat bran, and concentration of yeast extract were optimized using the Taguchi L8 orthogonal array where the 4 factors were considered at 2 levels (high and low). Results The optimized conditions given by model were obtained as follows: (i) pH 6, (ii) culture temperature 35 °C, (iii) concentration of xylan 2% w/v, (iv) concentration of wheat bran 2.5% w/v. The production was scaled upto 2.5 L bioreactor using optimized process parameters. A high xylanase titer of 400 U/ml could be achieved in less than 60 h of culture in the reactor. Conclusion Optimization was successful in achieving about threefold increase in the yield of xylanase. The optimized conditions resulted in a successful scale up and enhancement of xylanase production.


Author(s):  
Chang-Hun Shin ◽  
Hang Soo Cho ◽  
Hyung-Jin Won ◽  
Ho Jeong Kwon ◽  
Chan-Wha Kim ◽  
...  

Abstract Clavulanic acid (CA) produced by Streptomyces clavuligerus is a clinically important β-lactamase inhibitor. It is known that glycerol utilization can significantly improve cell growth and CA production of S. clavuligerus. We found that the industrial CA-producing S. clavuligerus strain OR generated by random mutagenesis consumes less glycerol than the wild-type strain; we then developed a mutant strain in which the glycerol utilization operon is overexpressed, as compared to the parent OR strain, through iterative random mutagenesis and reporter-guided selection. The CA production of the resulting S. clavuligerus ORUN strain was increased by approximately 31.3 per cent (5.21 ± 0.26 g/L) in a flask culture and 17.4 per cent (6.11 ± 0.36 g/L) in a fermenter culture, as compared to that of the starting OR strain. These results confirmed the important role of glycerol utilization in CA production and demonstrated that reporter-guided mutant selection is an efficient method for further improvement of randomly mutagenized industrial strains.


Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1802 ◽  
Author(s):  
Eric Weingart ◽  
Sarah Tschirner ◽  
Linda Teevs ◽  
Ulf Prüße

5-Hydroxymethylfurfural (HMF) is a very promising component for bio-based plastics. Efficient synthesis of HMF from biomass is still challenging because of fast degradation of HMF to by-products under formation conditions. Therefore, different studies, conducted mainly in monophasic and biphasic batch systems with and without water addition have been published and are still under investigation. However, to produce HMF at a large scale, a continuous process is preferable. Until now, only a few studies have been published in this context. In this work, it is shown that fluorous alcohol hexafluoroisopropanol (HFIP) can act as superior reaction solvent for HMF synthesis from fructose in a fixed bed reactor. Very high yields of 76% HMF can be achieved in this system under optimized conditions, whilst the catalyst is very stable over several days. Such high yields are only described elsewhere with high boiling reaction solvents like dimethylsulfoxide (DMSO), whereas HFIP with a boiling point of 58 °C is very easy to separate from HMF.


2020 ◽  
Vol 138 ◽  
pp. 109786
Author(s):  
María de la Luz Cádiz-Gurrea ◽  
María del Carmen Villegas-Aguilar ◽  
Francisco Javier Leyva-Jiménez ◽  
Sandra Pimentel-Moral ◽  
Álvaro Fernández-Ochoa ◽  
...  

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Xiaopei Zhang ◽  
Amal Al-Dossary ◽  
Myer Hussain ◽  
Peter Setlow ◽  
Jiahe Li

ABSTRACT The bacterium Bacillus subtilis has long been an important subject for basic studies. However, this organism has also had industrial applications due to its easy genetic manipulation, favorable culturing characteristics for large‐scale fermentation, superior capacity for protein secretion, and generally recognized as safe (GRAS) status. In addition, as the metabolically dormant form of B. subtilis, its spores have attracted great interest due to their extreme resistance to many environmental stresses, which makes spores a novel platform for a variety of applications. In this review, we summarize both conventional and emerging applications of B. subtilis spores, with a focus on how their unique characteristics have led to innovative applications in many areas of technology, including generation of stable and recyclable enzymes, synthetic biology, drug delivery, and material sciences. Ultimately, this review hopes to inspire the scientific community to leverage interdisciplinary approaches using spores to address global concerns about food shortages, environmental protection, and health care.


2009 ◽  
Vol 55 (9) ◽  
pp. 1070-1075 ◽  
Author(s):  
Chao Wang ◽  
XiaoLin Zhang ◽  
Zhi Chen ◽  
Ying Wen ◽  
Yuan Song

Spinosad is a new class of insecticides produced by Saccharopolyspora spinosa . The aim of this study was to construct a starch-utilizing strain that overproduced spinosad by intergeneric fusion between S. spinosa and Streptomyces avermitilis . Protoplast fusion is an important technique for engineering microbial strains, especially for microorganisms with few available molecular genetic tools. Protoplast fusion was conducted with UV-irradiated protoplasts of S. spinosa and S. avermitilis. Among 76 recombinants screened by ESI-MS and HPLC, a starch-utilizing strain F17, identified as S. spinosa, was obtained. The yield of spinosad in F17 was increased by 447.22%, compared with the yield of the wild-type strain. This is the first report of intergeneric protoplast fusion between S. spinosa and S. avermilitis, which shows great potential for industrial applications.


2009 ◽  
Vol 620-622 ◽  
pp. 105-108 ◽  
Author(s):  
Jong Bin Park ◽  
Sang Ho Lee ◽  
Chae Sung Gee ◽  
Hee Bum Pyun

Permeable pavement systems are suitable for a variety of residential, commercial and industrial applications because pavements such as water-retentive or water absorbing pavements are helpful to alleviate urban heat island phenomena by reducing pavement temperature, yet are confined to light duty and infrequent usage. And most of study for the permeable pavement is limited to asphalt pavement. Also, immense quantities of coal combustion by-products are produced every year, but only a small fraction of them are currently utilized, particularly bottom ash which is used in this study. So, in this study, it was intended to develop new permeable and water-absorbing pavement blocks to control pavement temperature and storm water runoff. And mechanical characteristics-compressive strength, porosity etc were carried out. Also, Experiments for thermal environment characteristics and pollution control were carried out in laboratory scale using modified pavement samples. Experimental results indicated that blocks with bottom ash were suited to standard and possessed excellent water-retentive and water purification ability.


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