Nitrite oxidation by phototrophic bacteria of Chlorobium, Thiocapsa and Lamprocystis genera under the influence of inorganic pollutants

Pollutants of inorganic nature (acids, alkalis, mineral salts of different composition, metals) change the course of biological processes of environmental purification, but their influence on the physiological properties of phototrophic sulfur bacteria has not been studied enough. The usage of nitrite ions as an electron donor of anoxygenic photosynthesis by cells of phototrophic green and purple sulfur bacteria Chlorobium limicola IMV K-8, Thiocapsa sp. Ya-2003 and Lamprocystis sp. Ya-2003, isolated from Yavorivske Lake, under the influence of the most widespread inorganic pollutants – hydro- and dihydrophosphates, sulfates, chlorides and chlorates, has been studied. It is shown that KH2PO4, K2HPO4, Na2SO4, NaCl and KClO3, present in the van Niel medium with 4.2 mM NaNO2 at concentrations that are 0.5, 1.0, 2.0, 3.0, 4.0 times different from the maximum permissible concentrations (MPC), influenced the biomass accumulation and nitrite ions oxidation by phototrophic green and purple sulfur bacteria. In media with hydro- and dihydrophosphate ions at concentrations 4.0 times higher than the MPC, inhibition of bacterial growth was up to 1.7 times lower than in the control. The biomass accumulation by bacteria in media with chloride and chlorate ions at concentrations 3.0–4.0 times higher than MPC was 2.0–2.8 times lower compared to the control. In the medium with Na2SO4 at concentrations 2.0–4.0 times higher than MPC, the biomass was 2.0–4.0 times lower than in the control. Nitrites’ oxidation by all strains in the media with the studied pollutants was slowed down. The residual content of nitrite ions in media with hydro- and dihydrophosphate, chloride and chlorate ions at their concentrations 4.0 times higher than MPC, exceeded the NO2– content in the control variants up to 1.7 times. If in the medium without pollutants the cells of C. limicola IMV K-8, Thiocapsa sp. Ya-2003 and Lamprocystis sp. Ya-2003 strains oxidized 72.7%, 72.2% and 71.4%, respectively, of nitrite ions present in the medium, then in the medium with sulfate ions at concentration 4.0 times higher than the MPC, bacteria oxidized nitrite ions only at 39.6%, 34.4% and 27.0%, respectively. Oxidation of a lower quantity of nitrites by phototrophic bacteria in the media with inorganic pollutants led to the production by them of a lower quantity of nitrates. The content of NO3– in the media with hydro-, dihydrophosphate and chlorate ions at all concentrations was up to 1.9 times lower than in the control. In media with sulfate ions at concentrations 2.0–4.0 times higher than MPC and chloride at concentration 4.0 times higher than MPC, the content of nitrate ions was 2.1–4.3 and 2.0 times, respectively, lower than in the control variants. Inorganic pollutants stimulated the synthesis of intracellular carbohydrates in C. limicola IMV K-8. If the content of intracellular glucose in cells grown in the medium without pollutants was 10.3 mg/g dry cell weight, then in cells grown in media with K2HPO4, KH2PO4, Na2SO4, NaCl and KClO3 at concentrations 4.0 times higher than MPC, its content increased by 12.2%, 10.7%, 51.6%, 17.1% and 35.9%, respectively. The glycogen content in the cells grown in the medium without pollutants was 45.1 mg/g dry cell weight. Hydro- and dihydrophosphate, chloride and chlorate ions at concentrations 4.0 times higher than MPC stimulated glycogen synthesis in cells by 47.5%, 57.6%, 67.4% and 74.6%, respectively. The glycogen content in cells grown in the medium with Na2SO4 at concentrations 3.0 and 4.0 times higher than MPC increased by 102.9% and 107.5%, respectively. Therefore, it is established that pollutants of inorganic nature affect the physiological properties of photosynthetic sulfur bacteria and thus change the course of biological processes of environment purification, in particular, from nitrite ions.

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Functional Analysis of Two l-Arabinose Transporters from Filamentous Fungi Reveals Promising Characteristics for Improved Pentose Utilization in Saccharomyces cerevisiae

Applied and Environmental Microbiology ◽

10.1128/aem.00165-15 ◽

2015 ◽

Vol 81 (12) ◽

pp. 4062-4070 ◽

Cited By ~ 22

Author(s):

Jingen Li ◽

Jing Xu ◽

Pengli Cai ◽

Bang Wang ◽

Yanhe Ma ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Sugar Transport ◽

Biomass Accumulation ◽

Kinetic Properties ◽

High Identity ◽

Content Type ◽

Substrate Specificities ◽

Dry Cell Weight ◽

Dry Cell

ABSTRACTLimited uptake is one of the bottlenecks forl-arabinose fermentation from lignocellulosic hydrolysates in engineeredSaccharomyces cerevisiae. This study characterized two novell-arabinose transporters, LAT-1 fromNeurospora crassaand MtLAT-1 fromMyceliophthora thermophila. Although the two proteins share high identity (about 83%), they display different substrate specificities. Sugar transport assays using theS. cerevisiaestrain EBY.VW4000 indicated that LAT-1 accepts a broad substrate spectrum. In contrast, MtLAT-1 appeared much more specific forl-arabinose. Determination of the kinetic properties of both transporters revealed that theKmvalues of LAT-1 and MtLAT-1 forl-arabinose were 58.12 ± 4.06 mM and 29.39 ± 3.60 mM, respectively, with correspondingVmaxvalues of 116.7 ± 3.0 mmol/h/g dry cell weight (DCW) and 10.29 ± 0.35 mmol/h/g DCW, respectively. In addition, both transporters were found to use a proton-coupled symport mechanism and showed only partial inhibition byd-glucose duringl-arabinose uptake. Moreover, LAT-1 and MtLAT-1 were expressed in theS. cerevisiaestrain BSW2AP containing anl-arabinose metabolic pathway. Both recombinant strains exhibited much fasterl-arabinose utilization, greater biomass accumulation, and higher ethanol production than the control strain. In conclusion, because of higher maximum velocities and reduced inhibition byd-glucose, the genes for the two characterized transporters are promising targets for improvedl-arabinose utilization and fermentation inS. cerevisiae.

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Complete biosynthesis of a sulfated chondroitin in Escherichia coli

Nature Communications ◽

10.1038/s41467-021-21692-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Abinaya Badri ◽

Asher Williams ◽

Adeola Awofiranye ◽

Payel Datta ◽

Ke Xia ◽

...

Keyword(s):

Chondroitin Sulfate ◽

Scale Up ◽

Production Methods ◽

E Coli ◽

Microbial Cell Factories ◽

Cell Factories ◽

Microbial Product ◽

Dry Cell Weight ◽

One Step ◽

Dry Cell

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.

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Optimisation of Recombinant Myrosinase Production in Pichia pastoris

International Journal of Molecular Sciences ◽

10.3390/ijms22073677 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3677

Author(s):

Zuzana Rosenbergová ◽

Kristína Kántorová ◽

Martin Šimkovič ◽

Albert Breier ◽

Martin Rebroš

Keyword(s):

Pichia Pastoris ◽

Plant Defence ◽

Plant Secondary Metabolites ◽

Specific Productivity ◽

Fermentation Conditions ◽

Threefold Increase ◽

Dry Cell Weight ◽

First Time ◽

Hydrolysis Of ◽

Dry Cell

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.

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Photophosphorylation by isolated chromatophores of the purple sulfur bacteria

Archives of Biochemistry and Biophysics ◽

10.1016/0003-9861(58)90131-0 ◽

1958 ◽

Vol 76 (1) ◽

pp. 168-179 ◽

Cited By ~ 31

Author(s):

I.C. Anderson ◽

R.C. Fuller

Keyword(s):

Purple Sulfur Bacteria ◽

Sulfur Bacteria

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Optimization of dry cell weight production of Scenedesmus sp. cultivation in biogas effluent using response surface methodology

10.13031/aim.20131620799 ◽

2013 ◽

Author(s):

G. Li ◽

F. Ji ◽

Y. Liu ◽

Y. Zhou ◽

L. Tian ◽

...

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Cell Weight ◽

Dry Cell Weight ◽

Dry Cell

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Kinetics and physiological characteristics of autotrophic dentrification by denitrifying sulfur bacteria

Water Science & Technology ◽

10.2166/wst.2000.0359 ◽

2000 ◽

Vol 42 (3-4) ◽

pp. 59-68 ◽

Cited By ~ 52

Author(s):

S.-E. Oh ◽

K.-S. Kim ◽

H.-C. Choi ◽

J. Cho ◽

I.S. Kim

Keyword(s):

Gas Production ◽

Parameter Estimates ◽

Production Volume ◽

Autotrophic Denitrification ◽

Nonlinear Regression Analysis ◽

Monod Equation ◽

Sulfur Bacteria ◽

The Media ◽

Parameter Values ◽

Mixotrophic Conditions

To study the kinetics and physiology of autotrophic denitrifying sulfur bacteria, a steady-state anaerobic master culture reactor (MCR) was operated for over six months under a semi-continuous mode and nitrate limiting conditions using nutrient/mineral/buffer (NMB) medium containing thiosulfate and nitrate. Characteristics of the autotropic denitrifier were investigated through the cumulative gas production volume and rate, measured using an anaerobic respirometer, and through the nitrate, nitrite, and sulfate concentrations within the media. The bio-kinetic parameters were obtained based upon the Monod equation using mixed cultures in the MCR. Nonlinear regression analysis was employed using nitrate depletion and biomass production curves. Although this analysis did not yield exact biokinetic parameter estimates, the following ranges for the parameter values were obtained: μmax =0.12-0.2 hr-1; k=0.3-0.4 hr-1; Ks=3-10mg/L; YNO3=0.4-0.5mg Biomass/mg NO3--N. Inhibition of denitrification occurred when the concentrations of NO3--N, and SO42- reached about 660mg/L and 2,000mg/L, respectively. The autotrophic denitrifying sulfur bacteria were observed to be very sensitive to nitrite but relatively tolerant of nitrate, sulfate, and thiosulfate. Under mixotrophic conditions, denitrification by these bacteria occurred autotrophically; even with as high as 2 g COD, autotrophic denitrification was not significantly affected. The optimal pH and temperature for autotrophic denitrification was about 6.5–7.5 and 33–35 °C, respectively.

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The effect of low initial medium pH on in vitro white poplar growth

Glasnik Sumarskog fakulteta ◽

10.2298/gsf1308067k ◽

2013 ◽

pp. 67-80

Author(s):

Branislav Kovacevic ◽

Dragana Miladinovic ◽

Marina Katanic ◽

Zoran Tomovic ◽

Sasa Pekec

Keyword(s):

Biomass Accumulation ◽

Dry Mass ◽

White Poplar ◽

Medium Ph ◽

Shoot Height ◽

Initial Ph ◽

The Media ◽

Initial Medium ◽

Shoot Mass

The effect of low initial medium pH on shoot and root development of five white poplar (Populus alba L.) genotypes was tested. The shoot height, fresh mass of shoots per jar, dry mass of shoots per jar, number of roots, as well as the length of the longest root were measured and final pH of the media determined, after 35 days of culture in vitro. Three initial pH values of the medium were tested: 3.0, 4.0 and 5.5 as control. Agar solidification at pH 3.0 was not achieved after sterilization in autoclave, but it was successful after sterilizing in a microwave oven. The obtained results indicate that the tested genotypes are able to significantly influence the changes of media pH during culture. The effect of differences among the examined media was significant for biomass accumulation and final media pH. Generally, significantly higher values of fresh and dry shoot mass, shoot height and the longest root length were recorded on a medium with initial pH 3.0 then on a standard medium with pH 5.5.The implications of the obtained results for the improvement of in vitro propagation of white poplars are discussed.

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Effect of the Concentration of Extracellular Polymeric Substances (EPS) and Aeration Intensity on Waste Glycerol Valorization by Docosahexaenoic Acid (DHA) Produced in Heterotrophic Culture of Schizochytrium sp.

Applied Sciences ◽

10.3390/app11209573 ◽

2021 ◽

Vol 11 (20) ◽

pp. 9573

Author(s):

Natalia Kujawska ◽

Szymon Talbierz ◽

Marcin Dębowski ◽

Joanna Kazimierowicz ◽

Marcin Zieliński

Keyword(s):

Docosahexaenoic Acid ◽

Culture Medium ◽

Extracellular Polymeric Substances ◽

Stationary Growth Phase ◽

Operating Costs ◽

Glycerol Conversion ◽

Waste Glycerol ◽

Dry Cell Weight ◽

Dha Production ◽

Dry Cell

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.

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