scholarly journals 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.

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.

scholarly journals Optimizing Docosahexaenoic Acid (DHA) Production by Schizochytrium sp. Grown on Waste Glycerol

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1685
Author(s):  
Natalia Kujawska ◽  
Szymon Talbierz ◽  
Marcin Dębowski ◽  
Joanna Kazimierowicz ◽  
Marcin Zieliński
Keyword(s):  
Docosahexaenoic Acid ◽  
Source Parameters ◽  
Waste Glycerol ◽  
Dry Cell Weight ◽  
Glycerin Concentration ◽  
Burman Design ◽  
High Production ◽  
Dha Production ◽  
Parameter Values ◽  
Plackett Burman Design

The aim of this study was to optimize biomass and docosahexaenoic acid (DHA) production by Schizochytrium sp. grown on waste glycerol as an organic carbon source. Parameters having a significant effect on biomass and DHA yields were screened using the fractional Plackett–Burman design and the response surface methodology (RSM). Schizochytrium sp. growth was most significantly influenced by crude glycerin concentration in the growth medium (150 g/dm3), process temperature (27 °C), oxygen in the bioreactor (49.99% v/v), and the concentration of peptone as a source of nitrogen (9.99 g/dm3). The process parameter values identified as optimal for producing high DHA concentrations in the biomass were as follows: glycerin concentration 149.99 g/dm3, temperature 26 °C, oxygen concentration 30% (v/v), and peptone concentration 2.21 g/dm3. The dry cell weight (DCW) obtained under actual laboratory conditions was 66.69 ± 0.66 g/dm3, i.e., 1.27% lower than the predicted value. The DHA concentration obtained in the actual culture was at 17.25 ± 0.33 g/dm3, which was 3.03% lower than the predicted value. The results obtained suggest that a two-step culture system should be employed, with the first phase focused on high production of Schizochytrium sp. biomass, and the second focused on increasing DHA concentration in the cells.

scholarly journals Poly-β-Hydroxybutyrate Production by the Cyanobacterium Scytonema geitleri Bharadwaja under Varying Environmental Conditions

Biomolecules ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 198 ◽  
Author(s):  
Manoj K. Singh ◽  
Pradeep K. Rai ◽  
Anuradha Rai ◽  
Surendra Singh ◽  
Jay Shankar Singh
Keyword(s):  
Carbon Source ◽  
Growth Phase ◽  
Environmental Conditions ◽  
Carbon Sources ◽  
Stationary Growth Phase ◽  
Stationary Growth ◽  
Cell Weight ◽  
Dry Cell Weight ◽  
Phb Production ◽  
Dry Cell

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.

scholarly journals Cultivation Method Effect on Schizochytrium sp. Biomass Growth and Docosahexaenoic Acid (DHA) Production with the Use of Waste Glycerol as a Source of Organic Carbon

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2952
Author(s):  
Natalia Kujawska ◽  
Szymon Talbierz ◽  
Marcin Dębowski ◽  
Joanna Kazimierowicz ◽  
Marcin Zieliński
Keyword(s):  
Fatty Acids ◽  
Docosahexaenoic Acid ◽  
Batch Culture ◽  
Acid Production ◽  
Carbon Sources ◽  
Fed Batch ◽  
Waste Glycerol ◽  
Total Fatty Acids ◽  
Fed Batch Culture ◽  
Dha Production

Inexpensive carbon sources offering an alternative to glucose are searched for to reduce costs of docosahexaenoic acid production by microalgae. The use of waste glycerol seems substantiated and prospective in this case. The objective of this study was to determine the production yield of heterotrophic microalgae Schizochytrium sp. biomass and the efficiency of docosahexaenoic acid production in various types of cultures with waste glycerol. Cultivation conditions were optimized using the Plackett–Burman method and Response Surface Methodology. The highest technological performance was obtained in the fed-batch culture, where the concentration of Schizochytrium sp. biomass reached 103.44 ± 1.50 g/dm3, the lipid concentration in Schizochytrium sp. biomass was at 48.85 ± 0.81 g/dm3, and the docosahexaenoic acid concentration at 21.98 ± 0.36 g/dm3. The highest docosahexaenoic acid content, accounting for 61.76 ± 3.77% of total fatty acids, was determined in lipid bodies of the Schizochytrium sp. biomass produced in the batch culture, whereas the lowest one, accounting for 44.99 ± 2.12% of total fatty acids, in those of the biomass grown in the fed-batch culture.

scholarly journals Overproduction of docosahexaenoic acid in Schizochytrium sp. through genetic engineering of oxidative stress defense pathways

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiao Han ◽  
Zhaohui Li ◽  
Ying Wen ◽  
Zhi Chen
Keyword(s):  
Oxidative Stress ◽  
Cell Growth ◽  
Docosahexaenoic Acid ◽  
Peroxidation Of Lipids ◽  
Ros Scavenging ◽  
Lipid Yield ◽  
Oxidative Stress Defense ◽  
Dry Cell Weight ◽  
Dha Production ◽  
Stress Defense

Abstract Background Oxidation and peroxidation of lipids in microorganisms result in increased levels of intracellular reactive oxygen species (ROS) and reactive aldehydes, and consequent reduction of cell growth and lipid accumulation. Results To reduce oxygen-mediated cell damage and increase lipid and docosahexaenoic acid (DHA) production in Schizochytrium sp., we strengthened the oxidative stress defense pathways. Overexpression of the enzymes thioredoxin reductase (TRXR), aldehyde dehydrogenase (ALDH), glutathione peroxidase (GPO), and glucose-6-phosphate dehydrogenase (ZWF) strongly promoted cell growth, lipid yield, and DHA production. Coexpression of ZWF, ALDH, GPO, and TRXR enhanced ROS-scavenging ability. Highest values of dry cell weight, lipid yield, and DHA production (50.5 g/L, 33.1 g/L, and 13.3 g/L, respectively) were attained in engineered strain OaldH-gpo-trxR by shake flask fed-batch culture; these were increases of 18.5%, 80.9%, and 114.5% relative to WT values. Conclusions Our findings demonstrate that engineering of oxidative stress defense pathways is an effective strategy for promoting cell robustness, lipid yield, and DHA production in Schizochytrium.

scholarly journals Complete biosynthesis of a sulfated chondroitin in Escherichia coli

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.

scholarly journals Optimisation of Recombinant Myrosinase Production in Pichia pastoris

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.

Mise en évidence d'une activité uréasique chez Streptococcus thermophilus

1988 ◽  
Vol 34 (6) ◽  
pp. 818-822 ◽  
Author(s):  
V. Juillard ◽  
M. J. Desmazeaud ◽  
H. E. Spinnler
Keyword(s):  
Amino Acids ◽  
Urease Activity ◽  
Culture Medium ◽  
Colorimetric Method ◽  
Streptococcus Thermophilus ◽  
Stationary Growth Phase ◽  
Optimal Temperature ◽  
Ammonium Ions ◽  
Stationary Growth ◽  
Optimal Ph

In Streptococcus thermophilus CNRZ 404, the presence of urease activity was demonstrated by means of a specific colorimetric method for ammonium ions. The main physicochemical properties of the enzyme were determined. The Km with urea as substrate was 1.19 mM and the optimal pH was approximately 7.5. Because both thermolability and enzyme activity increased as the temperature was increased to 70 °C, the optimal temperature could not be determined with precision. Urease activity was maximal at the beginning of the stationary growth phase; it was stimulated by the presence of urea and of certain amino acids such as arginine and glutamic acid in the culture medium. This activity has been detected in several other strains of Streptococcus thermophilus. [Translated by the journal]

scholarly journals Immobilization of β-Galactosidases on the Lactobacillus Cell Surface Using the Peptidoglycan-Binding Motif LysM

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 443 ◽  
Author(s):  
Mai-Lan Pham ◽  
Anh-Minh Tran ◽  
Suwapat Kittibunchakul ◽  
Tien-Thanh Nguyen ◽  
Geir Mathiesen ◽  
...  
Keyword(s):  
Cell Surface ◽  
Surface Display ◽  
Active Surface ◽  
Lactobacillus Delbrueckii ◽  
Binding Motif ◽  
Cell Weight ◽  
Lysm Domain ◽  
Dry Cell Weight ◽  
Dry Cell ◽  
Lactobacillus Spp

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.

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