Optimization Of Exopolysaccharide Production Research Articles

Selenium nanoparticles coated bacterial polysaccharide with potent antimicrobial and anti-lung cancer activities

Bacterial exopolysaccharides are homopolymeric or heteropolymeric polysaccharides with large molecular weights (10–1000 kDa). Exopolysaccharides' functional uses and potential have revolutionized the industrial and medicinal industries. Hence, the aim of the present study was to optimize the production of bacterial exopolysaccharide and apply it as a capping agent for selenium nanoparticles synthesis. Exopolysaccharide (EPS) producing Lactic acid bacteria (LAB) were isolated from dairy products then biochemically characterized and assessed for their potential antimicrobial effect. The most potent EPS producer was identified as Lactiplantibacillus plantarum strain A2 with accession number OP218384 using 16S rRNA sequencing. Overall, FTIR data of the extracted EPS revealed similarity with amylopectin spectrum. 1H NMR spectrum revealed an α-anomeric configuration of the glycosidic linkage pattern in the polysaccharides while the 13C NMR spectrum can also be separated into two main portions, the anomeric carbons region (δ 98–102 ppm) and the non-anomeric carbons region (δ 60–81 ppm). Antimicrobial activity of the produced EPS showed maximum activity against Staphylococcus aureus, MRSA, Enterobacter aerogenes, Klebsiella pneumoniae and Candida albicans respectively. The EPS capsule layer surrounding the bacterial cells was detected by TEM study. Optimization of EPS production was evaluated using Taguchi design, trial 23 reported the highest biomass yield and EPS output (6.5 and 27.12 g/L respectively) with 2.4 and 3.3 folds increase (from the basal media) respectively. The optimized exopolysaccharide was used as a capping and stabilizing agent for selenium nanoparticles (EPS-SeNPs) synthesis. Zeta potential, size and PDI of the synthesized nanoparticles were − 19.7 mV, 45–65 nm and 0.446 respectively with strong bactericidal and fungicidal effect against the tested pathogens. Complete microbial growth eradication was recorded after 6, 8 and 10 h against Staphylococcus aureus, Candida albicans and Klebsiella pneumoniae respectively. EPS-SeNPs showed a potent antioxidant effect reached 97.4% and anticancer effect against A549 lung cancer cell line (IC50 reached 5.324 µg/mL). EPS-SeNPs inhibited cancerous cell growth at S phase. Moreover, molecular studies revealed the anti-apoptotic activity of Bcl2's was inhibited and Bax was activated. The present investigation successfully synthesized selenium nanoparticles through bacterial EPS with significantly high antimicrobial and anticancer activity.

Biodiversity of exopolysaccharide-producing lactic acid bacteria from Iranian traditional Kishk and optimization of EPS yield by Enterococcus spp.

The production of polysaccharides derived from lactic acid bacteria (LAB) can be a valuable alternative to current polysaccharides. In this study, eight samples of Kishk (traditional dairy product) were collected in sterile conditions and directly cultured on MRS agar medium. Following purification and examination of microscopic, macroscopic characteristics and doing biochemical tests, 143 isolates were selected, and the production of exopolysaccharide (EPS) was investigated by the ruthenium red and disc methods. The EPS production of 79 isolates was confirmed. Total carbohydrate of EPS was determined by the phenol sulfuric acid method. Finally, Enterococcus durans K48, Enterococcus faecium R114, and Enterococcus faecium T52 strains were selected as the best EPS producers. The optimization of EPS production was then performed using Central Composite Design (CCD) and Response Surface Methodology (RSM) approaches. Optimization plots showed the highest EPS yield for E. durans K48, E. faecium R114, and E. faecium T52 occurred at 38.4, 37.4 and 36.7 °C and pH of 5.9, 5.6 and 5.8, respectively, cultured in a Sucrose-MRS medium. Under optimal conditions, the maximum predicted and actual production of EPSs for the examined isolates were 3.18, 3.21, 2.99 and 3.02, 3.15, 3.15, g L−1, respectively. As determined by Gel Permeation Chromatography, the EPSs molecular weights were in the range of 2.93 × 105 to 3.52 × 105 Da. Analysis of the component monosaccharides by HPLC showed that all three tested EPSs were heteropolysaccharides. After appropriate evaluation, the EPSs produced by native species of LAB isolated from Iranian Kishk could be of interest for industrial applications or as functional food ingredients.

Optimization of Exopolysaccharide Production by Soil Actinobacterium Streptomyces plicatus under Submerged Culture Conditions

Extracellular polymeric substances (EPSs) are ecologically friendly natural polymers produced by microorganisms in the surrounding media. Due to their varied chemical composition, exopolysaccharides are widely used in a variety of applications, including food, pharmaceuticals, and medical applications. In this work, thirty-six isolates of Actinobacteria isolated on starch nitrate medium from various locations of Egyptian soils were assessed for exopolysaccharide (EPS) synthesis. The isolated bacterium that produced the most EPS was Actinobacterium 10 (Streptomyces plicatus). Several culture and environmental parameters were investigated during the microbial growth in submerged culture to enhance bacterial growth and EPS production. The optimal crude EPS generation of 8.62 g/l was achieved after 7 days of incubation at 20 g/l starch concentration, at 35 °C and pH 7, under shaking at 120 rpm, with the most significant impacts. The findings of this study pave the door to produce large quantities of EPS from soil Actinobacteria for food and medicinal purposes.

Statistical optimization of exopolysaccharide production by Leuconostoc pseudomesenteroides JF17 from native Atlantic Forest juçara fruit

Leuconostoc pseudomesenteroides belongs to a group of lactic acid bacteria normally isolated from fruits, which has the capacity to produce exopolysaccharides (EPS). The present study aimed to optimize the EPS production of L. pseudomesenteroides JF17, isolated from juçara fruits (palm trees threatened with extinction in the Atlantic Forest), using the response surface methodology (RSM), besides evaluating the fermentation kinetics. The maximum production of EPS 53.77 mg/mL was obtained under ideal conditions of MRS broth supplemented with sucrose at 18%, w/v, fermentation temperature of 20 °C and initial pH of 7.30. The Luedeking-Piret model suggested that the production of EPS by the JF17 strain appeared to be associated with the cell growth of the microorganism, in addition to having high efficiency in the production of the polysaccharide from the substrate (Y p/s = 17.85 ± 0.74 mg EPS/log CFU ). Thus, the ideal optimization conditions and kinetic parameters can be useful for increasing the scale up of the fermentation process in the industrial production of EPS by L. pseudomesenteroides JF17.

Estimation and optimization of exopolysaccharide production from rice rhizospheric soil and its interaction with soil carbon pools

Exopolysaccharides (EPS) the high molecular weight microbial substances play an important role in enhancing soil aggregation as well as maintaining water holding capacity around the rhizosphere. Therefore, looking into the fact that rice is one of the important food crops for most of the people of the world and the ability of EPS to increase the uptake of nutrients by plants and protect from drought stress. The present investigation was carried out to study the EPS production by bacteria isolated from rice cultivar Naveen with four treatments viz., aerobic (−5 kPa), saturation (0 kPa), submerged (2 cm standing water) and control (without any water treatment) and their interaction with soil labile carbon pools. Soil (0–15 cm depth) was collected from panicle initiation stage of the crop growth to isolate EPS producing bacteria. Different parameters like microbial biomass carbon (MBC), readily mineralizable carbon (RMC) and organic carbon (OC) alongwith total and colloidal EPS were estimated. The total and colloidal EPS increased 26.0% and 9.0% among the treatments over saturation. The MBC, RMC and OC were found to increase 30.0%, 19.0% and 4.0% among the treatment over saturation. These findings indicated a positive correlation between carbon pools and total and colloidal EPS production. Similarly, in this study, 22 EPS producing bacteria were isolated from the rice rhizospheric region and amongst 4 isolates were found to tolerate maximum level of water stress (−0.73 MPa). Further, optimization studies indicated that all these 4 bacterial isolates produced EPS at 37 °C, 80 mM salt concentration and pH value 7.5 within 3 days of incubation. Further, among different carbon sources, sucrose followed by glucose was found to be best for production of EPS. Further work is going on to evaluate the efficacy of these potential EPS producing bacterial isolates under field conditions.

Optimization of exopolysaccharide production by response surface methodology from Enterococcus faecium isolated from the fermented foods of Western Himalaya

Optimization of exopolysaccharide production by response surface methodology from Enterococcus faecium isolated from the fermented foods of Western Himalaya

Optimization of exopolysaccharide production by probiotic yeast Lipomyces starkeyi VIT-MN03 using response surface methodology and its applications

In the present study, the cultural conditions for exopolysaccharide (EPS) production from probiotic yeast Lipomyces starkeyi VIT-MN03 were optimized using response surface methodology (RSM) to maximize the yield of EPS. Interactions among the various factors viz. sucrose concentration (1–3 g%), NaCl concentration (2–4 g%), pH (3–5), temperature (20–30 °C), and incubation period (20–40 days) during EPS production were studied using Box-Behnken design (BBD). The EPS was purified and characterized using various instrumental analyses. The properties like adhesion, antioxidant, biosurfactant, cholesterol removal, and binding ability to mutagens were also tested for EPS produced. Sixfold increase in EPS production (4.87 g L−1) by L. starkeyi VIT-MN03 was noted under optimized condition. EPS showed a high viscosity (1.8 Pa S−1) and good shear-thinning properties. Instrumental analysis showed that EPS was heteropolysaccharide composed of glucan, mannan, and rhamnan. Lipomyces starkeyi VIT-MN03 exhibited good self-adhesion (95%) and co-aggregation ability (93%). Adhesion efficiency for yeast inoculum containing 5.5 × 107 CFU mL−1 per 9.2 cm2 of Caco-2 cell (colorectal adenocarcinoma) was noted. The probiotic EPS displayed strong antioxidant ability to scavenge hydroxyl radical and DPPH by 58% and 71% respectively. In addition, biosurfactant activity (86%) and cholesterol removal (90%) ability of probiotic EPS was also tested. EPS bound cells of L. starkeyi VIT-MN03 showed good binding ability to mutagens. These results support the effectiveness of using RSM for maximum EPS production. To the best of our knowledge, this is the first report on optimization of EPS production by probiotic yeast.

Optimization of the Production of Extracellular Polysaccharide from the Shiitake Medicinal Mushroom Lentinus edodes (Agaricomycetes) Using Mutation and a Genetic Algorithm-Coupled Artificial Neural Network (GA-ANN).

Exopolysaccharide (EPS) production by a strain of Lentinus edodes was studied via the effects of treatments with ultraviolet (UV) irradiation and acridine orange. Furthermore, optimization of EPS production was studied using a genetic algorithm coupled with an artificial neural network in submerged fermentation. Exposure to irradiation and acridine orange resulted in improved EPS production (2.783 and 5.548 g/L, respectively) when compared with the wild strain (1.044 g/L), whereas optimization led to improved productivity (23.21 g/L). The EPS produced by various strains also demonstrated good DPPH scavenging activities of 45.40-88.90%, and also inhibited the growth of Escherichia coli and Klebsiella pneumoniae. This study shows that multistep optimization schemes involving physical-chemical mutation and media optimization can be an attractive strategy for improving the yield of bioactives from medicinal mushrooms. To the best of our knowledge, this report presents the first reference of a multistep approach to optimizing EPS production in L. edodes.

Statistical study on fermentation conditions in the optimization of exopolysaccharide production by Lactobacillus rhamnosus 519 in skimmed milk base media

To optimize the exopolysaccharide (EPS) production by Lactobacillus rhamnosus 519, fermentation experiments using response surface methodology (RSM) were carried out. Studying the effect of different carbon and nitrogen sources on EPS production in skimmed milk (SM) resulted in selecting of sucrose and yeast nitrogen base (YNB) for the optimization experiments. The effect of pH, incubation time, YNB concentration and sucrose concentration on EPS production in SM was studied. The results showed that pH, incubation time and sucrose concentration have significant effect on EPS production (P≤0.05). Maximum EPS production was 256 mg/L and the optimum pH, incubation time, YNB concentration and sucrose concentration for EPS production were found to be 5.7, 49 h, 9.8 g/L and 25.8 g/L, respectively.

Optimization of exopolysaccharide production from Pseudomonas stutzeri AS22 and examination of its metal-binding abilities.

To investigate the effect of culture conditions and medium components on exopolysaccharide (EPS) production by Pseudomonas stutzeri AS22 and to access the EPS performance as a metal-binding exopolysaccharide. The EPS production conditions of Ps. stutzeri AS22 in submerged culture were optimized using two approaches for EPS quantification, and its metal-binding capacity was evaluated using both single and mixed metal ions systems. Maximum EPS level was achieved after 24 h of incubation at 30°C with an initial pH of 8.0, 250 rev min(-1) stirring level and 10% inoculum size. 50 g l(-1) starch, 5 g l(-1) yeast extract, 0.5 g l(-1) NaCl, 1.4 g l(-1) K2 HPO4, 0.4 g l(-1) MgSO4, 0.4 g l(-1) CaCl2 and 1 g l(-1) mannose were found to be the most suitable carbon, nitrogen, mineral and additional carbohydrate sources, respectively. From metal-binding experiments, the crude EPS showed interesting metal adsorption capacity adopting the order Pb >> Co > Fe > Cu >> Cd. Lead was preferentially biosorbed with a maximal uptake of 460 mg g(-1) crude EPS. Under the optimal culture requirements, EPS level reached 10.2 g l(-1) after 24 h of fermentation, seven times more than the production under initial conditions. According to the metal-binding assay, the crude EPS has potential to be used as a novel biosorbent in the treatment of heavy metals-contaminated water. Our results are interesting in terms of yield as well as efficiency for the potential use of the Ps. stutzeri exopolysaccharide as a metal-absorbent polymer in the bioremediation field.

Optimization of exopolysaccharide production in submerged culture of Daedalea dickinsii and its antioxidant activity

The major nutrients, pH and temperature were evaluated for the exopolysaccharide (EPS) production by Daedalea dickinsii in submerged culture to derive an optimal medium composition and conditions as follows: 50 g/L maltose, 5 g/L soy peptone, 5 mM CaCl(2), at pH 6.0 and 28 °C. A purified EPS fraction was attained from gel filtration chromatography and its major molecular characteristics were determined. FT-IR spectral analysis revealed the prominent characteristic groups of polyhydric alcohols. GC analysis and NMR spectrum showed its major molecular composition of glucose and galactose. Furthermore, thermogravimetric analysis indicated its degradation temperature (T(d)) of 189 °C. The antioxidant activity of the EPS fraction showed a correlation with the molecular properties. It might be attributed to the functional groups in the EPS fraction, which can donate electrons to reduce the radicals to a more stable form or react with the free radicals to terminate the radical chain reaction.

Draft Genome Sequence of Exopolysaccharide-Producing Thermophilic Bacterium Brevibacillus thermoruber Strain 423

Brevibacillus thermoruber strain 423 is a Gram-positive, spore-forming, aerobic, and thermophilic bacterium that produces mannogalactoglucan exopolysaccharide (EPS). We report the draft genome sequence of B. thermoruber 423, which will accelerate research on the cellular organization of thermophilic bacteria, as well as the rational design and optimization of EPS production.

Optimization of exopolysaccharide production and diesel oil emulsifying properties in root nodulating bacteria

Bioremediation, a strategy mediated by microorganisms, is a promising way used in the degradation or removal of organic contaminants from soil or aquatic system. Exopolysaccharide (EPS) which was produced by a variety of Gram-negative bacteria has been demonstrated to be a potential bioemulsifier used in the degradation of hydrocarbons. In the present study, attempts were made to optimize the production of EPS from our newly isolates by adjusting the culture conditions and medium components. Besides, the performance of diesel oil emulsification using partially purified EPS derived from different conditions was also demonstrated. Out of 40 root nodulating bacteria the better emulsifying abilities were recorded from three strains namely Rhizobium miluonense CC-B-L1, Burkholderia seminalis CC-IDD2w and Ensifer adhaerens CC-GSB4, as can be seen from their emulsification index (E(24)) 66, 64 and 60%, respectively. These three strains produced 212, 203 and 198 mg l(-1) of EPS, respectively, in yeast extract mannitol (YEM) medium. After modifying culture conditions, better performances can be achieved from these three strains, with increases of 21.7, 21.4, 16.7% in the EPS production and 12.1, 10.9, 8.3% in E(24), respectively. When considered for strain CC-B-L1 and CC-IDD2w, the addition of 1.5% (v/v) of mannitol and 0.1% (v/v) of asparagine in YEM enhanced 42.9 and 34.7% in EPS production along with 28.8 and 37.5% higher in E(24). The supplement of 2.0% (v/v) glucose and 0.2% (v/v) asparagine in YEM increased 65.2% of EPS and 38.3% of E(24) in strain CC-GSB4. This is the first report demonstrating the optimization of diesel emulsification by EPS from root nodulating isolates, and these microbial agents might be used in the remediation of hydrocarbon contaminated soils in a near future.

Optimization of exopolysaccharide production fromArmillaria melleain submerged cultures

To study the optimization of submerged culture conditions for exopolysaccharide (EPS) production by Armillaria mellea in shake-flask cultures and also to evaluate the performance of an optimized culture medium in a 5-l stirred tank fermenter. Shake flask cultures for EPS optimal nutritional production contained having the following composition (in g l(-1)): glucose 40, yeast extract 3, KH(2)PO(4) 4 and MgSO(4) 2 at an optimal temperature of 22 degrees C and an initial of pH 4.0. The optimal culture medium was then cultivated in a 5-l stirred tank fermenter at 1 vvm (volume of aeration per volume of bioreactor per min) aeration rate, 150 rev min(-1) agitation speed, controlled pH 4.0 and 22 degrees C. In the optimal culture medium, the maximum EPS production in a 5-l stirred tank fermenter was 588 mg l(-1), c. twice as great as that in the basal medium. The maximum productivity for EPS (Q(p)) and product yield (Y(P/S)) were 42.02 mg l(-1) d(-1) and 26.89 mg g(-1), respectively. The optimal culture conditions we proposed in this study enhanced the EPS production of A. mellea from submerged cultures. The optimal culturing conditions we have found will be a suitable starting point for a scale-up of the fermentation process, helping to develop the production of related medicines and health foods from A. mellea.

Optimization of exopolysaccharide production by Tremella mesenterica NRRL Y-6158 through implementation of fed-batch fermentation.

In liquid culture conditions, the yeast-like fungus Tremella mesenterica occurs in the yeast state and synthesizes an exopolysaccharide (EPS) capsule, which is eventually released into the culture fluid. It is composed of an alpha-1,3-D-mannan backbone, to which beta-1,2 side chains are attached, consisting of D-xylose and D-glucuronic acid. Potato dextrose broth (PDB) seemed to be an excellent medium for both growth of the yeast cells and synthesis of the EPS. This medium is composed solely of an extract of potatoes to which glucose was added. Yet an important disadvantage of this production medium is the presence of starch in the potato extract, since Tremella cells are not capable of metabolizing this component; furthermore, it coprecipitates upon isolation of the polymer [3]. In this respect, it was essential to remove the starch in order to achieve high polysaccharide production and recovery. A good method was the removal of starch through ultrafiltration of the PDB medium before inoculation of the strain. This resulted in an excellent starch-free medium in which other components essential for polysaccharide production were still present [3]. Through implementation of single and cyclic fed-batch fermentations with glucose feed, 1.6- and 2.2-fold increases in EPS yield were obtained, respectively. Lowering the carbon source level by using a cyclic fed-batch technique might decrease the osmotic effect of glucose or any catabolite regulation possibly exerted by this sugar on enzymes involved in EPS synthesis.

Optimization of exopolysaccharide production by Tremella mesenterica NRRL Y-6158 through implementation of fed-batch fermentation

Optimization of exopolysaccharide production by Tremella mesenterica NRRL Y-6158 through implementation of fed-batch fermentation