scholarly journals The Proliferation Rule of Microcystis Aeruginosa Under Different Initial pH Conditions and its Influence on the pH Value of the Environment

2021 ◽  
Author(s):  
Sijie Wei ◽  
Guanjie Zhuang ◽  
Lirijian Cheng ◽  
Shoubing Wang
Keyword(s):  
Microcystis Aeruginosa ◽  
Ph Value ◽  
Control Strategies ◽  
Scientific Basis ◽  
Cyanobacterial Blooms ◽  
Ph Values ◽  
Inoculation Density ◽  
Initial Ph ◽  
Ph Conditions ◽  
Optimal Ph

Abstract This study investigated the characteristics of the proliferation process of Microcystis aeruginosa and its changes to environmental pH values under different initial pH values and different initial inoculation densities. The results showed that although the initial pH value or the initial inoculation density was different, the pH values of the culture systems fluctuated up and down throughout the proliferation of M. aeruginosa, both on a daily and hourly time scale, and then tended to stabilize around the same value of 10.0 at the end of proliferation. The optimal pH value for the proliferation of M. aeruginosa was 9.56. This study creatively proposes that the period when the environmental pH value starts to rise rapidly toward 9.0 could be selected as an early warning period for a cyanobacterial outbreak, and the environmental pH value could be adjusted to below 8.0 to delay the outbreak. These results provide a scientific basis for further understanding the mechanism of cyanobacterial blooms and formulating pH-based control strategies.

Characterisation of Norway spruce hemicelluloses extracted by pressurised hot-water extraction (ASE) in the presence of sodium bicarbonate

Holzforschung ◽  
2011 ◽  
Vol 65 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Tao Song ◽  
Andrey Pranovich ◽  
Bjarne Holmbom
Keyword(s):  
Sodium Bicarbonate ◽  
Norway Spruce ◽  
Ph Value ◽  
Hot Water ◽  
Water Extraction ◽  
Extraction Time ◽  
Plain Water ◽  
Hot Water Extraction ◽  
Ph Conditions ◽  
Optimal Ph

Abstract Ground spruce sapwood was extracted with pressurised hot water with addition of different amounts of sodium bicarbonate (NaHCO3) to find optimal pH conditions for extraction of hemicelluloses, especially of galactoglucomannans (GGMs). The extractions were carried out in an accelerated solvent extractor (ASE) at 170°C. When extraction was carried out with 2.5 mM NaHCO3 during 60–100 min extraction time (end-pH 3.9), more than 60% of the total extracted substances were hemicellulose-derived carbohydrates. Under these conditions, approximately 80% of the extracted carbohydrates were from GGMs (13% b.o. wood). At higher concentrations of NaHCO3, the yield of carbohydrates, especially those derived from GGMs, decreased. Hydrolytic depolymerisation of hemicelluloses occurring during extraction with plain water was largely inhibited in the presence of 2.5–5 mM NaHCO3. The hydrolytic deacetylation of GGM was diminished at low NaHCO3 concentrations but increased dramatically at higher NaHCO3 concentrations. It can be concluded that 2.5–5 mM NaHCO3 giving an end-pH value of 4 is better for GGM isolation than plain water.

Growth and Aflatoxin Production by Aspergillus parasiticus NRRL 2999 in the Presence of Lactic Acid and at Different Initial pH values

1987 ◽  
Vol 50 (11) ◽  
pp. 940-944 ◽  
Author(s):  
FATHY E. EL-GAZZAR ◽  
GULAM RUSUL ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Aspergillus Parasiticus ◽  
Ph Value ◽  
Aflatoxin Production ◽  
Reversed Phase ◽  
Ph Values ◽  
Initial Ph ◽  
Medium Weight

Twenty-five milliliters of glucose-yeast-salts medium containing 0, 0.5, 0.75, 1.0, 1.5 and 2.0% lactic acid with an initial pH of 3.5 or 4.5 were inoculated with 1 ml of a spore suspension containing 106 conidia of Aspergillus parasiticus NRRL 2999 and incubated at 28°C for 10 d. The pH of the medium, weight of mycelium and aflatoxin production were determined after 3, 7, and 10 d of incubation. Amounts of aflatoxin produced were determined using reversed-phase high-performance liquid chromatography. Cultures grown in the presence of 0.5 and 0.75% lactic acid at an initial pH of 4.5 produced more aflatoxin B1 than did the other cultures at the end of 3 d of incubation. This was not true for aflatoxin G1; with increasing concentrations of lactic acid, cultures produced decreasing amounts of aflatoxin G1. Also, cultures growing in the medium with an initial pH of 3.5 produced more aflatoxin B1 in the presence of lactic acid at the end of 3 d of incubation than did control cultures. Cultures growing in the presence of 0.5 and 0.75% lactic acid produced the most aflatoxin. Maximum amounts of aflatoxin G1 were produced after 7 d of incubation, with cultures growing in the presence of 0.5 and 0.75% lactic acid producing the most. Lactic acid did not inhibit growth (mycelium weight) of cultures in the medium with initial pH values of 3.5 or 4.5 except there was a slight decrease in mycelial weight when the medium contained 0.5% lactic acid and had an initial pH value of 3.5.

scholarly journals Characterizing the impact of MnO2 addition on the efficiency of Fe0/H2O systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Viet Cao ◽  
Ghinwa Alyoussef ◽  
Nadège Gatcha-Bandjun ◽  
Willis Gwenzi ◽  
Chicgoua Noubactep
Keyword(s):  
Ph Value ◽  
Iron Corrosion ◽  
Dissolved Iron ◽  
Ph Values ◽  
Solid Iron ◽  
Initial Ph ◽  
Fixation Capacity ◽  
Co Precipitation ◽  
The Impact

AbstractThe role of manganese dioxide (MnO2) in the process of water treatment using metallic iron (Fe0/H2O) was investigated in quiescent batch experiments for t ≤ 60 d. MnO2 was used as an agent to control the availability of solid iron corrosion products (FeCPs) while methylene blue (MB) was an indicator of reactivity. The investigated systems were: (1) Fe0, (2) MnO2, (3) sand, (4) Fe0/sand, (5) Fe0/MnO2, and (6) Fe0/sand/MnO2. The experiments were performed in test tubes each containing 22.0 mL of MB (10 mg L−1) and the solid aggregates. The initial pH value was 8.2. Each system was characterized for the final concentration of H+, Fe, and MB. Results show no detectable level of dissolved iron after 47 days. Final pH values varied from 7.4 to 9.8. The MB discoloration efficiency varies from 40 to 80% as the MnO2 loading increases from 2.3 to 45 g L−1. MB discoloration is only quantitative when the operational fixation capacity of MnO2 for Fe2+ was exhausted. This corresponds to the event where adsorption and co-precipitation with FeCPs is intensive. Adsorption and co-precipitation are thus the fundamental mechanisms of decontamination in Fe0/H2O systems. Hybrid Fe0/MnO2 systems are potential candidates for the design of more sustainable Fe0 filters.

scholarly journals Adsorption-Oxidation Mechanism of δ-MnO2 to Remove Methylene Blue

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ge Yan ◽  
Pu Wang ◽  
Yuqian Li ◽  
Zhangjie Qin ◽  
Shuai Lan ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Mechanism ◽  
Ph Value ◽  
Oxidation Mechanism ◽  
Superior Performance ◽  
Adsorption Ability ◽  
Initial Ph ◽  
Effects Of Ph ◽  
Ph Conditions ◽  
Positively Charged

The material, δ-MnO2, has exhibited superior performance on the removal of methylene blue (MB), but the process is significantly impacted by pH, and the impacting mechanism is still unclear. In this study, the effects of pH on the removal mechanism of MB using synthesized δ-MnO2 were investigated by distinguishing the adsorption and oxidation of MB by δ-MnO2 during the removal process in the dark. The results show that the total removal efficiency of MB by δ-MnO2 decreased significantly with an increase in the pH. MB could be removed by δ-MnO2 via an adsorption mechanism and oxidation mechanism, and the proportion of adsorptive removal and oxidative removal was different under different pH conditions. With an increase in the initial pH from 2.00 to 8.05, the redox potential of δ-MnO2 decreased, and its oxidation ability for the removal of MB also gradually decreased. In contrast, the surface negative charges of δ-MnO2 increased with an increase in the pH, and the adsorption ability towards positively charged MB also gradually increased. This indicates that the effects of pH on the removal of MB by δ-MnO2 are primarily dominated by its influence on the oxidation ability of δ-MnO2. In addition, it is further proved that the pH value has a significant effect on the oxidation and adsorption of MB on δ-MnO2. Moreover, the significant effects of pH on the oxidation of MB by δ-MnO2 are further demonstrated by observing the changes in Mn2+ and the UV-Vis spectra of intermediate products during the reaction, as well as the changes in the FTIR and XPS characterizations of δ-MnO2 after the reaction.

scholarly journals The Effect of Incubation Temperature, Substrate and Initial pH Value on Plantaricin Activity and the Relative Transcription of pln Genes of Six Sourdough Derived Lactiplantibacillus plantarum Strains

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 320
Author(s):  
Maria K. Syrokou ◽  
Panagiota Stasinopoulou ◽  
Spiros Paramithiotis ◽  
Loulouda Bosnea ◽  
Marios Mataragas ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Ph Value ◽  
Marginal Effect ◽  
Growth Substrate ◽  
Weak Correlation ◽  
Transcriptomic Response ◽  
Time Points ◽  
Ph Values ◽  
Initial Ph ◽  
Strain Dependent

The aim of the present study was to assess the effect of sourdough related parameters on the growth and plantaricin activity of six Lactiplantibacillus plantarum strains against a mixture of 5 Listeria monocytogenes strains and to analyze the transcriptomic response of their pln genes. Parameters included 3 substrates (MRS broth, mMRS broth, WFE), 3 temperatures (20, 30, 37 °C), 2 initial pH values (5.0, 6.0), 2 NaCl concentrations (0.0, 1.8%) and 12 time points (ranging from 0 to 33 h). The transcriptomic response of the plantaricin genes to the aforementioned parameters was assessed after 21 h of growth. In general, plantaricin activity was strain dependent with that of Lp. plantarum strains LQC 2422, 2441, 2485 and 2516, harboring four pln genes, namely, pln423 (plαΑ), plαΒ, plαC and plαD, reaching 2560 AU/mL. However, strains LQC 2320 and 2520, in which 18 pln genes were detected, namely, plNC8a, plNC8b, plNC8c, plnL, plnR, plnJ, plnK, plnE, plnF, plnH, plnS, plnY, plNC8-IF, plNC8-HK, plnD, plnI, plnM and plnG, exhibited plantaricin activity barely reaching 160 AU/mL. Substrate, temperature, initial pH value and strains significantly affected plantaricin activity, while NaCl had only a marginal effect. Similarly, growth substrate and temperature had a more pronounced effect than initial pH value on gene transcription. A strong correlation between the transcription of the genes belonging to the same locus was observed; however, only a weak correlation, if any, was observed between plantaricin activity and the transcription of the genes assessed.

Electrical and optical properties of well-dispersed MWCNTs/PVA nanocomposites under different pH conditions

2018 ◽  
Vol 32 (4) ◽  
pp. 442-453 ◽  
Author(s):  
Emad AM Farrag ◽  
Rami A Abdel-Rahem ◽  
SS Ibrahim ◽  
Ayman S Ayesh
Keyword(s):  
Room Temperature ◽  
Ph Value ◽  
Poly Vinyl Alcohol ◽  
Electrical And Optical Properties ◽  
Multiwalled Carbon ◽  
Casting Technique ◽  
Ph Values ◽  
Current Voltage ◽  
Optimum Ph ◽  
Ph Conditions

Series of polymer nanocomposites films consisting of pretreated multiwalled carbon nanotubes (PT-MWCNTs) and poly (vinyl alcohol) (PVA) were prepared at room temperature. The MWCNTs were initially pretreated with 1.0 M sulfuric acid (PT-MWCNTs) and then allowed to disperse in aqueous solutions at different pH values (2–14). It was found that the dispersion of the PT-MWCNTs is a pH dependent. The best PT-MWCNTs dispersion was obtained at pH = 10. Films of PT-MWCNTs/PVA, at this optimum pH-value, were then prepared by casting technique at different PT-MWCNTs weight fractions. The resulted PT-MWCNTs/PVA films were characterized through the direct visualization, Fourier transform infrared, and morphology test. Besides, current–voltage and direct current electrical conductivity for PT-MWCNTs/PVA nanocomposites at 60°C showed that the conductivity mechanism was ohmic and the percolation threshold was around 0.8 wt% PT-MWCNTs. Optical results showed that PT-MWCNTs are homogeneously distributed in the neat PVA and optical gap is significantly decreased from 4.40 to 2.96 eV.

Adsorption of As (v) from Water by Activated Aluminum Oxide

2012 ◽  
Vol 476-478 ◽  
pp. 1965-1968
Author(s):  
Da Lei Zhang ◽  
Fan Qiao ◽  
Mou Lv ◽  
Ying Jie Sun ◽  
Qing Yuan Guo
Keyword(s):  
Aluminum Oxide ◽  
Adsorption Equilibrium ◽  
Ph Value ◽  
Adsorption Properties ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Ph Values ◽  
Initial Ph ◽  
Langmuir Isotherm Model ◽  
Activated Aluminum Oxide

In this paper the adsorption properties of activated aluminum oxide (AAO ) to As(V) were researched. The effect of operating factors such as pH, contact time and initial As(V) concentration was investigated and the optimum operating conditions were established. Experimental results indicated that the optimal pH value adsorption of As(V)by activated aluminum oxide was from 4 to 6, and the optimum initial pH values was 5.5.The adsorption equilibrium was achieved within 5h.The adsorption capacity for As(V)increased with increasing concentration and the adsorption date was well fit by the Langmuir isotherm model. It is believed that activated aluminum oxide (AAO) is environmentally acceptable and industrially application for utilization in arsenic-containing wastewater treatment.

Study of Removing Bacteria and Microcystis aeruginosa by Hydroxyl Radical

2013 ◽  
Vol 864-867 ◽  
pp. 418-421
Author(s):  
Wei Xu ◽  
Rong Jie Yi ◽  
Jing Jing Li ◽  
Jin De Song ◽  
Chen Wu Yi ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Microcystis Aeruginosa ◽  
Large Scale ◽  
Microbial Contamination ◽  
Treatment Process ◽  
Treatment Time ◽  
Ph Value ◽  
High Concentration ◽  
Initial Ph ◽  
Strong Ionization Discharge

The 1.5t/h algae and bacteria wastewater with high concentration was treated by hydroxyl radical (OH) produced by a strong ionization discharge. In this paper, the feasibility of kill bacteria and alga by OH was investigated, and effects of OH concentration, treatment time and pollution initial concentration on degrading microorganisms by OH were investigated in detail. The results indicated that the treatment process was effective in the degradation of the bacteria and alga at the initial pH value of 7.1, OH dosage of 2.33mg/L, the initial microcystis aeruginosa concentration of 106/mL and the initial bacterial dosage of 106cfu/mL, the bacteria and alga degradation rate reached 99.99% at 303K after 15min treatment. The results provided a theoretical basis for the OH treatment of microbial contamination in drinking water in large-scale.

Biodegradation of Swainsonine by Stenotrophomonas maltophilia Strain YLZZ-2 and its Isolation and Identification

2010 ◽  
Vol 178 ◽  
pp. 59-64
Author(s):  
Xing Hua Zhao ◽  
Xin He ◽  
Jian Hua Wang
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Sole Carbon Source ◽  
Degradation Rate ◽  
Ph Value ◽  
Culture Conditions ◽  
Isolation And Identification ◽  
16S Rdna Sequence ◽  
Degrading Bacteria ◽  
Initial Ph ◽  
Optimal Ph

Eight swainsonine (SW)-degrading bacteria were isolated from the soil where locoweed was buried for 6 months and one of the strains (YLZZ-2) was selected for further study. Based on morphology, physiologic tests, 16S rDNA sequence, and phylogenetic characteristics, the strain showed the greatest similarity to members of the order Stenotrophomonap and the closest to members of the Stenotrophomonas maltophilia group. The ability of the strain to degrade SW, as sole carbon source, was investigated under different culture conditions. The preferential temperature and initial pH value for the strain were 25～35 °C and 6.0～9.0, respectively. The optimal temperature for the strain was 30 °C and the optimal pH value was 7.0. There was positive correlation between degradation rate and inoculation amount. The growth of stain YLZZ-2 and degradation rate were fast, and YLZZ-2 could completely degradate 400 mg/L swainsoine within 24 h. There was a linear relationship between the growth of stain YLZZ-2 and degradation of swainsonine. These results highlight the potential of this bacterium to be used in detoxifying of SW in livestock consuming locoweed.

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