Different Concentrations Of Sodium Bicarbonate Research Articles

Effect of different concentrations of carbonate on growth performance, intestinal health and hepatic lipid metabolism of Crucian carp

The effects of different concentrations of sodium bicarbonate (0 g/L, 1 g/L, 2 g/L, 3 g/L) on Hefang crucian carp (HCC) were studied. H&E staining, oil red O staining, scanning electron microscopy, transmission electron microscopy, 16S rDNA sequencing, transcriptomic analysis and other techniques were used to observe the pathological changes of intestinal and liver tissues, and detect the changes of intestinal flora and liver gene expression. The main findings are as follows: It was found that the WGR and SGR of the three treatment groups was significantly higher than that of the CK group (p < 0.05). Intestinal H&E staining results showed that the number of goblet cells and the width of submucosa gradually increased with the increase of carbonate concentration. The results of intestinal scanning electron microscopy showed that the roughness of intestinal villi increased slightly with the increase of carbonate concentration. The analysis of populations with large differences among groups treated with sodium bicarbonate of different concentrations found that the relative abundance of Lachnospiraceae varied greatly. LPS levels in the serum, intestinal tract and liver tissue were detected. The results showed that LPS content in MCA and HCA groups was significantly higher than that in CK group (p < 0.05). The expression of claudin 12, 7, c and occludin genes in HCA group and MCA group was significantly lower than that in CK group in intestinal (p < 0.05). The ALT, AST, T-CHO, TG, HDLC, ACC, ACS, CPT-1, HL, LPL and FAS content in HCA group was significantly higher than that in CK group in liver (p < 0.05). The liver was damaged by oil red O staining and transmission electron microscopy. Compared with the control group, the enrichment of steroid biosynthesis is the highest number of DEGs in the HCA group. The iron death pathway and autophagy pathway in HCA group were significantly different from those in CK group (p < 0.05). In summary, this study elucidates that carbonate exposure alters the gut microbiota homeostasis of HCC, leading to intestinal inflammation and increased mucosal barrier permeability, promoting LPS synthesis and absorption, subsequently entering the liver through the gut-liver, increasing liver autophagy and iron death, inducing lipid metabolism disorders, and causing liver injury. In summary, carbonate exposure may cause intestinal microbial disturbance and intestinal injury, and induce liver autophagy and iron death and lipid metabolism disturbance, leading to liver injury

Anaesthetic effects of different concentrations of sodium bicarbonate on common carp (Cyprinus carpio)

Sedation of fish before handling and transporting can help curtail undue stress that can affect their health. This study investigated the effectiveness of sodium bicarbonate (NaHCO3) utilised as an anaesthetic agent for common carp (Cyprinus carpio) with an average weight of 13.5 ± 0.55 g. The experimental fish were grouped and exposed to different concentrations at 0, 40, 45 and 50 g L–1 of NaHCO3 dissolved in water. Fishes were bath-immersed in different concentrations of NaHCO3 solution until such time that they became anesthetised. Results showed that induction time and recovery time increases with increasing NaHCO3 concentration. All fish reached complete anaesthesia in more than 3 minutes under a higher concentration of 50 g L–1. No mortality occurred under any of the concentrations tested. The most optimal concentration leading to complete anaesthesia in 2 minutes and recovery in less than 4 minutes was 45 g L–1. This study showed that NaHCO3 is a potential fish anaesthetic for the common carp.

Combination of Sodium Bicarbonate (SBC) with Bacterial Antagonists for the Control of Brown Rot Disease of Fruit.

Simultaneous treatment with antagonistic bacteria Bacillus amylolquefaciens (SF14), Alcaligenes faecalis (ACBC1), and the food additive sodium bicarbonate (SBC) to control post-harvest brown rot disease caused by Monilinia fructigena, and their effect on the post-harvest quality of nectarines were evaluated. Four concentrations of SBC (0.5, 2, 3.5, and 5%) were tested. Results showed that bacterial antagonists displayed remarkable compatibility with different concentrations of SBC and that their viability was not affected. The results obtained in vitro and in vivo bioassays showed a strong inhibitory effect of all treatments. The combination of each bacterial antagonist with SBC revealed a significant improvement in their biocontrol efficacies. The inhibition rates of mycelial growth ranged from 60.97 to 100%. These results also indicated that bacterial antagonists (SF14 or ACBC1) used at 1 × 108 CFU/ mL in combination with 2, 3.5, or 5% SBC significantly improved the control of M. fructigina by inhibiting the germination of spores. Interestingly, disease incidence and lesion diameter in fruits treated with SF14, ACBC1 alone, or in combination with SBC were significantly lower than those in the untreated fruits. In vivo results showed a significant reduction in disease severity ranging from 9.27 to 64.83% compared to the untreated control, while maintaining the appearance, firmness, total soluble solids (TSS), and titratable acidity (TA) of fruits. These results suggested that the improved disease control by the two antagonistic bacteria was more likely due to the additional inhibitory effects of SBC on the mycelial growth and spore germination of the pathogenic fungus. Overall, the combination of both bacteria with SBC provided better control of brown rot disease. Therefore, a mixture of different management strategies can effectively control brown rot decay on fruits.

Sodium Bicarbonate and Acetic Acid: An Effective Anaesthetic for Three Spotted Tilapia, Oreochromis andersonii Fingerlings

Abstract This study aimed to study the effectiveness of different concentrations of sodium bicarbonate (baking soda) combined with acetic acid (vinegar) in three spotted tilapia (Oreochromis andersonii) fingerlings. Fingerlings (body weight 0.82 ± 0.00 g, and body length of 3.91 ± 0.03 cm) were subjected to three concentrations of sodium bicarbonate (30 g/L, 40 g/L and 60 g/L) combined with three concentrations of acetic acid (30 ml/L, 45 ml/L and 60 ml/L), each replicated five times to assess the anaesthesia induction and recovery time. Sodium bicarbonate and acetic acid induced anaesthesia in three spotted tilapia fingerlings regardless of the concentration used. However, high concentrations induced anaesthesia within a short period of time. Meanwhile, the full recovery time increased with concentration combinations. In essence, low concentrations of sodium bicarbonate and acetic could be recommended for anaesthetizing three spotted tilapia fingerlings. However, more studies on sodium bicarbonate and acetic acids as anaesthetics in aquaculture and fisheries is deemed necessary.

Sodium bicarbonate augmentation enhances lutein biosynthesis in green microalgae Chlorella pyrenoidosa

Abstract The present study was carried out to investigate the effects of different concentrations of sodium bicarbonate (0, 50, 100, 150 and 200 mM) on the biosynthesis of lutein and lipids and also the expression of genes involved in lutein carotenogenesis in Chlorella pyrenoidosa. The algal extract from cultures treated with different concentrations of sodium bicarbonate was analyzed using high-performance liquid chromatography (HPLC) for lutein quantification. HPLC results revealed a three-fold increase of lutein in C. pyrenoidosa culture grown in 100 mM concentration (4.84 ± 0.56 mg/g of DCW), followed by 50 mM concentration (4.21 ± 0.11 mg/g of DCW) supplemented cultures compared to 150 mM and 200 mM concentration (2.32 ± 0.093 mg/g of DCW and 2.31 ± 0.114 mg/g of DCW) and control culture (1.45 ± 0.18 mg/g of DCW). The expression analysis of phytoene desaturase, lycopene cyclase and carotenoid hydroxylase genes also showed a significant up regulation in their expression when supplemented with sodium bicarbonate. Lipid yield was observed to be increased significantly when supplemented with sodium bicarbonate. Therefore, sodium bicarbonate (100–150 mM) can be used as a potential dissolved inorganic carbon source for enhancing lutein and lipid production during large scale cultivation of C. pyrenoidosa cultures.

Effectiveness of Sodium Bicarbonate (NaHCO3) on Physicochemical and Sensory Characteristic of Notopterus notopterus Bone Chips

This study was aimed to determine the physicochemical and sensory characteristics of chips made from bones of Notopterus notopterus previously soaked in sodium bicarbonate. Different concentrations of sodium bicarbonate (0; 0.5; 1; 1.5; 2; and 2.5%) were used to soak the bones. The parameters observed were chemical analysis, physical analysis, and sensory analysis. The soaking of the fish bones in sodium bicarbonate had significant effects (p&lt;0.05) on the chemical characteristics including water content, ash content, protein content, NaHCO3 residue as well as physical characteristic of the chips. However, on the soaking did not affect phosphorus, calcium and sensory characteristics of the chips.

Advantages of asymmetrical over symmetrical cells for detection of under deposit CO2 corrosion using electrochemical noise

Electrochemical noise (EN) measurements were done on symmetrical and asymmetrical cells after immersion in 3.5% NaCl solutions saturated with CO2 and containing different concentrations of sodium bicarbonate to get a better interpretation of the under‐deposit corrosion of mild steel. The symmetrical cell was constructed from two sand‐deposited electrodes and the asymmetrical cell was prepared from one sand‐deposited electrode and one bare electrode. The combination of the standard deviation of partial signal (SDPS) plots arising from wavelet analysis and recurrence plots for analyzing the EN signals obtained from symmetrical and asymmetrical cells confirmed the higher detective ability of the asymmetrical cells in comparison with the symmetrical cells for measuring the under‐deposit corrosion of mild steel. Both the SDPS and recurrence plots arising from symmetrical cells showed no significant change in the corrosion severity of the steel alloy with adding sodium bicarbonate. In contrast, the SDPS and recurrence plots of the asymmetrical cells proved that the corrosion severity decreased initially with adding the bicarbonate and thereafter remained constant with increasing the bicarbonate concentration. The optical microscopy images of the sand‐covered electrode surface confirmed the latter result.

Carbon sequestration potential of Scenedesmus quadricauda (Turpin) and evaluation on Zebra fish (Danio rerio)

Carbon dioxide sequestration by microalgae is receiving increased attention in alternative impact of increasing CO2 in the atmosphere. For this study, we have chosen three different microalgae such as Chlorococcum humicola, Chlorella vulgaris and Scenedesmus quadricauda were treated with 3 W/m2 UV-B radiation in different time durations (10, 15, 30, 45 and 60 min) and supplemented with bold basal medium. Parameters such as Total Chlorophyll, protein, Carbohydrate, and CO2 fixation rate were determined. Based on the parameters Scenedesmus quadricauda is used for carbon sequestration study. Different concentrations of sodium bicarbonate (0.2%–1%) were supplemented to bold basal medium for carbon utilization it can act as an alternative source of atmospheric CO2. In this maximum amount of chlorophyll content were observed in 0.6% of Sodium bicarbonate. The uttermost amount of CO2 fixation rate and lipid content was recorded at 0.4% sodium bicarbonate concentration. Finally, the result indicated that Scenedesmus quadricauda could be used for CO2 mitigation and having a rich source of polyunsaturated fatty acid. Further urea and glucose in the media positively influence growth and CO2 fixation rate of micro algae. These carbon and PUFA rich microalgae can be used as dietary feed fish usually obtain necessary nutrients via bioaccumulation through the food chain. Thus, this study proves to be an encouraging source of discovery of alternating the dietary source for fish and also helping in carbon utilization process in a natural way.

A comparative study on the effect of l-tartaric acid and sodium bicarbonate on the growth and characterization of KDP single crystals

Potassium dihydrogen phosphate (KDP) is one of the efficient inorganic single crystals employed in second harmonic generation (SHG) conversion applications. Present work describes the growth and characterization of optically transparent single crystals of KDP and KDP in presence of two different concentrations of l-tartaric acid and three different concentrations of sodium bicarbonate by slow evaporation solution growth technique at ambient temperature. FT-IR analysis did not reveal any main vibrations of LTA or NaHCO3. The UV–Vis–NIR study suggest that the crystals are highly transparent in the region 373–1200 nm and percentage of transmittance slightly increased in case of KDP crystals grown in presence of 0.1 M% sodium bicarbonate. Improvement in SHG efficiency was observed in KDP grown in presence of 0.1 M% l-tartaric acid. Thermal stability of the KDP grown in presence of impurities showed marginal increase when compared to pristine KDP.

Effect of sodium bicarbonate on quality of pear fruits under low temperature storage

The aim of study was to investigate the effect of sodium bicarbonate on physiochemical and enzymatic changes of ‘Patharnakh’ pear fruits stored at low temperature. Pear fruits were dipped in different concentrations of sodium bicarbonate (0.0, 1.0, 2.0 and 3.0%) and stored at 0–1°C and 90–95% RH for 70 days. Physical and biochemical attributes of the fruits were determined at 0, 20, 40, 60 and 70 days during storage. Exogenous applications of sodium bicarbonate reduced cellulase, PME and PPO enzyme activities. As compared to control, sodium bicarbonate (3%) resulted in 27 per cent higher fruit firmness, 14.3% greater sensory quality and 26.4% higher total phenolics content at 60 days of storage. Furthermore, sodium bicarbonate application effectively retarded the degradation of titratable acidity, ascorbic acid content, weight loss and total soluble solids. Thus, sodium bicarbonate was found to be useful for extending the shelf life and maintaining quality of pear fruits during low temperature storage.

Low concentration of sodium bicarbonate improves the bioactive compound levels and antioxidant and α-glucosidase inhibitory activities of tartary buckwheat sprouts.

This study aimed to investigate the effects of different concentrations of sodium bicarbonate (NaHCO3) on the accumulation of flavonoids, total phenolics and d-chiro-inositol (DCI), as well as the antioxidant and α-glucosidase inhibitory activities, in tartary buckwheat sprouts. Treatment with low concentrations of NaHCO3 (0.05, 0.1, and 0.2%) resulted in an increase in flavonoids, total phenolic compounds and DCI concentrations, and improved DPPH radical-scavenging and α-glucosidase inhibition activities compared with the control (0%). The highest levels of total flavonoids (26.69mg/g DW), individual flavonoids (rutin, isoquercitrin, quercetin, and kaempferol), total phenolic compounds (29.31mg/g DW), DCI (12.56mg/g DW), as well as antioxidant and α-glucosidase inhibition activities, were observed in tartary buckwheat sprouts treated with 0.05% NaHCO3 for 96h. These results indicated that appropriate treatment with NaHCO3 could improve the healthy benefits of tartary buckwheat sprouts.

ANAESTHETIC EFFECTS OF SODIUM BICARBONATE AT DIFFERENT CONCENTRATIONS ON AFRICAN CATFISH (Clarias gariepinus) JUVENILES

In the present study, anaesthetic effects of different si-zes (5, 10, 15, 20, 25, 30, 35 and 40g) of African cat-fish (Clarias gariepinus) juveniles was investigated at different concentrations (0/control, 10, 15, 20, 25, 30, 35, 40, 45, 50 g/L) of sodium bicarbonate. Juveniles were bath immersed in each of the different concentra-tions of sodium bicarbonate solution for 5 minutes and recovery times in clean aerated water was established. Juveniles took between 0.67 to 5.44 minutes to reach full anaesthesia and 0.66 to 4.25 minutes to recover fully from anaesthesia. An inverse exponential relati-onship was observed between sodium bicarbonate concentrations and induction time, whereas exponen-tial relationship was observed between sodium bicar-bonate concentrations and recovery time. Size of C. gariepinus juveniles significantly affected the induc-tion time (P < 0.05) with smaller juveniles getting to full anaesthesia faster than bigger juveniles at the sa-me concentration of sodium bicarbonate. In addition, recovery time was size dependent where smaller C. gariepinus juveniles took significantly longer time (P < 0.05) to recover from anaesthesia than bigger juve-niles. All juveniles reached anaesthesia and recovered in less than 5 minutes except for 30 g juveniles at 15g/L of sodium bicarbonate which was anaesthetized at 5.44 minutes.

Cloning and expression of gamma carbonic anhydrase from Serratia sp. ISTD04 for sequestration of carbon dioxide and formation of calcite

Bacterial strains isolated from marble mines rock and enriched in the chemostat culture with different concentrations of sodium bicarbonate. The enriched consortium had six bacterial isolates. One of bacterium isolate showed carbonic anhydrase (CA) activity by catalyzing the reversible hydration reaction of carbon dioxide to bicarbonate. The bacterium was identified as Serratia sp. by 16S rRNA sequence analysis. The carbonic anhydrase gene from Serratia sp. was found to be homologous with gamma carbonic anhydrase. The carbonic anhydrase gene was cloned in PET21b(+) and expressed it in recombinant Escherichia coli BL21 (DE3) with His-tag at the C-terminus. The recombinant protein was purified efficiently by using one-step nickel affinity chromatography. Expected size of carbonic anhydrase was approximately 29kDa in SDS–PAGE gel. Recombinant carbonic anhydrase enzyme was used for biomineralization-based conversion of atmospheric CO2 into valuable calcite minerals. The calcification was confirmed by using XRD, FTIR, EDX and SEM analysis.

Optimization of biomass and fatty acid productivity of Scenedesmus obliquus as a promising microalga for biodiesel production

Nowadays, microalgae are discussed as a promising feedstock for biodiesel production. The present study examines the possibility of enhancement of fatty acid productivity of Scenedesmus obliquus by modifications of the culture medium composition. The effect of different concentrations of sodium bicarbonate, salinity, potassium nitrate, glycerol and sugarcane molasses on the enhancement of biomass and esterified fatty acids production was studied. NaHCO3 caused an increase in the biomass productivity at low concentrations (0.5 g L(-1)), while negatively affected fatty acid productivity at all tested concentrations. Increase of salinity enhanced both biomass and fatty acid productivity. The optimum NaCl concentration and sea water ratio were 0.94 g L(-1) and 25 % which resulted in 56 and 39 % increase in fatty acid productivity, respectively. Nitrogen deficiency showed increase in fatty acid content by 54 % over control but fatty acid productivity was decreased as a result of growth inhibition. Nitrogen-free cultures and cultures treated with -50 % concentrations of KNO3 showed 96 and 42 % decrease in EFA productivity, respectively, as compared with the control. Addition of 0.05 and 0.1 M of glycerol increased the biomass productivity by 6 and 5 %, respectively but showed no significant effect on fatty acid productivity as a result of decrease in fatty acid content. Finally, usage of sugarcane molasses stimulated both biomass and fatty acid content. The increase in fatty acid productivity was 32, 65 and 73 % above the control level at 1, 3 and 5 g L(-1) of sugarcane molasses, respectively.

IMPROVEMENT THE RELEASE AND AVAIALBILITY OF CELECOXIB CO-ADSORBATE FROM FLOATING CAPSULES

Celecoxib is a selective COX-2 inhibitor non-steroidal anti-inflammatory drug (NSAID) used in the treatment of osteoarthritis, rheumatoid arthritis, and to reduce numbers of colon and rectum polyps in patients with familial adenomatous polyposis. Celecoxib is practically inslouble in GIT pH. Consequently, it suffers from low and variable bioavailability following oral administration of solutions (64-88%) and capsules (20-40%) In the present study, gastroretentive controlled release single-unit floating capsules of Celecoxib were designed and evaluated. Various grades of low and high viscosity polymers of HPMC 4000 and 15.000 cps and NaCMC were used for formulation of Celecoxib capsules. For the purpose of enhancing the poor dissolution rate of Celecoxib, co-adsorption with Tween 80 onto surface of Florite® was investigated in this study. Thus, controlled release limited by drug solubility was percluded and delivery of active material was controlled by the formulation. In the present study conventional capsules containing Celecoxib using HPMC and NaCMC were developed and evaluated. Floating capsules containing Celecoxib, co-adsorption with Tween 80 onto surface of Florite and Aerosil 200 in different ratios were also formulated and investigated for the release of the drug from these capsules. The results obtained of this study showed that Celecoxib capsules containing HPMC 15000cps as a swelling matrix has a good floating behaviour and retarding effect on the drug release. Also, different concentrations of sodium bicarbonate confirmed and maintained the floating properties of the prepared formulations without affecting the drug release. From DSC and X-ray diffraction studies it was found that crystalline Celecoxib was converted into the amorphous form in the presence of Florite® at (1:5 w/w drug: carrier ratio) in the adsorbate and co-adsorbate with Tween 80. The loaded and ground mixtures of Celecoxib with either Florite® or Aerosil 200 increased the dissolution rate of the drug. Furthermore, co-adsorbate of the drug with Florite® and Tween 80 at these ratios of (1:5:3 and 1:5:5) gave the highest percentage released of Celecoxib (reached about 100% at 30 and 45 min., respectively).

Studies on the growth behavior of Chlorella, Haematococcus and Scenedesmus sp. in culture media with different concentrations of sodium bicarbonate and carbon dioxide gas

Growth studies were conducted on green algae Chlorella, Scenedesmus andHaematococcus strains in batch mode cultures. In this study, the effect of sodium bicarbonate salt (NaHCO3) and carbon dioxide (CO2) gas as carbon source on microalgal cultures were investigated. For this purpose, growth response of theaforementioned three strains under varying concentrations of NaHCO3 (15, 30, 45, 60 and 75 mg/L,) and CO2 gas (7929, 4758 and 4400 mg/L,) were investigated. The best growth response showed by chlorella strain was observed at 75 mg/L (ppm) bicarbonate (% increase in biomass=82.6mg/L/day for 12 days) and 4758 mg/L CO2 gas concentration (189.1 mg/L/day for 7 days). While Haematococcus strain showed its best growth in 30 ppm bicarbonate (72.9 mg/L/day for 17 days) and 4758 mg/L CO2 gas (134.1 mg/L for 7 days), the Scenedesmus strain showed its best growth in 45 ppm bicarbonate (30.9 mg/L/day for 17 days) and 4758 mg/L CO2gas (103.8 mg/L for 7 days). All the strains showed good growth when CO2 gas was supplied in terms of increase in cell number, biomass and lipid content compared to bicarbonate utilization as carbon source, except Haematococcusstrain which fail to grow when high concentration of CO2 gas (7929 ppm) was supplied. Out of the three strains, it was Chlorella sp. which showed highest growth rate and lipid content when CO2 gas was supplied, (specific growth=0.704; 189.1% increase in biomass, g/L/day and 1.015 doubling/day, 31% lipid content in terms of dry cell weight). Key words: Microalgae, bicarbonate, biomass, lipid.

An assessment of Fourier Transform Infrared spectroscopy to identify adulterated raw milk in Brazil

The aim of this study was to evaluate the application of the methodology of Fourier Transform Infrared spectroscopy (FT-IR) to the identification of adulterated raw milk. A reference spectrum with 800 representative samples of the study area was built. Through the analysis of principal components, equations with a distinct number of factors were developed. For the validation test, 100 adulterated samples were used at three different concentrations of sodium bicarbonate, sodium citrate and non-acid cheese whey. Results indicate that the FT-IR can be used for the identification of adulterated milk with 0,05% and 0,075% of sodium bicarbonate and citrated respectively.

Resposta em parâmetros sanguíneos e urinários de vacas leiteiras ao aumento no balanço cátion-aniônico da dieta

Estudou-se efeito de quatro níveis de dietas catiônicas sobre os parâmetros ácido-base do sangue e o pH urinário de vacas em lactação. Para a manipulação dos níveis do balanço cátion-amônico da dieta (BCAD), foram adicionadas diferentes concentrações de bicarbonato de sódio às dietas, obtendo-se os seguintes tratamentos: +150, +250, +400 e +500mEq/kg de matéria seca. O experimento foi realizado durante o verão, por um período total de 72 dias, utilizando-se oito vacas da raça Holandesa após o pico de lactação, distribuídas em quadrado latino (4x4), replicado, em que cada período teve duração de 18 dias. O pH urinário e o bicarbonato, o pH, o CO2 total e a pCO2 do sangue aumentaram linearmente (P&lt;0,01) com o aumento do BCAD. As concentrações de sódio e potássio do sangue não foram modificadas (P&gt;0,05) pelo BCAD. A concentração de cloro no sangue diminuiu linearmente (P&lt;0,01) com o aumento do BCAD. O aumento do BCAD afetou o equilíbrio ácido-base das vacas, promovendo efeito alcalinogênico, o que poderia levar a diferenças significativas no desempenho do animal.

The Influence of Biofilm on the Effectiveness of Ion Exchange Process

The ion exchange of ammonia in a synthetic zeolite has been investigated in the presence of Biofilm of nitrifying bacteria. The Biofilm has been cultivated on the zeolite carrier under different hydrodynamic conditions in a plug flow reactor and in a fluidized bed reactor. Samples of the carrier covered by Biofilm have been withdrawn from the reactors and packed into a miniature ion exchange column that has been used to analyze the ion exchange characteristics, i.e., to determine ion exchange equilibria and the mass transport kinetics. For this purpose, the breakthrough curves have been registered at different ammonia loadings and different concentrations of sodium bicarbonate in the solution. To analyze the mass transport mechanism and quantify kinetic coefficients, we have exploited a linear driving force model (i.e., the LDF model) and the generalized model. The ion exchange and mass transfer characteristics of the Biofilm-covered carrier have been compared to those of the virgin zeolite. The effect of Biofilm on the mass transfer kinetics and ion exchange capacity was found to be induced by swelling properties of zeolite.

The effect of varying levels of sodium bicarbonate on polychlorinated biphenyl dechlorination in Hudson River sediment cultures

The addition of different concentrations of sodium bicarbonate had a profound effect on 2,3,4,5-chlorobiphenyl (2,3,4,5-CB) dechlorination in Hudson River sediment cultures. The most extensive dechlorination was observed in cultures to which 100 mg l(-1) bicarbonate was added. Cultures amended with 1000 mg l(-1) bicarbonate had the least extensive dechlorination, with 2,4-CB and 2,5-CB as predominant end-products. A significant loss of total chlorinated biphenyl mass was observed in cultures to which < or = 500 mg l(-1) bicarbonate was added, suggesting that degradation beyond chlorinated biphenyls occurred. The dynamics of acetate formation were different among the treatments, with high acetate concentrations detected throughout the 303-day experiment in cultures to which 1000 mg l(-1) bicarbonate had been added. Sodium bicarbonate addition also had a significant impact on bacterial community structure as detected by polymerase chain reaction-denaturant gradient gel electrophoresis (PCR-DGGE) of 16S rRNA gene fragments. Three putative polychlorinated biphenyl (PCB) dechlorinators were identified; one Dehalococcoides-like population was detected in all enrichment cultures, whereas two Dehalobacter-like populations were only detected in the enrichment cultures with the most extensive dechlorination. These results suggest that the availability of bicarbonate, and potentially sodium, may affect PCB dechlorination in Hudson River sediment and thus need to be taken into consideration when assessing the fate of PCBs or implementing bioremediation.