Addition Of Bicarbonate Research Articles

Enhancement of Pigments Production by Nannochloropsis oculata Cells in Response to Bicarbonate Supply

In this study, the effects of bicarbonate addition on growth and pigment contents of the unicellular microalga Nannochloropsis oculata, were evaluated. N. oculata represents an interesting source of biomolecules widely used for food supplements and nutraceuticals. The bicarbonate was supplemented to microalgae cultures at concentrations of 0, 6, 18, 30, 42 and 60 mM. The cultures supplemented with salt at highest concentrations (42 and 60 mM) showed a significant increase in algal growth, demonstrated by the optical density spread. The intracellular content of pigments such as chlorophyll a and total carotenoids reached the highest values in cells from cultures supplied with bicarbonate. In fact, concentrations of bicarbonate from 30 to 60 mM strongly improved, for a short period of only 72 h, the cellular levels of chlorophylls and carotenoids. These are interesting pigments with commercial applications. The utilization of bicarbonate could represent an interesting sustainable opportunity to improve microalgae cultivation for cellular growth and pigment contents.

Deodorizing Methods for Recycled High-density Polyethylene Plastic Wastes

The recycling of high-density polyethylene plastic (HDPE) plays a crucial role in sustainable development. However, obstacles to the use of recycled HDPE remain because of the material and processing properties and odors of recycled HDPE. The odor of recycled detergent bottle plastic leads to rejection by most detergent manufacturers. Recently, some recycling enterprises have adapted recycling with odor reduction processes involving the use of solvents, antimicrobial additives, and odor extraction units in feeders and extruders. However, these processes may affect the quality and cost of recycled plastic. Most small and medium businesses (SMBs) may not favor these effects due to their limited models and resources. In addition, most SMBs are unwilling to replace their current recycling operation units. Hence, this study aimed to find alternative and economical ways for odor reduction in the recycling process. A modification of the recycling process was introduced in the pretreatment of plastic flakes before entry into the feeder of an extrusion unit. The effect of selected washing temperatures, i.e., 65℃, 75℃, 85℃, and 95℃, on the removal of odor from recycled HDPE was further studied. The addition of sodium bicarbonate, calcium carbonate, and citric acid into a heated water bath enhanced the deodorizing effect. The relationship of these three chemicals with the deodorization of HDPE plastics was investigated through sensory evaluation. Lastly, the potential of the deodorized recycled HDPE for resin pellet production and commercialization were investigated.

Environmentally Friendly Emergency Lighting System Using Bio Batteries from Pineapple Skin Waste as Energy Source

This study examines the use of bio batteries from pineapple skin paste as an energy source. Bio-battery is a battery with a paste derived from natural materials that are environmentally friendly. The bio-battery is capable of generating electrical power by using a pineapple peel electrolyte paste and copper (Cu) and zinc (Zn) electrodes arranged in series. Parameters measured are voltage, current and duration of the LED (Light Emitting Diode) light. The pasta variations used were pure pasta, pasta with the addition of sodium bicarbonate, pasta with the addition of salt and pasta fermented using LEDs with the total of 6 pieces arranged in parallel and the implementation using pasta with the addition of 0.75 gr salt and 4 LEDs. The research results reveal that the pure paste produces a maximum voltage of 2.410 volts, a maximum current of 0.12 mA with a 14-hour LED light; paste added with sodium bicarbonate produces a maximum voltage of 2,342 volts, a maximum current of 0.21 mA with LED lights on for 12 hours; paste added with salt produces a maximum voltage of 2.432 volts, a maximum current of 0.33 mA with an LED lamp on for 13 hours; and the fermented pasta produced a maximum voltage of 2.542 volts, a maximum current of 0.91 mA. The results showed that bio-battery with pineapple skin paste can produce electrical power that can be used as an energy source for emergency lights.

Utilisation of CO2 from Sodium Bicarbonate to Produce Chlorella vulgaris Biomass in Tubular Photobioreactors for Biofuel Purposes

Microalgae are one of the most promising sources of renewable substrates used for energy purposes. Biomass and components accumulated in their cells can be used to produce a wide range of biofuels, but the profitability of their production is still not at a sufficient level. Significant costs are generated, i.a., during the cultivation of microalgae, and are connected with providing suitable culture conditions. This study aims to evaluate the possibility of using sodium bicarbonate as an inexpensive alternative CO2 source in the culture of Chlorella vulgaris, promoting not only the increase of microalgae biomass production but also lipid accumulation. The study was carried out at technical scale using 100 L photobioreactors. Gravimetric and spectrophotometric methods were used to evaluate biomass growth. Lipid content was determined using a mixture of chloroform and methanol according to the Blight and Dyer method, while the carbon content and CO2 fixation rate were measured according to the Walkley and Black method. In batch culture, even a small addition of bicarbonate resulted in a significant (p ≤ 0.05) increase in the amount of biomass, productivity and optical density compared to non-bicarbonate cultures. At 2.0 g∙L–1, biomass content was 572 ± 4 mg·L−1, the maximum productivity was 7.0 ± 1.0 mg·L–1·d–1, and the optical density was 0.181 ± 0.00. There was also an increase in the lipid content (26 ± 4%) and the carbon content in the biomass (1322 ± 0.062 g∙dw–1), as well as a higher rate of carbon dioxide fixation (0.925 ± 0.073 g·L–1·d–1). The cultivation of microalgae in enlarged scale photobioreactors provides a significant technological challenge. The obtained results can be useful to evaluate the efficiency of biomass and valuable cellular components production in closed systems realized at industrial scale.

Physicochemical, sensorial and rheological characterisation of whole‐fat or low‐fat milk jams as influenced by calcium chloride, sodium bicarbonate and sucrose content

SummaryRheological properties of sixteen milk jam treatments produced from commercial full‐fat (3 g/100 g) and skimmed (0.15 g/100 g) cow milk by the addition of sucrose, sodium bicarbonate and CaCl2 were examined. pH, titratable acidity, total solids and ash contents in the milk jam samples ranged from 6.2 to 6.8, 1.3 to 3.3 g/100 g, 56.7 to 70.5 g/100 g and 1.7 to 3 g/100 g, respectively, with a significant variability (P < 0.05). The flow behaviour and consistency indices ranged from 0.7 to 0.9 and 2.7 to 208 Pa.sn, respectively. Rheological measurements showed that the maximal G' × 102 value showed considerable variation (5–932 Pa). As sucrose content increased, pH and total solid content increased, whereas ash content and the L value decreased. Also, a negative correlation between pH and L* (lightness) was found (P < 0.05). Dynamic rheology showed that the jam from skimmed milk with full sucrose and without sodium bicarbonate exhibited more solid‐like behaviour than the ones prepared with full sucrose and with sodium bicarbonate. In conclusion, the increase in milk fat caused a decrease in resistance of the mixture subjected to the deformation, which is very important for production of quality milk jam.

Short time biomimetic oxidation of styrene with aqueous hydrogen peroxide: Crucial roles played by acetic acid

Short time oxidation of styrene with aqueous hydrogen peroxide catalyzed by a series of manganese porphyrins, MnT(aryl)PP(OAc), (aryl = phenyl, 2-chlorophenyl, 2-methylphenyl, 4-chlorophenyl or 4-methoxyphenyl) was studied under different conditions. In contrast to most previous catalytic systems containing manganese porphyrins and terminal oxidants other than hydrogen peroxide, no oxidation products were observed in the presence of the manganese porphyrins and various amounts of a nitrogen donor co-catalyst. Also, the addition of small and large alcohols to the reaction mixture had no positive effect on the efficiency of the catalyst, although the oxidative stability of the catalyst increased in the case of methanol. The oxidative stability and catalytic activity of the catalysts were remarkably increased in the presence of acetic acid. Furthermore, conducting the oxidation reaction in the presence of acetic acid and an optimized amount of imidazole decreased the reaction time from 120 to 20 min. However, the addition of bicarbonate had no effect on the catalytic performance of the catalysts. A mechanism was proposed to explain the crucial roles played by acetic acid in this catalytic system, using competitive epoxidation of cis-and trans-stilbene to elucidate the active oxidant species involved in the catalytic cycle of the oxidation reaction.

The PsbJ protein is required for photosystem II activity in centers lacking the PsbO and PsbV lumenal subunits.

Photosystem II (PS II) of oxygenic photosynthesis is found in the thylakoid membranes of plastids and cyanobacteria. The mature PS II complex comprises a central core of four membrane proteins that bind the majority of the redox-active cofactors. In cyanobacteria the central core is surrounded by 13 low-molecular-weight (LMW) subunits which each consist of one or two transmembrane helices. Three additional hydrophilic subunits known as PsbO, PsbU and PsbV are found associated with hydrophilic loops belonging to the core proteins protruding into the thylakoid lumen. During biogenesis the majority of the LMW subunits are known to initially associate with individual pre-assembly complexes consisting of one or more of the core proteins; however, the point at which the PsbJ LMW subunit binds to PS II is not known. The majority of models for PS II biogenesis propose that the three extrinsic proteins and PsbJ bind in the final stages of PS II assembly. We have investigated the impact of creating the double mutants ∆PsbJ:∆PsbO, ∆PsbJ:∆PsbU and ∆PsbJ:∆PsbV to investigate potential cooperation between these subunits in the final stages of biogenesis. Our results indicate that PsbJ can bind to PS II in the absence of any one of the extrinsic proteins. However, unlike their respective single mutants, the ∆PsbJ:∆PsbO and ∆PsbJ:∆PsbV strains were not photoautotrophic and were unable to support oxygen evolution suggesting a functional oxygen-evolving complex could not assemble in these strains. In contrast, the PS II centers formed in the ∆PsbJ:∆PsbU strain were capable of photoautotrophic growth and could support oxygen evolution when whole-chain electron transport was supported by the addition of bicarbonate.

Internal carbonation of belite-rich Portland cement: An in-depth observation at the interaction of the belite phase with sodium bicarbonate

The potential for the internal carbonation of belite-rich Portland cement with the addition of sodium bicarbonate is proposed in the present study with a particular observation of the microstructural evolution of the belite phase. Cement paste samples having additional dosages of NaHCO3 of 0, 1, 2, and 5 wt% were fabricated and characterized by means of X-ray diffractometry, pH measurements, thermogravimetry analyses, isothermal calorimetry, and solid-state 29Si nuclear magnetic resonance spectroscopy. The test results indicated that the CO2 released from the added NaHCO3 was uniformly dissolved in the matrix, facilitating internal carbonation. In addition, the formation of C–S–H was further promoted upon the incorporation of NaHCO3, signifying a reaction of belite with the NaHCO3. Isothermal calorimetry results confirmed that the NaHCO3 enhanced the early reaction kinetics. Meanwhile, the pH value of the samples increased due to the anion exchange between the NaHCO3 and Ca(OH)2.

Pengaruh Lama Presto dan Konsentrasi Natrium Bikarbonat (NaHCO3) terhadap Karakteristik Tepung Tulang Ikan Tenggiri (Scomberomorus commerson)

Most fish processing industries only use fish meat as raw material for industry. Whereas fish bones are contain high mineral content needed by the human body and can be utilized as high calcium fishbone meal. Fishbone meal in this reaseach was made from waste from the fishery industries in Tanjungpinang, Riau Islands. Mackerel fishbone meal was made in several steps consist of preparation of raw materials, boiling of fishbones, washing and cleaning of the bones, presto processing of fish bones with the addition of sodium bicarbonate (NaHCO3), drying, siege and sieving. The purpose of this study is to determine the effect of presto duration and concentration of NaHCO3. This research was conducted by the factorial randomized block design method (RAKF) with two factors: duration of presto (2 hours (P1) and 4 hours (P2)) and concentration of NaHCO3 (0% (N1), 1% (N2) and 2% (N3)). The results showed that the duration of presto treatment and the concentration of sodium bicarbonate (NaHCO3) had a significant effect on the 5% level of yield but not significant on calsium content. The best results showed on 2 hours presto with addition NaHCO3 1%. The best treatment was used as a sample to measure the chemical characteristics of mackerel fish bone meal. Fish bone meal obtained 4.86% water content, 69.84% ash content, 3.72% protein content, 17.21% fat content, 12.56% phosphorus content, and 0.46% crude fiber. The chemical content of fishbone meal has been appropriate with Indonesian Nasional Standard.

APLIKASI FOSFAT PADA PROSES EKSTRAKSI TEH HIJAU UNTUK MINUMAN TEH HIJAU SIAP MINUM

Color is one of quality parameters that affects consumer intention to purchase ready to drink (RTD) green tea. Consumers expect RTD green tea to have yellow greenish color, however the color becomes brown and darker during the shelf life. This study aimed to evaluate the effect of phosphate mix addition to water prior to green tea leaves extraction on pH, color, and the tannin in tea extract, pre-RTD, and RTD during incubation period at 60°C for 2 days. The pre-RTD contained tea extract, sugar, and ascorbic acid. Addition of sodium bicarbonate was done in pre-RTD to obtain RTD with pH of 6.1±0.2. The type of phos-phate used was sodium acid pyrophosphate (SAPP) and phosphoric acid. The concentrations of SAPP were 650 and 1300 mg/L, while those of phosphoric acid were 125, 250, and 500 mg/L.The total phospho-rous added from the combination of SAPP and phosphoric acid was 221-521 mg/L. Meanwhile, green tea extracted without phosphate was used as a control. The results showed that phosphate addition to water prior to green tea extraction caused decrease in pH of tea extract from 5.83±0.18 to 2.8-3.8, decrease in browning intensity, and reduced tannin degradation during the incubation period. Sugar and ascorbic acid added to the tea extract resulted in pH in all samples <4.0 and maintained the lightness of the pre-RTD. Phosphate application was not able to retain the color of RTD after incubation period. This study showed that addition of phosphorous as a combination of SAPP and phosphoric acid to water at concentrations of 221-521 mg/L prior to green tea extraction had positive impact in reducing browning intensity of RTD green tea with pH of lower than 4.0.

Zootechnical Fattening Protocol for Mixed Breed Young Bulls with Zoo-sanitary Management System

The objective of this study is to reduce the cost of raising beef cattle in Algeria by proposing a Zootechnical fattening protocol for breeders. The study was carried out on mixed-breed young bulls (Charolais x local breeds). Food rations were distributed daily; the first ration (F1) was made up of soybeans while the second ration (F2) was made of tomato pulp supplemented with sodium bicarbonate. Parameters calculated were the Average Daily Gain (ADG), quantity of faeces eliminated, and weight of each bull. The ADG results shown in F1 and F2 are close. The addition of Sodium Bicarbonate in the F2 ration helps to alleviate certain digestive disorders, particularly acidosis and diarrhoea; therefore, reducing the production costs per kg of meat obtained from bulls fed with tomato which was available annually. The proposed protocol improved fillet yield and lowered the cost per kg of meat. It can be applied internationally in any rudimentary livestock farm.

Leaching Kinetics of Secondary Zinc Oxide in a NH3–NH4HCO3–H2O System

Secondary zinc oxide (SZO), which comes from the zinc industry, is an important secondary resource of zinc and other valuable metals. In this study, the production feasibility and rationality of a cleaner zinc recovery process using SZO and a hydrometallurgical method were described. Zinc extraction is promoted by the addition of ammonium bicarbonate to a NH3–H2O system, and the maximum recovery of zinc could be close to 80% at the optimum leaching conditions of a stirring rate of 400 rpm, an ammonia/ammonium ratio of 7:3, a total ammonia concentration of 4 mol/L, and a liquid/solid ratio of 7 mL/g for 30 min at 35 °C. The kinetics of leaching were modeled using the shrinking core model of constant-size particles, and the rate-controlling step was determined to be the diffusion through the product layer. The apparent activation energy of the reaction was estimated to be 11.04 KJ·mol−1, while the order of reaction with respect to total ammonia concentration was 1.53 and the liquid/solid ratio was 2.26. The analysis results of the initial residue and the leached residue indicated that lead was transferred from PbCl2 to PbCO3 and that ZnFe2O4 was not leached in the NH3-NH4HCO3-H2O system.

Evidenced-based local anaesthesia—is there a difference in practice between specialties in a major trauma centre?

BackgroundLocal anaesthesia (LA) is used widely in several clinical scenarios in hospital practice. A number of minor trauma wounds are treated under LA at the North Bristol Trust, and on most occasions, these patients are admitted to the emergency department (ED) and treated there. On other occasions, more complex wounds may be treated by the plastic surgery team. The aim of this study is to compare the preferences of LA agents between these departments in cases of minor trauma. The authors also present a narrative review of the literature and determine best practice.MethodsA single-centre clinical practice survey was developed and distributed to both departments which involved two case scenarios, one involving a head injury to the occiput (scenario 1) and one nailed repair (scenario 2) both requiring treatment under LA.ResultsIn both scenarios ED favoured lidocaine (89%) whereas the plastic surgery team preferred to mix solutions. In scenario 1, 89% of ED participants chose lidocaine 1%, but only 38% of the plastic surgery team chose it. Forty-two percent of ED chose to use adrenaline but 100% plastic surgery team chose it. Both teams refrained from using adrenaline in digits, but 23% of the plastic surgery team chose it. Eighty-four percent of ED chose 25G needles, and the plastic surgery team’s choices varied.ConclusionsThis study has shown marked differences in the use of LA between two specialties in a major trauma centre. There is good quality evidence to support the safety of adrenaline use in digits with the addition of sodium bicarbonate to decrease the pain inflicted to the patient upon infiltration of LA. This study serves to raise awareness of the surgical dogma around adrenaline use and provide clinicians with an evidence-based guide to managing minor trauma with LA.Level of evidence: Not ratable.

Evaluation of Addition of Sodium Bicarbonate to Dexamethasone and Ropivacaine in Supraclavicular Brachial Plexus Block for Upper Limb Orthopedic Procedures.

Background:Peripheral nerve blocks have taken over as the principle technique for upper limb surgeries. A number of adjuvants have been tried individually, but very few studies have investigated the cumulative effect of two or more adjuvants given together along with local anesthetic.Aim:This study aimed to evaluate the effect of addition of sodium bicarbonate to dexamethasone and ropivacaine in supraclavicular brachial plexus block.Settings and Design:This was a prospective, randomized, double-blind study that comprised 90 American Society of Anaesthesiologist (ASA) 1 and 2 patients posted upper limb orthopedic procedures.Materials and Methods:Ninety ASA 1 and 2 patients were selected and divided into three groups of 30 each: Group R received 30 mL of 0.75% ropivacaine plus 4 mL normal saline; Group RD 30 mL of 0.75% ropivacaine, 2 mL normal saline and 2 mL of dexamethasone were given; Group RB 30 mL of 0.75% ropivacaine plus 2 mL of dexamethasone and 2 mL of sodium bicarbonate. Onset and duration of sensory and motor block and postoperative pain scores were studied in each group.Statistical Analysis:Student's independent t-test was employed for comparing the continuous variables and Chi-square test for the categorical variables. Kruskal–Wallis test was used for postoperative pain score data.Results:Addition of sodium bicarbonate to dexamethasone and ropivacaine quickens onset and prolongs duration of sensory and motor block.Conclusion:Sodium bicarbonate produces a synergistic and potentiating effect with dexamethasone as adjuvant in supraclavicular brachial plexus block.

Deficit Therapy in Children with Acute Diarrhoea and Severe Dehydration Presenting with Severe Non-Anion Gap Metabolic Acidemia: Should Bicarbonate Be an Integral Component?

Background: Acute diarrhea and severe dehydration (ADSD) is a common cause of under-5 mortality in low- and middle-income countries. There is a paucity of data on clinical profile of ADSD children presenting with severe non-anion gap metabolic acidemia (sNAGMA). Study was planned to delineate clinical profile, critical care needs, and outcome of these children. Methods: For this retrospective chart review, children (1mo-12yr) with ADSD and sNAGMA (pH <7.2 and/or bicarbonate <15 mEq/L, and anion gap <16) over 3 years (Jan’16-Dec’18) were included. sNAGMA was classified further in three increasing grades of severity. Pure high anion-gap metabolic acidemia and other suspected causes of metabolic acidemia were exclusions. Patients were managed with standard deficit therapy protocol. Primary outcome was time taken for resolution of acidemia. Adverse outcome was defined as composite of PICU admission and/or death. Findings: Out of 929 diarrhea patients admitted for intravenous deficit therapy, 121 (13%) (median age, 4mo) had ADSD and sNAGMA. Median pH was 7.11(7.01-7.22); 21% patients had pH<7.00. Hyperchloremia (96%) and hypernatremia (45%) were common. Twelve percent required inotropes (n=14) and ventilation (n=15), while 58% had acute kidney injury (AKI). Adverse outcome was seen in 32(26%) patients. Higher grades of sNAGMA were associated with shock(p=0.012), AKI(p=0.004), coma(p=0.005), hypernatremia(p=0.0004), hyperkalemia(p=0.006), adverse outcome(p=0.024) and lesser Acute Care Area Free Days in 5 days (p=0.003). Time for resolution of acidemia among survivors was 24h (12-24). Shock, need for ventilation, renal replacement therapy and higher grades of sNAGMA were predictors of adverse outcome, former two being independent ones. Interpretations: sNAGMA is common in children with ADSD in tertiary care centres of LMICs, and associated with shock, dyselectrolytemias and AKI. Higher grade of sNAGMA was predictor of adverse outcome. Trials are required to evaluate addition of bicarbonate to the standard deficit therapy protocol in this select group of patients. Funding: None to declare. Declaration of Interest: None to declare. Ethical Approval: The study protocol was approved by the Institute thesis Committee and by the designated Ethics Committee of Postgraduate Institute of Medical Education & Research, Chandigarh (INT/IEC/2019/000485 dated 15.03.2019). Being a retrospective chart review, written informed consent was waived off. The manuscript has been approved by the Departmental Review Board.

Виявлення фальсифікації меду домішкою натрію гідрокарбонату із застосуванням індикатора бромтимолового синього

A method for detecting honey falsification with sodium bicarbonate, added deliberately to reduce the mass fraction of water in honey, increase its density and consistency, eliminate signs of fermentation and reduce contamination by microorganisms, has been substantiated. The used indicator is bromothymol blue alcohol solution with a mass concentration of 0.01% in an amount of 2-3 drops. In the absence of sodium bicarbonate admixture in honey, the colour of the solution is olive; in case of the sodium bicarbonate addition up to 1.0% of the honey volume - it turns light blue; from 1.1 to 2.0% – sky blue; from 2.1 to 3.0% – dark blue. The proposed method is reliable, fast, easy to carry out, does not require a lot of cost for reagents and can be used in combination with other methods for determining the safety and quality of honey, as well as detecting its falsifications. The developed method can be used to detect honey falsification with sodium bicarbonate when determining its safety and quality in production laboratories at facilities for the production of honey and apiproducts, supermarkets, wholesale depots, stores, state laboratories of the State Service of Ukraine on Food Safety and Consumer Protection (SSUFSCP), in government laboratories, in laboratories at designated border inspection posts when carrying out simple laboratory tests using express methods, as well as during the forensic examination of honey. Based on the results of the developed author’s method, it is possible to obtain qualitative characteristics for assessing the honey safety and its quality. The possibility of using an express and effective control system within the framework of simple laboratory tests at designated border inspection posts will allow the implementation of an effective food control system at the stage of their state border verification. Establishing mismatches at the stage of border control and sending laboratory samples for extended laboratory studies (tests) to the state laboratory of the State Service of Ukraine on Food Safety and Consumer Protection, will strengthen the effectiveness of the control system at the stage of early detection of insecurity indicators and prevent the products release that do not meet safety and quality characteristics into circulation. The development of a methodological concept and the creation of a base of methods for detecting honey falsification will contribute to the distribution of safe and high-quality products for consumers, systematization of simple methods for food products study, including honey, in laboratories at designated border inspection posts, during the implementation of state control measures at the Ukrainian state border, will increase the reliability, objectivity and accuracy of the results of the examination, in case of carrying out.

Cell size influences inorganic carbon acquisition in artificially selected phytoplankton.

Cell size influences the rate at which phytoplankton assimilate dissolved inorganic carbon (DIC), but it is unclear whether volume-specific carbon uptake should be greater in smaller or larger cells. On the one hand, Fick's Law predicts smaller cells to have a superior diffusive CO2 supply. On the other, larger cells may have greater scope to invest metabolic energy to upregulate active transport per unit area through CO2 -concentrating mechanisms (CCMs). Previous studies have focused on among-species comparisons, which complicates disentangling the role of cell size from other covarying traits. In this study, we investigated the DIC assimilation of the green alga Dunaliella tertiolecta after using artificial selection to evolve a 9.3-fold difference in cell volume. We compared CO2 affinity, external carbonic anhydrase (CAext ), isotopic signatures (δ13 C) and growth among size-selected lineages. Evolving cells to larger sizes led to an upregulation of CCMs that improved the DIC uptake of this species, with higher CO2 affinity, higher CAext and higher δ13 C. Larger cells also achieved faster growth and higher maximum biovolume densities. We showed that evolutionary shifts in cell size can alter the efficiency of DIC uptake systems to influence the fitness of a phytoplankton species.

Effect of temperature, nitrate concentration, pH and bicarbonate addition on biomass and lipid accumulation in the sporulating green alga PW95

The mixed effects of temperature (20 °C, 25 °C and 30 °C), nitrate concentration (0.5 mM and 2.0 mM), pH buffer, and bicarbonate addition (trigger) on biomass growth and lipid accumulation were investigated in the environmental alga PW95 during batch experiments in standardized growth medium. PW95 was isolated from coal-bed methane production water and classified as a Chlamydomonas-like species by morphological characterization and phylogenetic analysis (18S, ITS, rbcL). A factorial experimental design tested the mixed effects on PW95 before and after nitrate depletion to determine a low cost, high efficiency combination of treatments for biomass growth and lipid accumulation. Results showed buffer addition affected growth for most of the treatments and bicarbonate trigger had no statistically significant effect on growth and lipid accumulation. PW95 displayed the highest growth rate and chlorophyll content at 30 °C and 2.0 mM nitrate and there was an inverse relation between biomass accumulation and lipid accumulation at the extremes of nitrate concentration and temperature. The combination of higher temperature (30 °C) and lower nitrate level (0.5 mM) without the use of a buffer or bicarbonate addition resulted in maximal daily biomass accumulation (5.30 × 106 cells/mL), high biofuel potential before and after nitrate depletion (27% and 20%), higher biofuel productivity (16 and 15 mg/L/d, respectively), and desirable fatty acid profiles (saturated and unsaturated C16 and C18 chains). Our results indicate an important interaction between low nitrate levels, temperature, and elevated pH for trade-offs between biomass and lipid production in PW95. This work serves as a model to approach and advance the study of physiological responses of novel microalgae to diverse culture conditions that mimic environmental changes for outdoor biofuel production. The most promising conditions for growth and biofuel production were identified for PW95 and this approach can be implemented for other microalgal production systems.

An external magnetic field moderating Cr(VI) stress for simultaneous enhanced acetate production and Cr(VI) removal in microbial electrosynthesis system

A stressful heavy metal circumstance disfavors production of acetate from bicarbonate reduction in the biocathode of microbial electrosynthesis system (MES) with simultaneous function of heavy metal removal/recovery. It is of great interest to explore effective approaches to moderate the heavy metal stress with achievement of simultaneous enhanced acetate production and heavy metal removal in MES. Herein, a magnetic field strength of 100 mT was successfully employed to moderate Cr(VI) stress, achieving simultaneous production of acetate at a rate of 1.48 ± 0.01 mg/L/h and Cr(VI) removal at a rate of 1.67–2.42 mg/L/h in the Serratia marcescens Q1 catalyzed cathode of MES under periodical addition of bicarbonate and Cr(VI), 1.35-fold (acetate production) and 1.34–1.46 times (Cr(VI) removal) of those in the controls in the absence of magnetic field. This simultaneous efficient acetate production and Cr(VI) removal was regulated by the magnetic field and the stressful Cr(VI), which induced the S. marcescens to physiologically release additive amounts of extracellular polymeric substances with a compositional diversity and containing the electrochemically active c-type cytochromes to facilitate extracellular electron transfer. This study confirmed the importance of magnetic field in developing the S. marcescens catalytic activity for moderating Cr(VI) stress, and thus provided a feasible approach for simultaneous efficient acetate production and Cr(VI) removal/recovery in MES, from waters contaminated with Cr(VI).

Lightweight Gypsum Materials with Potential Use for Thermal Insulations.

This article presents the influence of three additions i.e., hydroxyethyl methyl cellulose (HEMC), sodium bicarbonate and flue gas desulfurization (FGD) gypsum on the porosity of gypsum-based materials. The specific microstructure for a material with good thermal insulation properties i.e., numerous closed pores distributed in the binding matrix, was achieved using HEMC (0.3 wt.%) and sodium bicarbonate (0.5–2 wt.%). The addition of HEMC to the gypsum binder determines, as expected, an increase of the porosity due to its ability to stabilize entrained air. In the case of a sodium bicarbonate addition, the pores are formed in the binding matrix due to the entrapment of the gas (CO2) generated by its reaction. Sodium bicarbonate addition delays the setting of gypsum binder therefore in this study FGD gypsum (waste produced in the desulfurization process of combustion gases generated in power plants) was also added to the mixture to mitigate this negative effect. The decrease of geometrical density (up to 13%, in correlation with the additive nature and dosage) correlated with the increase of the porosity, determines, as expected, the decrease of flexural and compressive strengths (33–75%), but improves the thermal properties i.e., decreases the thermal conductivity (9–18%).