Ammonium Sulfate Concentration Research Articles

Biodecolourisation of Reactive Red 120 as a Sole Carbon Source by a Bacterial Consortium-Toxicity Assessment and Statistical Optimisation.

The application of microorganisms in azo dye remediation has gained significant attention, leading to various published studies reporting different methods for obtaining the best dye decolouriser. This paper investigates and compares the role of methods and media used in obtaining a bacterial consortium capable of decolourising azo dye as the sole carbon source, which is extremely rare to find. It was demonstrated that a prolonged acclimation under low substrate availability successfully isolated a novel consortium capable of utilising Reactive Red 120 dye as a sole carbon source in aerobic conditions. This consortium, known as JR3, consists of Pseudomonas aeruginosa strain MM01, Enterobacter sp. strain MM05 and Serratia marcescens strain MM06. Decolourised metabolites of consortium JR3 showed an improvement in mung bean’s seed germination and shoot and root length. One-factor-at-time optimisation characterisation showed maximal of 82.9% decolourisation at 0.7 g/L ammonium sulphate, pH 8, 35 °C, and RR120 concentrations of 200 ppm. Decolourisation modelling utilising response surface methodology (RSM) successfully improved decolourisation even more. RSM resulted in maximal decolourisation of 92.79% using 0.645 g/L ammonium sulphate, pH 8.29, 34.5 °C and 200 ppm RR120.

Homogeneous batch micro-crystallization of proteins from ammonium sulfate.

The emergence of X-ray free-electron lasers has led to the development of serial macromolecular crystallography techniques, making it possible to study smaller and more challenging crystal systems and to perform time-resolved studies on fast time scales. For most of these studies the desired crystal size is limited to afew micrometres, and the generation of large amounts of nanocrystals or microcrystals of defined size has become a bottleneck for the wider implementation of these techniques. Despite this, methods to reliably generate microcrystals and fine-tune their size have been poorly explored. Working with three different enzymes, L-aspartate α-decarboxylase, copper nitrite reductase and copper amine oxidase, the precipitating properties of ammonium sulfate were exploited to quickly transition from known vapour-diffusion conditions to reproducible, large-scale batch crystallization, circumventing the tedious determination of phase diagrams. Furthermore, the specific ammonium sulfate concentration was used to fine-tune the crystal size and size distribution. Ammonium sulfate is a common precipitant in protein crystallography, making these findings applicable to many crystallization systems to facilitate the production of large amounts of microcrystals for serial macromolecular crystallography experiments.

Screening of Methionine-producing <i>Bacillus</i> Species from Nigerian Fermented Food Condiments and Effects of Some Cultural Parameters on Methionine Accumulation

Fermented food condiments are sources of proteins and vitamins and are added as spices or sauces to food for flavour or taste enhancers. The major fermenting microorganisms, Bacillus species, produce proteolytic enzymes that hydrolyze proteins and amino acids and peptides. Methionine is the most essential amino acid for chicken feeds and can be produced by Bacillus species. The screening of methionine-producing microorganisms from Nigerian fermented food condiments and the effect of some cultural parameters on methionine accumulation were conducted. Bacterial organisms isolated from fermented food condiments, ogiri and okpeye, were screened for methionine producers on minimal solid agar medium seeded with auxotrophic Escherichia coli and in submerged medium. The effects of medium to fermenter volume ratio, inoculum size, carbon and nitrogen sources on methionine accumulation by the isolates were investigated. Of the five methionine producers recovered, two of the active isolates identified as Bacillus pumilus and Bacillus amyloliquefaciens were used for methionine production. A 20.0ml fermentation medium and 5.0% inoculum size gave the highest methionine accumulation by the Bacillus species. At 8.0% glucose and 4.0% ammonium sulphate concentrations, methionine yields of 5.22mg/ml and 5.50mg/ml were accumulated in the broth cultures of B. pumilus and B. amyloliquefaciens respectively. B. pumilus and B. amyloliquefaciens recovered from Nigerian fermented food condiments were observed to produce methionine and the optimization of some cultural parameters enhanced methionine accumulation by the Bacillus species.

Biostimulation of Microbial Communities from Malaysian Agricultural Soil for Detoxification of Metanil Yellow Dye; a Response Surface Methodological Approach

In the present study, a mixed culture from a local agricultural soil sample was isolated for Metanil Yellow (MY) dye decolorization. The metagenomic analysis confirmed that 42.6% has been dominated by genus Bacillus, while Acinetobacter (14.0%) is present in the microbial communities of the mixed culture. For fungi diversity analysis, around 97.0% was “unclassified” fungi and 3% was Candida. The preliminary investigation in minimal salt media (MSM) showed that 100% decolorization was achieved after 24 h of incubation. Response surface methodology (RSM) was successfully applied using Box-Behnken design (BBD) to study the effect of four independent parameters—MY dye concentration, glucose concentration, ammonium sulfate concentration, and pH—on MY dye decolorization by the mixed bacterial culture. The optimal conditions predicted by the desirability function were 73 mg/L of MY, 1.934% glucose, 0.433 g/L of ammonium sulfate, and a pH of 7.097, with 97.551% decolorization The correlation coefficients (R2 and R2 adj) of 0.913 and 0.825 indicate that the established model is suitable to predict the effectiveness of dye decolorization under the investigated condition. The MY decolorization of the mixed bacterial culture was not affected by the addition of heavy metals in the growth media. Among the 10 heavy metals tested, only copper gave 56.19% MY decolorization, whereas the others gave almost 100% decolorization. The decolorization potential of the mixed bacterial culture indicates that it could be effective for future bioremediation of soil-contaminated sites and treatment solutions of water bodies polluted with the MY dye.

(Invited) Integrated Green Engineering Process for Simultaneous Hydrogen Production and Fertigation

The constant utilization of hydrocarbon-based fuels such as petroleum, coal, and natural Gas has resulted in the detection of high concentration levels of sulfur containing gases in the atmosphere of many countries, including Qatar. Among those potential air pollutants, the rising concentrations of H2S and SO2 are of serious concern. In this work, sulfur-based seed solutions (SBSSs) such as sulfite or sulfide solutions are made by purging sulfur-containing gases released from industry into alkaline solutions. These SBSS solutions are simultaneously utilized towards the production of renewable hydrogen energy via a photoelectrochemical (PEC) process, and are used as draw solutions (DS) to produce diluted fertilizer water by a forward osmosis (FO) desalination process for agricultural irrigation purposes. The continuous bench scale of the integrated PEC-FDFO system was successfully demonstrated for simultaneous hydrogen production and dilution of SBSS DS. The experimental results showed that the reduction potential of SBSS DS in the PEC cell changes with variation of SBSS DS concentration and pH. This resulted in the continuous oxidation of sulfite into sulfate and led to more hydrogen production. Moreover, FDFO process exhibited high percentage of water recovery and DS dilution up to 80% and 68% at high SBSS DS concentration, respectively. In binary mixture of SBSS DS, increasing the concentration of ammonium sulfate (NH4)2SO4 led to high water flux to about 42%. The outcomes of this experimental study showed a successful practical continuous integrated system toward hydrogen production and fertigation.

Nitrogen Recovery from Swine Manure Using a Zeolite-Based Process

Intensive pig farming produces huge amounts of swine manure, which can cause regional nutrient imbalances and represent a potential source of soil and water pollution due to manure over-application. In order to improve nutrient stewardship, technologies for manure treatment and selective recovery of nutrients (especially ammonia) have to be developed to foster agriculture–food system sustainability. In the present study, a combined stripping and ion exchange process using natural zeolite (ion-exchanger-loop-stripping process) is tested for nitrogen recovery from swine manure to determine its technical feasibility in this novel field of application. Ammonium removal rates of 85 to 96% were achieved in pilot scale experiments with preprocessed manure (~500 L h−1 after mechanical filtration; input concentration: ~1.3 g NH4+ L−1). NH4+ was successfully transferred to a concentrated ammonium sulfate solution (final concentration: 66 g NH4+ L−1), with no significant transfer of other manure components. Hence, various utilizations of the product solution are possible, e.g., for industrial off-gas cleaning (DeNOx) or as raw material for fertilizer production. Based on these findings, the ILS-process can be regarded as a promising option for nitrogen recovery from swine manure.

Effects of oxidising atmosphere on brewer’s yeast hydrothermal treatment and subsequent biopolymer recovery

• The presence of oxygen enhanced yeast disintegration. • Soluble proteins abated at long times when oxygen was present. • Oxygen caused a convergency in the different protein isoelectric points to 3. • Oxygen decreased protein hydrophobicity, worsening saline precipitation. • Oxygen reduced protein recovery but enhanced selectivity in IMAC. Spent brewer’s yeast is an underused by-product, whose current management offers low returns. This article studies, for the first time ever, the hydrothermal treatment of spent brewer’s yeast, paying special attention to the effect of the presence of oxygen on the physical properties, composition and potential recovery of valuable products from the hydrolysed yeast, as previous step towards the employment of these recovered proteins as renewable chemical feedstock for green industrial uses. Results showed a higher VSS disintegration employing an oxidising atmosphere, as well as a better solubilisation in terms of solid COD reduction, although it also lowered soluble COD but without significantly reducing soluble TOC. Both treatments led to an almost complete solubilisation of protein and carbohydrates from yeast, which were subsequently degraded in presence of oxygen if reaction times were lengthened. Looking at biopolymer recovery, protein precipitation by pH adjustment worked better in hydrolysates obtained in presence of oxygen, with almost 90% of protein precipitation and good selectivities at pH 2.5 and 3. Salting out was more effective, in terms of selectivity, for samples obtained in absence of oxygen and low concentrations of ammonium sulphate. The application of IMAC showed better results on yeast hydrolysates obtained under an inert atmosphere, reaching maximum sorption capacities of almost 100 mg protein/g dry resin, three times higher than those observed using the hydrolysate produced in presence of oxygen. A new perspective in yeast management during beer production is open as renewable chemical feedstock for protein, although further studies are required to optimise protein recovery and purification with respect to its applications.

Statistical optimisation for enhancement of phenol biodegradation by the Antarctic soil bacterium Arthrobacter sp. strain AQ5-15 using response surface methodology

Aim: Effective bioremediation requires optimisation of conditions under which the process takes place. In this study, an Antarctic soil bacterium, Arthrobacter sp. strain AQ5-15, was evaluated for phenol biodegradation under statistically optimised conditions. Methodology: The composition of degradation media and the culture conditions for this study were determined according to the experimental requirements obtained from Plackett-Burman factorial design (PB) and Box-Wilson Central Composite Design (CCD), respectively. Phenol degradation was monitored by 4-aminoantipyrine colorimetric assay and bacterial growth was quantified by measuring optical density (OD600 nm) at 72 hr. Results: A preliminary screening experiment using the Plackett-Burman design indicated that all the factors screened (ammonium sulphate concentration, sodium chloride concentration, pH and temperature) had significant influence on degradation performance. Response Surface Methodology was then utilised to further optimise the phenol-degrading process using Central Composite Design. The maximum percentage of phenol degradation achieved with CCD was 99.42%, under medium conditions of 0.15 g l-1 (NH4)2SO4, 0.13 g l-1 NaCl, pH 7.25 and incubation at 15°C for 72 hr. The strain could degrade phenol when exposed to an initial concentration of up to 1.5 g l-1 under these optimised conditions. Interpretation: The tolerance and degradation characteristics of strain AQ5-15 suggest that it has potential application in bioremediation of polluted sites and in the treatment of relatively cool water bodies contaminated with phenol.

Improvement of glutathione production by a metabolically engineered Yarrowia lipolytica strain using a small-scale optimization approach.

In this study, we aimed to maximize glutathione (GSH) production by a metabolically engineered Yarrowia lipolytica strain using a small-scale optimization approach. A three levels four factorial Box-Behnken Design was used to assess the effect of pH, inulin extract, yeast extract and ammonium sulfate concentrations on cell growth and to generate a mathematical model which predict optimal conditions to maximize biomass production and thus GSH titer. The obtained results revealed that only yeast and inulin extract concentrations significantly affect biomass production. Based on the generated model, a medium composed of 10g/L of yeast extract and 10g/L of inulin extract from Jerusalem artichoke was used to conduct batch cultures in 2 L bioreactor. After 48h of culture, the biomass and the glutathione titer increased by 55% (5.8 gDCW/L) and 61% (1011.4mg/L), respectively, as compared to non-optimized conditions. From the obtained results, it could be observed that the model established from small scale culture (i.e. 2mL) is able to predict performance at larger scale (i.e. 2 L bioreactor, two orders of magnitude scale-up). Moreover, the results highlight the ability of the optimized process to ensure high titer of glutathione using a low-cost carbon source.

Lignin peroxidase-based cross-linked enzyme aggregates (LiP-CLEAs) as robust biocatalytic materials for mitigation of textile dyes-contaminated aqueous solution

Lignin peroxidase (LiP) produced by basidiomycetous fungi displays a high potential in various biotechnological applications. Extracellular LiP from Schizophyllum commune IBL-06 was insolubilized in the form of CLEAs as a sequential step of protein precipitation, followed by glutaraldehyde cross-linking. The highest relative activity of LiP-immobilized cross-linked enzyme aggregates (LiP-CLEAs) was achieved at 80% saturation with ammonium sulfate and glutaraldehyde concentration of 2.5% (v/v). The optimum pH for the free enzyme was 3.0, whereas the immobilization process caused a slight shift in the pH optima to 4.0. After CLEA formation, the temperature optimum of soluble LiP (35 °C) was favorably increased to 60 °C. Though LiP-CLEAs exhibited a reduced affinity towards its substrate, Vmax values were increased to 951.9 U/mL compared to 845.1 U/mL by the free enzyme. LiP-CLEAs efficiently catalyzed the biodegradation of representative reactive dyes with 89.6% degradation of Sandal-fix Black CKF dye following 81.46% and 79.6% of Sandal-fix Turq Blue GWF and Sandal-fix Red C4BLN, respectively, after 6 h of treatment. The degradation percentage achieved in the case of LiP-CLEAs was 33.91%, 53.35%, and 25.24% higher than the free form of LiP, respectively. Interestingly, LiP-CLEAs retained 62.3, 64.8, and 68.6% residual activities for the degradation of S.F. Red, S.F. Black, and S.F. Turq Blue, respectively, after three repeated cycles. Overall, the results suggest that the LiP-CLEAs might have a robust biotechnological potential to mitigate a wide range of dyes and emerging contaminants.

Study of Effect of Potassium Nitrate and Ammonium Sulphate on Dielectric Properties of Soil at X and J-Band Microwave Frequencies

Microwave has prominent role in the present era due to its application in remote sensing. Present investigation is emphasized to explore the impact of potassium nitrate and ammonium sulphate on dielectric traits of soil samples by exposing it to X and J-band microwave frequencies. For this two different soil samples were collected from Jalna and badnapur of Maharashtra. The infinite sample method was employed for the determination of dielectric constant (e’), dielectric loss (e”), AC Conductivity and Relaxation Time of the soils. The variation in values of all the parameters of these samples mixed with different concentration of potassium nitrate and ammonium sulphate were then measured at fixed frequency X-band (6 GHz) and J-band (9.86 GHz).

Optimization of media and culture conditions for the production of tacrolimus by Streptomyces tsukubaensis in shake flask and fermenter level

Abstract Goal of present research based on optimization of tacrolimus production by One-factor-at-a-time method and response surface methodology (RSM) using Streptomyces tsukubaensis NBRC 108819. Plackett–Burman Design was adopted for the selection of main nutrients inducing the production of tacrolimus. Out of 19 factors studied by Plackett–Burman Design, three variables (ammonium sulphate, yeast extract and 1, 2 propylene glycol) influenced the tacrolimus production most significantly. Thus in Central Composite Design the optimum concentrations of ammonium sulphate, yeast extract and 1, 2 propylene glycol were optimized for the maximum production of tacrolimus. The optimum medium composition for tacrolimus production was glucose (4 g/L), yeast extract (14.32 g/L), 1, 2 propylene glycol (1.49%), glycine (0.2 g/L) and ammonium sulphate (30 g/L). Optimized medium by statistical approach demonstrated the significant effect on tacrolimus production and increased it production from 205 ± 22.0 mg/L to 604 ± 54.6 mg/L in comparison to basal media. In addition optimized conditions were also used at bioreactor level to scale up the fermentation process in which tacrolimus production was attained 616 ± 52.2 mg/L after 168 h fermentation.

Influence of Ammonium Sulfate Seed Particle on Optics and Compositions of Toluene Derived Organic Aerosol in Photochemistry

Aromatic secondary organic aerosol (SOA) particles are known to contribute to radiative forcing and light absorption of atmosphere. However, the complex refractive index (CRI), single-scattering albedo (SSA) and other optical parameters of aromatic SOA are not well understood. SOA generated from photooxidation of toluene with a variety concentration of ammonium sulfate ((NH4)2SO4) seed particles in a smog chamber were investigated in the current study. The real part CRI of toluene SOA without seeds derived and based on aerosol albedometer measurements is 1.486 ± 0.002 at λ = 470 nm, showing a good agreement with available experimental data, and its SSA was measured to be 0.92 ± 0.02 at λ = 470 nm, indicating that the SOA particles without seeds have strong scattering ability. The SSA of SOA formed in the presence of 300 μg/m3 (NH4)2SO4 seed was 0.81 ± 0.02 at λ = 470 nm, less than the SSA of SOA without seed. SSA of SOA decreased, while the imaginary part of CRI (k) of SOA increased with increasing concentration of (NH4)2SO4 seed, demonstrating that the adsorption capacity of SOA formed in the presence of (NH4)2SO4 seed is enhanced. Different from the carboxyl compounds measured in the SOA without seed, imidazoles with strong chromophores of C=N that are responsible for the light absorption were detected as the principal constituents of SOA formed in the presence of (NH4)2SO4 seed. These would provide valuable information for discussing the optics and components of aromatic SOA in the urban atmosphere containing a high concentration of (NH4)2SO4 fine particles.

Critical aspects on traditional antivenom production processes and their optimization by factorial analysis

Most antivenoms are produced by techniques developed over 50 years ago, with minor modifications. Herein we revise the core of traditional antivenom production processes aiming to optimize key determinants for both consistent antivenom production and the best balance between F(ab')2 quality and recovery. Factorial design analysis revealed that pepsin digestion of 1:3 saline diluted equine plasma for 60 min under pH: 3.20, 37 °C temperature and a 1:15 pepsin to protein ratio conditions, allowed to achieve maximal IgG to F(ab')2 conversion with minimal protein aggregate formation. Further downstream processing by salting out with ammonium sulfate was also studied by factorial analysis. The influence of ammonium sulfate (AS) concentration, temperature (T) and the albumin to total plasma protein ratio plasma (Alb:P) were assayed, revealing that both AS, T and their interaction have a significant impact in F(ab')2 quality and recovery. Taking into account the existing compromise between F(ab')2 monomer recovery and quality two alternative conditions were selected: 14 g/dl AS at 56 °C and, alternatively 16 g/dl AS at 30 °C. Reasonable yields (42%) and product quality (2.5% of aggregates) without significant changes in production cost of traditional methodologies was achieved under the optimized conditions found.

Application of Plackett Burman and Box Behnken Design for the Optimization of a-glucosidase Production by Thermophillic Thermomyces dupontii

A consecutive optimization based on statistical approach was applied for a-glucosidase production by both wild and mutant T. dupontii. Plackett Burman design (PBD) with two levels was employed in order to screen the significant effect of different nutritional and physical parameters through submerged fermentation. Among all nine variables tested in PBD, incubation time, inoculum size and ammonium sulphate concentration were selected. The Box-Behnken approach was further applied for process optimization. The a-glucosidase production for both wild and mutant T.dupontii was obtained at 72 h of incubation, 1.25 mL inoculum size and 0.25% ammonium sulphate concentration with relatively 95% correlation between the experimentally predicted and observed values. The duration of maximum enzyme production in RSM was cost-saving and fast. The quadratic model was in satisfactory adjustment with the experimental data with high R2 value which describes 98.90% of response variability of the model. Moreover, the novel approach of this present work is that, consecutive optimization were applied for maximum a-glucosidase production using response surface methodology by both wild and mutant thermophillic T. dupontii. Results revealed that thermophillic mutant T. dupontii could be potential candidate for industrial applications.

Optimization Study of Marmelosin (Imperatorin) Extraction from Aegle marmelos Using Three Phase Partitioning

Aegle marmelos is a prominent tree in Indian Ayurveda and occupies an important place in Ayurvedic, Unani and Siddha system of Indian medicine due to its ethnomedicinal values. The current work demonstrates the use of three-phase partitioning (TPP) for the first time to isolate and purify a potent bioactive compound marmelosin from A. marmelos fruit. Marmelosin exhibits antibacterial, anticancer, hepatoprotective and antidiabetic activity. Here, various experimental conditions were optimized for TPP, and comparison was made between conventional techniques like Soxhlet and batch extraction. The impact of various TPP parameters such as ammonium sulphate concentration, solute to solvent ratio, time, slurry to t-butanol, and pH on the yield of marmelosin was studied. TPP shows maximum marmelosin yield of 0.494 mg/g at the optimized condition as solute to solvent ratio 1:50 , time 2.5 h, ammonium sulphate concentration 30 w/v %, slurry to t- butanol ratio 1:1, pH 5. Conventional techniques, i.e., Soxhlet and batch extraction, resulted in yield of 0.250 mg/g in 7 h and 0.150 mg/g respectively in 4 h. Thus, TPP enhances the yield as well as reduces the extraction time that shows it is a simple, effective, promising, and cost-effective technique for the extraction of marmelosin thereby reducing the processing time.

Effects of aerosol type and simulated aging on performance of low-cost PM sensors

Studies that characterize the performance of low-cost particulate matter (PM) sensors are needed to help practitioners understand the accuracy and precision of the mass and number concentrations reported by different models. We evaluated Plantower PMS5003, Sensirion SPS30, and Amphenol SM-UART-04L PM sensors in the laboratory by exposing them to: (1) four different polydisperse aerosols (ammonium sulfate, Arizona road dust, NIST Urban PM, and wood smoke) at concentrations ranging from 10 to 1000 μg m−3, (2) hygroscopic and hydrophobic aerosols (ammonium sulfate and oil) in an environment with varying relative humidity (15%–90%), (3) polystyrene latex spheres (PSL) ranging from 0.1 to 2.0 μm in diameter, and (4) extremely high concentrations of Arizona road dust (18-h mean total PM = 33,000 μg m−3; 18-h mean PM2.5 = 7300 μg m−3). Linear models relating PMS5003- and SPS30-reported PM2.5 concentrations to TEOM-reported ammonium sulfate concentrations up to 1025 μg m−3, nebulized Arizona road dust concentrations up to 540 μg m−3, and NIST Urban PM concentrations up to 330 μg m−3 had R2 ≥ 0.97; however, an F-test identified a significant lack of fit between the model and the data for each sensor/aerosol combination. Ratios of filter-derived to PMS5003-reported PM2.5 concentrations were 1.4, 1.7, 1.0, 0.4, and 4.3 for ammonium sulfate, nebulized Arizona road dust, NIST Urban PM, wood smoke, and oil mist, respectively. For SPS30 sensors, these ratios were 1.6, 2.1, 2.1, 0.6, and 2.2, respectively. Collocated PMS5003 sensors were less precise than collocated SPS30 sensors when measuring ammonium sulfate, nebulized Arizona road dust, NIST Urban PM, oil mist, or PSL. Our results indicated that particle count data reported by the PMS5003 were not reliable. The number size distribution reported by the PMS5003 (a) did not agree with APS data and (b) remained roughly constant whether the sensors were exposed to 0.1 μm PSL, 0.27 μm PSL, 0.72 μm PSL, 2.0 μm PSL, or any of the other laboratory-generated aerosols. The size distribution reported by the SPS30 did not always agree with APS data, but did shift towards larger particle sizes when the sensors were exposed to 0.72 PSL, 2.0 μm PSL, oil mist, or Arizona road dust from a fluidized bed generator. The proportions of PM mass assigned as PM1, PM2.5, and PM10 by all three sensor models shifted as the PSL size increased. After the sensors were exposed to high concentrations of Arizona road dust for 18 h, PM2.5 concentrations reported by SPS30 sensors remained consistent, whereas 3/8 PMS5003 sensors and 2/7 SM-UART-04L sensors began reporting erroneously high values.

<p>Bioconversion of waste cooking oil for the production of poly-3-hydroxybutyrate using <em>Bacillus cereus </em>MPTDC</p>

Used cooking oil is generated as a byproduct during frying process. It cannot be reused for cooking process due to health issues such as cancer and other digestive disorders. Alternative strategy is utilization of this waste cooking oil for production of poly-3-hydroxybutyrate (PHB) a biopolymer which can be used as a substitute for petroleum derived plastics [ABG1] or other value added products. In the present investigation, we used waste cooking oil as carbon source for PHB production by Bacillus cereus MPTDC. The optimum conditions of PHB production by Bacillus cereus MPTDC were waste cooking oil concentration of 2% (v/v), incubation time of 96 h, ammonium sulphate concentration of 7.5% and yeast extract concentration of 0.2%. Under optimized conditions the strain produced 3.777 g/L of PHB. The results indicate the potential of used cooking oil as carbon source for PHB production by Bacillus cereus MPTDC

Effects of ammonium sulfate on stress physiology and innate immunity of Western mosquitofish (Gambusia affinis).

Fertilizers increase yield of crops but may have unintended negative effects on fish as a byproduct of runoff into bodies of freshwater. The objective of this study was to determine if environmentally relevant concentrations of an ammonium fertilizer impacts stress and innate immunity in Western mosquitofish (Gambusia affinis). The mosquitofish were exposed to different concentrations of ammonium sulfate fertilizer: 0 ppm, 40 ppm, and 80 ppm. To test the effects of ammonium sulfate on stress physiology, cortisol released into water by individual fish was collected after 1 week of exposure and again after 2 weeks of exposure and quantified with an enzyme immunoassay. Cortisol levels in the 0-ppm group were not significantly different over the course of the study, but we found a significant increase in cortisol levels in the fish exposed to 40 ppm and 80 ppm. We found reduced survival in fish from the 40 ppm and 80 ppm of ammonium sulfate groups compared with the 0-ppm group. We also used blood samples to complete a lysozyme assay as a measure of innate immune defense. Higher concentrations of ammonium sulfate correlated with significantly lower lysozyme activity in the fish. Overall, our results suggest that relatively low amounts of ammonium sulfate runoff into bodies of water are likely to have negative sublethal and lethal effects on small fishes.

Preparation of high-purity R-phycoerythrin and R-phycocyanin from Pyropia yezoensis in membrane chromatography

R-phycoerythrin and R-phycocyanin are the main light-harvesting pigment-protein complexes in Pyropia yezoensis. They have bright colors and a high degree of fluorescence, and are now widely used in biomedicine, food, and cosmetic industries. Therefore, membrane chromatography was used to isolate and purify phycobiliprotein from P. yezoensis. Algal cells were disrupted by repeated freeze-thaw cycles. Then ammonium sulfate was added into the crude phycobiliprotein extract, so that the saturation of ammonium sulfate in the solution reached 20%, 30%, and 40% in sequence. At 30% and 40% ammonium sulfate saturation, precipitates of R-phycoerythrin and R-phycocyanin mixture in different proportions were obtained. The precipitates were ultra-filtrated to remove the salt, and then, the retentate was taken for membrane chromatographic treatment. In the membrane chromatographic treatment, salt-sensitive PVDF (polyvinyl difluoride) membranes were used for the follow-up experiments. By adjusting the concentration of ammonium sulfate, the membrane system changed the binding strength of various proteins, and then separated different types of phycobiliproteins. The final products of R-phycoerythrin (Aλmax/A280 purity 4.25, yield 45%) and R-phycocyanin (two purity grades: purity 5.8, yield 14.70% and purity 4.18, yield 39.89%) were obtained and then characterized by spectrophotometric and fluorometric measurements and SDS-PAGE. However, the large-scale production of R-phycocyanin and R-phycoerythrin remains a bottleneck as the column chromatography is difficult to be applied for industrial production. This method avoids the problem of easy clogging of column chromatography and can be useful for mass-production of R-phycoerythrin and R-phycocyanin in the future based on the laboratory results.