Displaying publications 341 - 360 of 624 in total

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  1. Increasing the fertilizer value of palm oil mill sludge: bioaugmentation in nitrification
    Onyia CO, Uyu AM, Akunna JC, Norulaini NA, Omar AK
    Water Sci Technol, 2001;44(10):157-62.
    PMID: 11794647
    Malaysia is essentially an agricultural country and her major polluting effluents have been from agro-based industries of which palm oil and rubber industries together contribute about 80% of the industrial pollution. Palm oil sludge, commonly referred to, as palm oil mill effluent (POME) is brown slurry composed of 4-5% solids, mainly organic, 0.5-1% residual oil, and about 95% water. The effluent also contains high concentrations of organic nitrogen. The technique for the treatment of POME is basically biological, consisting of pond systems, where the organic nitrogen is converted to ammonia, which is subsequently transformed to nitrate, in a process called nitrification. A 15-month monitoring program of a pond system (combined anaerobic, facultative, and aerobic ponds in series) confirmed studies by other authors and POME operators that nitrification in a pond system demands relatively long hydraulic retention time (HRT), which is not easily achieved, due to high production capacity of most factories. Bioaugmentation of POME with mixed culture of nitrifiers (ammonia and nitrite oxidizers) has been identified as an effective tool not only for enhancing nitrification of POME but also for improving quality of POME as source of liquid nitrogen fertilizer for use in the agricultural sector, especially in oil palm plantations. Nitrate is readily absorbable by most plants, although some plants are able to absorb nitrogen in the form of ammoniun. In this study, up to 60% reduction in HRT (or up to 20% reduction in potential land requirement) was achieved when bioaugmentation of POME was carried out with the aim of achieving full nitrification.
    Matched MeSH terms: Nitrogen/metabolism*
  2. Food intake, nutrient utilization and water turnover in the lesser mouse-deer (Tragulus javanicus) given lundai (Sapium baccatum)
    Nolan JV, Liang JB, Abdullah N, Kudo H, Ismail H, Ho YW, et al.
    Comp. Biochem. Physiol. A Physiol., 1995 May;111(1):177-82.
    PMID: 7735907
    Voluntary food intake, digestibility and water turnover were determined in adult Malaysian lesser mouse-deer (Tragulus javanicus) given unlimited access to lundai foliage (Sapium baccatum). Daily dry matter (DM) intake was 42.4 g/kg metabolic live mass (M0.73) or 3.7% M. Digestible energy intake was 853 kJ/day (571 kJ metabolisable energy per M0.73), calculated to be used with 79% efficiency. Apparent digestibility (%) of organic matter was 83.8, crude fibre 63.7, acid detergent fibre 60.5, neutral detergent fibre 72.1 and crude protein 65.0. Urinary excretion of the purine derivative, allantoin, was 0.05 mg/g digestible DM intake suggesting rumen microbial yield efficiency may be lower than in other ruminant species. Total water intake was 182 ml/M0.82. The body-water content of the fed mouse-deer, from tritiated water dilution, was 77% M, consistent with a very lean carcass. Turnover of body water was 17% per day. The mouse-deer produced relatively dry, well-defined faecal pellets.
    Matched MeSH terms: Nitrogen/analysis
  3. [Quality changes in iced shrimps (Pandalus borealis). III. Indole and pH in shrimps caught in the Barents Sea compared with shrimps caught in the Far East (author's transl)]
    Solberg T, Nesbakken T
    Nord Vet Med, 1981 Sep-Nov;33(9-11):446-53.
    PMID: 7329786
    The content of indole and the pH have been determined post mortem in shrimps (Pandalus borealis) caught in the Barents Sea and in shrimps caught outside Malaysia, India and Taiwan. These two criteria were compared with organoleptic assessment and the contents of volatile nitrogen bases (ammonia, trimethylamine) and living bacteria. For shrimps caught in the Barents Sea, both raw shrimps stored in ice and processed (broiled, peeled and single-frozen) shrimps were investigated. The results showed that only low levels of indole had been formed during ice-storage. Not until an advanced state of spoilage could a distinct increase in the indole content in raw and in boiled, peeled shrimps be discerned. pH increased slowly and varied in the area between acceptable and not acceptable quality. Neither the indole content nor the pH seems therefore to be a useful criterion for quality assessment either of raw shrimps caught in the Barents Sea or of such shrimps after processing (boiling and peeling). Most of the samples of boiled, peeled shrimps from the Far East were assessed organoleptically as less good-spoiled, and bacterial growth was significant. The content of trimethylamine oxide and volatile nitrogen was low, while the content of indole was high and exceeded 25 microgram/100 g in 8 or 14 samples. This is the upper limit for import in USA. The content of indole seems to be an important quality criterion for shrimps caught in warmer countries. The content of indole exceeded 25 microgram/100 g in some samples which were assessed organoleptically as acceptable. The pH was lower in brine-treated shrimps than in the others.
    Matched MeSH terms: Nitrogen/analysis
  4. Nutrition in adverse environments, 3. The metabolic effects of a restricted food intake on men working in a tropical environment
    Crowdy JP, Consolazio CF, Forbes AL, Haisman MF, Worsley DE
    Hum Nutr Appl Nutr, 1982 Oct;36(5):325-44.
    PMID: 7141879
    As part of a research programme concerned with the need to lighten the load carried by soldiers engaged in long foot patrols, a field experiment was undertaken in West Malaysia. For 12 d a group of 15 men consumed 7.4 MJ/d (1770 kcal/d) whilst a control group of 14 men ate 12.9 MJ/d (3080 kcal/d); both groups expended on average about 15.8 MJ/d (3770 kcal/d). The low-energy group incurred an energy deficit of 98 MJ (23 410 kcal) with a weight loss of 3.9 kg, whereas corresponding figures for the control group were 37 MJ (8840 kcal) and 2.4 kg. Before, during and after the energy deprivation phase, assessment was made of work capacity (estimated VO2 max), vigilance and military skills but no difference was found between the groups.
    Matched MeSH terms: Nitrogen/metabolism
  5. Utilization of waste fish oil and glycerol as carbon sources for polyhydroxyalkanoate production by Salinivibrio sp. M318
    Van Thuoc D, My DN, Loan TT, Sudesh K
    Int J Biol Macromol, 2019 Dec 01;141:885-892.
    PMID: 31513855 DOI: 10.1016/j.ijbiomac.2019.09.063
    A moderately halophilic bacterium isolated from fermenting shrimp paste, Salinivibrio sp. M318 was found capable of using fish sauce and mixtures of waste fish oil and glycerol as nitrogen and carbon sources, respectively, for poly(3-hydroxybutyrate) (PHB) production. A cell dry weight (CDW) of up to 10 g/L and PHB content of 51.7 wt% were obtained after 48 h of cultivation in flask experiment. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] was synthesized when 1,4-butanediol, γ-butyrolactone, or sodium 4-hydroxybutyrate was added as precursors to the culture medium. The biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] was achieved by supplying precursors such as sodium valerate, sodium propionate, and sodium heptanoate. Salinivibrio sp. M318 was able to accumulate the above mentioned PHAs during the growth phase. High CDW of 69.1 g/L and PHB content of 51.5 wt% were obtained by strain Salinivibrio sp. M318 after 78 h of cultivation in fed-batch culture. The results demonstrate Salinivibrio sp. M318 to be a promising wild-type bacterium for the production of PHA from aquaculture residues.
    Matched MeSH terms: Nitrogen/chemistry
  6. Effects of tourism-derived sewage on coral reefs: Isotopic assessments identify effective bioindicators
    Lachs L, Johari NAM, Le DQ, Safuan CDM, Duprey NN, Tanaka K, et al.
    Mar Pollut Bull, 2019 Nov;148:85-96.
    PMID: 31422307 DOI: 10.1016/j.marpolbul.2019.07.059
    Pulau Redang and Pulau Tioman have experienced huge tourism growth over the last two decades, but minimal sewage treatment may threaten the resilience of their coral reefs. This study uses stable isotope techniques to identify suitable bioindicators of sewage nutrients (δ15N) at these islands by measuring macroalgae (Lobophora spp.), gastropods (Drupella spp.), scleractinian coral (Acropora spp.), and leather coral (Sinularia spp.). At tourist hubs using seepage septic tank systems, enrichment of Acropora δ15N (Redang, +0.7‰) and Sinularia δ15N (Tioman, +0.4‰) compared to pristine background levels indicate enhanced sewage nutrient discharge. Carbon isotopes and survey data suggest that sedimentation did not confound these δ15N trends. Potential damaging effects of sewage discharge on the coral reef communities at both islands are highlighted by strong correlations between Acropora δ15N and regional variation in coral reef community structure, and exclusive occurrence of degraded reefs at regions of high sewage influence.
    Matched MeSH terms: Nitrogen Isotopes/analysis*
  7. Fulltext Development of Palm Fatty Acid Distillate-Containing Medium for Biosurfactant Production by Pseudomonas sp. LM19
    Nurfarahin AH, Mohamed MS, Phang LY
    Molecules, 2019 Jul 18;24(14).
    PMID: 31323769 DOI: 10.3390/molecules24142613
    High production costs of biosurfactants are mainly caused by the usage of the expensive substrate and long fermentation period which undermines their potential in bioremediation processes, food, and cosmetic industries even though they, owing to the biodegradability, lower toxicity, and raise specificity traits. One way to circumvent this is to improvise the formulation of biosurfactant-production medium by using cheaper substrate. A culture medium utilizing palm fatty acid distillate (PFAD), a palm oil refinery by-product, was first developed through one-factor-at-a-time (OFAT) technique and further refined by means of the statistical design method of factorial and response surface modeling to enhance the biosurfactant production from Pseudomonas sp. LM19. The results shows that, the optimized culture medium containing: 1.148% (v/v) PFAD; 4.054 g/L KH2PO4; 1.30 g/L yeast extract; 0.023 g/L sodium-EDTA; 1.057 g/L MgSO4·7H2O; 0.75 g/L K2HPO4; 0.20 g/L CaCl2·2H2O; 0.080 g/L FeCl3·6H2O gave the maximum biosurfactant productivity. This study demonstrated that the cell concentration and biosurfactant productivity could reach up to 8.5 × 109 CFU/mL and 0.346 g/L/day, respectively after seven days of growth, which were comparable to the values predicted by an RSM regression model, i.e., 8.4 × 109 CFU/mL and 0.347 g/L/day, respectively. Eleven rhamnolipid congeners were detected, in which dirhamnolipid accounted for 58% and monorhamnolipid was 42%. All in all, manipulation of palm oil by-products proved to be a feasible substrate for increasing the biosurfactant production about 3.55-fold as shown in this study.
    Matched MeSH terms: Nitrogen/metabolism
  8. Fulltext Role of Pyridine Nitrogen in Palladium-Catalyzed Imine Hydrolysis: A Case Study of (E)-1-(3-bromothiophen-2-yl)-N-(4-methylpyridin-2-yl)methanimine
    Ahmad G, Rasool N, Rizwan K, Altaf AA, Rashid U, Mahmood T, et al.
    Molecules, 2019 Jul 17;24(14).
    PMID: 31319634 DOI: 10.3390/molecules24142609
    In the present study, 4-methylpyridin-2-amine was reacted with 3-bromothiophene-2-carbaldehyde and the Schiff base (E)-1-(3-bromothiophen-2-yl)-N-(4-methylpyridin-2-yl)methanimine was obtained in a 79% yield. Coupling of the Schiff base with aryl/het-aryl boronic acids under Suzuki coupling reaction conditions, using Pd(PPh3)4 as catalyst, yielded products with the hydrolysis of the imine linkages (5a-5k, 6a-6h) in good to moderate yields. To gain mechanistic insight into the transition metal-catalyzed hydrolysis of the compounds, density functional theory (DFT) calculations were performed. The theoretical calculations strongly supported the experiment and provided an insight into the transition metal-catalyzed hydrolysis of imines.
    Matched MeSH terms: Nitrogen/chemistry
  9. Fulltext Kinetics Growth and Recovery of Valuable Nutrients from Selangor Peat Swamp and Pristine Forest Soils Using Different Extraction Methods as Potential Microalgae Growth Enhancers
    Yaacob NS, Ahmad MF, Kawasaki N, Maniyam MN, Abdullah H, Hashim EF, et al.
    Molecules, 2021 Jan 27;26(3).
    PMID: 33513787 DOI: 10.3390/molecules26030653
    Soil extracts are useful nutrients to enhance the growth of microalgae. Therefore, the present study attempts for the use of virgin soils from Peninsular Malaysia as growth enhancer. Soils collected from Raja Musa Forest Reserve (RMFR) and Ayer Hitam Forest Reserve (AHFR) were treated using different extraction methods. The total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and dissolved organic carbon (DOC) concentrations in the autoclave methods were relatively higher than natural extraction with up to 132.0 mg N/L, 10.7 mg P/L, and 2629 mg C/L, respectively for RMFR. The results of TDN, TDP, and DOC suggested that the best extraction methods are autoclaved at 121 °C twice with increasing 87%, 84%, and 95%, respectively. Chlorella vulgaris TRG 4C dominated the growth at 121 °C twice extraction method in the RMRF and AHRF samples, with increasing 54.3% and 14%, respectively. The specific growth rate (µ) of both microalgae were relatively higher, 0.23 d-1 in the Ayer Hitam Soil. This extract served well as a microalgal growth promoter, reducing the cost and the needs for synthetic medium. Mass production of microalgae as aquatic feed will be attempted eventually. The high recovery rate of nutrients has a huge potential to serve as a growth promoter for microalgae.
    Matched MeSH terms: Nitrogen/chemistry
  10. Fulltext Logging and soil nutrients independently explain plant trait expression in tropical forests
    Both S, Riutta T, Paine CET, Elias DMO, Cruz RS, Jain A, et al.
    New Phytol, 2019 03;221(4):1853-1865.
    PMID: 30238458 DOI: 10.1111/nph.15444
    Plant functional traits regulate ecosystem functions but little is known about how co-occurring gradients of land use and edaphic conditions influence their expression. We test how gradients of logging disturbance and soil properties relate to community-weighted mean traits in logged and old-growth tropical forests in Borneo. We studied 32 physical, chemical and physiological traits from 284 tree species in eight 1 ha plots and measured long-term soil nutrient supplies and plant-available nutrients. Logged plots had greater values for traits that drive carbon capture and growth, whilst old-growth forests had greater values for structural and persistence traits. Although disturbance was the primary driver of trait expression, soil nutrients explained a statistically independent axis of variation linked to leaf size and nutrient concentration. Soil characteristics influenced trait expression via nutrient availability, nutrient pools, and pH. Our finding, that traits have dissimilar responses to land use and soil resource availability, provides robust evidence for the need to consider the abiotic context of logging when predicting plant functional diversity across human-modified tropical forests. The detection of two independent axes was facilitated by the measurement of many more functional traits than have been examined in previous studies.
    Matched MeSH terms: Nitrogen Isotopes/analysis
  11. Fulltext Enhancing microalga Chlorella sorokiniana CY-1 biomass and lipid production in palm oil mill effluent (POME) using novel-designed photobioreactor
    Cheah WY, Show PL, Yap YJ, Mohd Zaid HF, Lam MK, Lim JW, et al.
    Bioengineered, 2020 12;11(1):61-69.
    PMID: 31884878 DOI: 10.1080/21655979.2019.1704536
    Chlorella sorokiniana CY-1 was cultivated using palm oil mill effluent (POME) in a novel-designed photobioreactor (NPBR) and glass-made vessel photobioreactor (PBR). The comparison was made on biomass and lipid productions, as well as its pollutants removal efficiencies. NPBR is transparent and is developed in thin flat panels with a high surface area per volume ratio. It is equipped with microbubbling and baffles retention, ensuring effective light and CO2 utilization. The triangular shape of this reactor at the bottom serves to ease microalgae cell harvesting by sedimentation. Both biomass and lipid yields attained in NPBR were 2.3-2.9 folds higher than cultivated in PBR. The pollutants removal efficiencies achieved were 93.7% of chemical oxygen demand, 98.6% of total nitrogen and 96.0% of total phosphorus. Mathematical model revealed that effective light received and initial mass contributes toward successful microalgae cultivation. Overall, the results revealed the potential of NPBR integration in Chlorella sorokiniana CY-1 cultivation, with an aim to achieve greater feasibility in microalgal-based biofuel real application and for environmental sustainability.
    Matched MeSH terms: Nitrogen/metabolism
  12. Optimization of carbon and nitrogen sources for phytase production by Mitsuokella jalaludinii, a new rumen bacterial species
    Lan GQ, Abdullah N, Jalaludin S, Ho Y
    Lett Appl Microbiol, 2002;35(2):157-61.
    PMID: 12100593
    The effects of different carbon and nitrogen sources on phytase production by Mitsuokella jalaludinii were evaluated and the optimization of rice bran (RB) and soybean milk (SM) concentrations in the medium for phytase production was also determined.
    Matched MeSH terms: Nitrogen/metabolism*
  13. Burkholderia vietnamiensis isolated from root tissues of Nipa Palm (Nypa fruticans) in Sarawak, Malaysia, proved to be its major endophytic nitrogen-fixing bacterium
    Tang SY, Hara S, Melling L, Goh KJ, Hashidoko Y
    Biosci Biotechnol Biochem, 2010;74(9):1972-5.
    PMID: 20834139
    Root-associating bacteria of the nipa palm (Nypa fruticans), preferring brackish-water affected mud in Sarawak, Malaysia, were investigated. In a comparison of rhizobacterial microbiota between the nipa and the sago (Metroxylon sagu) palm, it was found that the nipa palm possessed a group of Burkholderia vietnamiensis as its main active nitrogen-fixing endophytic bacterium. Acetylene reduction by the various isolates of B. vietnamiensis was constant (44 to 68 nmol h(-1) in ethylene production rate) in soft gel medium containing 0.2% sucrose as sole carbon source, and the bacterium also showed motility and biofilm-forming capacity. This is the first report of endophytic nitrogen-fixing bacteria from nipa palm.
    Matched MeSH terms: Nitrogen Fixation*
  14. Fulltext Optimal reduction of chemical oxygen demand and NH3-N from landfill leachate using a strongly resistant novel Bacillus salmalaya strain
    Dadrasnia A, Azirun MS, Ismail SB
    BMC Biotechnol, 2017 Nov 28;17(1):85.
    PMID: 29179747 DOI: 10.1186/s12896-017-0395-9
    BACKGROUND: When the unavoidable waste generation is considered as damaging to our environment, it becomes crucial to develop a sustainable technology to remediate the pollutant source towards an environmental protection and safety. The development of a bioengineering technology for highly efficient pollutant removal is this regard. Given the high ammonia nitrogen content and chemical oxygen demand of landfill leachate, Bacillus salmalaya strain 139SI, a novel resident strain microbe that can survive in high ammonia nitrogen concentrations, was investigated for the bioremoval of ammonia nitrogen from landfill leachate. The treatability of landfill leachate was evaluated under different treatment parameters, such as temperature, inoculum dosage, and pH.

    RESULTS: Results demonstrated that bioaugmentation with the novel strain can potentially improve the biodegradability of landfill leachate. B. salmalaya strain 139SI showed high potential to enhance biological treatment given its maximum NH3-N and COD removal efficiencies. The response surface plot pattern indicated that within 11 days and under optimum conditions (10% v/v inoculant, pH 6, and 35 °C), B. salmalaya strain139SI removed 78% of ammonia nitrogen. At the end of the study, biological and chemical oxygen demands remarkably decreased by 88% and 91.4%, respectively. Scanning electron microscopy images revealed that ammonia ions covered the cell surface of B. salmalaya strain139SI.

    CONCLUSIONS: Therefore, novel resistant Bacillus salmalaya strain139SI significantly reduces the chemical oxygen demand and NH3-N content of landfill leachate. Leachate treatment by B. salmalaya strain 139SI within 11 days.

    Matched MeSH terms: Nitrogen/metabolism
  15. Evaluation of solid-state bioconversion of domestic wastewater sludge as a promising environmental-friendly disposal technique
    Hossain Molla A, Fakhru'l-Razi A, Zahangir Alam M
    Water Res, 2004 Nov;38(19):4143-52.
    PMID: 15491662
    Natural and environmental-friendly disposal of wastewater sludge is a great concern. Recently, biological treatment has played prominent roles in bioremediation of complex hydrocarbon- rich contaminants. Composting is quite an old biological-based process that is being practiced but it could not create a great impact in the minds of concerned researchers. The present study was conducted to evaluate the feasibility of the solid-state bioconversion (SSB) processes in the biodegradation of wastewater sludge by exploiting this promising technique to rejuvenate the conventional process. The Indah Water Konsortium (IWK) domestic wastewater treatment plant (DWTP) sludge was considered for evaluation of SSB by monitoring the microbial growth and its subsequent roles in biodegradation under two conditions: (i) flask (F) and (ii) composting bin (CB) cultures. Sterile and semi-sterile environments were allowed in the F and the CB, respectively, using two mixed fungal cultures, Trichoderma harzianum with Phanerochaete chrysosporium 2094 (T/P) and T. harzianum with Mucor hiemalis (T/M) and two bulking materials, sawdust (SD) and rice straw (RS). The significant growth and multiplication of both the mixed fungal cultures were reflected in soluble protein, glucosamine and color intensity measurement of the water extract. The color intensity and pH of the water extract significantly increased and supported the higher growth of microbes and bioconversion. The most encouraging results of microbial growth and subsequent bioconversion were exhibited in the RS than the SD. A comparatively higher decrease of organic matter (OM) % and C/N ratio were attained in the CB than the F, which implied a higher bioconversion. But the measurement of soluble protein, glucosamine and color intensity exhibited higher values in the F than the CB. The final pH drop was higher in the CB than the F, which implied that a higher nitrification occurred in the CB associated with a higher release of H+ ions. Both the mixed cultures performed almost equal roles in all cases except the changes in moisture content.
    Matched MeSH terms: Nitrogen/metabolism
  16. Biosolids accumulation and biodegradation of domestic wastewater treatment plant sludge by developed liquid state bioconversion process using a batch fermenter
    Alam MZ, Fakhru'l-Razi A, Molla AH
    Water Res, 2003 Sep;37(15):3569-78.
    PMID: 12867323
    The biosolids accumulation and biodegradation of domestic wastewater treatment plant (DWTP) sludge by filamentous fungi have been investigated in a batch fermenter. The filamentous fungi Aspergillus niger and Penicillium corylophilum isolated from wastewater and DWTP sludge was used to evaluate the treatment performance. The optimized mixed inoculum (A. niger and P. corylophilum) and developed process conditions (co-substrate and its concentration, temperature, initial pH, inoculum size, and aeration and agitation rate) were incorporated to accelerate the DWTP sludge treatment process. The results showed that microbial treatment of higher strength of DWTP sludge (4% w/w of TSS) was highly influenced by the liquid state bioconversion (LSB) process. In developed bioconversion processes, 93.8 g/kg of biosolids was enriched with fungal biomass protein of 30 g/kg. Enrichment of nutrients such as nitrogen (N), phosphorous (P), potassium (K) in biosolids was recorded in 6.2% (w/w), 3.1% (w/w) and 0.15% (w/w) from its initial values of 4.8% (w/w), 2.0% (w/w) and 0.08% (w/w) respectively after 10 days of fungal treatment. The biodegradation results revealed that 98.8% of TSS, 98.2% of TDS, 97.3% of turbidity, 80.2% of soluble protein, 98.8% of reducing sugar and 92.7% of COD in treated DWTP sludge supernatant were removed after 8 days of microbial treatment. The specific resistance to filtration (SRF) in treated sludge (1.4x10(12) m/kg) was decreased tremendously by the microbial treatment of DWTP sludge after 6 days of fermentation compared to untreated sample (85x10(12) m/kg).
    Matched MeSH terms: Nitrogen/metabolism
  17. Degradation of 17α-ethinylestradiol by nano zero valent iron under different pH and dissolved oxygen levels
    Karim S, Bae S, Greenwood D, Hanna K, Singhal N
    Water Res, 2017 11 15;125:32-41.
    PMID: 28826034 DOI: 10.1016/j.watres.2017.08.029
    The catalytic properties of nanoparticles (e.g., nano zero valent iron, nZVI) have been used to effectively treat a wide range of environmental contaminants. Emerging contaminants such as endocrine disrupting chemicals (EDCs) are susceptible to degradation by nanoparticles. Despite extensive investigations, questions remain on the transformation mechanism on the nZVI surface under different environmental conditions (redox and pH). Furthermore, in terms of the large-scale requirement for nanomaterials in field applications, the effect of polymer-stabilization used by commercial vendors on the above processes is unclear. To address these factors, we investigated the degradation of a model EDC, the steroidal estrogen 17α-ethinylestradiol (EE2), by commercially sourced nZVI at pH 3, 5 and 7 under different oxygen conditions. Following the use of radical scavengers, an assessment of the EE2 transformation products shows that under nitrogen purging direct reduction of EE2 by nZVI occurred at all pHs. The radicals transforming EE2 in the absence of purging and upon air purging were similar for a given pH, but the dominant radical varied with pH. Upon air purging, EE2 was transformed by the same radical species as the non-purged system at the same respective pH, but the degradation rate was lower with more oxygen - most likely due to faster nZVI oxidation upon aeration, coupled with radical scavenging. The dominant radicals were OH at pH 3 and O2- at pH 5, and while neither radical was involved at pH 7, no conclusive inferences could be made on the actual radical involved at pH 7. Similar transformation products were observed without purging and upon air purging.
    Matched MeSH terms: Nitrogen/chemistry
  18. Biochemical events leading to the diversion of carbon into storage lipids in the oleaginous fungi Mucor circinelloides and Mortierella alpina
    Wynn JP, Hamid AA, Li Y, Ratledge C
    Microbiology (Reading), 2001 Oct;147(Pt 10):2857-2864.
    PMID: 11577164 DOI: 10.1099/00221287-147-10-2857
    The biochemical events associated with the onset of lipid accumulation in Mucor circinelloides and Mortierella alpina, under conditions of nitrogen-limited growth, have been elucidated; they differ in key aspects from those described in oleaginous yeasts. The NAD+:isocitrate dehydrogenases of Mc. circinelloides and Mort. alpina were not absolutely dependent on AMP for activity. Furthermore, changes in the cellular adenine nucleotide pools and energy charge were different from those reported for oleaginous yeasts. In Mc. circinelloides ATP, ADP and AMP concentrations all decreased by 50% after nitrogen limitation, leading to a constant energy charge at the expense of the size of the total adenylate pool. Pyruvate carboxylase in Mc. circinelloides was cytosolic, having implications for the organization of lipid synthesis in filamentous fungi. As a result of the data obtained, a revised and more concerted mechanism for the initiation of storage lipid accumulation is put forward for filamentous fungi.
    Matched MeSH terms: Nitrogen/metabolism
  19. Enhanced volatile fatty acid production from sago hampas by Clostridium beijerinckii SR1 for bioelectricity generation using microbial fuel cells
    Jenol MA, Ibrahim MF, Kamal Bahrin E, Abd-Aziz S
    Bioprocess Biosyst Eng, 2020 Nov;43(11):2027-2038.
    PMID: 32572569 DOI: 10.1007/s00449-020-02391-9
    Sago hampas is a starch-based biomass from sago processing industries consisted of 58% remaining starch. This study has demonstrated the bioconversion of sago hampas to volatile fatty acids (VFAs) by Clostridium beijerinckii SR1 via anaerobic digestion. Higher total VFAs were obtained from sago hampas (5.04 g/L and 0.287 g/g) as compared to commercial starch (5.94 g/L and 0.318 g/g). The physical factors have been investigated for the enhancement of VFAs production using one-factor-at-a-time (OFAT). The optimum condition; 3% substrate concentration, 3 g/L of yeast extract concentration and 2 g/L of ammonium nitrate enhanced the production of VFAs by 52.6%, resulted the total VFAs produced is 7.69 g/L with the VFAs yield of 0.451 g/g. VFAs hydrolysate produced successfully generated 273.4 mV of open voltage circuit and 61.5 mW/m2 of power density in microbial fuel cells. It was suggested that sago hampas provide as an alternative carbon feedstock for bioelectricity generation.
    Matched MeSH terms: Nitrogen/chemistry*
  20. Gas-pressurized dispersive powder flow tester for low volume sample characterization
    Majid AM, Wong TW
    Int J Pharm, 2013 May 1;448(1):150-8.
    PMID: 23506957 DOI: 10.1016/j.ijpharm.2013.03.008
    The conventional powder flow testers require sample volumes larger than 40g and are met with experimental hiccups due to powder cohesion. This study designed a gas-pressurized dispersive powder flow tester where a high velocity air is used to disaggregate powder (9g) and eliminate its cohesion. The pressurized gas entrained solid particles leaving an orifice where the distance, surface area, width and weight of particle dispersion thereafter are determined as flow index. The flow indices of seven lactose grades with varying size, size distribution, shape, morphology, bulk and tapped densities characteristics were examined. They were compared against Hausner ratio and Carr's index parameters of the same powder mass. Both distance and surface area attributes of particle dispersion had significant negative correlations with Hausner ratio and Carr's index values of lactose. The distance, surface area and ease of particle dispersion varied proportionately with circular equivalent, surface weighted mean and volume weighted mean diameters of lactose, and inversely related to their specific surface area and elongation characteristics. Unlike insensitive Hausner ratio and Carr's index, an increase in elongation property of lactose particles was detectable through reduced powder weight loss from gas-pressurized dispersion as a result of susceptible particle blockage at orifice. The gas-pressurized dispersive tester is a useful alternative flowability measurement device for low volume and cohesive powder.
    Matched MeSH terms: Nitrogen/chemistry
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