Displaying publications 1 - 20 of 209 in total

Abstract:
Sort:
  1. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Comput Softw Big Sci, 2020;4(1):10.
    PMID: 33196702 DOI: 10.1007/s41781-020-00041-z
    We describe a method to obtain point and dispersion estimates for the energies of jets arising from b quarks produced in proton-proton collisions at an energy of s = 13 TeV at the CERN LHC. The algorithm is trained on a large sample of simulated b jets and validated on data recorded by the CMS detector in 2017 corresponding to an integrated luminosity of 41 fb - 1 . A multivariate regression algorithm based on a deep feed-forward neural network employs jet composition and shape information, and the properties of reconstructed secondary vertices associated with the jet. The results of the algorithm are used to improve the sensitivity of analyses that make use of b jets in the final state, such as the observation of Higgs boson decay to b b ¯ .
  2. Omar N, Shafiee SI, Nor'hisham SH, Ibrahim Z, Jamaluddin R, Rahamat S, et al.
    JMIR Res Protoc, 2023 Jan 31;12:e42496.
    PMID: 36719732 DOI: 10.2196/42496
    BACKGROUND: Geriatric malnutrition in hospitals is common and can be affected by many things, including poor satisfaction toward hospital foodservice. Hospital foodservice plays an important role in a patient's recovery process by providing adequate nutrients. On top of that, patients' foodservice satisfaction can easily be afflicted by the quality of food served and the overall foodservice experience. Furthermore, malnutrition can occur from poor foodservice quality, especially among geriatric patients.

    OBJECTIVE: This study aims to assess the effectiveness of the Malaysian Geriatric Patients' Hospital Foodservice Protocol (MYGERYFS).

    METHODS: The protocol comprises 3 phases. Phase One is a cross-sectional study that took place at public hospitals with geriatric wards in the Klang Valley. Univariate data from Phase One were analyzed descriptively. Pearson correlation and chi-square were conducted to find factors associated with foodservice satisfaction. Phase Two involves the collaboration of health care professionals in the geriatric field. In Phase Three, a feasibility study will be conducted to determine the feasibility of the MYGERYFS protocol in a hospital among 60 geriatric patients. These patients will be randomized into control and intervention groups, respectively. Intervention care will be done to ensure the safety of the protocol.

    RESULTS: Data collection for Phase One of the study has been completed. A total of 233 geriatric respondents with the mean age of 71.39 (SD 7.99) years were gathered. Approximately 51.5% (n=120) of the respondents were female, while 48.5% (n=113) were male, with a mean BMI of 24.84 (SD 6.05) kg/m2. Their mean energy and protein intakes were 1006.20 kcal (SD 462.03 kcal) and 42.60 (SD 22.20) grams, respectively. Based on the Mini Nutritional Assessment, older patients who scored 12-14 (normal) were 27.9% (n=65), those who scored 8-11 (at risk) were 54.9% (n=128), and those who scored 0-7, which is the lowest (malnutrition), were 17.2% (n=40) of the study population. Hence, most patients were at risk of malnutrition. Although a majority of the patients claimed to have good foodservice satisfaction 26.2% (n=61), they also experienced at least 3 barriers during mealtimes. It was found that dietary intake and mealtime barriers were significantly associated with the respondent's foodservice satisfaction. Data for Phase Two and Phase Three are yet to be collected and analyzed.

    CONCLUSIONS: This study protocol could potentially benefit the hospital foodservice system and aid in improving geriatric nutritional status.

    TRIAL REGISTRATION: ClinicalTrials.gov NCT04858165; https://clinicaltrials.gov/ct2/show/NCT04858165.

    INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/42496.

  3. Arif MA, Mohamad MS, Abd Latif MS, Deris S, Remli MA, Mohd Daud K, et al.
    Comput Biol Med, 2018 11 01;102:112-119.
    PMID: 30267898 DOI: 10.1016/j.compbiomed.2018.09.015
    Metabolic engineering involves the modification and alteration of metabolic pathways to improve the production of desired substance. The modification can be made using in silico gene knockout simulation that is able to predict and analyse the disrupted genes which may enhance the metabolites production. Global optimization algorithms have been widely used for identifying gene knockout strategies. However, their productions were less than theoretical maximum and the algorithms are easily trapped into local optima. These algorithms also require a very large computation time to obtain acceptable results. This is due to the complexity of the metabolic models which are high dimensional and contain thousands of reactions. In this paper, a hybrid algorithm of Cuckoo Search and Minimization of Metabolic Adjustment is proposed to overcome the aforementioned problems. The hybrid algorithm searches for the near-optimal set of gene knockouts that leads to the overproduction of metabolites. Computational experiments on two sets of genome-scale metabolic models demonstrate that the proposed algorithm is better than the previous works in terms of growth rate, Biomass Product Couple Yield, and computation time.
  4. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Brandstetter J, et al.
    Eur Phys J C Part Fields, 2020;80(3):237.
    PMID: 32215380 DOI: 10.1140/epjc/s10052-020-7773-5
    A search in an all-jet final state for new massive resonances decaying to W W , W Z , or Z Z boson pairs using a novel analysis method is presented. The analysis is performed on data corresponding to an integrated luminosity of 77.3 fb - 1 recorded with the CMS experiment at the LHC at a centre-of-mass energy of 13  Te . The search is focussed on potential narrow-width resonances with masses above 1.2  Te , where the decay products of each W or Z boson are expected to be collimated into a single, large-radius jet. The signal is extracted using a three-dimensional maximum likelihood fit of the two jet masses and the dijet invariant mass, yielding an improvement in sensitivity of up to 30% relative to previous search methods. No excess is observed above the estimated standard model background. In a heavy vector triplet model, spin-1 Z ' and W ' resonances with masses below 3.5 and 3.8   Te , respectively, are excluded at 95% confidence level. In a bulk graviton model, upper limits on cross sections are set between 27 and 0.2 fb for resonance masses between 1.2 and 5.2   Te , respectively. The limits presented in this paper are the best to date in the dijet final state.
  5. Shahar S, Ibrahim Z, Fatah AR, Rahman SA, Yusoff NA, Arshad F, et al.
    Asia Pac J Clin Nutr, 2007;16(2):346-53.
    PMID: 17468093
    A multidimensional assessment of nutritional and health status comprised of subjective global assessment (SGA), anthropometry function, biochemistry, dietary intake, social and health aspects was carried out on 820 older people (52.8% men and 47.2% women) from four rural areas of Peninsular Malaysia. A proportion of the subjects had been classified as either overweight (25.7%) or chronic energy deficient (20.3%). Although 49% of subjects had normal body weight, 68.4% have been classified as having mild to moderate malnutrition according to the SGA. Only 1.1% and 2.3% had low serum albumin and ferritin, respectively. Almost 80% of subjects, especially men, were at high risk of cardiovascular diseases on the basis of the assessment of total cholesterol and LDL-cholesterol. The majority of the subjects (87.2%) were fully independent in performing daily tasks, with men having a significantly higher score compared to women (p<0.001). However, men were less likely to be able to perform a flexibility test (50.7%) than were women (27.0%) (p<0.05). The mean energy intake for men (1412 +/- 461 kcal/d) and women (1201 +/- 392 kcal/d) were below the Recommended Nutrient Intake (RNI) for Malaysia, although this is a difficult assertion to make in an age-group which generally experiences declining energy expenditure. Moreover, 52.5% of men and 47.5% of women might have underreported their food intake. Dietary micronutrients most likely to be deficient were thiamin, riboflavin and calcium. It is concluded that a substantial proportion of rural elderly Malays had problems related to both undernutrition and overnutrition. An appropriate nutrition intervention program is needed to improve the nutritional status of rural elderly Malays.
  6. Daud KM, Mohamad MS, Zakaria Z, Hassan R, Shah ZA, Deris S, et al.
    Comput Biol Med, 2019 10;113:103390.
    PMID: 31450056 DOI: 10.1016/j.compbiomed.2019.103390
    Metabolic engineering is defined as improving the cellular activities of an organism by manipulating the metabolic, signal or regulatory network. In silico reaction knockout simulation is one of the techniques applied to analyse the effects of genetic perturbations on metabolite production. Many methods consider growth coupling as the objective function, whereby it searches for mutants that maximise the growth and production rate. However, the final goal is to increase the production rate. Furthermore, they produce one single solution, though in reality, cells do not focus on one objective and they need to consider various different competing objectives. In this work, a method, termed ndsDSAFBA (non-dominated sorting Differential Search Algorithm and Flux Balance Analysis), has been developed to find the reaction knockouts involved in maximising the production rate and growth rate of the mutant, by incorporating Pareto dominance concepts. The proposed ndsDSAFBA method was validated using three genome-scale metabolic models. We obtained a set of non-dominated solutions, with each solution representing a different mutant strain. The results obtained were compared with the single objective optimisation (SOO) and multi-objective optimisation (MOO) methods. The results demonstrate that ndsDSAFBA is better than the other methods in terms of production rate and growth rate.
  7. Bahari Z, Ibrahim Z, Adznam SNA, Yusof BNM
    Asia Pac J Clin Nutr, 2017 8 15;26(5):781-787.
    PMID: 28802285 DOI: 10.6133/apjcn.102016.02
    BACKGROUND AND OBJECTIVES: Assessment of the nutrition care process (NCP) knowledge, attitudes, practices, and perceived barriers (KAPB) of dietetics practitioners is imperative before NCP is implemented completely in dietetics practice. No questionnaire assessing NCP KAPB has been developed and validated. Hence, we developed an NCP KAPB questionnaire called the KAPB-NCP and established its content validity.

    METHODS AND STUDY DESIGN: A total of 116 items associated with sociodemographic characteristics (7 items), professional development (3 items), organisational culture's support for the NCP (2 items), knowledge (27 items), attitudes (39 items), practices (20 items), and perceived barriers to implementing the NCP (14 items) were generated for potential inclusion in the KAPB-NCP questionnaire. The questionnaire was reviewed online by an expert panel for its content validity. An in-depth review was conducted by the research team for evaluating the overall comprehensiveness of the questionnaire.

    RESULTS: In total, 87 of 100 items of the KAPB sections showed an excellent content validity index (CVI; k* >0.74), whereas 10 showed a satisfactory CVI (k*=0.60-0.74). Only 3 items had a low CVI (k* <0.40). According to the expert panel revisions and the in-depth review, 72 items were incorporated into the questionnaire.

    CONCLUSIONS: The KAPB-NCP questionnaire is a content-valid instrument that can assess NCP KAPB.

  8. Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, et al.
    Eur Phys J C Part Fields, 2017;77(5):294.
    PMID: 28579921 DOI: 10.1140/epjc/s10052-017-4787-8
    A search for new phenomena is performed in final states containing one or more jets and an imbalance in transverse momentum in pp collisions at a centre-of-mass energy of 13[Formula: see text]. The analysed data sample, recorded with the CMS detector at the CERN LHC, corresponds to an integrated luminosity of 2.3[Formula: see text]. Several kinematic variables are employed to suppress the dominant background, multijet production, as well as to discriminate between other standard model and new physics processes. The search provides sensitivity to a broad range of new-physics models that yield a stable weakly interacting massive particle. The number of observed candidate events is found to agree with the expected contributions from standard model processes, and the result is interpreted in the mass parameter space of fourteen simplified supersymmetric models that assume the pair production of gluinos or squarks and a range of decay modes. For models that assume gluino pair production, masses up to 1575 and 975[Formula: see text] are excluded for gluinos and neutralinos, respectively. For models involving the pair production of top squarks and compressed mass spectra, top squark masses up to 400[Formula: see text] are excluded.
  9. Nipun TS, Khatib A, Ahmed QU, Redzwan IE, Ibrahim Z, Khan AYF, et al.
    Molecules, 2020 Sep 11;25(18).
    PMID: 32932994 DOI: 10.3390/molecules25184161
    The plant Psychotria malayana Jack belongs to the Rubiaceae family and is known in Malaysia as "meroyan sakat/salung". A rapid analytical technique to facilitate the evaluation of the P. malayana leaves' quality has not been well-established yet. This work aimed therefore to develop a validated analytical technique in order to predict the alpha-glucosidase inhibitory action (AGI) of P. malayana leaves, applying a Fourier Transform Infrared Spectroscopy (FTIR) fingerprint and utilizing an orthogonal partial least square (OPLS). The dried leaf extracts were prepared by sonication of different ratios of methanol-water solvent (0, 25, 50, 75, and 100% v/v) prior to the assessment of alpha-glucosidase inhibition (AGI) and the following infrared spectroscopy. The correlation between the biological activity and the spectral data was evaluated using multivariate data analysis (MVDA). The 100% methanol extract possessed the highest inhibitory activity against the alpha-glucosidase (IC50 2.83 ± 0.32 μg/mL). Different bioactive functional groups, including hydroxyl (O-H), alkenyl (C=C), methylene (C-H), carbonyl (C=O), and secondary amine (N-H) groups, were detected by the multivariate analysis. These functional groups actively induced the alpha-glucosidase inhibition effect. This finding demonstrated the spectrum profile of the FTIR for the natural herb P. malayana Jack, further confirming its medicinal value. The developed validated model can be used to predict the AGI of P. malayana, which will be useful as a tool in the plant's quality control.
  10. Mohamad MS, Omatu S, Deris S, Yoshioka M, Abdullah A, Ibrahim Z
    Algorithms Mol Biol, 2013;8(1):15.
    PMID: 23617960 DOI: 10.1186/1748-7188-8-15
    Gene expression data could likely be a momentous help in the progress of proficient cancer diagnoses and classification platforms. Lately, many researchers analyze gene expression data using diverse computational intelligence methods, for selecting a small subset of informative genes from the data for cancer classification. Many computational methods face difficulties in selecting small subsets due to the small number of samples compared to the huge number of genes (high-dimension), irrelevant genes, and noisy genes.
  11. Ismail AM, Mohamad MS, Abdul Majid H, Abas KH, Deris S, Zaki N, et al.
    Biosystems, 2017 Dec;162:81-89.
    PMID: 28951204 DOI: 10.1016/j.biosystems.2017.09.013
    Mathematical modelling is fundamental to understand the dynamic behavior and regulation of the biochemical metabolisms and pathways that are found in biological systems. Pathways are used to describe complex processes that involve many parameters. It is important to have an accurate and complete set of parameters that describe the characteristics of a given model. However, measuring these parameters is typically difficult and even impossible in some cases. Furthermore, the experimental data are often incomplete and also suffer from experimental noise. These shortcomings make it challenging to identify the best-fit parameters that can represent the actual biological processes involved in biological systems. Computational approaches are required to estimate these parameters. The estimation is converted into multimodal optimization problems that require a global optimization algorithm that can avoid local solutions. These local solutions can lead to a bad fit when calibrating with a model. Although the model itself can potentially match a set of experimental data, a high-performance estimation algorithm is required to improve the quality of the solutions. This paper describes an improved hybrid of particle swarm optimization and the gravitational search algorithm (IPSOGSA) to improve the efficiency of a global optimum (the best set of kinetic parameter values) search. The findings suggest that the proposed algorithm is capable of narrowing down the search space by exploiting the feasible solution areas. Hence, the proposed algorithm is able to achieve a near-optimal set of parameters at a fast convergence speed. The proposed algorithm was tested and evaluated based on two aspartate pathways that were obtained from the BioModels Database. The results show that the proposed algorithm outperformed other standard optimization algorithms in terms of accuracy and near-optimal kinetic parameter estimation. Nevertheless, the proposed algorithm is only expected to work well in small scale systems. In addition, the results of this study can be used to estimate kinetic parameter values in the stage of model selection for different experimental conditions.
  12. Talib MHN, Ibrahim Z, Abd Rahim N, Zulhani R, Nordin N, Farah N, et al.
    ISA Trans, 2020 Oct;105:230-239.
    PMID: 32475537 DOI: 10.1016/j.isatra.2020.05.040
    Fuzzy Logic Speed Controller (FLSC) has been widely used for motor drive due to its robustness and its non-reliance to real plant parameters. However, it is computationally expensive to be implemented in real-time and prone to the fuzzy rules' selection error which results in the failure of the drive's system. This paper proposes an improved simplified rules method for Fuzzy Logic Speed Controller (FLSC) based on the significant crisp output calculations to address these issues. A systematic procedure for the fuzzy rules reduction process is first described. Then, a comprehensive evaluation of the activated crisp output data is presented to determine the fuzzy dominant rules. Based on the proposed method, the number of rules was significantly reduced by 72%. The simplified FLSC rule is tested on the Induction Motor (IM) drives system in which the real-time implementation was carried out in the dSPACE DS1103 controller environment. The simulation and experimental results based on the proposed FLSC have proved the workability of the simplified rules without degrading the motor performance.
  13. Murugesu, S., Khatib, A., Ibrahim, Z., Ahmed, Q. U., Uzir, B.F., Nik-Yusoff, N.I., et al.
    MyJurnal
    Clinacanthus nutans (Acanthaceae) is a local plant consumed as tisane in Indonesia and ‘ulam’ in Malaysia. This plant has been claimed for its ability to prevent many diseases including diabetes. However, the scientific proof on this claim is still lacking. Therefore, the present work study was designed to evaluate the antidiabetic potential and antioxidant capacity of C. nutans leaves extracts using in vitro bioassay tests. The 80% methanolic crude extract of this plant was further partitioned using different polarity solvents namely hexane, hexane:ethyl acetate (1:1, v/v), ethyl acetate, ethyl acetate:methanol (1:1, v/v), and methanol. All the sub-fractions were analysed for antioxidant effect via 2, 2-diphenyl-2-picrylhydrazil (DPPH) scavenging activity, ferric reducing power (FRAP) and xanthine oxidase (XO) assays followed by antidiabetic evaluation via α-glucosidase and dipeptidyl peptidase-IV (DPP-IV) inhibitory assays and glucose uptake experiment. The ethyl acetate fraction showed a good antioxidant potential while the hexane fraction exhibited high α-glucosidase and DPP-IV enzyme inhibition. The hexane fraction also improved glucose uptake in a dose-dependent manner. The present work thus provides an informative data on the potential of C. nutans to be developed as a functional food in preventing diabetes.
  14. Koosha S, Mohamed Z, Sinniah A, Ibrahim Z, Seyedan A, Alshawsh MA
    Life Sci, 2019 Jul 03.
    PMID: 31278947 DOI: 10.1016/j.lfs.2019.116633
    AIMS: The compound 8-prenylnaringenin (8-PN) is a prenylflavonoid that can be isolated from hops and beer and has anti-cancer properties against breast cancer. The aim of this study is to investigate the anti-proliferative and apoptotic activities of 8-PN against human colon cancer HCT-116 cells.

    MAIN METHODS: Colon cancer HCT-116 cells were treated with 8-PN and subjected to MTT and acridine orange/propidium iodide (AO/PI) staining to investigate the cytotoxicity of 8-PN. Arrest of the cells at different phases of cell cycle was monitored in the presence of 8-PN. Moreover, the apoptotic effects of 8-PN was assessed via annexin V and caspase activity assays and compared to the untreated cells.

    KEY FINDINGS: The findings showed that 8-PN revealed strong inhibitory effect against HCT-116 cells with an IC50 value of 23.83 ± 2.9 μg/ml after 48 h. However, at similar concentrations and experimental time-points, the compound did not show cytotoxic effect to non-cancerous colon cells (CCD-41). Annexin-V assay indicates that 38.5% and 14.4% of HCT-116 cells had entered early and late stages of apoptosis, respectively after exposure of the cells to 8-PN for 48 h. Caspase activity assay illustrates that apoptosis is activated through both intrinsic and extrinsic pathways. Moreover, flow cytometry cell cycle results indicate that treatment with 8-PN significantly arrested the HCT-116 cells at G0/G1 phase.

    SIGNIFICANCE: These findings reveal that 8-PN has anti-proliferative activity against HCT-116 colon cancer cells via induction of intrinsic and extrinsic pathway-mediated apoptosis. Further investigations should be carried out to unravel the mechanistic pathways underlying these activities.

  15. Lim CK, Bay HH, Neoh CH, Aris A, Abdul Majid Z, Ibrahim Z
    Environ Sci Pollut Res Int, 2013 Oct;20(10):7243-55.
    PMID: 23653315 DOI: 10.1007/s11356-013-1725-7
    In this study, the adsorption behavior of azo dye Acid Orange 7 (AO7) from aqueous solution onto macrocomposite (MC) was investigated under various experimental conditions. The adsorbent, MC, which consists of a mixture of zeolite and activated carbon, was found to be effective in removing AO7. The MC were characterized by scanning electron microscopy (SEM), energy dispersive X-ray, point of zero charge, and Brunauer-Emmett-Teller surface area analysis. A series of experiments were performed via batch adsorption technique to examine the effect of the process variables, namely, contact time, initial dye concentration, and solution pH. The dye equilibrium adsorption was investigated, and the equilibrium data were fitted to Langmuir, Freundlich, and Tempkin isotherm models. The Langmuir isotherm model fits the equilibrium data better than the Freundlich isotherm model. For the kinetic study, pseudo-first-order, pseudo-second-order, and intraparticle diffusion model were used to fit the experimental data. The adsorption kinetic was found to be well described by the pseudo-second-order model. Thermodynamic analysis indicated that the adsorption process is a spontaneous and endothermic process. The SEM, Fourier transform infrared spectroscopy, ultraviolet-visible spectral and high performance liquid chromatography analysis were carried out before and after the adsorption process. For the phytotoxicity test, treated AO7 was found to be less toxic. Thus, the study indicated that MC has good potential use as an adsorbent for the removal of azo dye from aqueous solution.
  16. Asadi Haris S, Altowayti WAH, Ibrahim Z, Shahir S
    Environ Sci Pollut Res Int, 2018 Oct;25(28):27959-27970.
    PMID: 30062542 DOI: 10.1007/s11356-018-2799-z
    A Gram-negative, arsenite-resistant psychrotolerant bacterial strain, Yersinia sp. strain SOM-12D3, was isolated from a biofilm sample collected from a lake at Svalbard in the Arctic area. To our knowledge, this is the first study on the ability of acid-treated and untreated, non-living biomass of strain SOM-12D3 to absorb arsenic. We conducted batch experiments at pH 7, with an initial As(III) concentration of 6.5 ppm, at 30 °C with 80 min of contact time. The Langmuir isotherm model fitted the equilibrium data better than Freundlich, and the sorption kinetics of As(III) biosorption followed the pseudo-second-order rate equation well for both types of non-living biomass. The highest biosorption capacity of the acid-treated biomass obtained by the Langmuir model was 159 mg/g. Further, a high recovery efficiency of 96% for As(III) was achieved using 0.1 M HCl within four cycles, which indicated high adsorption/desorption. Fourier transformed infrared (FTIR) demonstrated the involvement of hydroxyl, amide, and amine groups in As(III) biosorption. Field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDAX) indicated the different morphological changes occurring in the cell after acid treatment and arsenic biosorption. Our results highlight the potential of using acid-treated non-living biomass of the psychrotolerant bacterium, Yersinia sp. Strain SOM-12D3 as a new biosorbent to remove As(III) from contaminated waters.
  17. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Eur Phys J C Part Fields, 2019;79(9):773.
    PMID: 31713548 DOI: 10.1140/epjc/s10052-019-7276-4
    A measurement for inclusive 2- and 3-jet events of the azimuthal correlation between the two jets with the largest transverse momenta, Δ ϕ 12 , is presented. The measurement considers events where the two leading jets are nearly collinear ("back-to-back") in the transverse plane and is performed for several ranges of the leading jet transverse momentum. Proton-proton collision data collected with the CMS experiment at a center-of-mass energy of 13 Te and corresponding to an integrated luminosity of 35.9 fb - 1 are used. Predictions based on calculations using matrix elements at leading-order and next-to-leading-order accuracy in perturbative quantum chromodynamics supplemented with leading-log parton showers and hadronization are generally in agreement with the measurements. Discrepancies between the measurement and theoretical predictions are as large as 15%, mainly in the region 177 ∘ < Δ ϕ 12 < 180 ∘ . The 2- and 3-jet measurements are not simultaneously described by any of models.
  18. Sahari NS, Shahir S, Ibrahim Z, Hasmoni SH, Altowayti WAH
    Environ Sci Pollut Res Int, 2023 Nov;30(51):110069-110078.
    PMID: 37814051 DOI: 10.1007/s11356-023-30067-w
    This review discusses the application of bacterial nanocellulose (BNC) and modified BNC in treating wastewater containing heavy metals and dye contaminants. It also highlights the challenges and future perspectives of BNC and its composites. Untreated industrial effluents containing toxic heavy metals are systematically discharged into public waters. In particular, lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), zinc (Zn), and arsenic (As) are very harmful to human health and, in some cases, may lead to death. Several methods such as chemical precipitation, ion exchange, membrane filtration, coagulation, and Fenton oxidation are used to remove these heavy metals from the environment. However, these methods involve the use of numerous chemicals whilst producing high amount of toxic sludge. Meanwhile, the development of the adsorption-based technique has provided an alternative way of treating wastewater using BNC. Bacterial nanocellulose requires less energy for purification and has higher purity than plant cellulose. In general, the optimum growth parameters are crucial in BNC production. Even though native BNC can be used for the removal of heavy metals and dyes, the incorporation of other materials, such as polyethyleneimine, graphene oxide, calcium carbonate and polydopamine can improve sorption efficiencies.
  19. Neoh CH, Lam CY, Lim CK, Yahya A, Bay HH, Ibrahim Z, et al.
    Environ Sci Pollut Res Int, 2015 Aug;22(15):11669-78.
    PMID: 25850745 DOI: 10.1007/s11356-015-4436-4
    Extensive use of recalcitrant azo dyes in textile and paper industries poses a direct threat to the environment due to the carcinogenicity of their degradation products. The aim of this study was to investigate the efficiency of Curvularia clavata NZ2 in decolorization of azo dyes. The ability of the fungus to decolorize azo dyes can be evaluated as an important outcome as existing effluent treatment is unable to remove the dyes effectively. C. clavata has the ability to decolorize Reactive Black 5 (RB5), Acid Orange 7 (AO7), and Congo Red azo dyes, utilizing these as sole sources of carbon and nitrogen. Ultraviolet-visible (UV-vis) spectroscopy and Fourier infrared spectroscopy (FTIR) analysis of the extracted RB5's metabolites along with desorption tests confirmed that the decolorization process occurred due to degradation and not merely by adsorption. Enzyme activities of extracellular enzymes such as carboxymethylcellulase (CMCase), xylanase, laccase, and manganese peroxidase (MnP) were also detected during the decolorization process. Toxicity expressed as inhibition of germination was reduced significantly in fungal-treated azo dye solution when compared with the control. The cultivation of C. clavata under sequential batch system also recorded a decolorization efficiency of above 90%. The crude enzyme secreted by C. clavata also showed excellent ability to decolorize RB5 solutions with concentrations of 100 ppm (88-92%) and 1000 ppm (70-77%) without redox mediator. This proved that extracellular enzymes produced by C. clavata played a major role in decolorization of RB5.
  20. Gan HM, Shahir S, Ibrahim Z, Yahya A
    Chemosphere, 2011 Jan;82(4):507-13.
    PMID: 21094980 DOI: 10.1016/j.chemosphere.2010.10.094
    A co-culture consisting of Hydrogenophaga sp. PBC and Ralstonia sp. PBA, isolated from textile wastewater treatment plant could tolerate up to 100 mM 4-aminobenzenesulfonate (4-ABS) and utilize it as sole carbon, nitrogen and sulfur source under aerobic condition. The biodegradation of 4-ABS resulted in the release of nitrogen and sulfur in the form of ammonium and sulfate respectively. Ninety-eight percent removal of chemical oxygen demand attributed to 20 mM of 4-ABS in cell-free supernatant could be achieved after 118 h. Effective biodegradation of 4-ABS occurred at pH ranging from 6 to 8. During batch culture with 4-ABS as sole carbon and nitrogen source, the ratio of strain PBA to PBC was dynamic and a critical concentration of strain PBA has to be reached in order to enable effective biodegradation of 4-ABS. Haldane inhibition model was used to fit the degradation rate at different initial concentrations and the parameters μ(max), K(s) and K(i) were determined to be 0.13 h⁻¹, 1.3 mM and 42 mM respectively. HPLC analyses revealed traced accumulation of 4-sulfocatechol and at least four unidentified metabolites during biodegradation. This is the first study to report on the characterization of 4-ABS-degrading bacterial consortium that was isolated from textile wastewater treatment plant.
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links