Displaying publications 21 - 40 of 209 in total

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  1. Luo D, Ibrahim Z, Ma J, Ismail Z, Iseley DT
    Sensors (Basel), 2016 Dec 16;16(12).
    PMID: 27999245 DOI: 10.3390/s16122149
    In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the vibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM) system in civil engineering.
  2. 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.
  3. Neoh CH, Yahya A, Adnan R, Abdul Majid Z, Ibrahim Z
    Environ Sci Pollut Res Int, 2013 May;20(5):2912-23.
    PMID: 23054764 DOI: 10.1007/s11356-012-1193-5
    The conventional treatment process of palm oil mill effluent (POME) produces a highly colored effluent. Colored compounds in POME cause reduction in photosynthetic activities, produce carcinogenic by-products in drinking water, chelate with metal ions, and are toxic to aquatic biota. Thus, failure of conventional treatment methods to decolorize POME has become an important problem to be addressed as color has emerged as a critical water quality parameter for many countries such as Malaysia. Aspergillus fumigatus isolated from POME sludge was successfully grown in POME supplemented with glucose. Statistical optimization studies were conducted to evaluate the effects of the types and concentrations of carbon and nitrogen sources, pH, temperature, and size of the inoculum. Characterization of the fungus was performed using scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and Brunauer, Emmet, and Teller surface area analysis. Optimum conditions using response surface methods at pH 5.7, 35 °C, and 0.57 % w/v glucose with 2.5 % v/v inoculum size resulted in a successful removal of 71 % of the color (initial ADMI of 3,260); chemical oxygen demand, 71 %; ammoniacal nitrogen, 35 %; total polyphenolic compounds, 50 %; and lignin, 54 % after 5 days of treatment. The decolorization process was contributed mainly by biosorption involving pseudo-first-order kinetics. FTIR analysis revealed that the presence of hydroxyl, C-H alkane, amide carbonyl, nitro, and amine groups could combine intensively with the colored compounds in POME. This is the first reported work on the application of A. fumigatus for the decolorization of POME. The present investigation suggested that growing cultures of A. fumigatus has potential applications for the decolorization of POME through the biosorption and biodegradation processes.
  4. Anyika C, Abdul Majid Z, Ibrahim Z, Zakaria MP, Yahya A
    Environ Sci Pollut Res Int, 2015 Mar;22(5):3314-41.
    PMID: 25345923 DOI: 10.1007/s11356-014-3719-5
    Amending polycyclic aromatic hydrocarbon (PAH)-contaminated soils with biochar may be cheaper and environmentally friendly than other forms of organic materials. This has led to numerous studies on the use of biochar to either bind or stimulate the microbial degradation of organic compounds in soils. However, very little or no attention have been paid to the fact that biochars can give simultaneous impact on PAH fate processes, such as volatilization, sorption and biodegradation. In this review, we raised and considered the following questions: How does biochar affect microbes and microbial activities in the soil? What are the effects of adding biochar on sorption of PAHs? What are the effects of adding biochar on degradation of PAHs? What are the factors that we can manipulate in the laboratory to enhance the capability of biochars to degrade PAHs? A triphasic concept of how biochar can give simultaneous impact on PAH fate processes in soils was proposed, which involves rapid PAH sorption into biochar, subsequent desorption and modification of soil physicochemical properties by biochar, which in turn stimulates microbial degradation of the desorbed PAHs. It is anticipated that biochar can give simultaneous impact on PAH fate processes in soils.
  5. Kasan NA, Ghazali NA, Ikhwanuddin M, Ibrahim Z
    Pak J Biol Sci, 2017;20(6):306-313.
    PMID: 29023055 DOI: 10.3923/pjbs.2017.306.313
    BACKGROUND AND OBJECTIVE: A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc.

    MATERIALS AND METHODS: For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC.

    RESULTS: Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp.

    CONCLUSION: In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.

  6. Loh PY, Shafigh P, Katman HY, Ibrahim Z
    Heliyon, 2024 Feb 29;10(4):e25859.
    PMID: 38390157 DOI: 10.1016/j.heliyon.2024.e25859
    The high alkaline condition of concrete naturally protects embedded steel bars from corrosion by forming a passive protective film. The pH of concrete is generally high, but concrete with different mix compositions may have various pH values. The pH of concrete may decrease over time due to long-term mechanical, chemical, biological and physical factors. Therefore, monitoring the pH value of concrete is crucial to checking if its alkalinity is within an acceptable range and ensuring that the concrete structure is in good health condition. However, the pH measurement for cement-based materials is not standardised. Ex-situ leaching, one of the recommended methods for pH measurement, is simple and practical. In this method, the sample will be crushed, leached and tested using a pH electrode probe. The lifespan of the pH electrode probe may decrease due to the existing suspended particles in the solution. Therefore, one recommendation is to filter the solution before using the probe. In this study, the effect of different filtering setups on the pH value of a cement mortar with a cement-to-sand ratio of 1:3 was evaluated. pH test results showed that filtering can produce similar outcomes to those without filtering, regardless of the type of filter paper and its pore size. However, filtering is strongly recommended for electrode protection of the pH meter. As an innovative filtering setup for cement-based materials, syringe filtering was introduced in this study because it is more economical and its operation is simpler compared to the other methods.
  7. Zulkarnaen M, Pan K, Shanmugam P, Ibrahim Z, Chan W
    Malays Orthop J, 2012 Mar;6(1):49-52.
    PMID: 25279044 MyJurnal DOI: 10.5704/MOJ.1203.003
    ABSTRACT: Synovial sarcoma is primarily a soft tissue malignancy that most often affects adolescents and young adults. It very rarely presents as a primary bone tumour and has only been reported in nine other cases to date. We report a case of primary synovial sarcoma arising from the proximal femur in a 57-year-old man.

    KEY WORDS: Synovial sarcoma, primary bone tumour.

  8. Razak AA, Abu-Hassan MI, Al-Makramani BM, Al-Sanabani FA, Al-Shami IZ, Almansour HM
    J Contemp Dent Pract, 2016 Nov 01;17(11):920-925.
    PMID: 27965501
    AIM: The aim of this study was to evaluate the effect of surface treatments on shear bond strength (SBS) of Turkom-Cera (Turkom-Ceramic (M) Sdn. Bhd., Puchong, Malaysia) all-ceramic material cemented with resin cement Panavia-F (Kuraray Medical Inc., Okayama, Japan).

    MATERIALS AND METHODS: Forty Turkom-Cera ceramic disks (10 mm × 3 mm) were prepared and randomly divided into four groups. The disks were wet ground to 1000-grit and subjected to four surface treatments: (1) No treatment (Control), (2) sandblasting, (3) silane application, and (4) sandblasting + silane. The four groups of 10 specimens each were bonded with Panavia-F resin cement according to manufacturer's recommendations. The SBS was determined using the universal testing machine (Instron) at 0.5 mm/min crosshead speed. Failure modes were recorded and a qualitative micromorphologic examination of different surface treatments was performed. The data were analyzed using the one-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests.

    RESULTS: The SBS of the control, sandblasting, silane, and sandblasting + silane groups were: 10.8 ± 1.5, 16.4 ± 3.4, 16.2 ± 2.5, and 19.1 ± 2.4 MPa respectively. According to the Tukey HSD test, only the mean SBS of the control group was significantly different from the other three groups. There was no significant difference between sandblasting, silane, and sandblasting + silane groups.

    CONCLUSION: In this study, the three surface treatments used improved the bond strength of resin cement to Turkom-Cera disks.

    CLINICAL SIGNIFICANCE: The surface treatments used in this study appeared to be suitable methods for the cementation of glass infiltrated all-ceramic restorations.

  9. Mohd Bahari Z, Ali Hamood Altowayti W, Ibrahim Z, Jaafar J, Shahir S
    Appl Biochem Biotechnol, 2013 Dec;171(8):2247-61.
    PMID: 24037600 DOI: 10.1007/s12010-013-0490-x
    The ability of non-living biomass of an arsenic-hypertolerant Bacillus cereus strain SZ2 isolated from a gold mining environment to adsorb As (III) from aqueous solution in batch experiments was investigated as a function of contact time, initial As (III) concentration, pH, temperature and biomass dosage. Langmuir model fitted the equilibrium data better in comparison to Freundlich isotherm. The maximum biosorption capacity of the sorbent, as obtained from the Langmuir isotherm, was 153.41 mg/g. The sorption kinetic of As (III) biosorption followed well the pseudo-second-order rate equation. The Fourier transform infrared spectroscopy analysis indicated the involvement of hydroxyl, amide and amine groups in As (III) biosorption process. Field emission scanning electron microscopy-energy dispersive X-ray analysis of the non-living B. cereus SZ2 biomass demonstrated distinct cell morphological changes with significant amounts of As adsorbed onto the cells compared to non-treated cells. Desorption of 94 % As (III) was achieved at acidic pH 1 showing the capability of non-living biomass B. cereus SZ2 as potential biosorbent in removal of As (III) from arsenic-contaminated mining effluent.
  10. Lim KS, Ibrahim Z, Buyamin S, Ahmad A, Naim F, Ghazali KH, et al.
    ScientificWorldJournal, 2013;2013:510763.
    PMID: 23737718 DOI: 10.1155/2013/510763
    The Vector Evaluated Particle Swarm Optimisation algorithm is widely used to solve multiobjective optimisation problems. This algorithm optimises one objective using a swarm of particles where their movements are guided by the best solution found by another swarm. However, the best solution of a swarm is only updated when a newly generated solution has better fitness than the best solution at the objective function optimised by that swarm, yielding poor solutions for the multiobjective optimisation problems. Thus, an improved Vector Evaluated Particle Swarm Optimisation algorithm is introduced by incorporating the nondominated solutions as the guidance for a swarm rather than using the best solution from another swarm. In this paper, the performance of improved Vector Evaluated Particle Swarm Optimisation algorithm is investigated using performance measures such as the number of nondominated solutions found, the generational distance, the spread, and the hypervolume. The results suggest that the improved Vector Evaluated Particle Swarm Optimisation algorithm has impressive performance compared with the conventional Vector Evaluated Particle Swarm Optimisation algorithm.
  11. 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.
  12. Yusof AM, Keat LK, Ibrahim Z, Majid ZA, Nizam NA
    J Hazard Mater, 2010 Feb 15;174(1-3):380-5.
    PMID: 19879040 DOI: 10.1016/j.jhazmat.2009.09.063
    The removal of ammonium from aqueous solutions using zeolite NaY prepared from a local agricultural waste, rice husk ash waste was investigated and a naturally occurring zeolite mordenite in powdered and granulated forms was used as comparison. Zeolite NaY and mordenite were well characterized by powder X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and the total cation exchange capacity (CEC). CEC of the zeolites were measured as 3.15, 1.46 and 1.34 meq g(-1) for zeolite Y, powdered mordenite and granular mordenite, respectively. Adsorption kinetics and equilibrium data for the removal of NH(4)(+) ions were examined by fitting the experimental data to various models. Kinetic studies showed that the adsorption followed a pseudo-second-order reaction. The equilibrium pattern fits well with the Langmuir isotherm compared to the other isotherms. The monolayer adsorption capacity for zeolite Y (42.37 mg/g) was found to be higher than that powdered mordenite (15.13 mg/g) and granular mordenite (14.56 mg/g). Thus, it can be concluded that the low cost and economical rice husk ash-synthesized zeolite NaY could be a better sorbent for ammonium removal due to its rapid adsorption rate and higher adsorption capacity compared to natural mordenite.
  13. Ibrahim Z, Amin MF, Yahya A, Aris A, Umor NA, Muda K, et al.
    Water Sci Technol, 2009;60(3):683-8.
    PMID: 19657163 DOI: 10.2166/wst.2009.440
    Microbial flocs formed from raw textile wastewater in a prototype Aerobic Biofilm Reactor (ABR) system were characterised and studied for their potential use in the treatment of textile wastewater. After 90-100 days of operation, microbial flocs of loose irregular structures were obtained from the reactor with good settling velocity of 33 m/h and sludge volume index (SVI) of 48.2 mL/g. Molecular analysis of the flocs using PCR-amplified 16S rDNA sequence showed 98% homology to those of Bacillus sp, Paenibacillus sp and Acromobacter sp. Detection of Ca(2+)(131 mg/g) and Fe(2+)(131 mg/g) using atomic absorption spectrometer might be implicated with the flocs formation. In addition, presence of Co(2+) and Ni(2+) were indicative of the flocs ability to accumulate at least a fraction of the metals' present in the wastewater. When the flocs were used for the treatment of raw textile wastewater, they showed good removal of COD and colour about 55% and 70% respectively, indicating their potential application.
  14. Latiff LA, Ibrahim Z, Pei CP, Rahman SA, Akhtari-Zavare M
    Asian Pac J Cancer Prev, 2015;16(18):8495-501.
    PMID: 26745108
    PURPOSE: This study was conducted to assess the agreement and differences between cervical self-sampling with a Kato device (KSSD) and gynecologist sampling for Pap cytology and human papillomavirus DNA (HPV DNA) detection.

    MATERIALS AND METHODS: Women underwent self-sampling followed by gynecologist sampling during screening at two primary health clinics. Pap cytology of cervical specimens was evaluated for specimen adequacy, presence of endocervical cells or transformation zone cells and cytological interpretation for cells abnormalities. Cervical specimens were also extracted and tested for HPV DNA detection. Positive HPV smears underwent gene sequencing and HPV genotyping by referring to the online NCBI gene bank. Results were compared between samplings by Kappa agreement and McNemar test.

    RESULTS: For Pap specimen adequacy, KSSD showed 100% agreement with gynecologist sampling but had only 32.3% agreement for presence of endocervical cells. Both sampling showed 100% agreement with only 1 case detected HSIL favouring CIN2 for cytology result. HPV DNA detection showed 86.2%agreement (K=0.64, 95% CI 0.524-0.756, p=0.001) between samplings. KSSD and gynaecologist sampling identified high risk HPV in 17.3% and 23.9% respectively (p= 0.014).

    CONCLUSION: The self-sampling using Kato device can serve as a tool in Pap cytology and HPV DNA detection in low resource settings in Malaysia. Self-sampling devices such as KSSD can be used as an alternative technique to gynaecologist sampling for cervical cancer screening among rural populations in Malaysia.

  15. Nor MH, Mubarak MF, Elmi HSh, Ibrahim N, Wahab MF, Ibrahim Z
    Bioresour Technol, 2015 Aug;190:458-65.
    PMID: 25799955 DOI: 10.1016/j.biortech.2015.02.103
    A double-chambered membrane microbial fuel cell (MFC) was constructed to investigate the potential use of natural microflora anaerobic palm oil mill effluent (POME) sludge and pure culture bacteria isolated from anaerobic POME sludge as inoculum for electricity generation. Sterilized final discharge POME was used as the substrate with no addition of nutrients. MFC operation using natural microflora anaerobic POME sludge showed a maximum power density and current density of 85.11mW/m(2) and 91.12mA/m(2) respectively. Bacterial identification using 16S rRNA analysis of the pure culture isolated from the biofilm on the anode MFC was identified as Pseudomonas aeruginosa strain ZH1. The electricity generated in MFC using P. aeruginosa strain ZH1 showed maximum power density and current density of 451.26mW/m(2) and 654.90mA/m(2) respectively which were five times higher in power density and seven times higher in current density compared to that of MFC using anaerobic POME sludge.
  16. Zamakshshari NH, Ee GCL, Ismail IS, Ibrahim Z, Mah SH
    Food Chem Toxicol, 2019 Nov;133:110800.
    PMID: 31479710 DOI: 10.1016/j.fct.2019.110800
    The stem bark of Calophyllum depressinervosum and Calophyllum buxifolium were extracted and examined for their antioxidant activities, together with cytotoxicity towards human cancer cells. The methanol extract of C. depressinervosum exhibited good DPPH and NO scavenging effects. The strongest BCB inhibition and FIC effects were shown by dichloromethane and ethyl acetate extracts of both species. Overall, DPPH, FRAP and FIC assays showed strong correlation with TPC. For cytotoxicity, hexane extract of C. depressinervosum possessed the strongest anti-proliferative activities towards SNU-1 cells while the hexane extract of C. buxifolium showed the strongest activity towards LS-174T and K562 cells with the IC50 values ranging from 7 to 17 μg/mL. The purification of plant extracts afforded eight xanthones, ananixanthone (1), caloxanthone B (2), caloxanthone I (3), caloxanthone J (4) xanthochymone B (5), thwaitesixanthone (6), 1,3,5,6-tetrahydroxyxanthone (7) and dombakinaxanthone (8). All the xanthones, except 1 were reported for the first time from both Calophyllum species. The xanthones were examined for their cytotoxic effect against K562 leukemic cells. Compounds 1 and 2 showed strong cytotoxicity with the IC50 values of 2.96 and 1.23 μg/mL, respectively. The molecular binding interaction of 2 was further investigated by performing molecular docking study with promising protein receptor Src kinase.
  17. Ho CY, Ibrahim Z, Abu Zaid Z, Mat Daud Z', Md Yusop NB
    Trials, 2020 Jun 16;21(1):533.
    PMID: 32546217 DOI: 10.1186/s13063-020-04462-4
    INTRODUCTION: There has been growing evidence on the favourable outcomes of fast-track-recovery (FTR) surgery; to expedite recovery, minimise complications, and reduce the length of hospital stay for surgical patients. However, there is lack of evidence on the effectiveness of FTR in surgical gynaecological cancer (GC) patients. Most of the previous studies did not focus on feeding composition in the FTR surgery protocol. This study aims to determine the effectiveness of FTR feeding with a whey-protein-infused carbohydrate-loading drink pre-operatively and early oral feeding post-operatively on post-operative outcomes among surgical GC patients.

    METHODS/DESIGN: This open-labelled, randomised controlled trial (RCT) will randomly allocate patients into intervention and control groups. Ambulated Malaysian aged over 18 years and scheduled for elective surgery for (suspected) GC, will be included in this study. The intervention group will be given whey-protein-infused carbohydrate-loading drinks on the evening before their operation and 3 h before their operation as well as started on early oral feeding 4 h post-operatively. The control group will be fasted overnight pre-operation and only allowed plain water, and return to a normal diet is allowed when bowel sounds return post-operatively. The primary outcomes of study are length of post-operative hospital stay, length of clear-fluid tolerance, solid-food tolerance and bowel function. Additional outcome measures are changes in nutritional status, biochemical profile and functional status. Data will be analysed on an intention-to-treat basis.

    TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT03667755. Retrospectively registered on 12 September 2018; Protocol version: version 3 dated 27 September 2017.

  18. Lim JC, Goh KM, Shamsir MS, Ibrahim Z, Chong CS
    J Basic Microbiol, 2015 Apr;55(4):514-9.
    PMID: 25523650 DOI: 10.1002/jobm.201400621
    The Anoxybacillus sp. SK 3-4, previously isolated from a hot spring, was screened for its heavy metals resistance (Al(3+), Mn(2+), Cu(2+), Co(2+), Zn(2+), and Ni(2+)) and the strain was found to be most resistant to aluminum. Significant growth of the strain was observed when it was grown in medium containing aluminum (200 mg L(-1)-800 mg L(-1)) with relative growth rates ranging between 77% and 100%. A gene encoding the aluminum resistance protein (accession number: WP_021095658.1) was found in genome of strain SK 3-4, which revealed high sequence identity (>95%) to its homologues from Anoxybacillus species. Sequence comparisons with two functionally characterized aluminum resistance proteins, namely G2alt and ALU1-P, showed 97% and 81% of sequence identity, respectively. Four putative metal binding sites were detected in SK 3-4 aluminum resistance protein and G2alt at same amino acid residue positions of 186, 195, 198, and 201. Strain SK 3-4 was found to be able to remove aluminum from aqueous solution. This study demonstrated that Anoxybacillus sp. SK 3-4 could be applied in the treatment of aluminum contaminated wastewater.
  19. Lim JC, Thevarajoo S, Selvaratnam C, Goh KM, Shamsir MS, Ibrahim Z, et al.
    J Basic Microbiol, 2017 Feb;57(2):151-161.
    PMID: 27859397 DOI: 10.1002/jobm.201600494
    Anoxybacillus sp. SK 3-4 is a Gram-positive, rod-shaped bacterium and a member of family Bacillaceae. We had previously reported that the strain is an aluminum resistant thermophilic bacterium. This is the first report to provide a detailed analysis of the global transcriptional response of Anoxybacillus when the cells were exposed to 600 mg L(-1) of aluminum. The transcriptome was sequenced using Illumina MiSeq sequencer. Total of 708 genes were differentially expressed (fold change >2.00) with 316 genes were up-regulated while 347 genes were down-regulated, in comparing to control with no aluminum added in the culture. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the majority of genes encoding for cell metabolism such as glycolysis, sulfur metabolism, cysteine and methionine metabolism were up-regulated; while most of the gene associated with tricarboxylic acid cycle (TCA cycle) and valine, leucine and isoleucine metabolism were down-regulated. In addition, a significant number of the genes encoding ABC transporters, metal ions transporters, and some stress response proteins were also differentially expressed following aluminum exposure. The findings provide further insight and help us to understand on the resistance of Anoxybacillus sp. SK 3-4 toward aluminium.
  20. Muda K, Aris A, Salim MR, Ibrahim Z, van Loosdrecht MC, Ahmad A, et al.
    Water Res, 2011 Oct 15;45(16):4711-21.
    PMID: 21714982 DOI: 10.1016/j.watres.2011.05.012
    The physical characteristics, microbial activities and kinetic properties of the granular sludge biomass were investigated under the influence of different hydraulic retention times (HRT) along with the performance of the system in removal of color and COD of synthetic textile wastewater. The study was conducted in a column reactor operated according to a sequential batch reactor with a sequence of anaerobic and aerobic reaction phases. Six stages of different HRTs and different anaerobic and aerobic reaction time were evaluated. It was observed that the increase in HRT resulted in the reduction of organic loading rate (OLR). This has caused a decrease in biomass concentration (MLSS), reduction in mean size of the granules, lowered the settling ability of the granules and reduction of oxygen uptake rate (OUR), overall specific biomass growth rate (ìoverall), endogeneous decay rate (kd) and biomass yield (Yobs, Y). When the OLR was increased by adding carbon sources (glucose, sodium acetate and ethanol), there was a slight increase in the MLSS, the granules mean size, ìoverall, and biomass yield. Under high HRT, increasing the anaerobic to aerobic reaction time ratio caused an increase in the concentration of MLSS, mean size of granules and lowered the SVI value and biomass yield. The ìoverall and biomass yield increased with the reduction in anaerobic/aerobic time ratio. The HRT of 24 h with anaerobic and aerobic reaction time of 17.8 and 5.8 h respectively appear to be the best cycle operation of SBR. Under these conditions, not only the physical properties of the biogranules have improved, the highest removal of color (i.e. 94.1±0.6%) and organics (i.e. 86.5±0.5%) of the synthetic textile dyeing wastewater have been achieved.
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