Displaying publications 1 - 20 of 31 in total

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  1. A phytotoxicity test of bulrush (Scirpus grossus) grown with diesel contamination in a free-flow reed bed system
    Al-Baldawi IA, Abdullah SR, Anuar N, Suja F, Idris M
    J Hazard Mater, 2013 May 15;252-253:64-9.
    PMID: 23500791 DOI: 10.1016/j.jhazmat.2013.01.067
    In this study, bulrush (Scirpus grossus) was subjected to a 72 day phytotoxicity test to assess its ability to phytoremediate diesel contamination in simulated wastewater at different concentrations (0, 8700, 17,400 and 26,100mg/L). Diesel degradation by S. grossus was measured in terms of total petroleum hydrocarbon (TPH-D). The TPH-D concentration in the synthetic wastewater was determined with the liquid-liquid extraction method and gas chromatography. S. grossus was found to reduce TPH-D by 70.0 and 80.2% for concentrations of 8700 mg/L and 17,400mg/L, respectively. At a diesel concentration of 26,100mg/L, S. grossus died after 14 days. Additionally, the biomass of S. grossus plants was found to increase throughout the phytotoxicity test, confirming the ability of the plant to survive in water contaminated with diesel at rates of less than 17,400mg/L.
  2. A review of the treatment technologies for hexavalent chromium contaminated water
    Ramli NN, Kurniawan SB, Ighalo JO, Mohd Said NS, Marsidi N, Buhari J, et al.
    Biometals, 2023 May 20.
    PMID: 37209220 DOI: 10.1007/s10534-023-00512-x
    The toxicity of hexavalent chromium (Cr(VI)) present in the environment has exceeded the current limits or standards and thus may lead to biotic and abiotic catastrophes. Accordingly, several treatments, including chemical, biological, and physical approaches, are being used to reduce Cr(VI) waste in the surrounding environment. This study compares the Cr(VI) treatment approaches from several areas of science and their competence in Cr(VI) removal. As an effective combination of physical and chemical approaches, the coagulation-flocculation technique removes more than 98% of Cr(VI) in less than 30 min. Most membrane filtering approaches can remove up to 90% of Cr(VI). Biological approaches that involve the use of plants, fungi, and bacteria also successfully eliminate Cr(VI) but are difficult to scale up. Each of these approaches has its benefits and drawbacks, and their applicability is determined by the research aims. These approaches are also sustainable and environmentally benign, thus limiting their effects on the ecosystem.
  3. Fulltext A scoping review on the use of different blood sources and components in the artificial membrane feeding system and its effects on blood-feeding and fecundity rate of Aedes aegypti
    Suresh Y, Azil AH, Abdullah SR
    PLoS One, 2024;19(1):e0295961.
    PMID: 38252615 DOI: 10.1371/journal.pone.0295961
    In some laboratories, mosquitoes' direct blood-feeding on live animals has been replaced with various membrane blood-feeding systems. The selection of blood meal sources used in membrane feeding is crucial in vector mass rearing as it influences the mosquitoes' development and reproductive fitness. Therefore, this scoping review aimed to evaluate the existing literature on the use of different blood sources and components in artificial membrane feeding systems and their effects on blood-feeding and the fecundity rate of Ae. aegypti. A literature review search was conducted by using PubMed, Scopus, and Web of Science databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-ScR). The EndNote version 20 software was used to import all searched articles. Relevant information was retrieved for analysis into a Microsoft Excel Spreadsheet. A total of 104 full-text articles were assessed for eligibility criteria, whereby the articles should include the comparison between different types of blood source by using the membrane feeding systems. Only 16 articles were finally included in the analysis. Several studies had reported that human blood was superior in blood-feeding Ae. aegypti as compared to sheep blood which resulted in lower fecundity due to accumulation of free fatty acids (FFA) in the cuticles. In contrast, cattle whole blood and pig whole blood showed no significant differences in the blood-feeding and fecundity rate as compared to human blood. This review also indicated that bovine whole blood and pig whole blood enhanced Ae. aegypti's vitellogenesis and egg production as compared to plasma and blood cells. In addition, human blood of up to 10 days after the expiration date could still be used to establish Ae. aegypti colonies with good blood-feeding rates and number of eggs produced. Thus, future studies must consider the importance of selecting suitable blood sources and components for membrane blood feeding especially in mosquito colonisation and control measure studies.
  4. Application of response surface methodology (RSM) for optimisation of COD, NH3-N and 2,4-DCP removal from recycled paper wastewater in a pilot-scale granular activated carbon sequencing batch biofilm reactor (GAC-SBBR)
    Muhamad MH, Sheikh Abdullah SR, Mohamad AB, Abdul Rahman R, Hasan Kadhum AA
    J Environ Manage, 2013 May 30;121:179-90.
    PMID: 23542216 DOI: 10.1016/j.jenvman.2013.02.016
    In this study, the potential of a pilot-scale granular activated carbon sequencing batch biofilm reactor (GAC-SBBR) for removing chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N) and 2,4-dichlorophenol (2,4-DCP) from recycled paper wastewater was assessed. For this purpose, the response surface methodology (RSM) was employed, using a central composite face-centred design (CCFD), to optimise three of the most important operating variables, i.e., hydraulic retention time (HRT), aeration rate (AR) and influent feed concentration (IFC), in the pilot-scale GAC-SBBR process for recycled paper wastewater treatment. Quadratic models were developed for the response variables, i.e., COD, NH3-N and 2,4-DCP removal, based on the high value (>0.9) of the coefficient of determination (R(2)) obtained from the analysis of variance (ANOVA). The optimal conditions were established at 750 mg COD/L IFC, 3.2 m(3)/min AR and 1 day HRT, corresponding to predicted COD, NH3-N and 2,4-DCP removal percentages of 94.8, 100 and 80.9%, respectively.
  5. Aquaculture industry: Supply and demand, best practices, effluent and its current issues and treatment technology
    Ahmad A, Sheikh Abdullah SR, Hasan HA, Othman AR, Ismail N'
    J Environ Manage, 2021 Jun 01;287:112271.
    PMID: 33706093 DOI: 10.1016/j.jenvman.2021.112271
    The aquaculture industry has become increasingly important and is rapidly growing in terms of providing a protein food source for human consumption. With the increase in the global population, demand for aquaculture is high and is estimated to reach 62% of the total global production by 2030. In 2018, it was reported that the demand for aquaculture was 46% of the total production, and with the current positive trends, it may be possible to increase tremendously in the coming years. China is still one of the main players in global aquaculture production. Due to high demand, aquaculture production generates large volumes of effluent, posing a great danger to the environment. Aquaculture effluent comprises solid waste and dissolved constituents, including nutrients and contaminants of emerging concern, thereby bringing detrimental impacts such as eutrophication, chemical toxicity, and food insecurity. Waste can be removed through culture systems, constructed wetlands, biofloc, and other treatment technologies. Some methods have the potential to be applied as zero-waste discharge treatment. Thus, this article analyses the supply and demand for aquaculture products, the best practices adopted in the aquaculture industry, effluent characteristics, current issues, and effluent treatment technology.
  6. Arsenic toxicity on Ludwigia octovalvis in spiked sand
    Titah HS, Abdullah SR, Mushrifah I, Anuar N, Basri H, Mukhlisin M
    Bull Environ Contam Toxicol, 2013 Jun;90(6):714-9.
    PMID: 23595348 DOI: 10.1007/s00128-013-0996-5
    Wilting, especially of the leaves, was observed as an initial symptom of arsenate [As(V)] to Ludwigia octovalvis (Jacq.) P. H. Raven. The plants tolerated As(V) levels of 39 mg kg⁻¹ for as long as 35 days of exposure. After 91 days, the maximum concentration of As uptake in the plant occurred at As(V) concentration of 65 mg kg⁻¹ while As concentration in the stems, roots and leaves were 6139.9 ± 829.5, 1284.5 ± 242.9 and 1126.1 ± 117.2 mg kg⁻¹, respectively. In conclusion, As(V) could cause toxic effects in L. octovalvis and the plants could uptake and accumulate As in plant tissues.
  7. Bioflocculant production using palm oil mill and sago mill effluent as a fermentation feedstock: Characterization and mechanism of flocculation
    Hassimi AH, Ezril Hafiz R, Muhamad MH, Sheikh Abdullah SR
    J Environ Manage, 2020 Apr 15;260:110046.
    PMID: 32090804 DOI: 10.1016/j.jenvman.2019.110046
    This study was conducted to examine the production of bioflocculants using agricultural wastewater as a fermentation feedstock under different temperatures and incubation times. The mechanism of flocculation was studied to gain a detailed understanding of the flocculation activity. The highest bioflocculant yield (2.03 g/L) at a temperature of 40 °C was produced in a palm oil mill effluent medium (BioF-POME). Bioflocculant produced from a fermented SME medium (BioF-SME) showed the highest activity. The flocculation tests for colour and turbidity removal from lake water indicated that BioF-SME and BioF-POME performed comparably to commercial alum. Analyses of the bioflocculants using liquid chromatography-mass spectrometry (LC-MS) found that the bioflocculants contained xylose and glucose. The mechanism study showed that flocculation occurred through charge neutralization and interparticle bridging between the bioflocculant polymer and the particles in the lake water. Thus, agricultural wastewater can be used as a fermentation feedstock for high-quality bioflocculants.
  8. Fulltext Cell-based influenza vaccine: current production, halal status assessment, and recommendations towards Islamic-compliant manufacturing
    Zulkarnain NN, Anuar N, Abd Rahman N, Sheikh Abdullah SR, Alias MN, Yaacob M, et al.
    Hum Vaccin Immunother, 2021 07 03;17(7):2158-2168.
    PMID: 33539195 DOI: 10.1080/21645515.2020.1865044
    Influenza virus is a life-threatening pathogen that infects millions of people every year, with annual mortality in the hundreds of thousands. The scenario for controlling infection has worsened with increasing numbers of vaccine hesitancy cases reported worldwide due to objections on safety, religious and other grounds. Uses of haram (impermissible) and mashbooh (doubtful) ingredients in vaccine production has raised doubts among Muslim consumers and consequently stimulated serious vaccine hesitancy. To address this major problem, we have reviewed and recommended some alternatives appropriate for manufacturing cell-based influenza vaccine which comply with Islamic laws and consumers' needs. Intensive assessments of current influenza vaccine production in both scientific and Islamic views have led to the identification of four main ingredients deemed impermissible in novel sharia-compliant (approved by Islamic laws) vaccine manufacturing. Only some of these impermissible components could be replaced with halal (permissible) alternatives, while others remain impermissible due to unavailability and unsuitability.
  9. Comparative performance of free surface and sub-surface flow systems in the phytoremediation of hydrocarbons using Scirpus grossus
    Al-Baldawi IA, Abdullah SR, Suja F, Anuar N, Mushrifah I
    J Environ Manage, 2013 Nov 30;130:324-30.
    PMID: 24113536 DOI: 10.1016/j.jenvman.2013.09.010
    Two types of flow system, free surface flow (FSF) and sub-surface flow (SSF), were examined to select a better way to remove total petroleum hydrocarbons (TPH) using diesel as a hydrocarbon model in a phytotoxicity test to Scirpus grossus. The removal efficiencies of TPH for the two flow systems were compared. Several wastewater parameters, including temperature (T, °C), dissolved oxygen (DO, mgL(-1)), oxidation-reduction potential (ORP, mV), and pH were recorded during the experimental runs. In addition, overall plant lengths, wet weights, and dry weights were also monitored. The phytotoxicity test using the bulrush plant S. grossus was run for 72 days with different diesel concentrations (1%, 2%, and 3%) (Vdiesel/Vwater). A comparison between the two flow systems showed that the SSF system was more efficient than the FSF system in removing TPH from the synthetic wastewater, with average removal efficiencies of 91.5% and 80.2%, respectively. The SSF system was able to tolerate higher diesel concentrations than was the FSF system.
  10. Comparison of the efficiencies of attached- versus suspended-growth SBR systems in the treatment of recycled paper mill wastewater
    Muhamad MH, Sheikh Abdullah SR, Abu Hasan H, Abd Rahim RA
    J Environ Manage, 2015 Nov 1;163:115-24.
    PMID: 26311084 DOI: 10.1016/j.jenvman.2015.08.012
    The complexity of residual toxic organics from biologically treated effluents of pulp and paper mills is a serious concern. To date, it has been difficult to choose the best treatment technique because each of the available options has advantages and drawbacks. In this study, two different treatment techniques using laboratory-scale aerobic sequencing batch reactors (SBRs) were tested with the same real recycled paper mill effluent to evaluate their treatment efficiencies. Two attached-growth SBRs using granular activated carbon (GAC) with and without additional biomass and a suspended-growth SBR were used in the treatment of real recycled paper mill effluent at a chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 h and a COD:N:P ratio of approximately 100:5:1. The efficiency of this biological treatment process was studied over a 300-day period. The six most important wastewater quality parameters, namely, chemical oxygen demand (COD), turbidity, ammonia (expressed as NH3-N), phosphorus (expressed as PO4(3)-P), colour, and suspended solids (SS), were measured to compare the different treatment techniques. It was determined that these processes were able to almost completely and simultaneously eliminate COD (99%) and turbidity (99%); the removals of NH3-N (90-100%), PO4(3)-P (66-78%), colour (63-91%), and SS (97-99%) were also sufficient. The overall performance results confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of performance efficiency and process stability under fluctuations of organic load. Hence, this hybrid system is recommended for the treatment of pulp and paper mill effluents.
  11. Cytotoxicity evaluation of ketoprofen found in pharmaceutical wastewater on HEK 293 cell growth and metabolism
    Zulkarnain NN, Anuar N, Johari NA, Sheikh Abdullah SR, Othman AR
    Environ Toxicol Pharmacol, 2020 Nov;80:103498.
    PMID: 32950717 DOI: 10.1016/j.etap.2020.103498
    Inefficient ketoprofen removal from pharmaceutical wastewater may negatively impact the ecosystem and cause detrimental risks to human health. This study was conducted to determine the cytotoxicity effects of ketoprofen on HEK 293 cell growth and metabolism, including cyclooxygenase-1 (COX-1) expression, at environmentally relevant concentrations. The cytotoxic effects were evaluated through the trypan blue test, DNS assay, MTT assay, and the expression ratio of the COX-1 gene. The results of this study show insignificant (p > 0.05) cytotoxic effects of ketoprofen on cell viability and cell metabolism. However, high glucose consumption rates among the treated cells cause an imitation of the Warburg effect, which is likely linked to the development of cancer cells. Apart from that, the upregulation of COX-1 expression among the treated cells indicates remote possibility of inflammation. Although no significant cytotoxic effects of ketoprofen were detected throughout this study, the effects of prolonged exposure of residual ketoprofen need to be evaluated in the future.
  12. Demodicosis among university medical students in Malaysia and the effects of facial cleanser and moisturizer usage
    Isa NH, Loong LW, Fang GH, Mohamad AM, Razali N, Rani NI, et al.
    Southeast Asian J. Trop. Med. Public Health, 2011 Nov;42(6):1375-80.
    PMID: 22299405
    Demodicosis is an infestation of the skin with Demodex, an ectoparasite commonly found on the face. A cross-sectional study was conducted to detect the presence of the ectoparasite and the outcome of facial cleanser and moisturizer usage on its infestation. Universal sampling was performed among 390 medical students, age 20-25 years old in the Klang Valley of Malaysia. The biodata of the participants and information on the use of facial cleanser and moisturizer were obtained through questionnaire. Skin samples were obtained using both skin scraping and cellophane tape method and were subsequently examined directly by microscopy. The results show an overall prevalence of 17.2%. Males (21.5%) were affected more often than females (12.8%) (p = 0.022). There were no significant differences in the prevalence of the ectoparasite among different ethnic groups, age-groups and the presence of existing facial problems among the subjects. A lower infestation rate (11.45%) was found to be associated with the use of a moisturizer (p = 0.033). Both species of ectoparasites that infest man, Demodexfolliculorum and D. brevis, were detected in this study either as single or mixed infestations.
  13. Fulltext Design, Operation and Optimization of Constructed Wetland for Removal of Pollutant
    Rahman ME, Bin Halmi MIE, Bin Abd Samad MY, Uddin MK, Mahmud K, Abd Shukor MY, et al.
    Int J Environ Res Public Health, 2020 Nov 11;17(22).
    PMID: 33187288 DOI: 10.3390/ijerph17228339
    Constructed wetlands (CWs) are affordable and reliable green technologies for the treatment of various types of wastewater. Compared to conventional treatment systems, CWs offer an environmentally friendly approach, are low cost, have fewer operational and maintenance requirements, and have a high potential for being applied in developing countries, particularly in small rural communities. However, the sustainable management and successful application of these systems remain a challenge. Therefore, after briefly providing basic information on wetlands and summarizing the classification and use of current CWs, this study aims to provide and inspire sustainable solutions for the performance and application of CWs by giving a comprehensive review of CWs' application and the recent development of their sustainable design, operation, and optimization for wastewater treatment. To accomplish this objective, thee design and management parameters of CWs, including macrophyte species, media types, water level, hydraulic retention time (HRT), and hydraulic loading rate (HLR), are discussed. Besides these, future research on improving the stability and sustainability of CWs are highlighted. This article provides a tool for researchers and decision-makers for using CWs to treat wastewater in a particular area. This paper presents an aid for informed analysis, decision-making, and communication. The review indicates that major advances in the design, operation, and optimization of CWs have greatly increased contaminant removal efficiencies, and the sustainable application of this treatment system has also been improved.
  14. Effective microbes for simultaneous bio-oxidation of ammonia and manganese in biological aerated filter system
    Abu Hasan H, Abdullah SR, Kofli NT, Kamarudin SK
    Bioresour Technol, 2012 Nov;124:355-63.
    PMID: 22995166 DOI: 10.1016/j.biortech.2012.08.055
    This study determined the most effective microbes acting as ammonia-oxidising (AOB) and manganese-oxidising bacteria (MnOB) for the simultaneous removal of ammonia (NH(4)(+)-N) and manganese (Mn(2+)) from water. Two conditions of mixed culture of bacteria: an acclimatised mixed culture (mixed culture: MC) in a 5-L bioreactor and biofilm attached on a plastic medium (stages of mixed culture: SMC) in a biological aerated filter were isolated and identified using Biolog MicroSystem and 16S rRNA sequencing. A screening test for determining the most effective microbe in the removal of NH(4)(+)-N and Mn(2+) was initially performed using SMC and MC, respectively, and found that Bacillus cereus was the most effective microbe for the removal of NH(4)(+)-N and Mn(2+). Moreover, the simultaneous NH(4)(+)-N and Mn(2+) removal (above 95% removal for both NH(4)(+)-N and Mn(2+)) was achieved using a biological aerated filter under various operating conditions. Thus, the strain could act as an effective microbe of AOB and a MnOB for the simultaneous removal of NH(4)(+)-N and Mn(2+).
  15. Electrocoagulation of palm oil mill effluent as wastewater treatment and hydrogen production using electrode aluminum
    Nasution MA, Yaakob Z, Ali E, Tasirin SM, Abdullah SR
    J Environ Qual, 2011 Jul-Aug;40(4):1332-9.
    PMID: 21712603 DOI: 10.2134/jeq2011.0002
    Palm oil mill effluent (POME) is highly polluting wastewater generated from the palm oil milling process. Palm oil mill effluent was used as an electrolyte without any additive or pretreatment to perform electrocoagulation (EC) using electricity (direct current) ranging from 2 to 4 volts in the presence of aluminum electrodes with a reactor volume of 20 L. The production of hydrogen gas, removal of chemical oxygen demand (COD), and turbidity as a result of electrocoagulation of POME were determined. The results show that EC can reduce the COD and turbidity of POME by 57 and 62%, respectively, in addition to the 42% hydrogen production. Hydrogen production was also helpful to remove the lighter suspended solids toward the surface. The production of Al(OH)XHO at the aluminum electrode (anode) was responsible for the flocculation-coagulation process of suspended solids followed by sedimentation under gravity. The production of hydrogen gas from POME during EC was also compared with hydrogen gas production by electrolysis of tap water at pH 4 and tap water without pH adjustment under the same conditions. The main advantage of this study is to produce hydrogen gas while treating POME with EC to reduce COD and turbidity effectively.
  16. Integrating phytoremediation and mycoremediation with biosurfactant-producing fungi for hydrocarbon removal and the potential production of secondary resources
    Ahmad J, Marsidi N, Sheikh Abdullah SR, Hasan HA, Othman AR, Ismail N', et al.
    Chemosphere, 2024 Feb;349:140881.
    PMID: 38048826 DOI: 10.1016/j.chemosphere.2023.140881
    Treatment of petroleum-contaminated soil to a less toxic medium via physical and chemical treatment is too costly and requires posttreatment. This review focuses on the employment of phytoremediation and mycoremediation technologies in cleaning hydrocarbon-contaminated soil which is currently rare. It is considered environmentally beneficial and possibly cost-effective as it implements the synergistic interaction between plants and biosurfactant producing mycorrhiza to degrade hydrocarbon contaminants. This review also covers possible sources of hydrocarbon pollution in water and soil, toxicity effects, and current technologies for hydrocarbon removal and degradation. In addition to these problems, this review also discusses the challenges and opportunities of transforming the resultant treated sludge and treating plants into potential by-products for a higher quality of life for future generations.
  17. Fulltext Investigating Genetic and Other Determinants of First-Onset Myocardial Infarction in Malaysia: Protocol for the Malaysian Acute Vascular Events Risk Study
    Chowdhury R, Noh MFM, Ismail SR, van Daalen KR, Kamaruddin PSNM, Zulkiply SH, et al.
    JMIR Res Protoc, 2022 Feb 10;11(2):e31885.
    PMID: 35142634 DOI: 10.2196/31885
    BACKGROUND: Although the burden of premature myocardial infarction (MI) is high in Malaysia, direct evidence on the determinants of MI in this multi-ethnic population remains sparse.

    OBJECTIVE: The Malaysian Acute Vascular Events Risk (MAVERIK) study is a retrospective case-control study established to investigate the genomic, lipid-related, and other determinants of acute MI in Malaysia. In this paper, we report the study protocol and early results.

    METHODS: By June 2019, we had enrolled approximately 2500 patients with their first MI and 2500 controls without cardiovascular disease, who were frequency-matched by age, sex, and ethnicity, from 17 hospitals in Malaysia. For each participant, serum and whole blood have been collected and stored. Clinical, demographic, and behavioral information has been obtained using a 200-item questionnaire.

    RESULTS: Tobacco consumption, a history of diabetes, hypertension, markers of visceral adiposity, indicators of lower socioeconomic status, and a family history of coronary disease were more prevalent in cases than in controls. Adjusted (age and sex) logistic regression models for traditional risk factors indicated that current smoking (odds ratio [OR] 4.11, 95% CI 3.56-4.75; P30 kg/m2; OR 1.19, 95% CI 1.05-1.34; P=.009) were associated with MI in age- and sex-adjusted models.

    CONCLUSIONS: The MAVERIK study can serve as a useful platform to investigate genetic and other risk factors for MI in an understudied Southeast Asian population. It should help to hasten the discovery of disease-causing pathways and inform regionally appropriate strategies that optimize public health action.

    INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/31885.

  18. Isotherm equilibria of Mn²⁺ biosorption in drinking water treatment by locally isolated Bacillus species and sewage activated sludge
    Hasan HA, Abdullah SR, Kofli NT, Kamarudin SK
    J Environ Manage, 2012 Nov 30;111:34-43.
    PMID: 22813857 DOI: 10.1016/j.jenvman.2012.06.027
    Manganese (Mn(2+)) is one of the inorganic contaminant that causes problem to water treatment and water distribution due to the accumulation on water piping systems. In this study, Bacillus sp. and sewage activated sludge (SAS) were investigated as biosorbents in laboratory-scale experiments. The study showed that Bacillus sp. was a more effective biosorbent than SAS. The experimental data were fitted to the Langmuir (Langmuir-1 & Langmuir-2), Freundlich, Temkin, Dubinin-Radushkevich (D-R) and Redlich-Peterson (R-P) isotherms to obtain the characteristic parameters of each model. Mn(2+) biosorption by Bacillus sp. was found to be significantly better fitted to the Langmuir-1 isotherm than the other isotherms, while the D-R isotherm was the best fit for SAS; i.e., the χ(2) value was smaller than that for the Freundlich, Temkin, and R-P isotherms. According to the evaluation using the Langmuir-1 isotherm, the maximum biosorption capacities of Mn(2+) onto Bacillus sp. and SAS were 43.5 mg Mn(2+)/g biomass and 12.7 mg Mn(2+)/g biomass, respectively. The data fitted using the D-R isotherm showed that the Mn(2+) biosorption processes by both Bacillus sp. and SAS occurred via the chemical ion-exchange mechanism between the functional groups and Mn(2+) ion.
  19. Lead (Pb) removal from contaminated water using constructed wetland planted with Scirpus grossus: Optimization using response surface methodology (RSM) and assessment of rhizobacterial addition
    Tangahu BV, Sheikh Abdullah SR, Basri H, Idris M, Anuar N, Mukhlisin M
    Chemosphere, 2022 Mar;291(Pt 3):132952.
    PMID: 34798103 DOI: 10.1016/j.chemosphere.2021.132952
    Lead (Pb) is one of the toxic heavy metals that pollute the environment as a result of industrial activities. This study aims to optimize Pb removal from water by using horizontal free surface flow constructed wetland (HFSFCW) planted with Scirpus grossus. Optimization was conducted using response surface methodology (RSM) under Box-Behnken design with the operational parameters of initial Pb concentration, retention time, and aeration. Optimization results showed that 37 mg/L of initial Pb concentration, 32 days of retention time, and no aeration were the optimum conditions for Pb removal by using the systems. Validation test was run under two different conditions, namely, non-bioaugmented and bioaugmented with rhizobacteria (Bacillus cereus, B. pumilus, B. subtilis, Brevibacillus choshinensis, and Rhodococcus rhodochrous). Results of the validation test showed that Pb removal in water achieved 99.99% efficiency with 0.2% error from the RSM prediction, while the adsorption of Pb by plants reached 5160.18 mg/kg with 10.6% error from the RSM prediction. The bioaugmentation of the five rhizobacterial species showed a slight improvement in Pb removal from water and Pb adsorption by plants. However, no significant improvement was achieved (p 
  20. Fulltext Marine microalgae co-cultured with floc-forming bacterium: Insight into growth and lipid productivity
    Yee CS, Okomoda VT, Hashim F, Waiho K, Sheikh Abdullah SR, Alamanjo C, et al.
    PeerJ, 2021;9:e11217.
    PMID: 33981498 DOI: 10.7717/peerj.11217
    This study investigated the effect of co-culturing microalgae with a floc-forming bacterium. Of the six microalgae isolated from a biofloc sample, only Thalassiosira weissflogii, Chlamydomonas sp. and Chlorella vulgaris were propagated successfully in Conway medium. Hence, these species were selected for the experiment comparing microalgae axenic culture and co-culture with the floc-forming bacterium, Bacillus infantis. Results obtained showed that the co-culture had higher microalgae biomass compared to the axenic culture. A similar trend was also observed concerning the lipid content of the microalgae-bacterium co-cultures. The cell number of B. infantis co-cultured with T. weissflogii increased during the exponential stage until the sixth day, but the other microalgae species experienced a significant early reduction in cell density of the bacteria at the exponential stage. This study represents the first attempt at co-culturing microalgae with B. infantis, a floc-forming bacterium, and observed increased biomass growth and lipid accumulation compared to the axenic culture.
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