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Mohd Halmi
Department of Land Management, Faculty of Agriculture, University Putra Malaysia, Serdang 43400, Selangor, Malaysia

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Journal article
Published: 21 June 2021 in International Journal of Environmental Research and Public Health
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Predicting the crucial effect of single metal pollutants against the aquatic ecosystem has been highly debatable for decades. However, dealing with complex metal mixtures management in toxicological studies creates a challenge, as heavy metals may evoke greater toxicity on interactions with other constituents rather than individually low acting concentrations. Moreover, the toxicity mechanisms are different between short term and long term exposure of the metal toxicant. In this study, acute and chronic toxicity based on luminescence inhibition assay using newly isolated Photobacterium sp.NAA-MIE as the indicator are presented. Photobacterium sp.NAA-MIE was exposed to the mixture at a predetermined ratio of 1:1. TU (Toxicity Unit) and MTI (Mixture Toxic Index) approach presented the mixture toxicity of Hg2+ + Ag+, Hg2+ + Cu2+, Ag+ + Cu2+, Hg2+ + Ag+ + Cu2+, and Cd2+ + Cu2+ showed antagonistic effect over acute and chronic test. Binary mixture of Cu2+ + Zn2+ was observed to show additive effect at acute test and antagonistic effect at chronic test while mixture of Ni2+ + Zn2+ showing antagonistic effect during acute test and synergistic effect during chronic test. Thus, the strain is suitable and their use as bioassay to predict the risk assessment of heavy metal under acute toxicity without abandoning the advantage of chronic toxicity extrapolation.

ACS Style

Nur Adnan; Mohd Halmi; Siti Abd Gani; Uswatun Zaidan; Mohd Abd Shukor. Comparison of Joint Effect of Acute and Chronic Toxicity for Combined Assessment of Heavy Metals on Photobacterium sp.NAA-MIE. International Journal of Environmental Research and Public Health 2021, 18, 6644 .

AMA Style

Nur Adnan, Mohd Halmi, Siti Abd Gani, Uswatun Zaidan, Mohd Abd Shukor. Comparison of Joint Effect of Acute and Chronic Toxicity for Combined Assessment of Heavy Metals on Photobacterium sp.NAA-MIE. International Journal of Environmental Research and Public Health. 2021; 18 (12):6644.

Chicago/Turabian Style

Nur Adnan; Mohd Halmi; Siti Abd Gani; Uswatun Zaidan; Mohd Abd Shukor. 2021. "Comparison of Joint Effect of Acute and Chronic Toxicity for Combined Assessment of Heavy Metals on Photobacterium sp.NAA-MIE." International Journal of Environmental Research and Public Health 18, no. 12: 6644.

Journal article
Published: 03 June 2021 in Agronomy
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A pot experiment was conducted to measure the phyto-tolerance and accumulation of heavy metals in petroleum oily sludge POS by Cajanus cajan (pigeon pea) on soils treated with five different concentrations (1%, 2%, 3%, 4%, and 5% w/w) of the POS. The response of the plant to oily sludge varied significantly from the untreated control and among the various treatments. The growth of C. cajan was slightly (but not significantly) influenced by the oily sludge in soil; growth of C. cajan at relatively lower concentrations of POS (1 to 3%) was greater than in the treatments with relatively higher concentrations POS (4 to 5%). A significant interaction was observed in the relative growth rates (RGRs) of C. cajan, which significantly increased in the treatments with relatively low POS (1 to 3%) and decrease significantly at higher POS concentrations. The heavy metal content of the plant roots as the POS concentrations were increase show that the concentration of all heavy metals in the roots increased accordingly. Cu showed the highest accumulation with an increase from 1.9 to 6.8 mg/kg followed by Pb, Zn, Ni, Mn, and Cr, which was the least-accumulated. Heavy metal analysis in C. cajan tissues indicated a considerable accumulation of the metals Pb, Zn, Ni, Mn, Cu, and Cr in the root and stem of the plant, with negligible metal concentrations detected in the plant leaves, suggesting a low translocation factor but indicating that C. cajan is resistant to heavy metals. As the search for more eco-friendly and sustainable remediating green plant continues, C. cajan shows great potential for reclaiming POS-contaminated soil due to the above properties including resistance to toxic heavy metals from oily sludge. These findings will provide solutions to polluted soils and their subsequent re-vegetation.

ACS Style

Ibrahim Allamin; Nur Yasid; Siti Abdullah; Mohd Halmi; Mohd Shukor. Phyto-Tolerance Degradation of Hydrocarbons and Accumulation of Heavy Metals by of Cajanus cajan (Pigeon Pea) in Petroleum-Oily-Sludge-Contaminated Soil. Agronomy 2021, 11, 1138 .

AMA Style

Ibrahim Allamin, Nur Yasid, Siti Abdullah, Mohd Halmi, Mohd Shukor. Phyto-Tolerance Degradation of Hydrocarbons and Accumulation of Heavy Metals by of Cajanus cajan (Pigeon Pea) in Petroleum-Oily-Sludge-Contaminated Soil. Agronomy. 2021; 11 (6):1138.

Chicago/Turabian Style

Ibrahim Allamin; Nur Yasid; Siti Abdullah; Mohd Halmi; Mohd Shukor. 2021. "Phyto-Tolerance Degradation of Hydrocarbons and Accumulation of Heavy Metals by of Cajanus cajan (Pigeon Pea) in Petroleum-Oily-Sludge-Contaminated Soil." Agronomy 11, no. 6: 1138.

Journal article
Published: 01 April 2021 in Plants
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Barleria lupulina Lindl. (Acanthaceae) as an ornamental plant has been widely used in folklore medicine due to its abundancy in polyphenolic compounds. The present study examined conditions for optimal extraction of antioxidants from B. lupulina leaf extracts by using the microwave-assisted extraction (MAE) method. The effects of ethanol concentrations, microwave power, and extraction time on total phenolic content (TPC), total flavonoid content (TFC), 1-diphenyl-2-picrylhydrazyl (DPPH), and 2,20-azino-bis (3-ethylbenzothizoline-6-sulfonic acid) (ABTS) were investigated by single-factor experiments. Response surface methodology (RSM) was applied to observe interactions of three independent variables (ethanol concentrations, microwave power, and extraction time) on the dependent variables (TPC, TFC, DPPH, and ABTS) to establish optimal extraction conditions. Quadratic polynomial equations in all experimental models yielded favorably with fitted models with R2 and R2 adj of more than 0.90 and a non-significant lack of fit at p > 0.05. The optimal conditions for the extraction of antioxidant activity were established at 80% (v/v) ethanol, 400 W, and 30 s with TPC (238.71 mg gallic acid equivalent (GAE)/g sample), TFC (58.09 mg QE/g sample), DPPH (87.95%), and ABTS (89.56%). Analysis by ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS) successfully identified four new phenylethanoid glycoside compounds in the species.

ACS Style

Noor Ismail-Suhaimy; Siti Gani; Uswatun Zaidan; Mohd Halmi; Paiman Bawon. Optimizing Conditions for Microwave-Assisted Extraction of Polyphenolic Content and Antioxidant Activity of Barleria lupulina Lindl. Plants 2021, 10, 682 .

AMA Style

Noor Ismail-Suhaimy, Siti Gani, Uswatun Zaidan, Mohd Halmi, Paiman Bawon. Optimizing Conditions for Microwave-Assisted Extraction of Polyphenolic Content and Antioxidant Activity of Barleria lupulina Lindl. Plants. 2021; 10 (4):682.

Chicago/Turabian Style

Noor Ismail-Suhaimy; Siti Gani; Uswatun Zaidan; Mohd Halmi; Paiman Bawon. 2021. "Optimizing Conditions for Microwave-Assisted Extraction of Polyphenolic Content and Antioxidant Activity of Barleria lupulina Lindl." Plants 10, no. 4: 682.

Journal article
Published: 02 March 2021 in International Journal of Environmental Research and Public Health
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The application of microorganisms in azo dye remediation has gained significant attention, leading to various published studies reporting different methods for obtaining the best dye decolouriser. This paper investigates and compares the role of methods and media used in obtaining a bacterial consortium capable of decolourising azo dye as the sole carbon source, which is extremely rare to find. It was demonstrated that a prolonged acclimation under low substrate availability successfully isolated a novel consortium capable of utilising Reactive Red 120 dye as a sole carbon source in aerobic conditions. This consortium, known as JR3, consists of Pseudomonas aeruginosa strain MM01, Enterobacter sp. strain MM05 and Serratia marcescens strain MM06. Decolourised metabolites of consortium JR3 showed an improvement in mung bean’s seed germination and shoot and root length. One-factor-at-time optimisation characterisation showed maximal of 82.9% decolourisation at 0.7 g/L ammonium sulphate, pH 8, 35 °C, and RR120 concentrations of 200 ppm. Decolourisation modelling utilising response surface methodology (RSM) successfully improved decolourisation even more. RSM resulted in maximal decolourisation of 92.79% using 0.645 g/L ammonium sulphate, pH 8.29, 34.5 °C and 200 ppm RR120.

ACS Style

Motharasan Manogaran; Nur Yasid; Ahmad Othman; Baskaran Gunasekaran; Mohd Halmi; Mohd Shukor. Biodecolourisation of Reactive Red 120 as a Sole Carbon Source by a Bacterial Consortium—Toxicity Assessment and Statistical Optimisation. International Journal of Environmental Research and Public Health 2021, 18, 2424 .

AMA Style

Motharasan Manogaran, Nur Yasid, Ahmad Othman, Baskaran Gunasekaran, Mohd Halmi, Mohd Shukor. Biodecolourisation of Reactive Red 120 as a Sole Carbon Source by a Bacterial Consortium—Toxicity Assessment and Statistical Optimisation. International Journal of Environmental Research and Public Health. 2021; 18 (5):2424.

Chicago/Turabian Style

Motharasan Manogaran; Nur Yasid; Ahmad Othman; Baskaran Gunasekaran; Mohd Halmi; Mohd Shukor. 2021. "Biodecolourisation of Reactive Red 120 as a Sole Carbon Source by a Bacterial Consortium—Toxicity Assessment and Statistical Optimisation." International Journal of Environmental Research and Public Health 18, no. 5: 2424.

Journal article
Published: 25 December 2020 in Sustainability
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In the present study, a mixed culture from a local agricultural soil sample was isolated for Metanil Yellow (MY) dye decolorization. The metagenomic analysis confirmed that 42.6% has been dominated by genus Bacillus, while Acinetobacter (14.0%) is present in the microbial communities of the mixed culture. For fungi diversity analysis, around 97.0% was “unclassified” fungi and 3% was Candida. The preliminary investigation in minimal salt media (MSM) showed that 100% decolorization was achieved after 24 h of incubation. Response surface methodology (RSM) was successfully applied using Box-Behnken design (BBD) to study the effect of four independent parameters—MY dye concentration, glucose concentration, ammonium sulfate concentration, and pH—on MY dye decolorization by the mixed bacterial culture. The optimal conditions predicted by the desirability function were 73 mg/L of MY, 1.934% glucose, 0.433 g/L of ammonium sulfate, and a pH of 7.097, with 97.551% decolorization The correlation coefficients (R2 and R2 adj) of 0.913 and 0.825 indicate that the established model is suitable to predict the effectiveness of dye decolorization under the investigated condition. The MY decolorization of the mixed bacterial culture was not affected by the addition of heavy metals in the growth media. Among the 10 heavy metals tested, only copper gave 56.19% MY decolorization, whereas the others gave almost 100% decolorization. The decolorization potential of the mixed bacterial culture indicates that it could be effective for future bioremediation of soil-contaminated sites and treatment solutions of water bodies polluted with the MY dye.

ACS Style

Fatin Muliadi; Mohd Halmi; Samsuri Wahid; Siti Gani; Uswatun Zaidan; Khairil Mahmud; Mohd Abd Shukor. Biostimulation of Microbial Communities from Malaysian Agricultural Soil for Detoxification of Metanil Yellow Dye; a Response Surface Methodological Approach. Sustainability 2020, 13, 138 .

AMA Style

Fatin Muliadi, Mohd Halmi, Samsuri Wahid, Siti Gani, Uswatun Zaidan, Khairil Mahmud, Mohd Abd Shukor. Biostimulation of Microbial Communities from Malaysian Agricultural Soil for Detoxification of Metanil Yellow Dye; a Response Surface Methodological Approach. Sustainability. 2020; 13 (1):138.

Chicago/Turabian Style

Fatin Muliadi; Mohd Halmi; Samsuri Wahid; Siti Gani; Uswatun Zaidan; Khairil Mahmud; Mohd Abd Shukor. 2020. "Biostimulation of Microbial Communities from Malaysian Agricultural Soil for Detoxification of Metanil Yellow Dye; a Response Surface Methodological Approach." Sustainability 13, no. 1: 138.

Journal article
Published: 22 December 2020 in Sustainability
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In this study, the Metanil Yellow (MY) decolorizing mixed culture, namely FN3, has been isolated from agriculture soil. The mixed culture was immobilized using gellan gum. In order to optimize the immobilization process for maximal dye decolorization, Response Surface Methodology (RSM) was performed. The optimal conditions for immobilization predicted by desirability function are 130 mg/L of MY dye concentration, 1.478% of gellan gum concentration, 50 beads and 0.6 cm of beads size with the percentage of decolorization of 90.378%. The correlation coefficients of the model (R2 and R2 adj) are 0.9767 and 0.9533, respectively. This indicates that the established model is suitable to predict the effectiveness of dye decolorization under the investigated condition. The immobilized beads of mixed culture FN3 were able to be reused up to 15 batches of decolorization. The immobilized cells also have high tolerance towards heavy metals. This was proven by higher dye decolorization rate by the immobilized cells even with the addition of heavy metals in the media. The decolorization potential of the mixed culture indicates that it could be useful for future bioremediation of soil contaminated sites and treatment solutions of water bodies polluted with MY dye.

ACS Style

Fatin Muliadi; Mohd Halmi; Samsuri Wahid; Siti Gani; Khairil Mahmud; Mohd Shukor. Immobilization of Metanil Yellow Decolorizing Mixed Culture FN3 Using Gelling Gum as Matrix for Bioremediation Application. Sustainability 2020, 13, 36 .

AMA Style

Fatin Muliadi, Mohd Halmi, Samsuri Wahid, Siti Gani, Khairil Mahmud, Mohd Shukor. Immobilization of Metanil Yellow Decolorizing Mixed Culture FN3 Using Gelling Gum as Matrix for Bioremediation Application. Sustainability. 2020; 13 (1):36.

Chicago/Turabian Style

Fatin Muliadi; Mohd Halmi; Samsuri Wahid; Siti Gani; Khairil Mahmud; Mohd Shukor. 2020. "Immobilization of Metanil Yellow Decolorizing Mixed Culture FN3 Using Gelling Gum as Matrix for Bioremediation Application." Sustainability 13, no. 1: 36.

Journal article
Published: 19 November 2020 in International Journal of Environmental Research and Public Health
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Potentially toxic metals pollution in the Straits of Malacca warrants the development of rapid, simple and sensitive assays. Enzyme-based assays are excellent preliminary screening tools with near real-time potential. The heavy-metal assay based on the protease ficin was optimized for mercury detection using response surface methodology. The inhibitive assay is based on ficin action on the substrate casein and residual casein is determined using the Coomassie dye-binding assay. Toxic metals strongly inhibit this hydrolysis. A central composite design (CCD) was utilized to optimize the detection of toxic metals. The results show a marked improvement for the concentration causing 50% inhibition (IC50) for mercury, silver and copper. Compared to one-factor-at-a-time (OFAT) optimization, RSM gave an improvement of IC50 (mg/L) from 0.060 (95% CI, 0.030–0.080) to 0.017 (95% CI, 0.016–0.019), from 0.098 (95% CI, 0.077–0.127) to 0.028 (95% CI, 0.022–0.037) and from 0.040 (95% CI, 0.035–0.045) to 0.023 (95% CI, 0.020–0.027), for mercury, silver and copper, respectively. A near-real time monitoring of mercury concentration in the Straits of Malacca at one location in Port Klang was carried out over a 4 h interval for a total of 24 h and validated by instrumental analysis, with the result revealing an absence of mercury pollution in the sampling site.

ACS Style

Garba Uba; Motharasan Manogaran; Baskaran Gunasekaran; Mohd Izuan Effendi Halmi; Mohd Yunus Abd Shukor. Improvement of Ficin-Based Inhibitive Enzyme Assay for Toxic Metals Using Response Surface Methodology and Its Application for Near Real-Time Monitoring of Mercury in Marine Waters. International Journal of Environmental Research and Public Health 2020, 17, 8585 .

AMA Style

Garba Uba, Motharasan Manogaran, Baskaran Gunasekaran, Mohd Izuan Effendi Halmi, Mohd Yunus Abd Shukor. Improvement of Ficin-Based Inhibitive Enzyme Assay for Toxic Metals Using Response Surface Methodology and Its Application for Near Real-Time Monitoring of Mercury in Marine Waters. International Journal of Environmental Research and Public Health. 2020; 17 (22):8585.

Chicago/Turabian Style

Garba Uba; Motharasan Manogaran; Baskaran Gunasekaran; Mohd Izuan Effendi Halmi; Mohd Yunus Abd Shukor. 2020. "Improvement of Ficin-Based Inhibitive Enzyme Assay for Toxic Metals Using Response Surface Methodology and Its Application for Near Real-Time Monitoring of Mercury in Marine Waters." International Journal of Environmental Research and Public Health 17, no. 22: 8585.

Review
Published: 11 November 2020 in International Journal of Environmental Research and Public Health
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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.

ACS Style

Ekhlasur Rahman; Mohd Izuan Effendi Bin Halmi; Mohd Yusoff Bin Abd Samad; Kamal Uddin; Khairil Mahmud; Mohd Yunus Abd Shukor; Siti Rozaimah Sheikh Abdullah; S M Shamsuzzaman. Design, Operation and Optimization of Constructed Wetland for Removal of Pollutant. International Journal of Environmental Research and Public Health 2020, 17, 8339 .

AMA Style

Ekhlasur Rahman, Mohd Izuan Effendi Bin Halmi, Mohd Yusoff Bin Abd Samad, Kamal Uddin, Khairil Mahmud, Mohd Yunus Abd Shukor, Siti Rozaimah Sheikh Abdullah, S M Shamsuzzaman. Design, Operation and Optimization of Constructed Wetland for Removal of Pollutant. International Journal of Environmental Research and Public Health. 2020; 17 (22):8339.

Chicago/Turabian Style

Ekhlasur Rahman; Mohd Izuan Effendi Bin Halmi; Mohd Yusoff Bin Abd Samad; Kamal Uddin; Khairil Mahmud; Mohd Yunus Abd Shukor; Siti Rozaimah Sheikh Abdullah; S M Shamsuzzaman. 2020. "Design, Operation and Optimization of Constructed Wetland for Removal of Pollutant." International Journal of Environmental Research and Public Health 17, no. 22: 8339.

Journal article
Published: 08 October 2020 in Applied Sciences
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In this study, a simplex-centroid mixture design (SCMD) approach was used to select the optimal proportions of three different Melastomataceae leaves species (M. malabathricum, M. decemfidum, and M. hirta) extracts to determine the optimum antioxidant activities of total phenolic compound (TPC) and ABTS (2, 2′-azino-bis (ethylbenzthiazoline-6-sulfonic acid)) radical-scavenging activities. Twelve experimental designs were set up, consisting of points that were equally weighted mixtures of 0 to 1 components, which were pure blends (1, 0, …, 0), binary blends (1/2, 1/2, 0, …, 0), tertiary blends (1/3, 1/3, 1/3, 0, …, 0), and a control point. The in vitro anti-elastase and collagenase activities were evaluated in order to determine the anti-aging efficacy of the optimized mixture extracts. A high-performance liquid chromatography (HPLC) analysis was employed to identify the flavonoid content (rutin and quercetin) present in the optimized mixture extracts. The results showed that the best proportions of the optimum phenolic compounds and ABTS activity corresponded to 30%, 40%, and 30% of M. malabathricum, M. hirta, and M. decemfidum leaf extracts, respectively. The in vitro anti-collagenase and elastase activity evaluation of the optimized mixture extracts showed 70% inhibition against both elastase and collagenase enzymes. The HPLC analysis revealed two flavonoids (rutin and quercetin) at retention time 7.770 and 8.769 min, respectively, in the mixture extracts. This study suggests the potential exploitation of mixtures of Melastomataceae leaves (M. malabathricum, M. decemfidum, and M. hirta) as cosmetic ingredients for antioxidant and anti-wrinkles applications.

ACS Style

Nur Fauwizah Azahar; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Paiman Bawon; Mohd Izuan Effendi Halmi. Optimization of the Antioxidant Activities of Mixtures of Melastomataceae Leaves Species (M. malabathricum Linn Smith, M. decemfidum, and M. hirta) Using a Simplex Centroid Design and Their Anti-Collagenase and Elastase Properties. Applied Sciences 2020, 10, 7002 .

AMA Style

Nur Fauwizah Azahar, Siti Salwa Abd Gani, Uswatun Hasanah Zaidan, Paiman Bawon, Mohd Izuan Effendi Halmi. Optimization of the Antioxidant Activities of Mixtures of Melastomataceae Leaves Species (M. malabathricum Linn Smith, M. decemfidum, and M. hirta) Using a Simplex Centroid Design and Their Anti-Collagenase and Elastase Properties. Applied Sciences. 2020; 10 (19):7002.

Chicago/Turabian Style

Nur Fauwizah Azahar; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Paiman Bawon; Mohd Izuan Effendi Halmi. 2020. "Optimization of the Antioxidant Activities of Mixtures of Melastomataceae Leaves Species (M. malabathricum Linn Smith, M. decemfidum, and M. hirta) Using a Simplex Centroid Design and Their Anti-Collagenase and Elastase Properties." Applied Sciences 10, no. 19: 7002.

Preprint
Published: 31 August 2020
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Heavy metals pollution in the Straits of Malacca warrants the development of rapid, simple and sensitive assays. Enzyme-based assays are excellent preliminary screening tool with near real-time potential. The heavy-metal assay based on the protease ficin was optimized for mercury detection using Response Surface Methodology. The inhibitive assay is based on ficin action on the substrate casein and residual casein is determined using the Coomassie dye-binding assay. Heavy metals strongly inhibit the hydrolysis. A Central Composite Design (CCD) was utilized to optimize detection. The results show a marked improvement for the concentration causing 50% inhibition (IC50) for mercury, silver and copper. Compared to One-factor-at-a-time (OFAT) optimization, RSM gave an improvement of IC50 from 0.060 (95% CI, 0.0300.080) to 0.017 (95% CI, 0.0160.019), from 0.098 (95% CI, 0.0770.127) to 0.028 (95% CI, 0.0220.037) and from 0.040 (95% CI, 0.035.045) to 0.023 (95% CI, 0.0200.027), for mercury, silver and copper, respectively. A near real-time monitoring of mercury concentration in the Straits of Malacca at one location in Port Klang was carried out over a 4-h interval for a total of 24 h and validated by instrumental analysis with the result revealing an absence of mercury pollution in the sampling site.

ACS Style

Garba Uba; Motharasan Manogaran; Baskaran Gunasekaran; Mohd Izuan Effendi Halmi; Mohd Yunus Abd Shukor. Improvement of Ficin-Based Inhibitive Enzyme Assay for Mercury Using Response Surface Methodology and Its Application for Near Real-Time Monitoring of Mercury in Marine Waters. 2020, 1 .

AMA Style

Garba Uba, Motharasan Manogaran, Baskaran Gunasekaran, Mohd Izuan Effendi Halmi, Mohd Yunus Abd Shukor. Improvement of Ficin-Based Inhibitive Enzyme Assay for Mercury Using Response Surface Methodology and Its Application for Near Real-Time Monitoring of Mercury in Marine Waters. . 2020; ():1.

Chicago/Turabian Style

Garba Uba; Motharasan Manogaran; Baskaran Gunasekaran; Mohd Izuan Effendi Halmi; Mohd Yunus Abd Shukor. 2020. "Improvement of Ficin-Based Inhibitive Enzyme Assay for Mercury Using Response Surface Methodology and Its Application for Near Real-Time Monitoring of Mercury in Marine Waters." , no. : 1.

Journal article
Published: 08 April 2020 in Ecotoxicology and Environmental Safety
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Assessment of eco-toxicant using bioluminescent bacterial assay is a widely used and globally accepted method. In this work, a new luminescent bacterium was isolated from squid (Loligo duvauceli) and identified as Photobacterium leiognathi strain AK-MIE using 16S rRNA, phylogeny analysis. The predicted optimum conditions by RSM were 2.76% (w/v) NaCl, 2.28% (w/v) peptone, 0.34% (w/v) yeast extract, and pH 6.83 with 541,211.80 RLU of luminescent production whereas the predicted optimum conditions by ANN were 2.21% (w/v) NaCl, 2.27% (w/v) peptone, 0.39% (w/v) yeast extract, and pH 6.94 which produced 541,986.20 RLU. The validation analysis of both RSM and ANN show 0.60% and 0.69% deviation from the predicted results indicating that both models provided good quality predictions with ANN showing a superior data fitting capability for non-linear regression analysis. Toxicity tests show strain AK-MIE was sensitive to mercury (concentration causing 50% inhibition or IC50 of 0.00978 mgL−1), followed by cadmium (IC50 of 0.5288 mgL−1), copper IC50 of (0.8117 mgL−1), silver (IC50 of 1.109 mgL−1), and lead (IC50 of 10.71 mgL−1) which are more sensitive than previously isolated luminescent bacteria, suggesting that strain AK-MIE has the potential to be used in toxicity assessment of heavy metals in the environment. Based on the field trial results, several sediment samples from industrial areas in Bangi, Selangor managed to inhibit the bioluminescence of strain AK-MIE. Validation method carried out using ICP-MS proved the presence of several toxic heavy metal elements.

ACS Style

Adibah Kassim; Mohd Izuan Effendi Halmi; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Radziah Othman; Khairil Mahmud; Mohd Yunus Abd Shukor. Bioluminescent method for the rapid screening of toxic heayy metals in environmental samples using Photobacterium leiognathi strain AK-MIE. Ecotoxicology and Environmental Safety 2020, 196, 110527 .

AMA Style

Adibah Kassim, Mohd Izuan Effendi Halmi, Siti Salwa Abd Gani, Uswatun Hasanah Zaidan, Radziah Othman, Khairil Mahmud, Mohd Yunus Abd Shukor. Bioluminescent method for the rapid screening of toxic heayy metals in environmental samples using Photobacterium leiognathi strain AK-MIE. Ecotoxicology and Environmental Safety. 2020; 196 ():110527.

Chicago/Turabian Style

Adibah Kassim; Mohd Izuan Effendi Halmi; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Radziah Othman; Khairil Mahmud; Mohd Yunus Abd Shukor. 2020. "Bioluminescent method for the rapid screening of toxic heayy metals in environmental samples using Photobacterium leiognathi strain AK-MIE." Ecotoxicology and Environmental Safety 196, no. : 110527.

Journal article
Published: 12 February 2020 in Molecules
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The present study was conducted to optimize extraction process for defatted pitaya seed extract (DPSE) adopting response surface methodology (RSM). A five-level central composite design was used to optimize total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), and 2,2′-azino-bis (3-ethylbenzothizoline-6-sulfonic acid (ABTS) activities. The independent variables included extraction time (30–60 min), extraction temperature (40–80 °C) and ethanol concentration (60%–80%). Results showed that the quadratic polynomial equations for all models were significant at (p < 0.05), with non-significant lack of fit at p > 0.05 and R2 of more than 0.90. The optimized extraction parameters were established as follows: extraction time of 45 min, extraction temperature of 70 °C and ethanol concentration of 80%. Under these conditions, the recovery of TPC, TFC, and antioxidant activity based on FRAP and ABTS were 128.58 ± 1.61 mg gallic acid equivalent (GAE)/g sample, 9.805 ± 0.69 mg quercetin equivalent (QE)/g sample, 1.23 ± 0.03 mM Fe2+/g sample, and 91.62% ± 0.15, respectively. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) analysis identified seven chemical compounds with flavonoids constituting major composition of the DPSE.

ACS Style

Siti Atikah Zulkifli; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi. Optimization of Total Phenolic and Flavonoid Contents of Defatted Pitaya (Hylocereus polyrhizus) Seed Extract and Its Antioxidant Properties. Molecules 2020, 25, 787 .

AMA Style

Siti Atikah Zulkifli, Siti Salwa Abd Gani, Uswatun Hasanah Zaidan, Mohd Izuan Effendi Halmi. Optimization of Total Phenolic and Flavonoid Contents of Defatted Pitaya (Hylocereus polyrhizus) Seed Extract and Its Antioxidant Properties. Molecules. 2020; 25 (4):787.

Chicago/Turabian Style

Siti Atikah Zulkifli; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi. 2020. "Optimization of Total Phenolic and Flavonoid Contents of Defatted Pitaya (Hylocereus polyrhizus) Seed Extract and Its Antioxidant Properties." Molecules 25, no. 4: 787.

Research article
Published: 03 December 2019 in Proceedings of the National Academy of Sciences, India Section B: Biological Sciences
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The utilization of bioluminescent bacteria has served as a powerful bioassay in environmental monitoring as a result of simplicity of use, quick response and high sensitivity on the basis of the luminescence being produced. In the present study, the optimization process for the luminescence production of a newly isolated Photobacterium sp. NAA-MIE using response surface methodology (RSM) and artificial neural network (ANN) is investigated. RSM and ANN are the most favored techniques and efficient methods for the optimization of medium components, especially for nonlinear systems. This analysis presents the comparative evaluation between RSM and ANN aimed at their particular empirical modeling and predictive ability. RSM predicted the optimized condition with four major variables at glycerol concentration of 0.16%, NaCl of 2.49%, pH at 7.4 and tryptone of 2.97% with 260,748.94 RLU of the maximum luminescence production. The accuracy of the RSM model equations was measured with R2 of 0.9001 and adjusted R2 of 0.8001. ANN predicted optimum condition at a glycerol concentration of 0.10%, NaCl of 2.46%, pH at 7.5 and tryptone of 1.97% with 237,481.32 RLU. The study demonstrated that ANN accomplishes more than RSM with a higher R2 value of 0.968 and low mean percentage error and root mean square error, which were 0.003 and 3.66, respectively. Both models are presented as suitable predictive models on the basis of mathematical modeling to optimize and improve biological systems for future upscaling processes with ANN as more predictive and having more fitting potentiality compared to RSM.

ACS Style

Nur Adila Adnan; Mohd Izuan Effendi Halmi; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Radziah Othman; Mohd Yunus Abd Shukor. Statistical Modeling for the Optimization of Bioluminescence Production by Newly Isolated Photobacterium sp. NAA-MIE. Proceedings of the National Academy of Sciences, India Section B: Biological Sciences 2019, 90, 797 -810.

AMA Style

Nur Adila Adnan, Mohd Izuan Effendi Halmi, Siti Salwa Abd Gani, Uswatun Hasanah Zaidan, Radziah Othman, Mohd Yunus Abd Shukor. Statistical Modeling for the Optimization of Bioluminescence Production by Newly Isolated Photobacterium sp. NAA-MIE. Proceedings of the National Academy of Sciences, India Section B: Biological Sciences. 2019; 90 (4):797-810.

Chicago/Turabian Style

Nur Adila Adnan; Mohd Izuan Effendi Halmi; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Radziah Othman; Mohd Yunus Abd Shukor. 2019. "Statistical Modeling for the Optimization of Bioluminescence Production by Newly Isolated Photobacterium sp. NAA-MIE." Proceedings of the National Academy of Sciences, India Section B: Biological Sciences 90, no. 4: 797-810.

Journal article
Published: 16 February 2019 in Molecules
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This study investigates the ultrasound-assisted extraction of flavonoids from Malaysian cocoa shell extracts, and optimization using response surface methodology. There are three variables involved in this study, namely: ethanol concentration (70–90 v/v %), temperature (45–65 °C), and ultrasound irradiation time (30–60 min). All of the data were collected and analyzed for variance (ANOVA). The coefficient of determination (R2) and the model was significant in interaction between all variables (98% and p < 0.0001, respectively). In addition, the lack of fit test for the model was not of significance, with p > 0.0684. The ethanol concentration, temperature, and ultrasound irradiation time that yielded the maximum value of the total flavonoid content (TFC; 7.47 mg RE/g dried weight (DW)) was 80%, 55 °C, and 45 min, respectively. The optimum value from the validation of the experimental TFC was 7.23 ± 0.15 mg of rutin, equivalent per gram of extract with ethanol concentration, temperature, and ultrasound irradiation time values of 74.20%, 49.99 °C, and 42.82 min, respectively. While the modelled equation fits the data, the T-test is not significant, suggesting that the experimental values agree with those predicted by the response surface methodology models.

ACS Style

Arief Huzaimi Md Yusof; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi; Badrul Hisyam Zainudin. Optimization of an Ultrasound-Assisted Extraction Condition for Flavonoid Compounds from Cocoa Shells (Theobroma cacao) Using Response Surface Methodology. Molecules 2019, 24, 711 .

AMA Style

Arief Huzaimi Md Yusof, Siti Salwa Abd Gani, Uswatun Hasanah Zaidan, Mohd Izuan Effendi Halmi, Badrul Hisyam Zainudin. Optimization of an Ultrasound-Assisted Extraction Condition for Flavonoid Compounds from Cocoa Shells (Theobroma cacao) Using Response Surface Methodology. Molecules. 2019; 24 (4):711.

Chicago/Turabian Style

Arief Huzaimi Md Yusof; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi; Badrul Hisyam Zainudin. 2019. "Optimization of an Ultrasound-Assisted Extraction Condition for Flavonoid Compounds from Cocoa Shells (Theobroma cacao) Using Response Surface Methodology." Molecules 24, no. 4: 711.

Journal article
Published: 01 September 2018 in Applied Sciences
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In this study, response surface methodology (RSM) was employed for the optimization of the antioxidant potentials of red pitaya peels using independent variables: temperature (45–65 °C), ethanol concentration (70–90%, v/v) and time (80–120 min) through its responses, which were DPPH scavenging activity, ferric ion reducing antioxidant power (FRAP), and beta-carotene bleaching (BCB) inhibition, respectively. In Vitro anti-tyrosinase and vitamin C content assays were carried out spectrophotometrically to determine the skin whitening efficacy of the optimized red pitaya peel extract. A gas chromatography-mass spectrometry (GC-MS) analysis was employed to identify the chemical constituents present in the optimized extract. The optimized conditions were ethanol 82% (v/v) for 103 min at 56 °C with values of 75.98% for DPPH, 7.45 mM Fe2+/g dry weight for FRAP and 93.29% for BCB respectively. The in vitro anti-tyrosinase and vitamin C content evaluation of the optimized extract showed a good tyrosinase inhibition of 66.29% with IC50 of 24.06 µg/mL while the vitamin C content was 5.45 mg/g of the extract. The GC-MS analysis revealed the presence of thirty phytoconstituents with l-(+)-ascorbic acid 2,6-dihexadecanoate being the most abundant with a peak area of 14.66%. This study evidently suggests the potential of red pitaya peels to be exploited as a natural skin whitening agent in the cosmeceutical and pharmaceutical formulations.

ACS Style

Ramya Vijayakumar; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi. Optimization of the Antioxidant Potentials of Red Pitaya Peels and Its In Vitro Skin Whitening Properties. Applied Sciences 2018, 8, 1516 .

AMA Style

Ramya Vijayakumar, Siti Salwa Abd Gani, Uswatun Hasanah Zaidan, Mohd Izuan Effendi Halmi. Optimization of the Antioxidant Potentials of Red Pitaya Peels and Its In Vitro Skin Whitening Properties. Applied Sciences. 2018; 8 (9):1516.

Chicago/Turabian Style

Ramya Vijayakumar; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi. 2018. "Optimization of the Antioxidant Potentials of Red Pitaya Peels and Its In Vitro Skin Whitening Properties." Applied Sciences 8, no. 9: 1516.

Articles
Published: 03 May 2018 in International Journal of Phytoremediation
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In this study, the removal of arsenic (As) by plant, Ludwigia octovalvis, in a pilot reed bed was optimized. A Box-Behnken design was employed including a comparative analysis of both Response Surface Methodology (RSM) and an Artificial Neural Network (ANN) for the prediction of maximum arsenic removal. The predicted optimum condition using the desirability function of both models was 39 mg kg−1 for the arsenic concentration in soil, an elapsed time of 42 days (the sampling day) and an aeration rate of 0.22 L/min, with the predicted values of arsenic removal by RSM and ANN being 72.6% and 71.4%, respectively. The validation of the predicted optimum point showed an actual arsenic removal of 70.6%. This was achieved with the deviation between the validation value and the predicted values being within 3.49% (RSM) and 1.87% (ANN). The performance evaluation of the RSM and ANN models showed that ANN performs better than RSM with a higher R2 (0.97) close to 1.0 and very small Average Absolute Deviation (AAD) (0.02) and Root Mean Square Error (RMSE) (0.004) values close to zero. Both models were appropriate for the optimization of arsenic removal with ANN demonstrating significantly higher predictive and fitting ability than RSM.

ACS Style

Harmin Sulistiyaning Titah; Mohd Izuan Effendi Bin Halmi; Siti Rozaimah Sheikh Abdullah; Hassimi Abu Hasan; Mushrifah Idris; Nurina Anuar. Statistical optimization of the phytoremediation of arsenic by Ludwigia octovalvis- in a pilot reed bed using response surface methodology (RSM) versus an artificial neural network (ANN). International Journal of Phytoremediation 2018, 20, 721 -729.

AMA Style

Harmin Sulistiyaning Titah, Mohd Izuan Effendi Bin Halmi, Siti Rozaimah Sheikh Abdullah, Hassimi Abu Hasan, Mushrifah Idris, Nurina Anuar. Statistical optimization of the phytoremediation of arsenic by Ludwigia octovalvis- in a pilot reed bed using response surface methodology (RSM) versus an artificial neural network (ANN). International Journal of Phytoremediation. 2018; 20 (7):721-729.

Chicago/Turabian Style

Harmin Sulistiyaning Titah; Mohd Izuan Effendi Bin Halmi; Siti Rozaimah Sheikh Abdullah; Hassimi Abu Hasan; Mushrifah Idris; Nurina Anuar. 2018. "Statistical optimization of the phytoremediation of arsenic by Ludwigia octovalvis- in a pilot reed bed using response surface methodology (RSM) versus an artificial neural network (ANN)." International Journal of Phytoremediation 20, no. 7: 721-729.

Journal article
Published: 22 March 2018 in Molecules
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In this study, the optimal conditions for the extraction of antioxidants from the Buah Mahkota Dewa fruit (Phaleria macrocarpa) was determined by using Response Surface Methodology (RSM). The optimisation was applied using a Central Composite Design (CCD) to investigate the effect of three independent variables, namely extraction temperature (°C), extraction time (minutes) and extraction solvent to-feed ratio (% v/v) on four responses: free radical scavenging activity (DPPH), ferric ion reducing power assay (FRAP), total phenolic content (TPC) and total flavonoid content (TFC). The optimal conditions for the antioxidants extraction were found to be 64 °C extraction temperature, 66 min extraction time and 75% v/v solvent to-feed ratio giving the highest percentage yields of DPPH, FRAP, TPC and TFC of 86.85%, 7.47%, 292.86 mg/g and 3.22 mg/g, respectively. Moreover, the data were subjected to Response Surface Methodology (RSM) and the results showed that the polynomial equations for all models were significant, did not show lack of fit, and presented adjusted determination coefficients (R2) above 99%, proving that the yield of phenolic, flavonoid and antioxidants activities obtained experimentally were close to the predicted values and the suitability of the model employed in RSM to optimise the extraction conditions. Hence, in this study, the fruit from P. macrocarpa could be considered to have strong antioxidant ability and can be used in various cosmeceutical or medicinal applications.

ACS Style

Khurul Ain Mohamed Mahzir; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi. Development of Phaleria macrocarpa (Scheff.) Boerl Fruits Using Response Surface Methodology Focused on Phenolics, Flavonoids and Antioxidant Properties. Molecules 2018, 23, 724 .

AMA Style

Khurul Ain Mohamed Mahzir, Siti Salwa Abd Gani, Uswatun Hasanah Zaidan, Mohd Izuan Effendi Halmi. Development of Phaleria macrocarpa (Scheff.) Boerl Fruits Using Response Surface Methodology Focused on Phenolics, Flavonoids and Antioxidant Properties. Molecules. 2018; 23 (4):724.

Chicago/Turabian Style

Khurul Ain Mohamed Mahzir; Siti Salwa Abd Gani; Uswatun Hasanah Zaidan; Mohd Izuan Effendi Halmi. 2018. "Development of Phaleria macrocarpa (Scheff.) Boerl Fruits Using Response Surface Methodology Focused on Phenolics, Flavonoids and Antioxidant Properties." Molecules 23, no. 4: 724.