Browsing by Author "Radzi S.M."
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Publication Cu2+ montmorillonite K10 clay catalyst as a green catalyst for production of stearic acid methyl ester: Optimization using response surface methodology (RSM)(Diponegoro University, 2018) ;Almadani E.A. ;Harun F.W. ;Radzi S.M. ;Muhamad S.K. ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)Clay catalyst has received much attention to replace the homogeneous catalysts in the esterification re-action to produce fatty acid methyl ester as the source of biodiesel as it is low cost, easily available, as well as environmental friendly. However, the use of unmodified clay, in particular montmorillonite K10 (MMT K10), for the esterification of fatty acids showed that the acid conversion was less than 60% and this is not preferable to the production of biodiesel. In this study, synthesis of stearic acid methyl ester using Cu2+-MMT K10 (Cu-MMT K10) was successfully optimized via response surface methodo-logy (RSM) based on 3-variable of Box-Behnken design (BB). The parameters were; reaction time (5-180 minutes), reaction temperature (80-120 �C) and concentration of Cu2+ in MMT K10 (0.25-1 M). The use of RSM in optimizing the conversion of stearic acid was successfully developed as the actual experi-mental conversion of stearic acid was found similar to the actual values under the optimum conditions. The model equation predicted that the following conditions would generate the maximum conversion of stearic acid (87.05 % reaction time of 62 minutes, a reaction temperature of 80 'C and catalyst used is 1.0 M Cu-MMT K10. This finding can be considered as green catalytic process as it worked at moderate reaction temperature using low cost clay catalyst with a short reaction time. - Some of the metrics are blocked by yourconsent settings
Publication Effect of LiCF3SO3on L-Chitosan/PMMA Blend Polymer Electrolytes(Taylor and Francis Inc., 2014) ;Khiar A.S.A. ;Radzi S.M. ;Razak N.A.Universiti Sains Islam Malaysia (USIM)This paper focuses on the effect of lithium triflate (LiCF3SO3) on the structural and conduction properties of lauroyl (L)-chitosan/poly(metylmethacryalate) (PMMA)-based polymer electrolytes. Films of L-chitosan/PMMA blends and its complexes were prepared using a solution-casting technique. The ionic conductivity of the system was measured over a wide range of frequency between 50 Hz-1 MHz. Impedance plot for the samples demonstrates two well-defined regions. The disappearance of the high frequency semicircular region led to a conclusion that the current carriers are ions. Sample with 30 wt% of LiCF3SO3 showed the highest conductivity of 7.59 � 3.64 � 10-4 Scm-1 at room temperature. This is consistent with the results obtained from infrared spectroscopy. � 2014 Copyright � Taylor & Francis Group, LLC. - Some of the metrics are blocked by yourconsent settings
Publication Effects of environmental and growth conditions on protein produced by Bacillus subtilis ATCC21332 in the presence of Cymbopogon flexuosus essential oil(Malaysian Society of Applied Biology, 2018) ;Noor H.M. ;Alhadi N.A. ;Mohamed H.S. ;Rehan M.M. ;Radzi S.M. ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)The presence of antimicrobial substances at low concentration may act as chemical signals in altering metabolic processes that take place in bacteria. The chemical signals may activate lots of signal transduction that result in the secretion of bioactive proteins by the stimulated bacterial cells. The bioactive proteins production is strongly influenced by certain factors such as pH and nutrient sources. Therefore, the study of environmental stress factors and growth conditions is very important in inducing the production of bioactive proteins by microbes. The main objective of this study is to evaluate the effects of environmental stress factors and growth conditions on the production of bioactive proteins by Bacillus subtilis ATCC21332 in the presence of Cymbopogon flexuosus essential oil. The microbial proteins were produced by fermentation process using Nutrient broth with adjustment of pH media (pH 6, 7 and 8), and supplementation with 1% (w/w) of three different nutrients, including carbon sources (glucose, sucrose and starch), nitrogen sources (urea, casein and gelatin) and inorganic salts (calcium chloride, sodium nitrate, sodium dihydrogen phosphate) separately. The extracellular protein produced by B. subtilis ATCC21332 was isolated and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to detect appearance of new protein bands. Results showed that new extracellular proteins were synthesized by B. subtilis ATCC21332 after being induced with C. flexuosus essential oil and grown in each media with 1% (w/w) of starch, 1% (w/w) of gelatin, 1% (w/w) of casein, 1% (w/w) of sodium dihydrogen phosphate and 1% (w/w) of calcium chloride with approximate size of 30.43 kDa, 30.66 kDa, 31.92 kDa, 31.35 kDa and 30.80 kDa respectively. Hence, B. subtilis ATCC21332 in the presence of 0.01 MIC C. flexuosus essential oil under different conditions are able to produce or secrete new extracellular proteins. � 2018, Malaysian Society of Applied Biology. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Publication Evaluation of tyrosinase activity and radical scavenging activity of kojic acid and kojic acid monooleate(American Scientific Publishers, 2017) ;Syamsul K.M.W. ;Radzi S.M. ;Fadhil F.H.M. ;Noor H.M. ;Rehan M.M. ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)Kojic acid is a well known as natural whitening agent and widely use in skincare product formulation. However, kojic acid are water-soluble, unstable at high temperature for long term storage and cannot be directly incorporated in oil based skincare products. Therefore, natural-based kojic acid ester was produced to improve the properties via esterification reaction in the presence of immobilized lipase. The synthesized kojic acid ester was purified through crystallization method. Besides, bioassay study of the kojic acid ester and kojic acid performances on tyrosinase activity and free radical scavenging activity were also carried out. The result shows that, kojic acid gave the highest percentage of tyrosinase activity (77.16%) at 25% of ester concentration. While for kojic acid ester, it gave the highest percentage of tyrosinase activity (23.71%) at 50% of ester concentration. Whilst, the study on radical scavenging activity shows that kojic acid also yield higher percentage of radical scavenging activity which was 84.24% than kojic acid ester which gave 67.65% only. � 2017 American Scientific Publishers All rights reserved. - Some of the metrics are blocked by yourconsent settings
Publication High yield synthesis of kojic ester using dual enzymes system and their antibacterial activity(2014) ;Radzi S.M. ;Rahman N.J.A. ;Noor H.M. ;Basri M. ;Faculty of Science and Technology ;Universiti Sains Islam Malaysia (USIM)Universiti Putra Malaysia (UPM)Enzymatic synthesis of kojic ester, a bio-based whitening agent, was successfully carried out via esterification reaction between oleic acid and kojic acid. Commercial immobilized lipases of Novozym 435 and Lipozyme RM IM were used in combination as biocatalyst in the reaction system. Various reaction parameters were chosen to optimize the reaction in order to obtain a high yield of kojic ester including the best ratio of lipases, reaction time and reaction temperature. The optimum conditions for the synthesis of kojic ester was achieved at reaction time of 12 hours, temperature of 60 �C and equal ratio of lipases to produce more than 70 % yield. Antimicrobial tests of synthesized kojic ester towards several types of bacteria via Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) analyses were also examined. The results obtained suggested that kojic ester exhibits a good bactericidal effect towards all bacteria tested such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium. Copyright � 2014 Trans Tech Publications Ltd, Switzerland. - Some of the metrics are blocked by yourconsent settings
Publication Identification of bacteria associated with holothuria (Mertensiothuria) leucospilota from Pangkor Island(Malaysian Society of Applied Biology, 2018) ;Lutfi F.N.M. ;Rehan M.M. ;Kamarudin K.R. ;Che Zahri M.Z. ;Noor H.M. ;Radzi S.M. ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)Holothuria (Mertensiothuria) leucospilota is the most abundant sea cucumber species in Malaysia. This study aimed to identify bacteria isolated from the external and internal body parts of H. leucospilota collected from the coastal water of Pangkor Island, Perak, Malaysia. A total of 26 bacterial samples were isolated using streak plate method from eight body parts of two fresh H. leucospilota specimens and from the surrounding surface sediments and seawater. Identification of the bacterial isolates was based on microscopic examination, 16S rDNA amplification and phylogenetic analysis using the neighbour-joining method. Three genera of bacteria were identified namely Vibrio, Bacillus, and Acinetobacter. The genus Vibrio was found to be the main bacterial group associated with the H. leucospilota specimens from Pangkor Island. � 2018, Malaysian Society of Applied Biology. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Publication Isolation and identification of amylolytic bacteria from ragi(Malaysian Society of Applied Biology, 2018) ;Roslan R. ;Rehan M.M. ;Kamarudin K.R. ;Noor H.M. ;Faujan, Nur Huda ;Radzi S.M. ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)Ragi is a traditional dry starter culture frequently used in many fermented food products in Asian countries. Ragi contains starch that can be degraded by amylases provided by bacteria and other microorganisms during fermentation in producing fermented foods. This study was carried out to isolate bacteria from ragi and to screen for their ability to hydrolyse starch. Seven bacterial colonies were isolated from ragi, with three samples showing starch hydrolysis activity. Two of the starch-degrading bacterial isolates were identified using partial 16S rRNA gene sequencing as Bacillus licheniformis with 97% and 98% similarity, and one sample identified as a lactic acid bacteria, Enterococcus faecium (98%). Isolation and identification of these bacteria from ragi can provide a promising source of amylase that can be further studied and manipulated for the development of starter culture and to improve the quality of traditional ragi-based fermented food products. � 2018, Malaysian Society of Applied Biology. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Publication Kinetics of enzymatic synthesis of liquid wax ester from oleic acid and oleyl alcohol(Japan Oil Chemists Society, 2010) ;Radzi S.M. ;Mohamad R. ;Basri M. ;Salleh A.B. ;Ariff A. ;Rahman M.B.A. ;Abdul Rahman R.N.Z.R. ;Faculty of Science and Technology ;Universiti Putra Malaysia (UPM)Universiti Sains Islam Malaysia (USIM)The kinetics of wax ester synthesis from oleic acid and oleyl alcohol using immobilized lipase from Candida antartica as catalyst was studied with different types of impeller (Rushton turbine and AL-hydrofoil) to create different mixing conditions in 2l stirred tank reactor. The effects of catalyst concentration, reaction temperature, and impeller tip speed on the synthesis were also evaluated. Rushton turbine impeller exhibited highest conversion rate at lower impeller tip speed as compared to AL-hydrofoil impeller. A second-order reversible kinetic model from single progress curve for the prediction of fractional conversion at given reaction time was proposed and the corresponding kinetic parameter values were calculated by non-linear regression method. The results from the simulation using the proposed model showed satisfactory agreement with the experimental data. Activation energy shows a value of 21.77 Kcal/mol. The thermodynamic parameters of the process, enthalpy and entropy, were 21.15 Kcal/mol and 52.07 cal/mol.K, respectively. � 2010 by Japan Oil Chemists' Society. - Some of the metrics are blocked by yourconsent settings
Publication Optimization of lipase-catalyzed synthesis of palm amino acid surfactant using response surface methodology (RSM)(2009) ;Bidin H. ;Basri M. ;Radzi S.M. ;Ariff A. ;Abdul. Rahman R.N.Z.R. ;Salleh A.B. ;Faculty of Science and Technology ;Universiti Putra Malaysia (UPM)Universiti Sains Islam Malaysia (USIM)Amino acid surfactants are high-value surfactants which have excellent emulsifying characteristics and minimal toxicity to the living body. Enzymatic synthesis of palm kernel amino acid surfactant was optimized by response surface methodology (RSM) using palm kernel olein (PKO) and l(+)-lysine catalyzed by Lipozyme RM IM. The reaction was performed in batch mode stirred tank reactor (STR) with one multi-bladed impeller. A central composite rotatable design (CCRD) was employed to evaluate the interactive effects of various parameters. The parameters were temperature (A): (40.00-70.00 �C), impeller speed (B): (100.00-400.00 rpm), substrates ratio (C): (1.00-4.00 mmol) and enzyme amount (D): (5.00-8.00 g). The optimum condition derived via RSM at fixed reaction time of 24 h was temperature; 47.50 �C, impeller speed; 323.96 rpm, substrates ratio; 3.25 mmol and enzyme amount; 7.25 g. The experimental yield was 89.03% under the optimum condition, which compared well with the maximum predicted value of 93.77%. � 2009 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Publication Pharmacodynamic properties of essential oils from Cymbopogon species(2011) ;Mohd Fazrullah Innsan M.F. ;Shahril M.H. ;Samihah M.S. ;Asma O.S. ;Radzi S.M. ;Abd Jalil A.K. ;Hanina M.N. ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)Pharmacodynamic research plays an important role in the development of new antibacterial agents. Characterization of this pharmacodynamic can be used to design the best dose and dosing strategy for clinical trials. The pharmacodynamic properties can be determined by studying the bactericidal activity and the postantibiotic effects (PAE). Measurements of both bactericidal activity and the lag time could be useful in screening the efficacy of antimicrobial agents. In this study, the pharmacodynamic properties of essential oils from Cymbopogon flexuosus (lemongrass) and Cymbopogon nardus (citronella) as well as the combinations of both essential oils were evaluated against Staphylococcus aureus and Escherichia coli. At high concentrations (1.0 � minimum bactericidal concentration (MBC) and 0.5 � MBC), citronella and lemongrass essential oils alone or in combinations indicate high bactericidal activities toward S. aureus and E. coli, as shown by the decrease of optical absorbance values serially up to 24 h. However, these two essential oils or its combinations at lower concentrations (0.25 � MBC and 0.125 � MBC) showed the bacterial regrowth after 3 and 1 h of exposure time against S. aureus and E. Coli, respectively. Generally, citronella and lemongrass essential oils as well as its combinations indicate a significant lag of regrowth or PAE values which were more than 0.5 h towards both E. coli and S. aureus. This finding suggests that essential oils from Cymbopogon species showed a potential antimicrobial activity that can further be used for clinical treatment; thus, there is need for a study on the possible impact of PAE in the clinical situation. � 2011 Academic Journals. - Some of the metrics are blocked by yourconsent settings
Publication Preliminary study on the synthesis of kojic acid monooleate using dual enzymes system(American Institute of Physics Inc., 2018) ;Radzi S.M. ;Zulhilmi M.N.M. ;Noor H.M. ;Rehan M.M. ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)Kojic acid is an organic acid that widely used in cosmetic, health care, food and chemical industries. However, kojic acid is not stable at high temperature, for long storage and it has low lipophilic properties. To overcome this problem, a study was conducted to improve its properties by enzymatic reaction. This study was focused on the synthesis of kojic acid monooleate from kojic acid and oleic acid using enzymatic catalysts at optimized conditions. This study was divided into three parts starting from enzymatic synthesis of kojic ester or specifically kojic acid monooleate (KAMO) by using a dual enzymes system that consisted of Novozym 435 and Lipozyme RM IM. Then, optimization of four variables such as screening of dual enzymes ratio, temperature, substrate molar ratio and the reaction time via conventional method of one parameter at-a-time approach and lastly verification of the product using Fourier Transfer Infrared (FTIR) spectroscopy. The optimum conditions for the enzymatic synthesis of KAMO were at the dual enzymes ratio (1:1) of Novozym 435 and Lipozyme RMIM, temperature at 50C, the molar ratio of kojic acid and oleic acid were 4:1 respectively and 24 hours of reaction time. The highest percentage conversion of KAMO achieved at the most optimum conditions was 13.22 %. Finally, kojic ester produced was verified by using FTIR proved the presence of ester bond (C=O) at 1743 cm-1. � 2018 Author(s). - Some of the metrics are blocked by yourconsent settings
Publication Protein Produced by Bacillus subtilis ATCC21332 in the Presence of Cymbopogon flexuosus Essential Oil(Trans Tech Publications Ltd, 2014) ;Noor H.M. ;Muhamad H.S. ;Ismail I.N.A. ;Radzi S.M. ;Rehan M.M. ;Kader A.J.A. ;Mohamad R. ;Faculty of Science and Technology ;Universiti Sains Islam Malaysia (USIM)Universiti Putra Malaysia (UPM)Proteins levels produced by bacteria may be increased in stressful surroundings, such as in the presence of antibiotics. It appears that many antimicrobial agents or antibiotics, when used at low concentrations, have in common the ability to activate or repress gene transcription, which is distinct from their inhibitory effect. There have been comparatively few studies on the potential of antibiotics or natural compounds in nature as a specific chemical signal that can trigger a variety of biological functions. Therefore, this study was focusing on the effect of essential oil from Cymbopogon flexuosus in regulating proteins production by Bacillus subtilis ATCC21332. The Minimum Inhibition Concentration (MIC) of the C. flexuosus essential oil on B. subtilis was determined by using microdilution assay, resulting 1.76mg/ml. The bacteria cells were further exposed to the C. flexuosus essential oil at concentration of 0.01 MIC for 72 h. The proteins were then isolated and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Proteins profile showed that a band with approximate size of 30 kDa was appeared for the treated bacteria with C. flexuosus essential oil. Thus, B. subtilis ATCC21332 in stressful condition with the presence of C. flexuosus essential oils at low concentration could induce the protein production. The isolated protein also showed antimicrobial activity against selected Gram-positive and Gram-negative bacteria. Copyright � 2014 Trans Tech Publications Ltd, Switzerland.