Browsing by Author "Nurul Fakriah Che Hashim"

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    Antibacterial properties of eight synthentic thiourea derivate compounds
    (Terengganu: Universiti Malaysia Terengganu, 2012) Nurul Fakriah Che Hashim
    The importance of antibacterial to human health and hygiene has led intense research in biological activities of thiourea derivatives at large scale. Thiourea derivative compounds are synthetic elements. Their molecular structures are similar as urea except the oxygen is replaced by sulfur. Previous study showed that these compounds exhibit a wide spectrum of biological activities such as anti-amoeba, antifungi, antibacterial and anticancer. Thus, this study was conducted to explore the antibacterial properties of eight thiourea derivative compounds against four common pathogenic bacteria. Each compound with five different concentrations; 200 μg/ml, 100 μg/ml, 50 μg/ml, 25 μg/ml and 12.5 μg/ml were tested on three gram-negative bacteria; Pseudomonas aeruginosa, Escheria coli, Proteus sp. and one gram-positive bacteria; Staphylococcus aureus. All eights synthetic thiourea derivative compounds showed antibacterial activity towards Staphylococcus aureus at MIC value of 12.5 μg/ml while other gram-negative bacteria were not affected by the compounds. The morphology of affected bacteria, when observed under Scanning Electron Microscopy showed several abnormal appearances of the cell morphology including raptured of cell wall of Staphylococcus aureus. This study suggests that synthetic thiourea derivative compounds had different effect towards gram-positive and gram-negative bacteria due to their different in the cell wall structure and outer membrane and also the properties of the synthetic thiourea derivative compound itself.
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    Characterization of bioflocculant-producing bacteria isolated from bioflocs of shrimp pond
    (Universiti Malaysia Terengganu, 2017-04) Nurul Fakriah Che Hashim
    Characterization of bioflocculant-producing bacteria isolated from bioflocs was prompted to explore marine bacteria that enhanced bioflocculation process in aquaculture wastewater treatment. Certain bacteria were believed to secrete extracellular polymeric substances (EPS) which response to the physiological stress encountered in the natural environment that can act as bioflocculants. The objectives of this study were identification of bioflocculant-producing bacteria isolated from bioflocs, evaluation on their flocculating activity and characterization of protein composition in extracellular polymeric substances (EPS) produced by identified bioflocculant-producing bacteria. In this study, standard methods on phenotypic and genotypic identification of bacteria including biochemical test and molecular approaches were employed. Six species known as Halomonas venusta, Bacillus cereus, Bacillus subtilis, Bacillus pumilus, Nitratireductor aquimarinus and Pseudoalteromonas sp. were successfully identified as bioflocculant-producing bacteria. Their flocculating activities were examined using Jar Test. The highest flocculating activity was exhibited by Bacillus cereus with 93% while iv Halomonas venusta showed the lowest record with 59% of flocculating activity. Extracted EPS that acted as bioflocculants were obtained from culture supernatant by using cold ethanol precipitation method. Protein content determination using Bradford assay indicated all six species of bioflocculant-producing bacteria showed different protein concentration that ranged between 1.377 μg/mL to 1.455 μg/mL. On Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) gel, several protein bands with different molecular weight that ranged between 12 kDa to 100 kDa were observed