Special Issue 2(1) 2019
Chief Guest Editor
Dr. Nor Diyana Md Sin & Ts Dr. Norhayati Mohamed Noor
The first theme for this issue of the Engineering Journal is engineering and education for disciplinary diversity to drive towards future engineering. The second theme is biotechnology for wellness and industry. Full length papers, reviews and short communications are welcomed, on subjects such as experimentation (both techniques and data), new theoretical models, commentaries work and letters to the editor.
Table of Contents
|1.||Vulnerability Assessment of Buildings in Ranau Township: Methodological Design
Izni Izzati Mohamad, Mohd Zulkifli Mohd Yunus, Noor Sheena Herayani Harith & Pierino Lestuzzi
Structural damage usually happens during earthquake events. This had caused damage of properties and even worse, loss of lives. Usually, the greatest losses were not caused by the quake specifically, but rather because of the fall of the structures. The vulnerability is a degree which buildings are exposed to harmful and destruction and in this case, it’s to earthquake incident. The fast development in urbanization prompt higher hazard from earthquake occurrences; including in the area with intermediate earthquake activities city like this city. This study addresses the expeditious assessment of a great number of buildings in Ranau Township involving measures to identify hazards, evaluate building stocks and calculate vulnerability using a scoring method, FEMA 154 form. The selected area was selected based on building data from the local municipality. Two types of buildings were assessed; commercial buildings and residential buildings. The basic structural score was determined based on building types. Modifier score is a major factor that gives impacts to structural performance during earthquake. These two types of scores will determine the final score of the building and its vulnerability. The outcome of the study reveals a different vulnerability level where early precaution and modification are needed because of the high vulnerability risk. This method can be applied for further analysis in other seismic-prone areas.
Keywords: Vulnerability; Visual screening; Ranau; Seismic risk
|1 – 7|
|2.||Influence of Human Factors on the Uncertainties of Refurbishment Projects: A Proposed Conceptual Approach
Ridzuan Yacob, Masran Saruwono, Zulhabri Ismail,*, Low Sui Pheng
The number of building refurbishment projects has increased significantly over the past few years in Malaysia. The key features of such projects are that these are unique, with high uncertainties especially when these involve structural modifications with sensitive, dangerous and difficult operations as well as the high number of building services involved. From many past studies, uncertainty has always been identified as one of the reasons for poor performance in such projects. This seems to be the case because few considerations were given to the human factor compared to the technical issues. This emphasis is however questionable in the real world. This conceptually based paper therefore aims to determine and understand the influence of human factor on the uncertainties of refurbishment projects. The method used for this study is based on a comprehensive review of related journal papers, book chapters and conference papers from 1997 to 2017. The exercise identified 146 articles initially. 57 papers were subsequently included for further analysis after screening and assessment for eligibility. This study concludes that the human impact element is indeed one of the most important factors that tends to influence the levels of uncertainties in building refurbishment projects. As a result, there is still room for improving the performance of building refurbishment projects. The findings of this study form the basis for an extended investigation to identify the effect of human factors on the uncertainties of building refurbishment projects in Malaysia.
Keywords: Refurbishment projects, Uncertainties, Human factors
|9 – 17|
|3.||Perception of Ergonomic Safety Training among School Teachers in Kelantan, Malaysia
Nurul Husna Che Hassan, Ahmad Rasdan Ismail, Noor Adilah Hamzah, WNor Kamilah Makhtar, Muhammad Azwadi Sulaiman & Aryana Satrya
Ergonomic safety is one of the most important issues in many working sectors and this includes educational institutions especially school. It is important to get the information on the teachers’ perception of ergonomic safety training. Thus, the researcher manages to identify the suitable methods to prevent more ergonomic problem among teachers in future. Aim of this study was to analyze teachers’ perception on ergonomic safety in school and at the same time measured the training requirements on ergonomic safety. Ergonomic safety training in school is important in order to improve good body posture. Survey questionnaires were distributed to 400 teachers. 111 schools randomly selected from the 10 District Education Offices from whole state of Kelantan, Malaysia. Results were then analyzed by using the Statistical Package for the Social Sciences (SPSS) Version 24. Most of the respondents involved in this research are female with the percentage of 68%. Descriptive analysis showed that more than half of respondents understood about ergonomic safety, 78% of them possessed basic safety knowledge and 22% of them lacked on the basic understanding of safety. Interestingly most of the respondents agreed that ergonomic safety should be included in occupational safety and health training in school. It is suggested that all teacher must undergo ergonomic safety training to promote and improve ergonomic safety in school. Higher awareness and more information about ergonomic safety will help teachers teach their students about the importance of ergonomic safety and create a safer environment in their school. As for the conclusion, teachers and students having an important role to ensure ergonomic safety and their commitment will help in reducing the number of ergonomic problems in school.
Keywords : Graphene, photocatalytic, global warming, carbon dioxide reduction
|19 – 25|
|4.||Managing Voltage Fluctuation Issues in Distribution System Connected with Distributed Generation Using Decentralized Power Factor Control
Tengku Juhana Tengku Hashim & Nofri Yenita Dahalan
Power quality issues has evidently become one of the crucial issues in power system studies. With the integration of distributed generations (DGs) in the power system, the issue of voltage control has become very important as the power system has become dynamic due to the bidirectional power flow. Delivering power while maintaining acceptable voltage limits has become very challenging for the distribution network operators (DNOs). In order to maintain power delivery to the customers whilst maintaining good power quality, the DNOs has undertaken several measures including implementing several voltage control methods to guarantee that the voltage limits in the power system are within permissible limits. This includes the centralized and decentralized voltage control techniques in the system connected with DGs. The DGs are connected to buses 9 and 14 of the test system where these two buses have been identified as the weakest bus. The decentralized voltage control method has also become an acceptable option due to its ease in having limited communication and lower costs in the system. One of the decentralized voltage control method which has been widely used is the power factor control (PFC) method. The IEEE 14 bus distribution test system has been used and integrated with DGs to show the effectiveness of the PFC method in managing the voltage fluctuation issues in the distribution system.
Keywords: Distributed generations; decentralized voltage control; power quality; power factor control; distribution system
|27 – 33|
|5.||Determining Factors on Technical Instructors’ Safety Culture Using Structural Analysis Approach
Nor Kamilah Makhtar, Balakrishnan Parasuraman, Mohd Nazri Zakaria, Ahmad Rasdan Ismail & Aryana Satrya
Studies on safety culture have been increasing and several proposed models have been developed and evaluated to identify their key dimensions contributed to many occupational sectors. However, less of safety culture studies focused at education sector especially in Malaysia. This study aims to seek a deeper understanding of the structures of safety culture in Malaysian education sector mainly at Technical and Vocational Education Training (TVET). The objective also to investigate the relationship between psychological, behaviourial and situational dimension with safety culture, and to find out what can be done by the top management to increase safety culture in education sector. Data was collected from 391 Vocational Colleges’ (VC) instructor all over Malaysia that being selected using multistage sampling. Data was analyzed using SPSS 24 and SmartPLS-Structural Equation Modeling (SEM) technique. Partial least squares analysis revealed Influence of Peers, Safety Knowledge, Safety Communication, Safety Rules, Personnel Protective Equipment and Safety Training plays a pivotal role in inspiring the safety culture among the instructor. Assessment of Importance Performance Matrix Analysis (IPMA) showed that Safety Knowledge, Safety Rule, Influence of Peers and Safety Training are very important factors in determining a safety culture due to their relatively higher importance values compared to the rest of the variables. The study will help to improve safety culture in education sector and expected to bring in more safety awareness among instructor, which will inevitably bring in a culture of safe behavior. The ultimate result will be a substantial reduction or elimination in safety-related incidents and make an education sector as a safe workplace. Only a very few have examined the safety culture factors among VCs’ instructor as one of the TVET organisastion, and the used of Smart PLS is a novel idea, with the post analysis of IPMA gives an indicator to the top management of TVET’s education and Malaysia Ministry of Education (MOE) in build safety culture in this sector. Compliance of OSHA 1994 is seen as a good measure to build an education sector as a safe workplace.
Keywords: Safety culture; Education; Instructors; Vocational college; PLS-SEM
|35 – 43|
|6.||Acetic Acid Fermentation of Kuini (Mangifera odorata) and Its Potential Substrate for Human Health
Hazniza Adnan, Mohd Shukri Mat Ali, Hadijah Hassan, Mohd Norfaizal Ghazalli, Zul Helmey Mohamad Sabdin, Musaalbakri Abdul Manan & Nur Syafiqah Nadhra Ramli
The kuini (Mangifera odorata) fruit has a strong scent, attractive orange-yellow colour of flesh and sweet-sour taste. Since ages, kuini parts have been used in folk medicine such as fever indicated that kuini contains prophylactic measures against certain illness and rich of beneficial constituents such as phenolics. In this study kuini underwent fermentation using inoculum (GAB) containing acetic acid bacteria of Gluconacetobacter sp. and the changes during fermentation were then observed. The objectives were (1) to identify the potential of kuini flesh as substrate to GAB inoculum, and (2) to evaluate the physicochemical and nutritional changes during fermentation process. Fermentation of kuini flesh had changed the acidity and affects the growth of inoculum and its biocellulose yield. Results indicated that fermentation using 3% of kuini substrate (KF3) exhibited slightly lower pH compared to 5% of kuini substrate (KF5) while the acetic acid production in KF3 was found higher than KF5. This finding indicated that only small amount of kuini at 3% (w/v) of substrate was able to change the physicochemical property in kuini fermentation thus create a favourable environment for the growth of GAB inoculum and production of its biocellulose. Effect of sucrose in the fermentation also showed that acidity and growth of inoculum were increased with increase of sucrose concentration however depressed the yield of biocellulose. Sucrose at 5 to 20% (w/v) in kuini fermentation had given no distinct effect on the pH and acetic acid content. During fermentation the GAB inoculum had exhibited a poor growth in control, a high growth at 5% (w/v) sucrose and moderate growth between 10-20% (w/v) sucrose in kuini substrates. The control and kuini substrate at 5% (w/v) sucrose also exhibited a high production of biocellulose (13.7 %) whereas high sucrose content in kuini substrate had exhibited low production of biocellulose (5.1%). The increase in sucrose concentration was found concurrently enhanced the total phenolic content and antioxidant activity during the fermentation. High total phenolic content (200 mg/mL GAE) was obtained from 15-20% (w/v) sucrose with control exhibited the least with less than 100 mg/mL GAE. All samples had exhibited high antioxidant activity at which the addition of sucrose into kuini substrate had increased nearly double the antioxidant activity. In conclusion, acetic acid fermentation able to change the physicochemical and nutritional properties of kuini flesh into a health beneficial fermented kuini produced with high antioxidant activity. The fermented kuini produce also contains prophylactic property and therefore potential to be studied for human health application. In near future the antimicrobial activity of kuini substrate with bioactive property against certain bacteria causing health-illness is also interested to be studied.
Keywords: Gluconacetobacter sp.; Sucrose; Physicochemical; Total phenolic; Antioxidant
|45 – 50|
|7.||Dual COX/LOX Inhibition: Screening and Evaluation of the Effect of Pyroligneous acid Fractions of Palm kernel Shell as an Anti-inflammatory agents
Zainab Rabiu, Rosnani Hasham & Zainul Akmar ZakariaAbstract
Inflammation is treated using Steroidal (SAIDs) and Non-steroidal (NSAIDs) anti-inflammatory drugs. These synthetic drugs act by inhibiting the activity of inflammatory mediators (Prostaglandins and Leukotrienes) and are known to have various side effects. The use of natural products as alternatives is gaining prominence due to effective therapeutic function with reduced side effects. Palm kernel shell biomass can be thermo-chemically converted into Pyroligneous Acid (PA), which have been found to contain phenols that have antioxidant activities and potential anti-inflammatory effects. In this study, the PA is derived from slow pyrolysis of palm kernel shell by fractionation using column chromatography. The fractions are then screened for Total Phenolic content using Folin ciocalteau assay and free radical scavenging activity using FRAP and DPPH procedures. Anti-inflammatory activity of COX and LOX pathways with the screened fractions, is determined using the LOX-5 and COX-2 assay by ELISA method. The fractions were found to have phenolic and free radical scavenging activity with high percentage yield. The fractions were also found to have dual inhibition for COX and LOX enzymes with IC50 values ranging for COX enzymes IC50 (17.04% – 48.42%) and LOX with IC50 (5.23% -53.34%). The findings of the present study indicate the potential for use of various fractions of pyroligneous palm kernel shell as a viable source of anti-inflammatory agents.
Keywords: Palm kernel shell, Pyroligneous acids; Anti-inflammation; COX-2 and LOX-5.
|51 – 57|
|8.||Evaluation of Physicochemical Properties of Trigona sp. Stingless Bee Honey from Various Districts of Johor
Harisun Ya’akob, Nur Fatiha Norhisham, Muna Mohamed, Norasiah Sadek & Susi Endrini
Johor as one of the states of Malaysia is a good geographic location for meliponiculture activity. In this study, ten samples of stingless bee honey from each regions of Johor and one sample obtained from Institute Bioproduct Development, Universiti Teknologi Malaysia, Skudai were analyzed for the physicochemical properties of stingless bee honey. The physicochemical analyses were including moisture, total soluble solids, ash, pH, free acidity, conductivity, hydroxymethylfurfural (HMF) content, protein, carbohydrate, fat, dietary fibre, total phenolic content (TPC), total flavonoid content (TFC), and DPPH radical scavenging activity. Trigona sp. sample from Kluang have the highest value of phenolic content (778.23 ± 2.011 mg GAE/100 g) while Trigona sp. sample from Mersing have the highest value of flavonoid content (194.98 ± 0.350 mg RE/100 g). Among eleven samples tested for radical scavenging activity, Trigona sp. sample from Kota Tinggi have the highest scavenging activity (23.37 ± 0.36 mg/ml), but the value of HMF content exceeded the limit of Malaysian standard for stingless bee honey. All parameters were significantly different (p < 0.01) except for ash. This study showed a strong correlation between moisture and acidity (r = 0.601). However, low correlation was obtained between TPC and TFC with DPPH radical scavenging activity (r = -0.235, 0.011). The data obtained from this study could help for a better subsequent of Malaysian stingless bee honey industry.
Keywords: Trigona sp.; honey; physicochemical; hydroxymethylfurfural; antioxidant; DPPH
|59 – 67|
|9.||Polycaprolactone/Chlorophyllin Sodium Copper Salt Nanofibrous Mats Prepared by Electrospinning for Soft Tissue Engineering
Muhammad Zikri Aiman Zulkifli, Nur Hidayatul Nazirah Kamarudin & Darman NordinAbstract
This study examined the process of synthesising biodegradable nanofibres made up of polycaprolactone (PCL) and chlorophyllin sodium copper (CSC) through electrospinning for scaffolding in tissue engineering. Scaffolds provide a platform for cell regeneration for repairing damaged human tissues or organs. However, the issue lies in developing scaffolding that will provide a favourable environment for cell attachment and proliferation. One way to address this concern is to add CSC, which has been widely used in biomaterial applications, to the nanofibres. The structure and morphology of the nanofibres in this research were determined by using a scanning electron microscope (SEM), and their chemical properties were tested by using Fourier-transform infrared spectroscopy (FTIR). Moreover, the diameter and adhesive force of the nanofibres were investigated by using an atomic force microscope (AFM). The SEM examination revealed that the PCL/CSC nanofibres lost their fibrous structure, and the FTIR results proved that the nanofibres synthesised by electrospinning still consisted of PCL and CSC. The AFM examination showed that the diameter and adhesive force of PCL/CSC nanofibres were less than those of PCL nanofibres. This outcome resulted from the CSC’s inability to generate fibres on its own. Furthermore, its noncrystalloid structure prevented it from providing inner enhancement for PCL nanofibres. Hence, further studies are needed to ensure that PCL/CSC nanofibres can be used as an innovative type of scaffolding to provide an appropriate environment for living cells.
Keywords: Electrospinning; Biodegradable nanofibres; Polycaprolactone; Chlorophyllin; Tissue engineering
|69 – 76|
|10.||Density Functional Theory Calculations of Structure-Antioxidant Activity of Selected Phenolic Acids and Flavonoids Found in Malaysian Honey
Rosmahaida Jamaludin, Nurazean Maarop, Siti Fatimah Zaharah Mustafa, Hasmerya Maarof & Bishir Usman
Phenolic acids and flavonoids exist naturally in Malaysian honey and contribute significantly to antioxidant contents. Antioxidants plays an important role in scavenging free radicals and prevent health deterioration. Total antioxidant content is measured using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity. The phenolic acids such as gallic, caffeic, syringic and hydroxybenzoic acids and flavonoids like naringenin, apigenin, kaempferol, catechin and luteolin previously have been identified in Malaysian honey of tualang, gelam and borneo type using high-performance liquid chromatography (HPLC). In order to investigate the structure-antioxidant activity relationships of these phenolic compounds using hydrogen atom transfer (HAT) mechanism, density functional theory (DFT) calculation at B3LYP/6-311++G(d,p) levels of theory was performed. In this work, optimization of the compounds chemical structure and radical forms in gas-phase has been calculated with computation of bond dissociation enthalpy (BDE) as antioxidant descriptor. The finding showed that abstraction of H at different OH groups in the structure of the compound, led to a different scavenging free radical activity thus contribute to the overall variation in the antioxidant properties. Besides that, B ring of flavonoids and unsaturated bond in pyran ring are proposed factors that could lower the BDE values and consequently influence the antioxidant properties of the antioxidant compounds. Hence, DFT calculation with BDE descriptor had been successfully applied to investigate the relationship between structure of phenolic acids and antioxidant activity of Malaysian honey and the interesting results could contribute in future development of antioxidant compound.
Keywords: honey; phenolic acid; flavonoid; density functional theory; bond dissociation energy; structure-antioxidant activity
|77 – 83|
|11.||Development of Filtration System for the Collection of Soaking Water during Bedak Sejuk Preparation
Nurhasniza Ibrahim & Noorhisham Tan Kofli
“Bedak Sejuk” or fermented rice powder is a traditional cosmetic product used by locals that is made from fermented rice. To start the process, the rice grains are soaked in water at 1:1 (w:v) ratio and continuously soaked until the rice gains fully dissolved into flour paste slurry. The soaking water was discarded at end of the fermentation process although it is believed valuable active components still exist in the water. Thus, the aim of the present study is to develop filtration system to collect the soaking water and to analyze active components presence. Local rice grains were soaked in the water in a container and within 14 days interval, the soaking water was replaced. The soaking water collected was then filtered using muslin cloth, followed by membrane filter size of 0.45 and 0.20μm. The filtered soaking water was analyzed for amino acid analysis using HPLC. Sample (0.1 ml) was poured onto the nutrient agar plate for microbial growth to determine the effectiveness of the filtration system. Based on these observations, it can be concluded that the rice soaking water during bedak sejuk preparation content were rich in amino acids (15 types of amino acids detected) with the highest concentration were lycine, glutamic acid and arginine – 0.11, 0.12 and 0.16% respectively. After the filtration using 0.20μm, no microbial growth detected suggested that it can be applied directly onto the skin as organic cosmetic product that benefits the skin.
Keywords: Rice grains; organic cosmetic; Bedak sejuk; rice soaking water; amino acids
|85 – 90|
|12.||Optimization of Ultrasound-Assisted Extraction of Total Flavonoids Content from the White Flowering Variety of Melastoma Malabathricum
Chia Hau Lee, Ting Hun Lee, Harisun Ya’akob, Syieluing Wong & Hichem Ben Jannet
Melastoma malabathricum or Senduduk Putih is one of the herbs listed under National Key Economic Area (NKEA) of Malaysia. It has the potential to be used as remedies that is rich in natural flavonoids. One of the innovations for extraction in modern technology is Ultrasound-Assisted Extraction (UAE) that showed several advantages. Therefore, this study aimed to explore using UAE to extract the total flavonoids in M. malabathricum. After that, UAE is optimized coupled with a stirrer for total flavonoid extraction. Five operating parameters: ethanol concentration, plant material to solvent ratio, extraction temperature, extraction time and ultrasound power were investigated by one-factor-at-a-time (OFAT) method to choose the most important parameters. After that, the response surface methodology coupled with face-centered central composite design (FCCD) was employed to study the interaction of the three keys parameters. The optimized conditions to extract total flavonoids content by UAE with constant mixing speed (300 ± 6 rpm) were at a ratio of 1g of plant material: 30 mL of 100% (v/v) ethanol, extraction temperature at 70oC, 19 min of extraction time and 280 W of ultrasound power. The experimental yields of total flavonoids content were 64.94 mg/g, which is well matched with the predicted value of 63.75 mg/g.
Keywords: Melastoma malabathricum; Flavonoids; Optimization; Ultrasound-assisted extraction.
|91 – 102|
|13.||Towards Efficient Membrane Filtration for Microalgae Harvesting: A Review
Nur Farahah Mohd Khairuddin, Ani Idris & Muhammad Irfan
Microalgae contain pigments such as chlorophyll and ß-carotene that are found to be useful as ingredients in human foods. Downstream processing is the key step to obtain the pigments but before that, harvesting process is required. The purpose of harvesting is to separate the microalgae cells from its culture media. There are many harvesting methods including membrane filtration. Besides simple in operation, membrane filtration technology involves no chemicals, no phase changes and offers complete solid retention. However, high flux requirement and reducing operating and maintenance cost of membrane filtration are challenges for microalgae harvesting. Another issue with membrane filtration is membrane fouling. One of the common approaches used currently in anti-fouling harvesting is by modifying the configuration of the filtration system itself by adding auxiliaries such as air scouring and vibration into the filtration systems. Thus, this review covers recent microalgae species that have been harvested by membrane filtration and their efficiency. Chlorella vulgaris, Nannochloropsis oculata and Scenedesmus sp. are among the species that have been harvested using membranes. Techniques that can be applied for tailoring membrane filtration to be a universal harvesting method for all microalgae species are also highlighted. Having this in mind, factors such as membrane formulation and types of membrane making process which play significant roles in determining the efficiency of harvesting were discussed.
Keywords: Microalgae; harvesting; filtration; membrane; efficiency
|103 – 112|
|14.||Overview on Bio-refinery Concept in Malaysia: Potential High Value Added Products from Palm Oil Biomass
Nursia Hassan, Ani Idris & Junaid Akhtar
This paper presents an overview of bio-refinery concept in Malaysia emphasing on diversifying and maximizing the value of palm oil biomass feedstock to produce bio-based chemicals that demonstrated strong market growth. The oil palm mills and plantations contributes to large amounts of biomasss such as oil palm fronds (OPF), oil palm trunks (OPT) and empty fruit bunches (EFB) which are sources of renewable energy. A majority of these lignocellulosic palm oil byproducts are not effectively utilized and some parts of the biomass are utilized as biofertilizers and solid biofuels. Thus, the potential of palm oil biomass should be explored by diversifying the consumption of these biomass to produce high value added chemicals and biofuels which can generate additional revenue for the country. A number of technologies; namely biochemical conversion, pyrolysis etc. have been established to convert such biomass into a wide spectrum of biobased commodities such as biodiesel, succinic acid, lactic acid, bioethanol and polyhydroxyalkanoates (PHA). This article comprehensively reviews the potential of high value added products generated from palm oil biomass via different bio-refinery approach with special attention on the biochemical conversion process followed by their development stage towards full commercial scale. Limitations and challenges in each process were also discussed in detail.
Keywords: palm oil biomass; biorefinery; biofuel; bioconversion; lignocellulosic biomass
|113 – 124|
|15.||Effects of Organic Solvent and Temperature on the Extraction of Lutein from Scenedesmus sp Biomass
Low Keat Long, Iqbal Ahmed & Ani Idris
Lutein is a valuable bioactive compound that has various industrial applications. In nature, lutein is a yellow coloured isoprenoid polyene pigment, being produced by many photosynthetic organisms. With regard to Scenedesmus sp as the studied organism, this study aims to investigate the efficiency of microalgae-derived lutein extraction process. Repetitive solvent extraction method had been examined with four different organic solvents under different treatment temperatures for their lutein extraction effectiveness. Results showed that diethyl ether was the most effective organic solvent to extract lutein as compared to acetone, ethanol and dichloromethane. Under the extraction temperature of 60oC, diethyl ether was able to extract a total of 14.61 ± 0.31 mg/g of lutein from microalgae biomass. All the studied extraction treatments showed that lutein content in the extractants decreased as the number of extraction repetitions increased. By increasing the extraction repetition to 7 cycles using diethyl ether, treatment temperature at 60 °C resulted in a total of 16.07 ± 0.26 mg/g of lutein being extracted. Therefore, by selecting the most suitable organic solvent in lutein extraction, higher extraction treatment temperature shall provide sufficient energy required for the extraction process, thus further enhancing the overall extraction performance.
Keywords: Microalgae; Scenedesmus sp; Organic Solvent Extraction; Temperature
|125 – 130|
|16.||Kinetic Analysis of Biohydrogen Formation using Immobilized Hydrogen-producing Bacteria on Activated Carbon Sponge from Pineapple Residues
Nur Kamilah Abd Jalil, Umi Aisah Asli, Aidee Kamal Khamis, Haslenda Hashima, Johari Kamaruddina, Mimi Haryani Hassim & Suleeporn Bunbongkarn Choopavang
Pineapple residues are one of potential biomass feedstock for biohydrogen production. The most convenient way to produce biohydrogen from pineapple residual is through fermentation proses. The process is environmentally friendly and consumes low energy, but generally the process has low yield production. Various strategies can be used to increase production, including the use of immobilized cells in fermentation. The performance of the process can be explained as realistically as possible by the appropriate kinetic model. In this work, a kinetic analysis on fermentative biohydrogen production using different hydrogenproducing bacteria immobilized onto activated carbon sponge has been performed. The performance of cumulative and biohydrogen production rate were assessed using modified Gompertz equation via Excel solver application. All fermentation processes were carried out at a condition of initial pH 7 and temperature of 32 ± 1°C, with 30% v/v inoculum of working volume in batch process. Three different hydrogen-producing bacteria were used, namely Escherichia coli, Enterobacter aerogenes and Clostridium sporogenes, were immobilized onto activated carbon sponge and in free cell form as comparison. Based on best fitting curve results on the cumulative biohydrogen production, it was found that modified Gompertz equation were fitted well with all the experimental results of all regression values, R2 were greater than 0.9. This study also presented that E. aerogenes and C. sporogenes able to produce better result compared to E.coli in term of production of biohydrogen The modified Gompertz equation would be useful for further analysis of biohydrogen production performance of selected hydrogen-producing bacteria culture immobilized onto activated sponge from pineapple residues.
Keywords: Kinetic analysis, Gompertz model, bacteria culture, immobilization, biohydrogen production, pineapple residues
|131 – 135|
|17.||Enhancement of Bioelectricity Production from Soil Microbial Fuel Cell (SMFC) by Additional Glucose, Nutrient Broth and Escherichia coli bacteria
Shahirah Raiyan Saleh & Nur Kamilah Binti Abd Jalil, Umi Aisah Asli, Aidee Kamal Khamis, Anwar Johari, Nadzreeq Nor Majid, Nugroho A. Sasongko & Wisnu Ramadhan
Soil Microbial Fuel Cell (SMFC) is a device that using bacteria in soils as a biocatalyst. These bacteria, called exoelectrogenic bacteria are oxidizing organic substrates to release electrons, which then harvested in an external circuit to produce bioelectricity. Despite all the potential, the bioelectricity production from soils is still low and its relation with SMFC conditions is uncertain. Hence, the main objective in this study is to enhance and stabilize the bioelectricity production of SMFC by additional glucose, nutrient broth and Escherichia coli (E. coli) as exoelectrogenic bacteria. A number of factors of SMFC performance were first identified to be preliminary investigated, that is the type of electrode, water addition to soil and distance between anode to cathode. It has been established in this study to use SMFC with the configuration of 9.5 cm in diameter and 15 cm height of the plastic container, with the 12 cm distance between carbon felt of anode and cathode. The electricity produced was measured by using a multimeter in term of voltage reading (mV). From this study, the highest bioelectricity produced was obtained from SMFC using nutrient broth with a maximum voltage of 700 mV. It has found that the additional E. coli bacteria did not increase the bioelectricity production. The use of E. coli needed to be combined with nutrient broth in order to achieve high and stable bioelectricity. It can be suggested that the indigenous bacteria that exist in the soils possibly played the role in producing bioelectricity.
Keywords: Microbial Fuel Cell; Soil Microbial Fuel Cell; Bioelectricity; Exoelectrogenic bacteria, Escherichia coli
|137 – 142|
|18.||Effect of Processing Condition on the Yield of Oscimum Gratissimum Extract
Farah Ashikin Rasit, Nurul Farahin Sakinah Marzuki, Nur Amanina Abd Aziz, Mazlina Mohd Said, Ma. Louisa De Asis-Enriquez & Rosnani Hasham @ Hisam
Ocimum gratissimum (O. gratissimum) is a medicinal plant which native in Southeast Asia. Containing various compound with medicinal value, it acts as herb and spices in cooking, perfumery and used in traditional preparation. It is reported that O. gratissimum has many phenolic compounds which responsible for many biological activities such as eugenol, limonene, ocimene and rosmarinic acid. Scientific studies regarding O. gratissimum are widely known due to its beneficial therapeutic properties, such as antioxidant, antibacterial, anti-inflammatory and others. However, different extraction techniques approaches will give different effects on extraction yield of bioactive compounds according to the processing condition such as solvent polarity, concentration of solvent, temperature and solvent to sample ratio that applied. This study applied Soxhlet and Ultrasonic-assisted Extraction (UAE) techniques to determine the extraction yield of O. gratissimum. The results indicated Soxhlet techniques requires 2 hours, sample to solvent ratio; 1:10 and temperature at 60oC to obtained highest yield of O. gratissimum extract with percentage yield at 1.723% compared to others processing conditions. Meanwhile, UAE techniques showed highest yield of O. gratissimum extract at sample to solvent ratio at 1:10 with results 20.60% and 60% Methanol as the best solvent for extraction. Throughout analysis, UAE techniques was chosen as the methods of extraction for O. gratissimum with processing conditions that gives high yield of extraction.
Keywords: Ocimum gratissimum; Extraction Yield; One-factor-at-a-time (OFAT); Soxhlet; ultrasonic-assisted extraction (UAE)
|143 – 149|
|19.||Bacterial Cellulose as a Potential Hard Gelatin Capsule
Norliza Abd. Rahman, Nur Syafiqah Kamarudin, Faezah Esa, Mohd Sahaid Kalil & Siti Kartom Kamarudin
Matured coconut water is considered as an industrial waste where about 5.3m3 of this solution was discarded everyday especially in the coconut processing industry. An improper disposal process can cause environmental pollution especially to nearest river of processing industry. Despite all the advantages of bacterial cellulose (BC) over plant cellulose, its production is relatively expensive process primarily due to the low productivity and expensive culture medium. Thus, coconut water can be used as a medium for fermentation bacterial cellulose and the production cost can be reduced up to 50 to 60%. Acetobacter xylinum 0416 is often used in industry because they can be produced large quantity of BC. There are many applications of BC in industries such as in the food industry, pharmaceutical industry, textiles and etc. However, this study only focuses on the characteristics of hard gelatin capsule (pharmaceutical industry) and BC. This is because, in market there are about 80-90% hard gelatin capsule are non-halal and this situation cause very high demand of halal hard gelatin capsule especially in Islamic countries. This study focus on determination of optimum condition for BC production by manipulation of variable with a certain pH range which is (4-6), the incubator temperature (28-32°C), and time of fermentation (3-7 days). Comparison of BC and hard gelatin capsule properties were made through FESEM, XRD and FTIR analysis. Study found that optimum BC was obtained about 2.28 g/L at 32°C, in pH4 for 7 days fermentation period.
Keywords: Matured coconut water; Fermentation; Bacterial cellulose; Hard gelatin capsule
|151 – 156|