Rachel Fran Mansa

Review paper on cell membrane electroporation of Microalgae using Electric Field Treatment Method for Microalgae Lipid extraction

The paper reviews the recent studies on the lipid extraction of microalgae that mainly highlighted on the cell disruption method using variety of microalgae species. Selection of cell disruption method and devices are crucial in order to achieve the highest extraction percentage of lipid and other valuable intracellular (proteins, carotenoids and chlorophylls) from microalgae cell. Pulsed electric field (PEF) and electrochemical lysis methods were found to be potential for enhancing the extraction efficiencies either conducted in single step extraction or used as pre-treatment followed by conventional extraction method. The PEF technology capable to extract lipid as high as 75%. While, electrochemical lysis treatment capable to extract lipid approximately 93% using Stainless Steel (SS) and Ti/IrO2 as the cathode and anode electrode respectively. PEF technology and electrochemical lysis are still considered to be a new method for microalgae lipid extraction and further investigation can still be done for better improvement of the system.

Fermentation Study on Macroalgae Eucheuma cottonii for Bioethanol Production via Varying Acid Hydrolysis

The depletion of fossil fuel and the increase of human population lead to the search for more sustainable alternatives. Currently, bioethanol is produced from land-based crops, but in the future, marine biomass could be used as an alternative biomass source because it does not take up land area for cultivation. In this chapter, seaweed Eucheuma cottonii (cultivated in Sabah, Malaysia) was tested for its potential for bioethanol production via fermentation by yeast Saccharomyces cerevisiae. E. cottonii contains cellulose and carrageenan which will be hydrolysed into glucose and galactose, which in turn was converted to ethanol by the yeast. This study showed that the extracted seaweed gives higher percentage of ethanol (9.6% v/v) compared to non-extracted seaweed. Subsequently, it was found that low molarity and high-temperature acid hydrolysis at 0.0M, 100% (8.4% v/v) produced the most ethanol. It was followed by hydrolysis 0.1M, 30% (7.7% v/v); 0.4M, 30% (4.7% v/v); and 0.4M, 100% (3.4% v/v) with fresh feedstock. In this research, among the three fermentation media, it was found that Yeast Peptone Dextrose (YPD) broth yields the highest percentage of ethanol (9.6% v/v) followed by Yeast Extract Peptone (YP) broth producing 4.7% v/v ethanol. This productivity level makes macroalgae a promising substrate for bioethanol production.

Review on Metallic and Plastic Flexible Dye Sensitized Solar Cell

Dye sensitized solar cells (DSSCs) are a promising alternative for the development of a new generation of photovoltaic devices. DSSCs have promoted intense research due to their low cost and eco-friendly advantage over conventional silicon-based crystalline solar cells. In recent years, lightweight flexible types of DSSCs have attracted much intention because of drastic reduction in production cost and more extensive application. The substrate that used as electrode of the DSSCs has a dominant impact on the methods and materials that can be applied to the cell and consequently on the resulting performance of DSSCs. Furthermore, the substrates influence significantly the stability of the device. Although the power conversion efficiency still low compared to traditional glass based DSSCs, flexible DSSCs still have potential to be the most efficient and easily implemented technology.

Review: Pre-treatments and Fermentation of Seaweed for Bioethanol Production

This article reviews the current studies on the production of bioethanol from seaweed with a focus on the process pre-treatments and variety of microorganisms used in the process. Pre-treatment selection is essential to maximize the amount of reduced sugar for the fermentation to produce bioethanol. Specific microbial strains are matched to their ability to utilize sugar sources. Some studies focus mainly on general processing with variable microbial strains to gauge their abilities in fermentation. A summary of the current studies was carried out, and it is evident that two or more yield increasing techniques can coexist within a single process. The integration of the findings may be the key to make seaweed fermentation more efficient and affordable to serve as a sustainable and renewable energy source.

Dye Sensitized Solar Cell Based on Polyethylene Glycol/4,4’-Diphenylmethane Diisocyanate Copolymer Quasi Solid State Electrolyte

In this study, quasi-solid state electrolyte (QSE) was prepared by blending the polyethylene glycol (PEG) with molecular weight of 400, 4,4’-diphenylmethane diisocyanate (MDI), potassium iodide (KI) and iodine (I2) under a low reaction temperature (50oC) for two hours. QSEs with a different ratio of PEG to MDI were formulated. Adding 15 vol% of MDl into the QSE was found to give the highest open circuit voltage, short circuit current and energy conversion efficient, which were 360 mV, 0.077 mA/cm2 and 0.02% respectively.

Sol gel synthesized nanosilica as photoanode material for dye sensitized solar cells (DSSCs) system

Dye-sensitized solar cells (DSSCs) have been extensively studied due to their promising potential for high efficiency, low production cost and eco-friendly production. The photoanode of DSSCs is traditionally composed of randomly packed TiO2 nanoparticles which have large specific surface area and suitable band gap (3.2 eV) for the effective injection of electrons from the dye molecules to the semiconductor. However, its high surface charge recombination rate accounts for its low efficiency. Alternatively, silica which is chemically inert, thermally stable, high surface area, and inexpensive can be used to substitute TiO2 as photoanode material. However, bulk silica has a wide band gap of 8.9 eV and its band gap need to be narrowed in order to use it as photoanode materials. Thus, in this study, the effect of nanosilica photoanode and its particle size on the performance of dye sensitized solar cell are investigated and characterized. The result is then compared with the fumed silica and conventional TiO2 DSSCs. Although the results shows that photon-electron conversion is inferior compared to TiO2 photoanode, it has a great potential as the fabrication cost is low and more environmental friendly.Keywords : Dye Sensitized Solar Cell, Photoanode material, Nanosilica, Sol gel synthesis

A Brief Review on Photoanode, Electrolyte, and Photocathode Materials for Dye-Sensitized Solar Cell Based on Natural Dye Photosensitizers

The dye-sensitized solar cell is a promising alternative for a new generation of photovoltaic devices due to its lightweight, flexibility, low cost, environmentally friendly materials. One important aspect of the DSSC is the potential of using dyes found in flowers, leaves, and fruits to be used as they are cheap and easily attained. However, the photovoltaic performances of dye-sensitized solar cells are greatly dependent on the CR which can be attributed to dye molecular size, semiconductor nanostructures properties, interaction between the semiconductor and dye, semiconductor/dye/electrolyte resistance, and dye aggregation (Narayan 2012). This paper briefly reviews recent developments in DSSC using natural dye photosensitizers, photoanode materials, various phases of the electrolytes, and nonmetal photocathode materials.

Comparative studies on the alcohol types presence in Gracilaria sp. and rice fermentation using Sasad

Alternative fuel sources such as biofuels are needed in order to overcome environmental problem caused by fossil fuel consumption. Currently, most biofuel are produced from land based crops and there is a possibility that marine biomass such as macroalgae can be an alternative source for biofuel production. The carbohydrate in macroalgae can be broken down into simple sugar through thermo-chemical hydrolysis and enzymatic hydrolysis. Dilute-acid hydrolysis was believed to be the most available and affordable method. However, the process may release inhibitors which would affect alcohol yield from fermentation. Thus, this work was aimed at investigating if it is possible to avoid this critical pre-treatment step in macroalgae fermentation process by using Sasad, a local Sabahan fermentation agent and to compare the yield with rice wine fermentation. This work hoped to determine and compare the alcohol content from Gracilaria sp. and rice fermentation with Sasad. Rice fermentation was found containing ethanol and 2 - methyl - 1 - propanol. Fermentation of Gracilaria sp. had shown the positive presence of 3 - methyl - 1 - butanol. It was found that Sasad can be used as a fermentation agent for bioalcohol production from Gracilaria sp. without the need for a pretreatment step. However further investigations are needed to determine if pre-treatment would increase the yield of alcohol.

Effect of varying acid hydrolysis condition in Gracilaria sp. fermentation using sasad

Macroalgae or seaweed is being considered as promising feedstock for bioalcohol production due to high polysaccharides content. Polysaccharides can be converted into fermentable sugar through acid hydrolysis pre-treatment. In this study, the potential of using carbohydrate-rich macroalgae, Gracilaria sp. as feedstock for bioalcohol production via various acid hydrolysis conditions prior to the fermentation process was investigated and evaluated. The seaweed used in this research was from the red algae group, using species of Gracilaria sp. which was collected from Sg. Petani Kedah, Malaysia. Pre-treatment of substrate was done using H2SO4 and HCl with molarity ranging from 0.2M to 0.8M. The pretreatment time were varied in the range of 15 to 30 minutes. Fermentation was conducted using Sasad, a local Sabahan fermentation agent as a starter culture. Alcohol extraction was done using a distillation unit. Reducing sugar analysis was done by Benedict test method. Alcohol content analysis was done using specific gravity test. After hydrolysis, it was found out that acid hydrolysis at 0.2M H2SO4 and pre-treated for 20 minutes at 121°C has shown the highest reducing sugar content which has yield (10.06 mg/g) of reducing sugar. It was followed by other samples hydrolysis using 0.4M HCl with 30 minutes pre-treatment and 0.2M H2SO4, 15 minutes pre-treatment with yield of 8.06 mg/g and 5.75 mg/g reducing sugar content respectively. In conclusion, acid hydrolysis of Gracilaria sp. can produce higher reducing sugar yield and thus it can further enhance the bioalcohol production yield. Hence, acid hydrolysis of Gracilaria sp. should be studied more as it is an important step in the bioalcohol production and upscaling process.

Application of Six Sigma in oil and gas industry: Converting operation data into business value for process prediction and quality control

This study is to develop a dynamic prediction tool for daily operation quality control in PETRONAS Kertihs refinery using Design for Six Sigma (DFSS) methodology. Catalytic reforming process was selected as the case study background where the relationship of operation parameters which influences the coke content deposited on the process catalyst was studied. The prediction model allows future estimation of the coke content on the catalyst and in turn assist in reducing future downtime of the unit which might cause RM20,000 per day of PONC (Price of Non Conformance). The related input-output operation data were obtained from the plant and 10 process operation parameters were categorized as key process input variables. Using Response Surface Methodology, dynamic modeling of the coke content was developed for prediction and analysis of the relationship between the coke content and the 10 process inputs. The prediction model passed the 2-sample 2-T Test, hence the prediction model was reliable where there was no statistically difference between the mean in actual and the predicted values.