Nik Norulaini Nik Ab Rahman

Applications of Supercritical Fluid Extraction (SFE) of Palm Oil and Oil from Natural Sources

Supercritical fluid extraction (SFE), which has received much interest in its use and further development for industrial applications, is a method that offers some advantages over conventional methods, especially for the palm oil industry. SC-CO2 refers to supercritical fluid extraction (SFE) that uses carbon dioxide (CO2) as a solvent which is a nontoxic, inexpensive, nonflammable, and nonpolluting supercritical fluid solvent for the extraction of natural products. Almost 100% oil can be extracted and it is regarded as safe, with organic solvent-free extracts having superior organoleptic profiles. The palm oil industry is one of the major industries in Malaysia that provides a major contribution to the national income. Malaysia is the second largest palm oil and palm kernel oil producer in the World. This paper reviews advances in applications of supercritical carbon dioxide (SC-CO2) extraction of oils from natural sources, in particular palm oil, minor constituents in palm oil, producing fractionated, refined, bleached, and deodorized palm oil, palm kernel oil and purified fatty acid fractions commendable for downstream uses as in toiletries and confectionaries.

Supercritical Carbon Dioxide as Non-Thermal Alternative Technology for Safe Handling of Clinical Wastes

The expansions of communities and cities over the last two decades have led to the increase of the number of health care facilities, and thus, clinical wastes are generated in significant amounts. Clinical wastes are a potential source for many pathogens such as viruses, parasites, fungi and bacteria. Therefore, clinical wastes should be treated before disposal into the environment. The incineration is the most common technology applied for the treatment process. However, the negative effects of incineration on humans and the environment have led scientists to define alternative technologies for the safe disposal of clinical waste. Numerous treatment technologies have been investigated as an alternative for incineration, such as autoclave and microwave. These technologies generally depend on temperature while the recent direction is to use a non-thermal sterilization processes. SC-CO2 is one of the non-thermal sterilization technologies, which depends on pressure and low temperature. Currently, SC-CO2 has been extensively used for the inactivation of microorganisms in food and pharmaceutical industries. However, the application of SC-CO2 in treating clinical wastes has been on a rise. Studies conducted on the inactivation of fungi in food, normal saline and growth media indicate that SC-CO2 has the ability to inactivate these organisms. In clinical wastes, SC-CO2 has been found to be effective in the inactivation of pathogenic bacteria. Therefore, this review paper focuses on the potential of using SC-CO2 as alternative technology for inactivating fungi in clinical wastes.

Infectious Risk Assessment of Unsafe Handling Practices and Management of Clinical Solid Waste

The present study was undertaken to determine the bacterial agents present in various clinical solid wastes, general waste and clinical sharp waste. The waste was collected from different wards/units in a healthcare facility in Penang Island, Malaysia. The presence of bacterial agents in clinical and general waste was determined using the conventional bacteria identification methods. Several pathogenic bacteria including opportunistic bacterial agent such as Pseudomonas aeruginosa, Salmonella spp., Klebsiella pneumoniae, Serratia marcescens, Acinetobacter baumannii, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes were detected in clinical solid wastes. The presence of specific pathogenic bacterial strains in clinical sharp waste was determined using 16s rDNA analysis. In this study, several nosocomial pathogenic bacteria strains of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Lysinibacillus sphaericus, Serratia marcescens, and Staphylococcus aureus were detected in clinical sharp waste. The present study suggests that waste generated from healthcare facilities should be sterilized at the point of generation in order to eliminate nosocomial infections from the general waste or either of the clinical wastes.

Optimizing supercritical carbon dioxide in the inactivation of bacteria in clinical solid waste by using response surface methodology

Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO2) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and gram-negative Escherichia coli in CSW. The effects of SC-CO2 sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO2-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO2 exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials.

Supercritical carbon dioxide extraction of oil from Thunnus tonggol head by optimization of process parameters using response surface methodology

Total oil was extracted from ground fish head of Longtail tuna (Thunnus tonggol) using supercritical carbon dioxide (SC-CO2) at 20 to 40 MPa, 45 to 65 °C and 1 to 3 ml min−1. Response surface methodology (RSM) was employed to optimize the operating conditions of the SC-CO2 technique where the highest oil yield was obtained (35.6% on dry weight basis) at 40 MPa, 65 °C, and 3 ml min−1. The solubility of the oil in SC-CO2 increased from 2.9 to 14.2 g oil/100 g of CO2 with increasing pressure and temperature. The total saturated, monounsaturated and polyunsaturated fatty acids obtained were 41.6, 24.7 and 26.8%, respectively, where the omega-3 fatty acids were found to be 22.3%. A correlation was developed determining the coefficients of the second-order polynomial equation where the extraction parameters of SC-CO2 method to extract fish oil from fish sample were successfully optimized using response surface methodology.

Treatment of Clinical Solid Waste Using a Steam Autoclave as a Possible Alternative Technology to Incineration

A steam autoclave was used to sterilize bacteria in clinical solid waste in order to determine an alternative to incineration technology in clinical solid waste management. The influence of contact time (0, 5, 15, 30 and 60 min) and temperature (111 °C, 121 °C and 131 °C) at automated saturated steam pressure was investigated. Results showed that with increasing contact time and temperature, the number of surviving bacteria decreased. The optimum experimental conditions as measured by degree of inactivation of bacteria were 121 °C for 15 minutes (min) for Gram negative bacteria, 121 °C and 131 °C for 60 and 30 min for Gram positive bacteria, respectively. The re-growth of bacteria in sterilized waste was also evaluated in the present study. It was found that bacterial re-growth started two days after the inactivation. The present study recommends that the steam autoclave cannot be considered as an alternative technology to incineration in clinical solid waste management.

Characterization of Oily and Non-Oily Natural Sediments in Palm Oil Mill Effluent

Palm oil is one of the many vegetable oils widely consumed around the world. The production of palm oil requires voluminous amount of water with the concurrent generation of large amount of wastewater known as palm oil mill effluent (POME). POME is a mixture of water, oil, and natural sediments (solid particles and fibres).There is a dearth of information on the physical properties of these POME sediments. This study intends to distinguish the physical properties of oily and non-oily POME sediments which include sediment size, particle size distribution (PSD), sediment shape, sediment surface morphology, and sediment density. These characterizations are important for future researches because these properties have significant effects on the settling process that occurs either under natural gravity or by coagulations. It was found that the oily and non-oily POME sediments have different sizes with nonspherical irregular shapes, and because of that, the aspect ratio (AR) and circularity shape factors were adopted to describe the shapes of these sediments. The results also indicate that the density of oily POME sediment decreases as the sediment size increases.

Simultaneous Extraction and Fractionation of Fish Oil from Tuna By-Product Using Supercritical Carbon Dioxide (SC-CO2)

ABSTRACT Fish oil was extracted and simultaneously collected into six fractions based on molecular weight and the chain length of triglycerides in terms of fatty acid constituents without splitting of the triglycerides, using supercritical carbon dioxide (SC-CO2) at optimized conditions of 40 MPa, 65°C, and a flow rate 3 mL min−1. In each type of fractionation, the first fraction (F1) was rich in saturated fatty acids (SFA; 52.57 to 61.26%), followed by monounsaturated fatty acids (MUFA; 22.17 to 23.22%) and polyunsaturated fatty acids (PUFA; (0.54 to 20.37%); the sixth fraction (F6) was rich in PUFA (48.93%), followed by MUFA (33.59%) and SFA (13.61%). It was obvious that short-chain fatty acids were extracted at an earlier fraction; therefore, the latter fractions were dominant in long-chain fatty acids, especially MUFA and PUFA. Thus, omega-3 fish oil (last three fractions) was successfully separated to be used as a value-added health product.

The effect of testa on SC-CO2 extracted oil yield, nutrient and anti-nutrient content of palm kernel fibre

T maintenance of cholesterol homeostasis is vital for the human body therefore it is a largely controlled process at several levels (transcriptional, translational, enzyme modulation etc.). If this molecule is not absorbed with the diet, specific receptor senses the lack of the metabolite and activate specific genes and mechanisms to synthetize it. One of the not so well known but important factor in the cholesterol regulation is via thyroid. 3,3’,5-Triiodothyronine (T3) is a thyroid hormone involved in LDL-r gene expression regulation. A 20% of this hormone is secreted by thyroid but the major amount is produced from thyroxine (T4) by 5 -deiodination in peripheral tissues. This reaction is catalyzed by the selenoprotein deiodinase in (Dio1). This protein activates thyroid hormone by converting the prohormone T4 by outer ring deiodination (ORD) to bioactive T3. It also degrades both hormones by inner ring deiodination (IRD). On the other hand, a few reports indicated that 1 ppm selenium supplementation to rats decreased the total cholesterol and LDL levels, increased Dio1 expression (and T3 levels) and decreased the ApoB and HMGCoA reductase mRNAs expression. Edible mushrooms are a good source of selenium as well as hypocholesterolaemic compounds such as i.e. sterols, fibers, inhibitors of the 3-hydroxy-3-methyl-glutaryl-Co A reductase (HMGCR) and of the S-adenosylhomocysteine hydrolase (SAHH) such as eritadenine. Thus, several mushroom extracts were prepared and administrated to normo-and hypercholesterolaemic mice in order to investigate their potential influence on the Dio1 gene expression in liver, duodenum, ileum and cecum. Results indicated that hypercholesterolemia induced a marked reduction, particularly in liver, of the Dio1 mRNA expression. Moreover, the Dio1 gene expression was also modulated by the mushrooms extracts but not by the hypocholesterolaemic control drugs. Some of the extracts down-regulated its expression while others promoted its up-regulation. The effect was tissue dependent.

Managing Construction Development Risks to the Environment

The control of environmental risks arising from construction has become a major issue for the public. Environmental risk is defined as any risk or potential risk to the environment (of whatever degree or duration) and includes all types of impacts. Much of the research conducted has portrayed construction as a major contributor to environmental disruption and pollution. Pollution risks due to construction are typically classified as air pollution, waste pollution, noise pollution, and water pollution. Controlling the risks demands the ability to manage these types of pollution or eliminate their generation. The endorsement of environmental risk management and the mission of sustainable development have resulted in pressure demanding the adoption of proper methods to improve environmental performance in the construction industry. This chapter therefore places its focus on the risks arising from the construction industry, and how to manage these risks so as to strike a balance between development and environmental concerns. Real examples of construction activities are briefly presented to enable readers to envision the risks and the actual efforts undertaken to curb them. This chapter also presents the perception of the public at large regarding the risks caused by construction.