Statistical optimization of ethanol-based biodiesel production from sludge palm oil using locally produced candida cylindracea lipase

Face centered central composite design was used to optimize the enzyme loading, reaction temperature and mixing speed of sludge palm oil (SPO) transesterification reaction using locally produced Candida cylindracea lipase. The developed quadratic model was found to be significant at p < 0.05. The highest biodiesel yield of 57.5 % (w/w SPO) and 15.22 % free fatty acids (FFA) conversion to biodiesel with coefficient of determination R2 of 0.91 and 0.93, respectively were obtained at enzyme loading of 0.4 U/g SPO, 41 °C and 250 rpm mixing speed. Enzyme loading (U/g) gave little effect on the %FFA conversion to biodiesel and total biodiesel yield compared to temperature and mixing speed due to high FFA and water content, thus further studies are required for improvement. The study shows the low cost SPO and locally produced lipase have a promising potential in the utilization of waste for low cost biodiesel production

The importance of a standardized Islamic manufacturing (IMP) for food and pharmaceutical productions

As Muslims, the search for lawful (halal) and wholesome (tayyib) products such as food and medicines is not only a part of ibadah and to get pleasure of Allah SWT. In fact, it can also nourish the bodies and souls due to the permissibility and purity of the products. Currently, the awareness of some doubtful and questionable ingredients in the food and pharmaceutical products in the market has increased. Since the 23rd meeting of the Standing Committee for Economic and Commercial Cooperation (COMCEC) on November 2007, OIC has organized a conference and its sequential meeting on The OIC Halal Food Standard. Three main documents – OIC General Guidelines on Halal Food, Guidelines for Bodies Providing Halal Certification, and Guidelines for the Authorized Accreditation Body Accrediting Halal Certification Bodies – have been finalized. However, the concern is now wider and more complex in nature incorporating not only the traditional aspects but also the biopharmaceutical manufacturing processes and other relevant processes. Thus, there is an urgent need for a comprehensive guideline. The concept of Islamic Manufacturing Practice (IMP) has been introduced in Malaysia to fill this void but unfortunately, the contents of the IMP are still equivocal and limited. This paper discusses about some aspects of manufacturing processes in food and pharmaceutical industries that reflect the importance of a standardized IMP

Golden carbon nanotube membrane for continuous flow catalysis

In this work, a high-performance catalytic membrane, composed of ultrasmall gold nanoclusters (AuNCs) and high aspect-ratio carbon nanotubes (CNTs), was designed for the continuous-flow catalytic reactions. In this hybrid catalytic membrane, the Au core of the NCs serves as high-performance catalyst, and the ligand of the NCs plays two key roles: (1) as a well-defined surfactant assembly to effectively dissolve CNTs in aqueous solution and (2) as an efficient protecting ligand for Au core to avoid agglomeration. Due to the above-mentioned features, a homogeneous 3D self-support catalytic membrane can be readily fabricated by vacuum filtration of the hybrid AuNCs/CNTs. The catalytic activity of the as-designed catalytic membrane was evaluated using 4-nitrophenol hydrogenation as a model catalytic reaction. The data suggest that the continuous flow catalytic reactor could achieve complete conversion of the substrate (i.e., 4-nitrophenol) within a single flow through the membrane with a hydraulic residence time (τ) of 3.0 s. The catalytic membrane also showed enhanced catalytic kinetics as compared to the conventional batch reactor due to the convectively enhanced mass transfer. In addition, three important parameters, including the Au loading amount, substrate concentration, and flow rate, were identified as key factors that could affect the performance of the catalytic membrane

Heating or cooling: temperature effects on the synthesis of atomically precise gold nanoclusters

Developing an efficient, well-controlled synthesis strategy for gold nanoclusters (Au NCs) is crucial for delivering their expected applications in many fields; and such development requires fundamental understandings on the synthetic chemistry. The synthesis of Au NCs typically consists of a pair of reversible reactions: a fast reduction-growth reaction and a slow size-focusing reaction. Here we demonstrate that the above two reactions can be well-balanced while accelerated in a heated synthesis protocol, thus providing an efficient and scalable synthesis method to obtain thermodynamically favorable Au25(SR)18 NCs (SR denotes thiolate ligand) with high yield (>95% on gold atom basis) and fast kinetics. By investigating the Au NC formation behavior at different temperature, we identified the endothermic nature of the reductive formation of Au25(SR)18 NCs from Au(I)-thiolate complex precursors. More interestingly, if overheated, after the formation of Au25(SR)18, there exists an irreversible first-order reaction, which could transform Au25(SR)18 into Au NCs of mixed sizes. As a result, 40 °C is identified as the optimal temperature to synthesize Au25(SR)18 in aqueous solution, as the half-life of the transformation reaction (67.8 h) is much longer than the time needed to obtain high yield Au25(SR)18. The detailed understandings on the temperature effects of Au NC synthesis would facilitate the development of efficient synthesis strategies for atomically precise Au NCs with predesigned size, composition and structure

Toward greener synthesis of gold nanomaterials: from biological to biomimetic synthesis

In the past two decades, the use of biomolecules, either from biological or biomimetic systems (or so-called biological or biomimetic synthesis), has emerged as a promising green approach to synthesize gold nanomaterials (Au NMs). Here, we describe recent progress on the biological and biomimetic syntheses of Au NMs. We focus our discussions on the selection principles of biomolecules, synthesis mechanisms involving biomolecules, recent evolution from biological to biomimetic synthesis, and the contributions of bioinspired synthesis to green production of Au NMs. We hope this review will provide a guideline for the green synthesis of Au NMs and other metal NMs, further paving their way toward practical applications in the field of biomedicine

Toward the shell biorefinery: processing crustacean shell waste using hot water and carbonic acid

Biomass fractionation is a prerequisite for almost any biorefinery process. Yet, a cost-effective and environmentally benign approach to separate biomass feedstock into valuable fractions remain a challenge. Herein we introduce a new fractionation method to extract high-value chitin from crustacean shell (e.g., shrimp shell) using hot water for deproteinization and carbonic acid for demineralization (termed as the HOW-CA process). This method features high deproteinization and demineralization efficiencies (>90%), and the whole process is accomplished within hours. The desired final product chitin exhibits a high purity. This work addresses the major problems associated with the current industrial practice including the employment of corrosive reagents, the destructive removal of a useful component, and the generation of a large amount of waste. Economic and life cycle analyses imply that the HOW-CA process is superior to the conventional method, offering both economic and environmental benefit

ENGINEERING LIGAND-PROTECTED GOLD NANOCLUSTERS FOR CATALYTIC APPLICATION

Ph.DDOCTOR OF PHILOSOPH

The potential of artificial neural network (ANN) in optimizing media constituents of citric acid production by solid state bioconversion

This work aims at optimizing the media constituents for citric acid production from oil palm empty fruit bunches (EFB) as renewable resource using artificial neural networks (ANN) approach. The bioconversion process was done through solid state bioconversion using Aspergillus niger. ANN model was built using MATLAB software. A dataset consists of 20 runs from our previous work was used to develop ANN. The predictive and generalization ability of ANN and the results of RSM were compared. The determination coefficients (R2-value) for ANN and RSM models were 0.997 and 0.985, respectively, indicating the superiority of ANN in capturing the non-linear behavior of the system. Validation process was done and the maximum citric acid production (147.74 g/kg-EFB) was achieved using the optimal solution from ANN which consists of 6.1% sucrose, 9.2% mineral solution and 15.0% inoculum