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Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 137-138). / xi, 138 leaves, bound ill. (some col.) 29 cm

Th.--Sci.--Bordeaux 1, 1984. N°: 804.

Nattokinase is a potent fibrinolytic enzyme produced by Bacillus sutbilis, which is one of the most important sources of fibrinolytic enzymes. Nattokinase has a dual function of hydrolyzing blood thrombin directly and indirectly. It was found to be active between pH 6-12 and lose fibrinolytic activity dramatically when pH is lower than 5. Currently nattokinase preparations are not pure enough to get rid of the unique smell that is repulsive to the non-Japanese. These two reasons severely blocked nattokinase to be developed for food and pharmaceutical industrial usages as supplements and active ingredients. The objective of this study was to isolate the bacteria which have ability to produce nattokinase-like fibrinolytic enzyme, purify and characterize these enzymes to determine the actual biochemical properties. An industrial compatible aqueous protocol can be applied not only for the purification of nattokinase but also for other fibrinolytic enzymes from Bacillus source was established to purify the enzymes to homogeneous. The intrinsic stabilizing factors in raw nattokinase fermented broth were also identified in order to make natural stable nattokinase preparation for acidic environment. 71 strains belonging to 13 different genus was determined as the fibrinolytic enzyme producing bacteria. The fibrinoytic enzyme produced by Bacillus tequilensis, Bacillus amyloliquefaciens, and Bacillus cereus was purified and characterized. One of these three enzymes was determined to be a new fibrinolytic enzyme that never be reported. The purification protocol established here contained 3 operation units that including one chromatographic separation step followed by membrane polishing after nattokinase was extracted with 70% ammonium sulphate from the fermented broth. The purified nattokinase and other fibrinolytic enzymes showed single band as tested by SDS-PAGE and already pure enough to determine the N-terminal sequence directly by Edman degradation. A purification efficiency of 476.1 fold enzymatic activity increase with 48.3% recovery was obtained by using this protocol to purity nattokinase at lab level. The efficiency was 428.1-fold with 42.6% recovery at industrial compatible pilot scale (60-fold amplification). The efficiency was 329.7-fold with 42.7% recovery for purification of fibrinolytic enzyme produced by Bacillus tequilensis, 221.7-fold with the recovery of 32.5% for purification of fibrinolytic enzyme produced by Bacillus amyloliquefaciens and 288.5 fold with 38.7% recovery for purification of fibrinolytic enzyme produced by Bacillus cereus. The purification fold of most current protocols used for nattokinase and other fibrinolyitc enzymes purification was lower than 100 and the recovery fall in between 6.28% to 80%. Thus, the protocol established in this study has a very high purification efficiency. The result of intrinsic stabilizing factor identification shown both starch and levan have the stabilizing effect on nattokinase at low pH environment. The stabilizing ability of starch is much higher than levan, and was retained even hydrolyzed by amylase. The active concentration range of starch was from 20 and up to 500 æg/ml at the pH range of 4-5.

Biological wastewater treatment is typically aerobic and an energy intensive process, mainly due to the required aeration. Alternative sustainable processes are sought, such as Microbial fuel cells (MFC) where electrogenic bacteria can degrade organic matter present in the waste stream while simultaneously generating electricity. MFCs represent an emerging technology which may deliver the capability to reduce the pollution potential of low strength wastewaters (< 1500 mg COD l-1) while generating electricity which could be used to self-power the process. Waste streams high in volatile fatty acids (VFAs) with high conductivity are particularly preferred substrate streams. These may include the effluent from two stage bio-hydrogen and bio-methane systems, which in this study were treated in a four-module tubular MFC (V=1 l) to reduce the chemical oxygen demand (COD) and recover further energy from the substrate. It was shown that the power increased with increasing organic loading rate (0.036-0.572 g sCOD l-1 d-1), but COD removal efficiency decreased. The Coulombic Efficiency (CE) was found to decrease significantly at OLR ˃ 0.6 g sCOD l-1 d-1 and the energy recovery was 92.95 J l-1 (OLR=0.572 g sCOD l-1 d-1). Also, wash-down waters from a chilled food producing company were treated in the same tubular MFC, reducing the soluble COD content by 84.8%. The low power (≈ 30 W m-3) and cell potential (≈ 0.5 V) makes it necessary to investigate methods such as external capacitors, DC/DC converters or serial and parallel connection to improve the power quality. In this thesis, the use of the intrinsic capacitance was tested by switched mode, open and closed circuit (OC/CC) operation of a 2-module tubular MFC with high surface area carbon veil anode. The charge accumulated during OC and released when switched to CC was dependent on the external resistor (R = 100-3 kΩ) and duty cycle. Short period OC/CC switching further increased potential due to the pseudo-capacitance of the reactor, but only at the expense of energy efficiency, compared to continuous operation (CC) under constant load. Another approach to enhance the practical implementation of MFCs is integration with other processes such as reverse electrodialysis to increase MFC’s cell potential or e.g. desalination. In this study a MFC was integrated with supported liquid membrane technology (SLM) for the first time, for the removal of metal ions of wastewater. A three chamber reactor, with a common cathode/feed phase containing 400 mg Zn2+ l-1, enabled V the simultaneous treatment of organic- and heavy metal containing wastewaters. The MFC/SLM combination produces a synergistic effect which enhances the power performance of the MFC significantly; 0.233 mW compared to 0.094 mW in the control. It is shown that the 165±7 mV difference between the MFC/SLM system and the MFC control is partially attributable to the lower cathode pH in the integrated system experiment, the consequent lower activation overpotential and higher oxygen reduction potential. The system demonstrates that within 72 h, 93±4% of the zinc ions are removed from the feed phase. A further study, with continuously operated cathode/feed chamber (100 mg Zn2+ l-1), showed that an enhanced effect on increasing cell potential was possible and could also be maintained in continuous operation.

A polymer matrix of hydroxy ethyl methacrylate - ethylene glycol dimethacrylate was synthesised and coupled with the ligand p-aminobenzamidine. Although the adsorbent displayed sufficient affinity towards trypsin, the overall adsorption performance was not satisfactory. Subsequent studies were carried out with a p-aminobenzamidine silica adsorbent, which gave far superior results. Amounts of up to 35 mg of trypsin per g of silica could be adsorbed from a porcine pancreatic extract at buffer conditions of 0.05 M Tris, 0.5 M NaCl, pH 8. Complete elution was achieved with a buffer of 0.1 M acetic acid, pH 3. The system was characterised by fixed bed breakthrough studies of the adsorption, wash and desorption step. A method of data analysis was developed and applied to the experimental results. Axial dispersion could be identified as the predominant 'mass transfer' mechanism. A simulation model was build, based on the data analysis results. The model was verified successfully against the experimental data. Continuous separation experiments were performed with three fluidised beds, namely an adsorption, desorption and wash column, with circulation of solids between the columns. Purities of 83% and 66% were achieved in these runs with complete recovery of trypsin. A continuous process model, also based on the data analysis results and on fluidised bed characteristics, was found to agree fairly well with the experimental data. Simulation experiments were conducted to find the optimum configuration of the process. Best performances with respect to product purity were obtained for an adsorption column height of 3 cm and a wash column height of 4 cm. Step experiments revealed that the process is relatively easy to control if the solid flow rate is chosen as the control parameter.

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Thesis (MTech (Electrical Engineering))--Peninsula Technikon, Cape Town, 2002 / The problem for wastewater treatment is very important these days because of population increase and industry development. Ion exchange technology has proved its positive qualities in domestic lives and industry, but the ion exchange process still needs deeper understanding and improving. That is why a new pilot plant has been built in Chemical Engineering Department at Peninsula Technikon. In addition to the treatment of domestic effluents there are other processes which the ion exchange is suited for, such as the recovery and the reuse of industrial effluents. The proposed control system is developed in such a way that it does not have to depend on a certain effluent. The selection of the process and the development of techniques for its control fall into the national needs of improving people's lives (e.g. giving them excess to clean water) and quality of the environmental conditions (treatment of toxic waste substances). There is a need for an application area for modeling and control methods developed in the field of control engineering for the Department of Electrical Engineering; on the other hand a need of control techniques for the development in the Department of Chemical Engineering technological process. This multidisciplinary liaison between the two Engineering departments promotes joint research activities and relevance between them. It also equips the graduating engineer with the relevant experience into working in a team of multidisciplinary engineering fields.Community and industrial relevance of the research study is that in addition to treatment of domestic effluents, the ion exchange process is also particularly well suited for: the desalination of hard waters, combined neutralization and desalination of alcohol effluents, such as mine drainage, acid mineral tailings, paper bleach affluent. the pretreatment of reverse osmosis feed for the removal of organic and colloidal particulate.

Thesis (MTech (Chemical Engineering))--Cape Technikon, 2002. / The high purity 1-octene produced by Sasol Alpha Olefins in Secunda and which is sold to DOW Chemical Company for co-monomer application, has performed poorly over the DOW Ziegler-Natta catalysts. The reason for the poor performance was catalyst poisoning caused by low-level impurities present in the 1-octene. Much work from Sasol and DOW has gone into identifying the components responsible for catalyst deactivation, as well as methods suitable for removing them without significant 1-octene losses. Super NMP (n-Methyl-2-Pyrrolidone) extractive distillation piloting was performed previously on 1-octene in order to remove the low-level impurities that deactivate the DOW catalysts. VLE (vapour liquid equilibrium) test work performed previously indicated that all xylenol isomers are more promising as extractive distillation solvents than NMP.

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