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Submitted in fulfillment of the requirements for the Degree of Doctor of Technology: Biological Sciences, M.L. Sultan Technikon, 2002. / The extent of diffusion and surface modification of a purified 23.6 kDa xylanase isolated from Thermomyces lanuginosus on bagasse pulp was evaluated. Polyclonal anti-xylanase antibodies were raised in two rabbits and in conjunction with immunogold labeling and microscopic studies enzyme diffusion and degradation studies were performed. The purity of the xylanase was confirmed by SDS-PAGE and western blots confirmed the antigen-antibody hybrid on the nitrocellulose membrane. / D

Dissertation submitted in fulfilment of the requirements for the Degree of Masters in Technology: Business Administration, Durban University of Technology, 2013. / Leadership is defined as a process by which an individual attempts to influence other group members towards achieving group goals. Leadership is also viewed as a process which people use to bring out the best in themselves and others. National culture is said to play a pivotal role in determining the effectiveness of leadership styles. Literature on leadership identifies transformational leadership, transactional leadership and laissez-faire leadership as the three common leadership styles in the current climate, with transformational leadership and transactional leadership being the most dominant. Literature suggests that an employee’s job satisfaction is strongly influenced by leadership style. Current leadership styles are related to job satisfaction by varying degrees. Several studies have indicated that transformational leadership results in higher levels of job satisfaction than transactional or laissez-faire leadership. The overall aim of the study was to investigate the relationship between leadership styles and employee job satisfaction levels within the organisation. A quantitative study was conducted to accomplish the objectives of the study. Questionnaires were administered to employees within the selected target population in the organisation. The data received were analysed using statistical packages. The results of the study show that there are statistically significant relationships between overall transactional leadership and job satisfaction, overall transformational leadership and job satisfaction and laissez-faire leadership and job satisfaction. However, two attributes of transformational leadership best explain job satisfaction. Intellectual stimulation contributed most to explaining job satisfaction, followed by individualised consideration. The remaining attributes of transformational leadership, transactional leadership and laissez-faire contribution to job satisfaction.

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Thesis (PhD)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: White rot fungi are of interest in the paper and pulp industry because of their removal of lignin from wood. In this study over 600 Basidiomycete fungi were isolated from indigenous forests as well as from commercial Eucalyptus spp. and Pinus spp. plantations in South Africa. One hundred isolates were identified to genus level. Biochemical tests were done to screen the fungal cultures for characteristics that are favourable for biopulping, e.g. low cellulase activity with concomitant high activity of ligninolytic enzymes. Various Phanerochaete isolates with potentially high ligninolytic activity were identified. Although Phanerochaete chrysosporium Burds. has previously been isolated from the indigenous forest at Knysna in South Africa, this study showed that P. chrysosporium was a natural coloniser of wood chip piles in South Africa, indicating potential for application in industry. A possible new species of Phanerochaete, viz. Phanerochaete pseudomagnoliae nom. provo (strain PP25) from decayed wood collected in Stellenbosch, South Africa, was described and illustrated. It differs from previously described Phanerochaete species in having smaller basidiospares, and in the formation of few chlamydospores on malt extract agar but more on xylose containing media. The potential of using internal transcribed spacer DNA sequences (ITS) to infer phylogenetic relationships among species of the genus Phanerochaete was investigated. Consensus phylogenetic trees could be presented, but the presence of ambiguous aligning sequences within the ITS made inferring of phylogenetic relationships within the whole genus difficult. Fifty-five South African strains of P. chrysosporium were screened for lignin peroxidase (liP), manganese peroxidase (MnP) and glyoxal oxidase (GLOX) enzymes. Manganese peroxidase activity was quantified on agar media. The liP and GLOX activities of 13 selected strains, including control strains and P. pseudomagnoliae (PP25), were also quantified on agar media. Differences in MnP and GLOX activities existed among the strains. Preliminary biochemical characterisation of strain PP25 indicated that the most important difference was the apparent unique regulation of ligninolytic enzymes. Under low nitrogen, liP activity of the selected strains showed no significant variation, whereas strain PP25 had significantly increased liP levels under high nitrogen conditions. Restriction fragment length polymorph isms of the lignin and manganese peroxidase gene DNA fragments showed variability among strains, whereas there was probably only allelic variation for the glox gene DNA fragments. Previous research has indicated xylose oxidation activity within P. chrysosporium. To investigate whether GLOX can oxidise xylose, a purified recombinant GLOX (rGLOX) from P. chrysosporium BKM-F-1767 Burds. was used in this study. This rGLOX oxidised D-xylose and D-glucose (D-xylose > D-glucose) to produce H202. Xylose was oxidised to xylono-1 ,4-lactone with a 1:1 stoichiometric relationship between H202 produced and xylose used. Xylono-1,4-lactone was converted non-enzymatically to xylonate. This suggested that the furanose form of xylose, rather than the pyranose form, is a substrate of GLOX. The production of H202 and the removal of inhibitory compounds by GLOX could enhance ligninolytic activity. . To conclude, unique strains of P. chrysosporium have been isolated from South Africa with potential biotechnological use in paper manufacturing. The relationship of P. pseudomagnoliae nom. provo to other Phanerochaete species was evaluated and light was shed on the possible role of GLOX in lignin degradation. / AFRIKAANSE OPSOMMING: Witvrot swamme is van belang vir die papier en pulp industrie omdat hulle lignin vanaf hout kan verwyder. Meer as 600 Sasidiomiseet fungi, afkomstig vanaf inheemse woude asook kommersiële Eucalyptus spp. en Pinus spp. plantasies, IS geïsoleer. Een honderd isolate is tot op genusvlak geïdentifiseer. Die isolate is biochemies vir eienskappe wat voordelig vir "bioverpulping" kon wees, bv. die gelyktydige produksie van lae sellulosemaar hoë ligninolitiese ensiemaktiwiteit, getoets. Verskeie isolate met potensieel hoë vlakke van ligninolitiese aktiwiteit is verkry. Alhoewel Phanerochaete chrysosporium Surds. vantevore in die Knysna inheemse woud in Suid-Afrika geïsoleer is, het hierdie studie gewys dat P. chrysosporium natuurlik op hope houtblokkies voorgekom, met moontlike toepasing in die industrie. Isolaat PP25, geisoleer vannaf verrottende hout te Stellenbosch, Suid Afrika, is as 'n potensieel nuwe spesie van die genus Phanerochaete beskryf en as Phanerochaete pseudomagnoliae nom. provo benoem. Hierdie isolaat verskil van ander Phanerochaete-spesies daarin dat dit kleiner basidiospore vorm en nie klamydospore op moutekstrakagar produseer nie, maar wel op media wat xilose bevat. Die potensiaal van intern getranskribeerde spasieerder ONS opeenvolging vir die aflei van filogenetiese verhoudings tussen spesies van die genus Phanerochaete is ondersoek. Konsensus filogenetiese bome kon bepaal word, maar die teenwoordigheid van varieerbare areas het die afleiding van filogenetiese verwantskappe vir die hele genus bemoeilik. Vyf-en-vyftig Suid-Afrikaanse isolate van P. chrysosporium is vir die teenwoordigheid van lignienperoksidase- (liP), mangaanperoksidase- (MnP) en glioksaaloksidase (GLOX)-aktiwiteit getoets. Vlakke van MnP-aktiwiteit is op agarplate gekwantifiseer. Vlakke van LiP- en GLOX-ensieme op agarplate is vir 13 geselekteerde isolate, insluitend kontroles en ras PP25, gekwantifiseer. Aktiwiteit van MnP en GLOX het statisties betekenisvol tussen isolate verskil. Lignienperoksidase-aktiwiteit onder lae stikstof toestande het nie statisties betekenisvol van mekaar verskil nie. Onder hoë stikstof toestande het isolaat PP25 wel verhoogde liP-aktiwiteit getoon. Restriksie fragment polimorfismes van die lignien- en mangaanperoxidase-gene het variasie getoon, terwyl waarskynlik slegs alleliese variasie vir die glox geen waargeneem IS. Rekombinante GLOX (GLOX vanaf P. chrysosporium BKM-F-1767) het xilose en glukose (D-xilose > D-glukose) geoksideer met meegaande produksie van H202. Xilose is na xilono-1,4-laktoon geoksideer met 'n 1:1 stoigiometrie tussen H202-produksie en xilose verbruik. Xilono-1,4-laktoon is nieensiematies na xilonaat omgeskakel. Bogenoemde resultaat dui aan dat die furanose vorm van xilose die werklike substraat vir GLOX is. Deur die meegaande produksie van H202 en die verwydering van inhiberende produkte word lignoliese aangehelp. Ten slote, unieke P. chrysosporium rasse met potensiële gebruik in papiervervaardiging is in Suid-Afrika geisoleer. Die genetiese diversiteit van 'n nuwe spesie, P. pseudomagnoliae, is bepaal en nuwe lig is op die potensiële rol van GLOX in lignienafbraak gewerp.

Due to the opportunity for afforestation in South Africa being severely limited, extensive research is being carried out on obtaining more wood per given area, improving the quality and value of the wood and on gaining a better understanding of how wood properties influence the characteristics of the pulp it produces. The last mentioned is the main focus of this study. If the variations in pulp, due to variations in wood properties, are better understood, then the existing fibre resource could be more efficiently managed and utilised to maximise its value. The main objective of this study was to determine how variation in physical and chemical properties, from the existing P.patula resource drives variation in pulp strength properties. It is well known that differences in tree age and site index lead to major sources of variation of various wood properties. These two easily measured variables were used in this study to capture a significant amount of variation in the wood of the aforementioned genus that enters a mill. Samples were obtained from two extremes in site quality, as measured by site index, (viz. good and poor sites) and three age ranges (viz. 9-10 years, 13-14 years and 20-21 years) from the KwaZulu-Natal Midlands. Wood chips from each of the six sites were pulped for various lengths of time, using the Kraft pulping method and under the same pulping conditions. A wide range of anatomical and chemical properties of wood and pulp were measured to characterise these samples as extensively as possible. All pulp samples were beaten in a PFI mill, at four different levels. The freeness values of the beaten samples were measured. The physical properties measured on handsheets made from the pulp included sheet density, burst index, tear index, tensile index, tensile energy absorbed, stretch and zero-span tensile strength. Regression models were developed to quantify the impact of the measured variables on each of the strength properties. Principal component analysis was performed on the wood characteristics measured and indicated that tree age is a more critical source of variation in wood properties than site index. The predictions of whole tree wood properties from the properties measured at breast height were excellent. Pulping studies showed that pulp yield, at kappa 20-30, increased with tree age. Wood cellulose proved to be a very good predictor of pulp yield. Xylose and mannose appeared to be most resistant to degradation during pulping. The low yield pulps were easier to refine than those with high yield. This has important implications when considering high yield pulping processes. With regard to pulp strength, the younger material could not achieve the high tear strengths obtained by the older material. However, the tear strengths achieved by these younger sites were comparable with, if not higher than, that obtained by hardwood species. The implications of this is that younger P. patula trees could be used for grades of paper where very high tear strength is not essential, but tensile is (e.g. tissue paper) and that older material can be better used for the purpose of providing the high tear strength needed by certain paper grades (e.g. linerboard and sackkraft). The maximum tensile strength achieved by the younger material was higher than that of the older material. When compared at constant freeness or sheet density, longer cooking times had a deleterious effect on strength properties. Strong predictions of pulp strength from basic wood properties were obtained when strength results were compared at constant freeness and sheet density. Because of the great influence of fibre morphology and chemistry on refining rates and on the resultant strength properties, the results of the study suggest that fibres of greatly different chemical and anatomical characteristics should not be refined together, if beating energy and pulp strength are to be optimised. However, further work is required to evaluate if the separation of fibre resources, to improve pulp quality, would be economically viable. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2005.

At SAPPI-Tugela a continuous Kraft wood chip digester operates in EMCC mode (extended modified continuous cooking). Chips are initially exposed to a NaOH / Na2S liquor at high temperature in the top section. The chips move downward in plug flow passing circumferential screens used to draw liquor for various circulations. About midway down the spent black liquor is removed and the chips enter the cooler bottom section where some further reaction and washing occurs. Liquor level and chip level are maintained close to each other near the top. Chips require 8-12 hours to pass through the digester, depending on the chip feed rate. The key parameter of interest at the digester exit is the Kappa number, which is a measure of the extent of delignification which has occurred. Different board and paper products require different Kappa number pulp feed. (Final properties such as tensile, tear and bursting strengths will also depend on the way fibres have been modified in the digestion). The objective of this investigation is to predict the Kappa number of the product pulp in real-time, thus facilitating quicker reaction than the present dependence on laboratory analysis permits, possibly even allowing closed-loop control. The extent of delignification depends on liquor strength, temperature and exposure time, with final Kappa number also depending on the properties of the chip feed (wood type and moisture content). Compensation to maintain a steady Kappa number is made difficult by the long and varying residence time, and the fact that any changes apply to the whole profile held up in the digester. A number of static models for Kappa number prediction have been developed by previous workers, but these do not compare well with plant measurements. The collection of data from the Sappi-Tugela reactor, and the pulp quality reports, have been used to determine an efficient model. This step required a considerable data collection exercise, and similar results to the quality reports have been obtained using a simple linear model based on this data. The problem of model error is being reduced by arrangement as a Smith Predictor, in which the model is intermittently corrected by available laboratory analyses. At the same time, an interface was created, in order to synchronise measurement data for the chips presently leaving the reactor. In order to deal with the dead time, each parcel of chips entering the reactor is effectively tracked, and the changes in Kappa number integrated for reaction time under the varying conditions in transit. Knowing the present inventory of the reactor, this model can also be run forward in time as a predictive controller, to determine optimal control actions for maintenance of the target Kappa number. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2005.

At Mondi Paper Ltd, Merebank, South of Durban, Paper Machine 2 has recently been transferred onto a Distributed Control System (DCS). This was seen as a good opportunity to enhance the control of the pulp feed to the machine. A prime concern in operating a paper machine is to ensure consistent set-point paper properties in the Cross-Direction (CD: ie. across the paper width) and in the Machine-Direction (MD: ie. along the paper length). Sophisticated adjustments are available to ensure an even feed of the stock (consistencies around 2% m/m wood fibres in water) from the head-box across the receiving width of the paper machine. The properties of prime interest as the pulp is pumped through the head-box distributor onto the receiving belt of the machine are the basis weight (fibre mass per unit area) and moisture content (per unit area). However, the distribution system is highly dependent on the properties of the stock as it arrives at the head-box. Variations in upstream chest levels, the supplied pressure, flow-rate and fibre/water ratio, all cause MD and even CD variations. The problems of maintaining steady conditions at the head-box are well known, and are understood to arise from sub-optimal control in the preceding section involving a blend chest and machine chest, amongst other items, where several pulp streams and dilution water are combined. A number of control loops are involved, but appear to require different tuning for different paper grades. Often individual loops are taken off-line. In this study, an understanding of the controller interactions in the stock preparation section has been developed by detailed dynamic modelling, including all of the existing control loops. The model is built up in a modular fashion using a basic element, having one input (which can collect multiple streams originating elsewhere) and four outputs, linked through a vessel of variable volume. Several basic elements are linked together to form the overall system. All of the necessary properties can be defined so that the model allows the simulation of all features of the network: vessels, pipes, junctions, valves, levels and consistencies. A set of first order differential equations is solved which includes total water balance, species mass balances, derivatives of flow controller action, and derivatives of supervisory controller action. Supervisory controllers for consistency or level cascade onto flow controllers. Flow controllers manipulate valves which give a first-order dynamic response of actual flow. Where valves are manipulated directly by the supervisory level, the flow controller is effectively bypassed. This study involves a constraint problem around the blend chest, resulting in a loss of specification at the paper machine. This was solved by the implementation of a static optimiser. Its objective function penalizes deviations from setpoint of five parameters (ratios, consistency and level) using respective weight factors. Both the model and its optimiser were included in a simulator designed with the graphical user interface (GUI) of Matlab. The simulator has then been used to explore control performance over the operating range, by means of a set of scenarios. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2004.

The pulp and paper industry holds a reputation in the public eye for being a large consumer of water. This dissertation analyses water usage within the industry with a particular application to the South African pulp and paper industry. Unlike in other paper-producing countries, water in South Africa is a scarce commodity with a wide range of consumers. Faced with this, it is important for the leaders of the paper industry to have a tool with which to manage water consumption. This dissertation analyses the water usage aspects (including volumes needed and water quality needed) of the different processes, as well as the impact of different products, describing the reasons for water usage in each process. The application of best available technologies for water reduction is discussed. A theoretical or expected range and norm for water usage for each of seventeen South African mills is derived, based on each mill's particular processes, capacities and products. The actual water usage by each mill was surveyed by personally interviewing personnel at each mill. Comparisons are made between expected and actual water usage, and the total daily water consumption of the industry is derived. Only two mills operate below the expected norm level, most smaller mills operate close to the norm level, while five of the larger mills need to apply various techniques to reduce their water usage. The approximation of mill water usage to the predicted or expected norm clearly supports the hypothesis that water usage can be predicted by analysing process and capacity, and indicates that this dissertation can be used as a tool to manage water usage within the industry. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2004.