Children find decomposing bodies on a beach. A girl becomes a ghost and finds someone. A dog dies but its owner is out of his mind and eating waffles. Sheep are a perfect species. A woman experiences a pregnancy that is out of this world! A raccoon dies and you watch its body break down. A father does his best fathering. You take a textual road-trip tour of America’s oldest hobby. A trauma is slowed down, picked apart. A soupfin shark is dissected and you watch. A homestead becomesa ghost town in rural Oregon. Joseph Beuys is an artist. A sister falls in love with an object, has a difference of opinion with her sister.

Thesis (M.Sc. (Microbiology)) --University of Limpopo, 2013 / The production of cellulase is a key factor in the hydrolysis of cellulosic materials and it is essential to make the process economically viable. Cellulases are the most studied multi- enzyme complex and comprise of endo-glucanases (EG), cellobiohydrolases (CBH) and β- glucosidases (BGL). The complete cellulase system; comprising CBH, EG and BGL components thus acts synergistically to convert crystalline cellulose to glucose. Cellulases are currently the third largest industrial enzyme worldwide. This is due to their wide applications in cotton processing, paper recycling, juice extraction, as detergent enzymes and additives in animal feed. In this study, production of cellulase by five fungal isolates (BTU 251-BTU 255) isolated from mushrooms, was investigated and optimised. Internal transcribed spacer regions (ITS1 and ITS4) were applied to identify the five fungal microorganisms. Isolates were identified as follows: BTU 251 as Aspegillus niger,BTU 253 as Penicillium polonicum, and BTU 255 as Penicillium polonicum. Cellulase was produced in shake flask cultures using Mandel’s mineral solution medium and Avicel as a carbon source. Cellulase activity was tested using 3, 5-Dinitrosalicylic acid assay and zymography, A. niger BTU 251 showed five activity bands ranging from 25- 61 kDa had an average nkat of 7000. Cultures from BTU 252 were the least active with an average nkat/ml of 200 and one activity band of 25 kDa. P. polonicum BTU 253 showed three activity bands ranging between 45 and 60 kDa and had an average nkat/ml of 2200. BTU 254 showed five activity bands ranging from 22- 116 kDa and had average nkat of 350. P. polonicum BTU 255 produced the highest cellulase activity of 8000 nkat/ml and with three activity bands estimated at 45-60 kDa on zymography. The optimal temperature for activity of the cellulases was between 55-70°C and enzymes were most active within a pH range of 4-6. Optimal pH for production of cellulases by P. polonicum BTU 255, P. polonicum BTU 253 and A. niger BTU 251 was 4 while optimal temperature for production of the cellulases was between 50-55°C. Total cellulase activity was determined using Whatman No.1 filter paper as a substrate and β- glucosidase production was determined in polyacrylamide gels using esculin as a substrate. In the hydrolysis of crystalline cellulose (Avicel), a combination of A. niger BTU 251 and P. polonicum BTU 255 (1:1), (1:9), (1:3), and (1:2) produced maximum glucose as follows: 1:1 (0.83g/L), 1:9 (10.4g/L), 1:3 (0.77g/L) and 1:2 (0.73g/L). Cellulases from P. polonicum BTU 255 were partially purified using affinity precipitation and analysed using MALDI- TOF/TOF. Peptide sequences of P. polonicum obtained from MALDI-TOF/TOF analysis were aligned by multiple sequence alignment with C. pingtungium. Conserved regions were identified using BLAST anaylsis as sequences of cellobiohydrolases. More research is required in producing a variety of cellulases that are capable of hydrolysing crystalline cellulose, the current study contributes to possible provision of locally developed combinations of cellulases that can be used in the production of bioethanol.

In Western Australia dried meat baits containing 1080 are used extensively by agricultural and conservation organisations to control foxes and dingoes for the protection of agricultural production and native fauna. Field trials were conducted to assess 1080 loss from dried meat baits and this required the analysis of over five hundred baits. Because of this large number of baits it was essential to have a simple and efficient 1080 extraction procedure and method of 1080 analysis. In this study three methods of 1080 extraction and the new bioassay method for 1080 analysis were investigated. A simple and cost-effective 1080 extraction method using water with a 98% 1080 recovery rate was developed and modifications to the bioassay method were made.Factory-produced 1080 dried meat baits were laid in the field during different seasons at four locations in Western Australia, samples were collected over time and analysed for 1080 content using the bioassay. Rainfall was recorded and temperature data was collected for each site. Baits were exposed to the elements but were placed in mesh or wire cages to restrict invertebrate attack and prevent removal by vertebrates. Some baits were placed on the surface and others were buried. Initially 1080 loss from baits from all 4 sites was minimal, ranging from 0 - 21% at day 7 - 9. Further loss was gradual even when rainfall was recorded. Generally baits had to be exposed to at least 50 mm of rain before 1080 loss increased to 50%. At some sites baits continued to remain toxic to foxes even after long exposure. The mean 1080 content of baits from the Carnarvon site at day 226 was 2.0 mg (55% of the mean 1080 content of baits at day zero) with 137 mm of rainfall recorded for that period. Loss of 1080 from baits buried occurred at a faster rate than from baits placed on the surface during the same time period. By day 14 no 1080 was ++ / detected in the buried baits compared to the 68% detected in the surface baits. Under certain conditions 1080 loss from baits was minimal. Levels of 1080 in baits from Nangeen Hill remained fairly constant during the months of September to December 1995, and again during February to April 1996.Gastrolobium plant tissue and soil samples from the southwest of Western Australia were investigated for the presence of 1080 degrading microorganisms. Microbes were isolated and individually tested in solution containing 1080 as the sole carbon source. Isolates which showed 1080 degrading ability were further tested for their degrading efficiency in McClung carbon-free solution with added 1080 as the sole source of carbon and in factory 1080 waste solution, at 1080 concentrations of 20 and 200 mM. The effect of temperature on their rate of degradation was also examined. Thirteen isolates (7 fungi and 6 bacteria) showing varying degrees of 1080 degrading ability were obtained. Rates of 1080 degradation varied among isolates but were highest in the factory waste solution at the 20 mM concentration and in the McClung solution, where 1080 was the sole source of carbon, at the higher concentration of 200 mM. The most efficient isolates OSK and 10H (both Pseudomonas species) degraded all the 1080 present in sterile factory waste solution up to 20 mM 1080 concentration in 4 days and the isolate 1AF (Fusarium oxysporum) degraded 93% of 200 mM 1080 in the McClung solution in 9 days. The optimum temperatures for 1080 degradation were 30 degrees celsius and fluctuating ambient temperatures of 15 28 degrees celsius.

Biodegradation is the breakdown of a compound by a biological organism. Over the past few decades, the biodegradation of compounds such as phenol has been researched extensively. Phenol research has shown that certain organisms are capable of utilising it as an energy source, and a variety of methods are available for its removal. Unfortunately, there is lack of research on phenol degradation at low concentrations. The majority of research performed on phenol degradation has used concentrations above 500 mg, while phenol is highly toxic at levels below 25 mg. The aim of this research was to pursue the problem of phenol degradation at below 100 mg and develop a system able to degrade phenol at such levels. The system consisted of a bioreactor developed to run in continuous mode, using Ps. putida immobilised in calcium alginate. A standard method was modified to quantitatively analyze effluent phenol levels, and a medium designed to increase the longevity of calcium alginate beads in continuous culture. A continuous flow bioreactor was also designed using an overflow weir for use with immobilised cells. Based on the results obtained, immobilisation offers increased stability and increased protection for cells under extreme conditions and is able to use higher dilution rates than cells under continuous culture / Master of Science (Hons)

Includes bibliographical references

Graduation date: 2006

The aerobic transformation of TCE and cis-DCE by a tetrabutoxysilane-grown microorganism (Vancheeswaran et al., 1999) led to the investigation of novel substrates, including benzyl alcohol, for promoting cometabolism. The culture grew on carboxylic compounds and alcohols, but did not grow on formate, methanol, methane, propane, butane, ethylene, benzene, toluene, or p-xylene. Cis-DCE transformation was observed when the culture grew on butyrate, glucose, 1-propanol, 1-butanol, ethanol, benzyl alcohol, and phenol, and effectively transformed TCE, cis-DCE, and vinyl chloride when grown on phenol or benzyl alcohol. Several cycles of growth on benzyl alcohol led to increases in TCE transformation rates and transformation capacities. Products of benzyl alcohol degradation shifted from benzaldehyde to 2-hydroxy benzyl alcohol (2HBA) during the several cycles of growth. In resting cells studies, 2HBA production rates were highly correlated with TCE transformation rates. TCE transformation and 2HBA production rates doubled when the culture was grown on phenol and rates of TCE transformation were correlated with 2HBA production rates. Benzyl alcohol- and phenol-grown cells oxidized toluene to o-cresol, which indicated the similarity between benzyl alcohol ortho-monooxygenase, phenol hydroxylase, and toluene ortho-monooxygenase. 2-Butyne and 1-hexyne (but not acetylene) inhibited benzyl alcohol- and phenol-grown cells similarly, indicating the same ortho-monooxygenase was responsible for TCE cometabolism. Resting cell kinetic studies were performed with cells grown on phenol or benzyl alcohol. Benzyl alcohol degradation followed a Monod kinetics while phenol degradation followed a Haldane kinetics. The maximum transformation rates (k[subscript max]) of TCE, cis-DCE, and VC achieved by phenol-grown cells were about a factor of two higher than achieved with benzyl alcohol-grown cells, while the half-saturation constants (K[subscript s]) were in a similar range. Transformation capacities (Tc) for TCE, cis-DCE, and VC were about a factor of two to four higher with phenol-grown cells. The modeling of TCE, cis-DCE, and VC transformation using independently measured k[subscript max] and K[subscript s] values matched well with observed data from batch tests. Benzyl alcohol was shown to be an effective novel substrate for the aerobic cometabolism of TCE, cis-DCE, and vinyl chloride. Being a non-regulated compound, it might have applications for in-situ bioremediation. / Graduation date: 2004

Ryegrass residue consists of three main C fractions: readily available soluble C, intermediately available cellulose and hemicellulose, and slowly available lignin. Changes in chemical composition during decomposition influence rate of degradation as well as composition of the microbial community involved. Use of ����C-labeled plant material coupled with analysis of phospholipid fatty acids (PLEA) by isotope ratio mass spectrometry results in a powerful tool for linking microbial community structure and C cycling processes during decomposition. The objective was to investigate the role of soluble C in the decomposition of ryegrass straw. We wanted to determine (i) if the presence or absence of labile C in straw affects C mineralization by the microbial community, (ii) if community structure would differ based on the presence of labile C, and (iii) if community structure would shift as decomposition progressed. Residue was added to soil microcosms at rates that reflect field loads. Treatments were unleached straw (US), leached straw (LS), and leachate (L), plus an unamended control (C). Added substrates had ������C values between 120% and 180% the native soil signature was 26%. Respiration was measured every 4 to 6 hours for the first 5 d, and weekly thereafter. Destructive sampling took place after 0.6, 1 .6, 1 5, 1 8. 50, and 80 d of incubation and microbial biomass '��C (MBC) and PLFAs were analyzed. The soluble component of ryegrass straw strongly influenced C mineralization and assimilation, as well as microbial community composition and dynamics. CO2 evolution rates and ����C signatures were similar in US and L during the first 3 d of incubation. Most soluble C from leachate was consumed during that time, indicated by the rapid decrease in ������C value of CO2 evolved from L treatment. Substrate-derived C moved quickly into and through the microbial biomass. Distinct temporal shifts occurred in community composition. Early communities in amended soils were dominated by short and branched-chain PLFAs such as 15:Oa. Later samples contained more complex and longer PLFAs. 19:Ocy was an indicator for late succession communities in US and L, and 18:2w6,9 characterized late samples in LS. Soluble C affected when the temporal shift occurred in LS and L, communities shifted earlier than in US. Lipids were differentially enriched with ����C. Fungi, as indicated by 18:2w6,9, were more effective at incorporating substrate C into cellular lipids, as this was the most highly labeled of all PLFAs. / Graduation date: 2004

Graduation date: 2003

Graduation date: 1998