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Peatlands make up 3% of the earth's land surface and contain about one third of the C contained in soils globally. The role of peatlands in the C cycle is as a net sink. Organic matter accumulates in these areas because the rate of net primary productivity (NPP) exceeds the rate of decay. Peatlands are often harsh environments, characterized by cold, wet and anoxic conditions, therefore it is not accelerated NPP which exerts the main control over the accumulation of peat, but the slow rate of decomposition. During the decomposition process, nearly all organic matter passes through the soil microbial pool, and so the soil microbial community is an important factor in the decomposition process. Despite the obvious importance of the soil microbial community in decomposition in peatlands, our knowledge of their role in peatland C cycling is still largely limited. This thesis addresses some aspects of the soil microbial community and investigates their role in decomposition in a raised mire. The soils in a raised mire system may be categorized according to their nutrient input into nutrient rich, mineral soils and soils of the lagg fen, and nutrient poor, soils of the mire expanse. The soil microbial community in the three soils was characterized in terms of size, activity and composition. The size of the soil microbial community in the soils of the mire expanse was small in comparison with that of the mineral soils and soils of the lagg fen, however it was very active. The hypothesis that nutrients restrict the size of the soil microbial community in the soils of the mire expanse was tested. The data showed that nutrients did not significantly effect the size of the soil microbial community. Litterbags were used to investigate the decomposition of a range of plant species found on the different soils and mass loss and C02 production were used as indicators of decomposition. C02 production was a more sensitive and reliable measure of decomposition than mass loss. The size of the soil microbial community was an important factor in decomposition rate. Litter quality of the above ground biomass was not related to decomposition rate. The relationship between the size of the microbial community in contact with decaying plant material and decomposition was investigated. In this study, microbial colonization of decaying litter was not correlated with the measure of litter quality used. This work has provided baseline information the environmental factors that influence decomposition and future work should focus on investigating the changes in the soil microbial community during the decomposition process.

Biotransformation and biodegradation rate constants were determined for naphthalene, lindane, and phenol in water samples from three different sources. Rate constants produced from monitoring disappearance of the parent chemical (biotransformation) were compared to those obtained from mineralization of the chemical (ultimate biodegradation) by ¹⁴CO₂ evolution as well as acidification of the residual ¹⁴C-labeled compound (primary biodegradation). Rate constants were statistically different for the three chemicals. The water source affected the rate constants. When biomass measurements of the waters were considered and second-order rate constants were derived, there was no statistical evidence that this parameter gave a reliable rate constant statistic that could be useful in predicting the fate of any of naphthalene, lindane, and phenol in these waters.

ABSTRACT A new, non-pathogenic bioaugmentation product was formulated specifically for underground use in South African mines, using local bacterial isolates. This was designed for the remediation of various hydrocarbons via biochemical breakdown by sub-surface microorganisms. The active microorganisms were isolated from hydrocarbon-polluted areas of a gold mine. Many commercially available bioaugmentation products are already in existence however, all, to our knowledge, have been developed and tested primarily for use in the northern hemisphere. None have been formulated and tested in Africa. Our series of bacterial isolates are the first to be isolated from mine soils for hydrocarbon biodegradation purposes. Such isolates have further, not previously been tested on sub-surface contamination. The safety associated with the use of such a product in a closed mine-environment is of paramount importance. Initial batch-flask experiments were conducted using a readily-available commercial bioremediation product. This was tested on simple surfactant molecules and compared to the biodegradation observed under standard waste water treatment plant conditions. The bioremediation product increased biodegradation by 6% on average. Bacteria in the product were identified by 16S rDNA gene sequence analysis and found to be homologous to potentially pathogenic Bacillus cereus, known especially to effect immunocompromised individuals, this was of particular concern in the closed mine system. South African isolates were sourced from various hydrocarbon-polluted sources, with six bacteria ultimately being selected from deep sub-surface mine soil and water samples. The ability of these isolates to biodegrade waterborne monograde engine oil was assessed via GC-FID. The isolate showing average percentage growth increase, homologous to Pseudomonas pseudoalcaligenes, was found to degrade the motor oil by 98%. The new isolates were, on average, 16% more efficient at biodegrading petroleum hydrocarbons than the commercial bioremediation product isolates. Formulation of these isolates into the first commercially-available South African developed and tested bioaugmentation product will prove a successful conclusion to this study.

Many strains of Gram-negative bacteria, such as Pseudomonas, are able to utilize a variety of unusual chemicals, including a wide range or aromatic hydrocarbons and their derivatives for growth. Bacteria with the potential to degrade sodium benzoate were isolated, identified and grown as biofilms on sodium benzoate in a laboratory-scale fluidized bed biofilm bioreactor. Four Pseudomonas strains identified as P. aeruginosa (BDS2) P. putida (BDS1 and GR1) and Burkholderia cepecia (GR3FAR) were used in a laboratory-scale FBBR together with two Bacillus strains - Bacillus macroides (SBSY4) and Bacillus simplex (MAR). Sodium benzoate biodegradation capacities of these species were compared under batch and continuous operations. Biofilm and planktonic bacterial growth dynamics were monitored by plate counts, and optical density measurements (230nm) determined benzoate biodegradation. Overall, higher attached and planktonic bacterial counts were determined under batch compared to continuous mode. In addition to this, the ability of attached cells to use sodium benzoate as their sole carbon source was compared to their suspended counterparts in a batch system. There were more attached counts compared to suspended cells and attached cells apparently degraded sodium benzoate better than planktonic cells. Similarly, higher rates of benzoate depletion were found to occur under batch compared to the continuous system. It thus appeared that more cell growth implied more substrate consumption. SEM showed attached cells and microcolonies of all the isolates on GAC, indicating their biofilmforming abilities.

A dissertation submitted to the Faculty of Science for the degree of Master of Science University of the Witwatersrand, Johannesburg / It is well known that chlorinated organic compounds behave as highly toxic substances in the environment. Catalytic hydrodechlorination .... one of the more convenient approaches used to treat chlorinated organic substances with the aim of obtaining compounds with lower or null toxiciy. Further, the selective cleavage of the C-Cl bond plays a key role in processes related to the manufacture of fine chemicals. These reactions can be performed over noble-metal catalysts, either in the gas or liquid phase. (Abbreviation abstract) / Andrew Chakane 2018

Orientador: Ederio Dino Bidoia / Banca: Marta Siviero Guilherme Pires / Banca: Dejanira de Franceschi de Angelis / Banca: Regina Teresa Rosim Monteiro / Banca: Carlos Renato Corso / Reumo: O herbicida Gesapax® (ingrediente ativo: ametrina) é utilizado em culturas de cana-de-açúcar para o combate a plantas daninhas. Devido as suas propriedades físico-químicas é encontrado com frequência nos corpos hídricos. Ao adicionar surfactantes químicos ao solo contaminado com compostos orgânico, ocorre uma diminuição da tensão superficial entre o contaminante e a fração solúvel do solo, favorecendo a degradação de compostos orgânicos, uma vez que o mesmo fica de maneira biodisponível à microbiota. Dessa forma, neste trabalho teve por objetivo avaliar a influência do herbicida Gesapax na atividade microbiana em amostras de solo, utilizando o surfactante químico Tween 80, como em forma de bioestimulação e adição de consórcio microbiano como forma de bioaumentação, a fim de atuarem como coadjuvantes no processo de metabolização do herbicida. Avaliou-se a atividade microbiana utilizando frascos respirométricos de Bartha e Pramer e utilizando a técnica de colorimetria com DCPIP. Fez-se a análise da biodegradação do herbicida por meio de ensaio de cromatografia (HPLC) em amostras retiradas dos respirometros. Também, avaliou-se a toxicidade do solo com o herbicida através dos organismos testes Saccharomyces cerevisiae, sementes de Lactuca sativa, Eruca sativa e Cucumis sativus, e a mutagenicidade em amostras de solo com a Tradescantia pallida (coração púrpura). Fez-se também a quantificação de bactérias e fungos do solo, finalizando com ensaio de biologia molecular, a fim de avaliar a perturbação da presença do herbicida no solo para a estrutura microbiana nos tratamentos. A adição de surfactante ao solo contaminado com herbicida, possibilitou grande aumento da atividade microbiana, em comparação ao solo controle. O mesmo ocorreu nos tratamentos com ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The herbicide Gesapax® (active ingredient: ametryne) is used in sugarcane crops to combat weeds. Due to its physico-chemical properties it is frequently found in water bodies. By adding chemical surfactants to the soil contaminated with organic compounds, there is a decrease in the surface tension between the contaminant and the soluble fraction of the soil, favoring the degradation of organic compounds, in a bio-available way. Thus, the objective of this work was to evaluate the influence of the Gesapax herbicide on microbial activity in soil samples, using the chemical surfactant Tween 80, as in the form of biostimulation and addition of microbial consortium as a form of bioaumentation, to act as adjuvants in the process of metabolizing the herbicide. Microbial activity was evaluated using Bartha and Pramer respirometric flasks and using the DCPIP colorimetric technique. The biodegradation of the molecule was analyzed by chromatography assay (HPLC) on samples taken from the respirometers. Soil toxicity with the herbicide was evaluated through the test organisms Saccharomyces cerevisiae, seeds of Lactuca sativa, Eruca sativa and Cucumis sativus, mutagenicity in soil samples with Tradescantia pallida (purple heart), quantification of bacteria and fungi soil, finishing with molecular biology assay, to evaluate the perturbation of the presence of the herbicide in the soil to the microbial structure in the treatments. The addition of surfactant to the soil contaminated with herbicide, allowed a great increase of the microbial activity, in comparison to the control soil. The same occurred in the treatments with herbicide and microbial consortium. The herbicide was metabolized in the presence of the surfactant and microbial consortium. There was also an increase in the quantification of the soil microbiota in the presence of these ... (Complete abstract click electronic access below) / Doutor

A exposição ao Bisfenol A (BFA) ocorre frequentemente no nosso dia a dia,uma vez que esse composto é um plastificante presente em muitos utensílios domésticos, como, por exemplo, embalagens e garrafas. No entanto, esta exposição, mesmo em baixas concentrações (ng.L -¹), pode causar sérios danos ao sistema endócrino. Esses danos devem-se ao fato do BFA ser um disruptor endócrino, onde os receptores hormonais o confundem com o estrogênio ou o estriol. Diante deste cenário, o estudo de formas de mitigação deste composto no meio ambiente faz-se necessário. Uma das alternativas para remoção deste contaminante do meio ambiente é a biodegradação por bactérias selecionadas de ambientes contaminados com BFA. Neste contexto, este trabalho visou isolar bactérias degradadoras de BFA, analisar o crescimento celular das bactérias usando o BFA como fonte de carbono e quantificar a biodegradação deste composto. Foram isolados nesse trabalho 15 cepas diferentes de bactérias aeróbias do Sistema Estuarino de Santos (SES), o qual possui forte impacto antrópico pelo grande fluxo de pessoas. Além disso, o SES abriga o maior porto da América Latina (Porto de Santos) e o Polo Industrial de Cubatão. Dos micro-organismos isolados, a cepa de Shewanella sp. foi escolhida para o estudo de biodegradação, uma vez que a mesma foi capaz de tolerar até 150 mg.L- ¹ de BFA. A linhagem de Shewanella sp. isolada foi capaz de biotransformar aproximadamente 75 mg.L- ¹ de BFA em 10 horas com um µ máx de 0,123 e um Y(x/s) de 14 % em meio de cultura líquido. / The exposure to Bisphenol A (BPA) occurs frequently since this compound is a plasticizer present in many households items such as packaging and bottles. However, even the low exposure (ng.L-¹) can cause severe damage to the endocrine system and these damages are due to endocrine disruptor-activity of BPA. The hormonal receptors mistake this compound as estrogen or estriol, thus, mitigation studies to remove this contaminant from the environment are essential. One of the alternatives to remove this xenobiotic from the environment is the bioremediation by selected bacteria isolated from a BPA impacted environment. In this context, this paper aimed to isolate BPAdegrading bacteria, analyze cellular growth and biodegradation hability using BPA as a carbon source. It have been isolated fifteen different aerobic bacteria strains from the Santos Estuary System (SES), which represents one of the most important Brazilian examples of environmental degradation due to water or atmospheric pollution of industrial origin in coastal environment. In addition, SES it is home to the largest port in South America (Port of Santos) and a large industrial pole located in Cubatão. The isolated strain Shewanella halioti was chosen to this work, once is a few explored micro-organism regarding biodegradation of hydrocarbons. Shewanella halioti was able to tolerate up to 150 mg.L-¹ of BPA and biotransform 75 mg.L-¹ in 10 hours in liquid culture medium.

Chitin is known as an effective biosorbent, which is used to preconcentrate PCP for further treatment. In order to reuse and recover the biosorbent, magnetic separation is a cost-effective alternative to separate the PCP-adsorbed biosorbent (i.e. chitin) from the treated water. Therefore, chitin is immobilized by magnetite prior PCP adsorption. From the immobilization results, the solution pH, temperature, agitation rate do not show great effect on the immobilization of chitin and magnetite. Second, magnetite-immobilized chitin can be formed as quickly as 5 min. Moreover, the interaction of chitin and magnetite is very strong since it is not easy to separate by vigorous shaking, high temperature and changing pH. Although the underlying mechanism of magnetite and chitin is still obscure, the biosorbent is proved to have high stability and reusability. In addition, both Langmuir and Freundlich models indicate that immobilization of chitin by magnetite is favorable with the Langmuir model being the major one. / For PCP adsorption study, it is found that magnetite-immobilized chitin can retain the PCP adsorption ability as free chitin. In accordance with the results, the PCP adsorption of magnetite-immobilized chitin is influenced by altering the parameters of biosorbent concentration, solution pH, temperature, agitation rate, contact time and initial PCP concentration. In general, higher amount of biosorbent gives higher removal efficiency (RE) but lower removal capacity (RC) as more binding sites are available for PCP. The PCP removal is enhanced by lowering pH since uncharged PCP is favorable for adsorption. It is speculated that hydrophobic interaction, hydrogen bonding and electrostatic interaction are involved. In addition, the biosorption efficiency is impeded by high temperature. Evidence shows that the adsorption might be due to the exothermic force such as hydrogen bonding. The biosorption is described as biphasic mechanism with the fast initial phase followed by slow equilibrium phase. For the PCP (10 mg/L) adsorption, the optimized conditions are: 1,500 mg/L of magnetite-immobilized chitin, initial pH 6, 25°C, 200 rpm and 60 min. The RE is 57.9% and RC is 5.4 mg/g. However, the increase in the amount of immobilized chitin (24,000 mg/L) can increase the RE up to 98%. By considering the Langmuir and Freundlich isotherms, the adsorption might be heterogenous, as the correlation coefficient from Freundlich model is higher. / Pentachlorophenol (PCP), a highly chlorinated aromatic organic compound, was widely used as a biocide and is now restrictly used as a wood preservative. PCP is toxic and ubiquitous environmental pollutant. In the present study, integrated treatment of biosorption and photocatalytic oxidation (PCO) using magnetite-immobilized chitin is employed to completely degrade PCP. / To thoroughly remove PCP, PCO is also employed after the biosorption. One hundred % of PCP removal is achieved after 5 h irradiation time, in 100 mL solution at initial pH 9 with 20 mM of H2O2 and 200 mg/L of TiO2. The intermediates of PCP are identified as 2,3,5,6-tetrachlorohydroquinone (TeHQ) and 2,3,5,6-tetrachlorophenol (TeCP) by GC/MS analysis. In addition, the toxicity of sample is monitored by the solid-phase and aqueous-phase Microtox RTM tests, which the toxicity increases and then decreases along the irradiation time. The biosorbent shows no great changes on chitin content and functional groups after PCO. In addition, the results imply that magnetite-immobilized chitin has a good potential to be reused at least for four cycles with high RE and DE. Therefore, the combination of biosorption and PCO treatment was feasible for PCP removal and the system is economic and convenient for repeated use. / by Pang, King Man. / "Oct 2007." / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4636. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 186-212). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.