As production of ethanol climbs, nonood feedstocks need to be utilized such as lignocellulosic biomass. The sugars present in bio-oil produced by fast pyrolysis can potentially be fermented by microbial organisms to produce cellulosic ethanol. This study shows the potential for microbial digestion of the aqueous fraction of bio-oil in an enrichment medium to consume glucose and produce ethanol. In addition to glucose, inhibitors such as furans and phenols are present in the bio-oil. A pure glucose enrichment medium of 20 g/L was used as a standard to compare with glucose and aqueous fraction mixtures for digestion. 30% by volume of aqueous fraction in media was the most that could be consumed and yielded 0.4 g of ethanol per g of glucose. Inhibitor removal tests by extraction, activated carbon, air stripping, and microbial means were also mildly successful. Ethanol could potentially be produced for $14 per gallon using these methods.

Objectives This study was undertaken to confirm that patient reports on buprenorphine medication-assisted therapy in for-profit buprenorphine clinics in our community were personally costly. We contacted all 17 for-profit clinics in our community and confirmed the patient reports that a significant financial payment of ≤$100 was required for each visit. We also found that tapering of buprenorphine dosage in pregnancy was offered by several of the clinics. Methods A telephone survey was conducted with the 17 for-profit buprenorphine clinics located in the Johnson City, Tennessee area. The clinic representative who answered the telephone was asked questions regarding patient costs for therapy and availability of tapering programs for pregnant women. Results Patient reports that the for-profit clinics are costly were confirmed. None of the clinics accepted insurance reimbursement of any type. The most common weekly costs were $100 per visit. A majority of clinics offered biweekly or monthly visits at significantly increased rates. Clinic representatives stated that a majority of clinics would consider buprenorphine tapering programs for pregnant women. Conclusions The high cost of for-profit clinics is a barrier for patient access to medication-assisted therapy with buprenorphine. Tapering of buprenorphine dosage in pregnant women has penetrated buprenorphine management practice in our community. Further research is needed to determine whether elimination of cost barrier would have a positive effect on the rates of neonatal abstinence syndrome.

No description available.

published_or_final_version / abstract / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

The cytochrome P-450 dependent monooxygenase system plays a key role in the bioactivation and detoxication of xenobiotics. Isozyme-specific inhibitors of cytochrome P-450 may be useful in elucidating the role of particular isozymes in xenobiotic metabolism or in suppressing the bioactivation of xenobiotics and enhancing detoxication. The antibiotic chloramphenicol is a selective mechanism-based inactivator of rat liver cytochromes P-450, inactivating 6 of the 12 isozymes monitored, including the major phenobarbital-inducible isozyme PB-B. Analogs of chloramphenicol have been tested to determine the importance of various functional groups in regulating the effectiveness and isozyme selectivity of chloramphenicol as a mechanism-based inactivator of cytochromes P-450. This information will aid in the design of more effective and isozyme specific mechanism-based inactivators. The dihalomethyl group and the propanediol moiety were found to be important in determining the efficacy of inactivation and the ability to inactivate the enzyme by virtue of the modification of the protein as opposed to the modification of the heme moiety. The propanediol side chain also plays a role in the isozyme selectivity. Unlike chloramphenicol, N (2-p-nitrophenethyl)dichloroacetamide (pNO₂DCA), which contains an ethyl group in place of the propanediol side chain of chloramphenicol, is an effective inactivator of BNF-B, the major beta-naphthoflavone-inducible isozyme, as well as PB-B, in vitro and in vivo. Alkaline hydrolysis and enzymatic digestion of the covalently modified isozymes has shown that chloramphenicol and pNO₂DCA are both metabolized by cytochromes P-450 to oxamyl chlorides which bind to lysine and other amino acid residues of the enzyme. However, the mechanism by which pNO₂DCA inactivates BNF-B differs significantly from that by which chloramphenicol inactivates PB-B, although both involve an impairment of the transfer of electrons from NADPH-cytochrome P-450 reductase, suggesting that there are differences in the active sites of these two isozymes.

Experiments were conducted to examine the cause of lag-phase growth during phenol degradation by mixed microbial cultures that had been acclimated to one of four substrates. Four aerated Imhoff cones were inoculated with wastewater sludge and fed one of four substrates: acetate, egg albumin, vegetable oil, or phenol. Inocula from these cones were injected into batch reactors containing phenol. Time-dependent growth was measured by two methods: most probable number (MPN) and epifluorescence microscopy (EM). The MPN technique was used to distinguish two cell concentrations: total cells and a phenol-degrading community within the total; EM was also used to count total cells. The results indicated that a lag in phenol utilization for all cultures, except the phenol-acclimated cultures, was a result of growth of a phenol-degrading subpopulation, and not due to enzyme induction of the existing population. Similar experiments were conducted using 2,4-dichlorophenol (2,4-DCP), which resulted in no growth and no degradation of 2,4-DCP.

Background: Relatively little is known about the genomic basis and evolution of wood- feeding in beetles. We undertook genome sequencing and annotation, gene expression assays, studies of plant cell wall degrading enzymes, and other functional and comparative studies of the Asian longhorned beetle, Anoplophora glabripennis, a globally significant invasive species capable of inflicting severe feeding damage on many important tree species. Complementary studies of genes encoding enzymes involved in digestion of woody plant tissues or detoxification of plant allelochemicals were undertaken with the genomes of 14 additional insects, including the newly sequenced emerald ash borer and bull-headed dung beetle. Results: The Asian longhorned beetle genome encodes a uniquely diverse arsenal of enzymes that can degrade the main polysaccharide networks in plant cell walls, detoxify plant allelochemicals, and otherwise facilitate feeding on woody plants. It has the metabolic plasticity needed to feed on diverse plant species, contributing to its highly invasive nature. Large expansions of chemosensory genes involved in the reception of pheromones and plant kairomones are consistent with the complexity of chemical cues it uses to find host plants and mates. Conclusions: Amplification and functional divergence of genes associated with specialized feeding on plants, including genes originally obtained via horizontal gene transfer from fungi and bacteria, contributed to the addition, expansion, and enhancement of the metabolic repertoire of the Asian longhorned beetle, certain other phytophagous beetles, and to a lesser degree, other phytophagous insects. Our results thus begin to establish a genomic basis for the evolutionary success of beetles on plants.

Nitrite (NO2-) substrate under certain conditions can cause failure of N-removal processes relying on anaerobic ammonium oxidizing (anammox) bacteria. Detoxification of NO2- can potentially be achieved by using exogenous nitrate (NO3-). In this work, continuous experiments in bioreactors with anammox bacteria closely related to “Candidatus Brocadia caroliniensis” were conducted to evaluate the effectiveness of short NO3- additions to reverse NO2- toxicity. The results show that a timely NO3- addition immediately after a NO2- stress event completely reversed the NO2- inhibition. This reversal occurs without NO3- being metabolized as evidence by lack of any 30N2 formation from 15N-NO3-. The maximum recovery rate was observed with 5 mM NO3- added for 3 days; however, slower but significant recovery was also observed with 5 mM NO3- for 1 day or 2 mM NO3- for 3 days. Without NO3- addition, long-term NO2- inhibition of anammox biomass resulted in irreversible damage of the cells. These results suggest that a short duration dose of NO3- to an anammox bioreactor can rapidly restore the activity of NO2--stressed anammox cells. On the basis of the results, a hypothesis about the detoxification mechanism related to narK genes in anammox bacteria is proposed and discussed.

A fermentação de hidrolisados hemicelulósicos tem como principal dificuldade a presença de compostos inibidores ao metabolismo microbiano, derivados da degradação parcial da lignina, degradação dos açúcares e liberação de radicais acetil durante a etapa de hidrólise dos materiais lignocelulósicos. O presente trabalho teve por objetivo avaliar a influência de diferentes tratamentos de destoxificação sobre a composição e fermentabilidade do hidrolisado hemicelulósico de bagaço de cana-de-açúcar na produção de etanol e xilitol. Foram avaliados os seguintes tratamentos: a) alteração de pH com óxido de cálcio e ácido fosfórico seguido de adsorção com carvão ativo; b) utilização de resinas de troca iônica (A-860, A-500PS e C-150 - Amberlite); e c) extração líquido-líquido com interface imobilizada em membrana de fibra oca (Membrana, Charlote, NC - USA), na qual a fase orgânica foi uma mistura de octanol e Alamina 336 e a fase aquosa foi o próprio hidrolisado. De acordo com os resultados, os tratamentos aplicados (a, b e c) promoveram uma redução na concentração de ácido acético de 46,74%, 64,15% e 44,71% e uma redução na absorbância relativa (A.R.) de 82,0%, 94,59% e 46,07%, respectivamente. Na fermentação dos hidrolisados tratados, pela levedura Candida guilliermondii FTI 20037, após 48h de fermentação, os resultados para o fator de rendimento foram de 0,57g/g, 0,42g/g e 0,33 g/g após os tratamentos a, b e c, respectivamente. Quanto à produtividade volumétrica, na mesma ordem dos tratamentos foram obtidos os seguintes resultados: 0,39 g.L-1.h-1, 0,20 g.L-1.h-1 e 0,16 g.L-1.h-1. Nas fermentações dos hidrolisados tratados (a) e (b) pela levedura Pichia stipitis IMH 43.2, visando a produção de etanol, após 48h os resultados do fator de rendimento foram 0,38 g/g e 0,23 g/g, respectivamente, enquanto a produtividade volumétrica foi de 0,09 g.L-1.h-1 para o tratamento (a) e para o tratamento (b). Para o tratamento (c) não se observou a produção de etanol nas condições de fermentação utilizadas. Considerando os resultados obtidos, sugere-se que, para as condições experimentais empregadas, o hidrolisado seja tratado por alteração de pH seguido de tratamento com carvão ativado, uma vez que este tratamento resultou nos melhores resultados para o fator de rendimento tanto na produção de xilitol quanto na produção de etanol. / The fermentation of hemicellulosic hydrolysates has as main difficult the presence of compounds derived from partial degradation of lignin, sugars and release of acetyl groups, which are inhibitors of microbial metabolism, during the hydrolysis process of lignocellulosic materials. This study aimed to evaluate the influence of different detoxification treatments on the composition and fermentability of the sugarcane bagasse hemicellulosic hydrolyzate in the production of xylitol and ethanol. The following treatments were evaluated: a) change of pH with calcium oxide and phosphoric acid followed by adsorption with activated charcoal, b) use of ion exchange resins (A-860, A-500 PS and C-150 - Amberlite) and c) liquid-liquid extraction with immobilized interface in hollow-fiber membrane (Membrana, Charlote, NC - USA), in which the organic phase was a mixture of octanol and Alamine 336, and the aqueous phase was the hydrolyzate. According to the results, the employed treatments (a, b and c) promoted a reduction of 46.74%, 64.15% and 44.71% in the acetic acid concentration, and a reduction in the relative absorbance (RA) of 82.0%, 94,59% and 46.07% respectively. In the fermentation of the treated hydrolyzates by the Candida guilliermondii FTI 20037 yeast, aiming xylitol production, after 48h of fermentation, the results for xylitol yield were 0.57g/g, 0.42g/g and 0.33g/g, after the treatments a), b) and c), respectively. The volumetric productivity obtained was 0,39 g.L-1.h-1, 0,20 g.L-1.h-1 and 0,16 g.L-1.h-1, in the same order of treatments. In fermentation by Pichia stipitis IMH 43.2 of the hydrolyzates that used treatments (a) and (b), aiming the production of ethanol, after 48h, the results for yield were 0.38g/g and 0.23g/g, respectively, while the volumetric productivity was 0,09 g.L-1.h-1 for both treatments. For treatment (c) there was no ethanol production using the fermentation conditions applied in this work. Considering these results, it is suggested that for the experimental conditions used at this work, the hydrolyzate should be treated by pH change followed by treatment with activated charcoal, since this treatment resulted in better results of yield in the production of xylitol and ethanol.