published_or_final_version / Microbiology / Master / Master of Medical Sciences

No description available.

No description available.

Nitric oxide (NO) is one of the most important air pollutants in atmosphere mainly emitted from combustion exhaust gas. In this research, a biotrickling filter was designed and operated to remove this pollutant from an air stream using bacteria extracted from the sewage sludge of a municipal sewage-treatment plant. The bacteria were cultured and enriched by either petri dish’s cultivation or liquid cultivation. The adsorption capacity of the ceramic material, which was used as the packing material, was determined to be 34 g-NO/L under 37℃. However, the saturated adsorption capacity of the packing material with the recycling solution is 236 mg-NO/L under the operation temperature 37℃.The result suggested that the microporous structure of the ceramic material not the humidity is the main contributor to the ceramic material adsorption capacity. Both the ceramic material adsorption capacity and the removal capacity of the liquid were limited and saturated in 540 min and 2 min operation, respectively. To obtain the best operation conditions for the biotrickling filter, orthogonal experiments (L9 (34)) were designed. The experimental data were analyzed by the signal to noise (S/N) ratio and ANOVA. The optimal conditions of the biotrickling filter occurred at a temperature of 40℃, a pH of 8.00.05 and a chemical oxygen demand (COD) of 165 mg/L in the recycled water with no oxygen in the system. Inlet oxygen concentration was found to be the most significant factor of the biotrickling filter that has a significant negative effect on the NO removal efficiency. The DNA sequencing of four clones of bacteria showed 93-98% similarity to Pseudomonas mendocina strain. This strain has been analysed by full gene sequencing and proved to be a brand-new strain named as Pseudomonas mendocina DLHK. This strain can transfer nitrate to organic nitrogen. This result indicated the assimilation nitrogen process in this system and suggested that the main nitrogen removal capacity in this system was through biological function. Through the isotope experimental analysis, two intermediate products (15NO and 15N2O) have been found during the biological process of the system by using quantitative gas analysis (QGA). These results indicated the denitrification function in this biotrickling filter. A model was developed to explain the biological process in the biotrickling filter. The averaged error of the measured and modeled data is -0.047. The standard deviation of the error is 0.039. The model prediction is in good agreement with the experimental data, particularly at small packing height. Most NO removal capacity was achieved at the first 5 cm packing material. The effects of the axial interstitial velocity and the biofilm coverage to the NO elimination were studied by the model that provided a basic for the design of a biotrickling filter. The biotrickling filter could be used for exhaust gases treatment. The assimilation function in the biological system could be another way to utilize the nitrogen component in the waste gas from harmful to benign nature. The isotope labeling technology is a new method to detect gas components for complex gas samples. / published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

No description available.

No description available.

Anaerobes belonging to the genera Propionibacterium, Bacteroides, Peptococcus, Peptostreptococcus, Eubacterium, Streptococcus and Lactobacillus, which are commonly isolated from the human urogenital flora, were tested for their ability to inhibit the in vitro growth of Neisseria gonorrhoeae strains. / The antigonococcal effect of the anaerobic bacterial strains tested was found not to be due to nutrient depletion and pH change of the media which had supported their growth. This inhibition was not an all-or-none phenomenon since an inhibitory strain did not necessarily interfere with all the gonococcal strains tested. / All the 23 lactobacilli strains tested were found to inhibit the in vitro growth of N. gonorrhoeae. This inhibition was found to be dependent on the composition of the culture medium. In comparison to the gonococcus (GC) and dextrose starch agar (DSA) media, a modified deMan, Rogosa et Sharpe (MRS) medium was more appropriate to support both the growth of lactobacilli and the production of their antigonococcal activity. / For the other 32 anaerobic bacterial strains tested, six were selected for their large antigonococcal spectrum of activity. These strains were Peptostreptococcus anaerobius (Pc9,Ps11B,Ps11C), Bacteroides fragilis (B1A), Bacteroides ovatus (B24) and Eubacterium limosum (Ps11A). The antigonococcal activity produced by these six strains appeared to be specific to the gonococcus since a variety of anaerobes and aerobes were not generally inhibited. / E. limosum and B. fragilis strains were further selected to evaluate the production of their antigonococcal activity in liquid medium. E. limosum Ps11A strain produced its inhibitory activity in prereduced brain heart infusion (BHI) broth during the mid-logarithmic phase of growth, when no inhibitory concentration of short-chain fatty acids was detected in the culture medium. Furthermore, when the amounts of short-chain fatty acids produced by E. limosum increased, its antigonococcal activity decreased. Based on these results and on the individual amount of short-chain fatty acids excreted by E. limosum strains, it was concluded that the observed antigonococcal activity was not due to the presence of these acids. However, B. fragilis strains excreted propionic acid in amount reported to be inhibitory to the gonococcus. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI

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Graduation date: 1950

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1985. / Bibliography: leaves 122-143. / Photocopy. / xiii, 143 leaves, bound ill. 29 cm