The tannin extract industry disposes of large volumes of condensate liquors evolved during concentration of weak leach liquors obtained by extraction of wood chips. The liquors are highly corrosive due to acetic acid contained therein along with lesser quantities of other organic substances common to woody materials. Recovery of the acetic acid would be desirable from two standpoints: (1) the value of the acetic acid, and (2) reuse of the acid-free condensate in the manufacturing process. The purpose of this investigation was to recover acetic acid from the wastes of tannin extract manufacture. An ion exchange process was given primary consideration to accomplish the recovery by adsorption of the acetic acid from the waste liquor with subsequent elution of the acid from the ion exchange material by use of stronger acid. Tests were conducted using De-Acidite, a synthetic aliphatic amine anion exchange resin produced by the Permutit Company, New York, N.Y.. For all tests 200 ml. of resin were used at temperatures within 20-30°C. A total acid-binding capacity of 19,700 grains CaCO₃/ft.³ was found when De-Acidite was exposed to 0.5 percent acetic acid in batch operation. Optimum rate of flow determinations in column operation within the range of 1 to 5 gal./ft.²/min. were conducted. Variations of flow rates between these limits failed to produce substantial differences in breakthrough capacities. To prepare the De-Acidite bed in the ion exchange column between runs regeneration was effected with 1 percent sodium hydroxide. Rinse was by downflow operation until data was obtained which indicated its unsuitability; thereafter backwash rinse was used and found more satisfactory. The waste liquor used in the investigation was obtained from the 2nd and 3rd effects of a triple effect evaporator employed in the Mead Corporation Plant at Lynchburg, Virginia. Successive exposures of De-Acidite to the waste liquor resulted in sharp reduction of breakthrough capacity, discoloration of the De-Acidite, and deterioration of the resin with the formation of fines. It was found that the extremely small quantities of tannin present in the waste liquor were the cause of the rapid depreciation of the De-Acidite. / M.S.

Liquid extraction is a means of separating two or more components of a solution. The process involves mixing the solution with an immiscible solvent, separating the two phases, and recovery of the desired materials and of solvent from the solvent phase, usually by distillation. Separation is accomplished if certain of the solution components are more soluble in the extracting solvent employed than in the feed solution. Liquid extraction is used to concentrate aqueous solutions of acetic acid produced in the esterification of cellulose and in other manufacturing processes because acetic acid and water are not easily separated by direct rectification. Liquid extraction of acetic acid must always be followed by solvent-recovery systems. Then the selection of solvents suitable for extraction of acetic acid must be based not only on the relative affinity of the solvents for acetic acid but also on consideration of heat and other energy requirements of the extraction and solvent recovery systems. The purpose of this investigation was to develop a method of evaluating solvent extraction systems for the recovery of acetic acid from aqueous liquors, by comparisons of selected solvent systems on the basis of: (a) theoretical transfer units required for extraction, (b) in the case of solvents boiling below 100 °C, theoretical plates required for distillation of extracts, and (c) heat required for recovery of pure acetic acid and of solvent. / Master of Science

Zymomonas mobilis is one of the most promising microorganisms for bioethanol production. However, its practical use on industrial scale is impeded by its high sensitivity to acetate, which is present in high concentration in pretreated biomass. This research develops an adaptive mutation method for generating acetate-tolerant strains for bioethanol production. The goal is to obtain Zymomonas mobilis strain capable of growing and producing ethanol in the presence of acetate at a concentration typical of a pretreated biomass (2-3%). The interplay between the ability of fermentative production of ethanol and acetate tolerance will be investigated through careful fermentation studies. The potential cross-tolerance to other inhibitors, commonly present in pretreated biomass will be evaluated. A preliminary study on the mechanism of acetate tolerance at the cell membrane level will be conducted. The strain developed through this research will be useful in bioethanol production from biomass. The insights into tolerance mechanisms gained through this study will allow a more rational approach to further engineer a better producing strain.

published_or_final_version / Medicine / Master / Master of Philosophy

No description available.

The purpose of this study was to determine the endogenous levels of indole-3-acetic acid throughout the life cycle of Chlorella pyrenoidosa, and to show a correlation between onset of cell division and IAA levels.

It was the purpose of this study to investigate the effect of various concentrations of IAA on the nucleic acids of Chlorella pyrenoidosa TX 7-11-05. The time during the life cycle when the greatest effect occurred was investigated by the use of synchronous cultures.

Fungal infections are caused by a variety of fungi, and with a variety of clinical manifestations. Antifungal treatments are limited due to host toxicity and fungi gaining resistance. By utilizing the model organism Saccharomyces cerevisiae, we hope to elucidate the molecular mechanisms of fungal pathogenesis that we can then validate in the human pathogen Candida albicans, as well as explore options for novel therapies. Small molecule signaling is a method by which single-cell organisms can communicate with one another, enabling them to coordinate gene expression. This is a useful tool because it allows microbes to turn on phenotypes that are only valuable when done in large numbers, such as bioluminescence, or virulence traits. We have previously shown that the yeast Saccharomyces cerevisiae synthesizes the secondary metabolite indole-3-acetic acid (IAA) from tryptophan. IAA is secreted into the environment, where it acts as a signal. At low concentrations, the IAA signals yeast to induce virulence traits, while at high concentrations, it is lethal. The purpose of this thesis was to investigate the molecular mechanism of IAA (plant hormone auxin) regulation in fungi, specifically, Saccharomyces cerevisiae and the human pathogen Candida albicans. Towards this end, I first focused my efforts on evaluating the role of S. cerevisiae Grr1, as a putative IAA receptor. By evaluating the IAA response of several Grr1 mutants, I was able to show that the leucine-rich repeat region, while not required for function, likely plays a significant role in maintaining the structural integrity of the protein. Next, I evaluated IAA associated phenotypes, such as filamentation, surface adhesion and IAA uptake of the grr1 null mutant in the human pathogen Candida albicans. Together, these data support the hypothesis that GRR1 regulates IAA response, probably by regulating the IAA uptake carriers.

The work described in this thesis is in three parts:. Part I deals with the metabolism of 5-p-aminobenzene-sulphonamide- 3-methylisothiazole (sulphasomizole), 5-amino-3--methylisothiazole, sulphanilamide, and some of the acetyl derivatives. A marked species difference has been found in the metabolism of sulphasomizole.

The effects of polyamines, indole-3-acetic acid ( IAA ) and gibberellic acid ( GA3 ) on root elongation in radish ( Raphanus sativus L. cv. Luh Chin ) were studied. Incubation of radish seedlings in spermine or spermidine at 0.01 mM for 1hour, and then transferred to deionized water for 24 hours at 25¢J in the dark promoted root elongation as compared with concentration at 0.1 or 2 mM. When roots were treated with spermine or spermidine at 1 mM for 5 minutes, and then transferred to deionized water for 24 hours, root length increased significantly compared with controls. However, root length reduced gradually with increasing treatment times. Putrescine did not affect root elongation when treated in the same manner as spermine or spermidine. Exogenous spermidine synthesis inhibitor ( cyclohexylamine ) at 0.01, 0.1, 1 or 2 mM to the roots inhibited root elongation. The inhibition of root elongation was parallel to cyclohexylamine doses. Root length increased when spermine at 1 mM plus IAA at 10¡Â¹ ¡Ñ 6 nM was applied for 1 hour, and then transferred to deionized water for 24 hours compared with spermine at 1 mM plus IAA 10¡Â² or 1¡Ñ 6 nM. Root length was longer when treated with spermidine at 1 mM plus IAA at 10¡Â²¡Ñ 6 nM than at 10¡Â¹ or 1¡Ñ 6 nM. Root treated with spermine at 1 mM plus GA3 at 10¡Â²¡Ñ3 £gM Resulted in a longer root than treated with spermine at 1 mM plus GA3 at 10¡Â¹ or 1¡Ñ 3 £gM. Roots treated with spermidine at 1 mM plus GA3 at 10¡Â²¡Ñ3 £gM promoted root elongation. However, any treatments of spermine or spermidine in combination with IAA or GA3 significantly reduced the root length when compared with controls. Furthermore, either IAA or GA3 could not restore the inhibitory effects of root elongation caused by spermine or spermidine treatment at 1 mM for 1 hour and then transferred to deionized water for 24 hours. Endogenous spermidine and spermine contents after exogenous spermine plus GA3 treatment increased by increasing GA3 concentrations. But endogenous spermidine and spermine contents was the least in spermine 1 mM plus IAA 10¡Â¹ ¡Ñ 6 nM treatment. However, endogenous spermidine contents after exogenous spermidine plus IAA or GA3 application reduced significantly when compared with controls. But there is no significant difference of spermidine content between different exogenous IAA doses. In contrast, spermidine content maintained at a high level in spermidine at 1 mM plus GA3 at 10¡Â²¡Ñ3 £gM as compared with other spermidine plus GA3 combinations. However, endogenous spermine contents were not affected by exogenous spermidine plus IAA or GA3.