Browsing by Subject "Ethanol."
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Item Chemometric modeling of UV-visible and LC-UV data for prediction of hydrolysate fermentability and identification of inhibitory degradation products.(2011-12-19) Hedayatifar, Negar.; Chambliss, C. Kevin.; Chemistry and Biochemistry.; Baylor University. Dept. of Chemistry and Biochemistry.Production of ethanol from lignocellulosic biomass requires a pretreatment step to liberate fermentable sugars trapped within the plant. During pretreatment, lignin and some sugars undergo degradation to form compounds which have shown inhibitory effects to fermentative microorganisms. Accordingly, development of a rapid and accurate method for assessment of microbial inhibition and identification of inhibitory compounds is essential for gaining a better understanding of pretreatment and its downstream effects on fermentation processes. Traditional methods for identification of inhibitory compounds involve a “bottom-up” approach. Using this approach, one or more known degradation compounds are added to fermentation media and their effects on batch fermentation of ethanol are observed. These methods are extremely time-consuming and labor-intensive which makes them unattractive to researchers. Furthermore, they are carried out on degradation compounds that have already been identified. Given that biomass hydrolysates contain many unidentified constituents, identification of inhibitory compounds by traditional means is unlikely to occur on a timescale that is consistent with current mandates for commercial production of cellulosic ethanol. To address these limitations, we have developed a chemometric model that correlates ultraviolet (UV)-visible spectroscopic data of 21 different biomass hydrolysates with their fermentability (percent inhibition of ethanol production). This novel approach enables rapid prediction of hydrolysate fermentability using UV-visible spectroscopic data alone and offers significant improvements in throughput and labor when compared to traditional batch fermentation methods. The model was subsequently used to predict percent inhibition for five hydrolysate samples, with a root-mean-square error of prediction of 6%. To evaluate the use of chemometric modeling for identification of inhibitory compounds in biomass hydrolysate, a second model was developed to correlate HPLC-UV chromatographic data of the 21 hydrolysates with their percent inhibition. Detection was monitored at four specific wavelengths identified by the UV-visible model as significant spectral regions. Once constructed, the HPLC-UV model was used to identify retention times that had the highest correlation with inhibition. To determine whether better resolution or more universal detectability of sample constituents may lead to identification of additional retention times, a third chemometric model was developed with chromatographic data of hydrolysates obtained via ion chromatography with conductivity detection.Item Taurine : a novel approach to reducing the reinforcing properties of ethanol in adolescents.(2011-05-12T15:36:53Z) Helfand, Rebecca S.; Diaz-Granados, Jaime L.; Psychology and Neuroscience.; Baylor University. Dept. of Psychology and Neuroscience.Adolescent ethanol use continues to be a societal problem with ethanol drinking beginning as early as 11 years old. Early initiation of drinking behavior is indicative of an increased risk for future substance abuse problems. This may stem from ethanol-induced changes in the brain that could potentially increase the rewarding properties of ethanol, making a person more likely to drink in the future. The neuroprotective amino acid taurine may attenuate ethanol-induced changes in the brain, potentially reducing the reinforcing properties of ethanol. In this study, three experiments were conducted using behavioral tests and tissue analysis to investigate the effects of taurine treatment on ethanol self-administration in C57BL/6J mice. Experiment 1 measured ethanol consumption in adolescent mice with the two-bottle choice test resulting in reduced ethanol preference, but not consumption. Experiment 2 utilized the drinking in the dark protocol, in adolescents, revealing a 20% decrease in ethanol intake in the taurine-treated group. This effect was ethanol specific, as consumption of a sucrose solution was not similarly decreased by taurine treatment. Upon completion of drinking in the dark testing, two tissues within the mesolimbic dopamine system, the VTA and NAc, were extracted and analyzed for amino acid and dopamine content. Amino acid analysis revealed that taurine treatment effectively increased taurine concentrations in both the VTA and NAc. Dopamine turnover in the NAc of the taurine-treated/ethanol exposed group was significantly lower than their water-treated counterparts. Turnover of dopamine in the NAc increases in response to reinforcing stimuli. A reduction in turnover therefore indicates a decrease in the reward associated with ethanol consumption. The reduction in ethanol consumption, in the taurine-treated group, can therefore be explained, at least in part, by the decrease in dopamine turnover in the NAc. Experiment 3 investigated the efficacy of taurine treatment in adults using the drinking in the dark procedure. Treatment did not significantly change ethanol intake, revealing the effect to be adolescent specific. Given the efficacy of taurine treatment in reducing ethanol consumption in an adolescent population, it may be a potential new direction for the investigation into therapeutic mechanisms to reduce drinking behavior.