Thesis (Ph. D.)--Columbia University, 1925. / Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. [46].

Thesis (M. Sc.)--Carleton University, 1988. / Also available in electronic format on the Internet.

Thesis (Ph. D.)--Ohio state University, 1927. / Autobiography.

Inulin hydrolysis can occur as a result of the action of exoinulinases and endoinulinases acting alone or synergistically. Exoinulinases cleave the non-reducing β-(2, I) end of inulin releasing fructose while endoinulinases act on the internal linkages randomly to release inulotrioses (F₃), inulotetraoses (F₄) and inulopentaoses (F₅) as major products. Fructosyltransferases act by cleaving a sucrose molecule and then transferring the liberated fructose molecule to an acceptor molecule such as sucrose or another oligosaccharide to elongate the short chain fructooligosaccharide. The production of high yields of oligosaccharides of specific chain length from simple raw materials such as inulin and sucrose is a challenge. Oligosaccharides of chain length up to degree of polymerisation (DP) 5 and fructose were produced using preparations of three commercial microbial enzymes. Production of these novel oligosaccharides was achieved by employing response surface methodology (RSM) with central composite experimental design (CCD) for optimising product yield. Using a crude Novozyme 960 endoinulinase preparation isolated from Aspergillus niger, the following conditions gave a high inulooligosaccharide (lOS) yield, temperature (60 ºC), 150 g/L inulin concentration, 48 h incubation; pH 6.0 and enzyme dosage of 60 U/ml. Under these conditions, inulotrioses (70.3 mM), inulotetraoses (38.8 mM), and inulopentaoses, (3.5 mM) were produced. Response surface regression predicted similar product levels under similar conditions. The crude endoinulinase was purified through a three step purification procedure with a yield of 1.11 % and 3.5 fold purification. The molecular weight of this endoinulinase was estimated to be 68 .1 kDa by SDS-PAGE and its endoinulinase nature was confirmed by native PAGE. The purified endoinulinase was more efficient in production of lOS than the crude endoinulinase preparation. The purified endoinulinase demonstrated a high affinity for the inulin substrate (Km[subscript] 3.53 mM, Vmax[subscript] 666.67 μmol/min/ml). Pectinex Ultra SP-L, a commercial crude enzyme preparation isolated from Aspergillus aculeatus is a cocktail of several enzymes including a fructosyltransferase. The crude enzyme showed both transfructosylation and hydrolytic activity in 200 to 600 g/L sucrose. The main fructooligosaccharides produced from sucrose were l-kestose (GF₂), nystose (GF₃) and fructofuranosyl nystose (GF₄). After the first RSM, with the coded independent variables of temperature, incubation time, pH and sucrose concentration, the highest levels of GF₂, was 68.61 mM, under sucrose concentration 600 g/L, temperature 60°C, enzyme dosage 20 U/ml , pH 5.6, after 4 h incubation. A sucrose concentration of 400 g/L favoured the synthesis of high levels of GF₃ and GF₄. In the second RSM the maximal yields of GF₂, GF₃ and GF₄ were 152.07 mM, 131.38 mM and 43.99 mM respectively. A purified fructosyltransferase did not synthesise GF₄. Ammonium ions were demonstrated to enhance the yield of FOS. A mixture of glucose and fructose was used as substrate for FOS synthesis and no FOS were formed. Glucose was shown to be an end product inhibitor of the fructosyltransferase and therefore hinders the formation of high FOS yield. Fructozyme, isolated from Aspergillus ficuum is a mixture of exo and endoinulinases with the former being predominant was used for fructose production from inulin hydrolysis. The exoinulinase was purified to electrophoretic homogeneity by a three step purification procedure. The molecular weight of the enzyme was estimated to be 53 kDa with a 2 I % yield and 4.2-fold. Response surface regression was used to predict the maximum fructose levels achievable under the combinations of temperature, enzyme dosage and incubation time. A reaction time (48 h), enzyme dosage (100 U/ml) and inulin concentration (150 g/l) at pH 5.0 at 50°C gave higher fructose levels (106.6 mg/ml) using crude exoinulinase as compared to 98.43 mg/ml using the purified exoinulinase. These findings indicate that higher levels of fructose require longer incubation periods and higher inulin substrate concentrations with higher enzyme dosage. The crude exoinulinase preparation gave fairly higher levels of fructose than the purified exoinulinase and this is due to the presence of other hydrolytic enzymes in the crude preparation. The conditions established by RSM and CCO were adequate in producing high yield of oligosaccharides and fructose and can therefore be applied for their industrial production since they are in high demand due to their health benefits as prebiotics.

Creeping bentgrass (Agrostis stolonifera) used on golf course putting greens are some of the most intensively managed areas of turf and are subjected to high stress. Heat stress results in lowered photosynthetic efficiency and inadequate sugar production. An exogenous application of fructose could compensate for the lack of sugar being produced. The objectives of this research were to determine the effect of exogenous applications of fructose on heat stressed creeping bentgrass. Field results showed some phytotoxicity with high rates of fructose, while lower rates showed no visible damage compared to an untreated control. Low rates of surfactant resulted in little phytotoxicity, while high surfactant rates showed damage. Fructose had no positive effect on turf quality. A surfactant study was then designed to measure the effect of various surfactants on fructose uptake. This study revealed that as hydrophilic to lipophilic balance increased, absorption of fructose increased.

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A low, but significant, fraction of the carbohydrate portion of herbaceous biomass may be composed of fructose/fructosyl-containing components (“fructose equivalents”); such carbohydrates include sucrose, fructo-oligosaccharides, and fructans. Standard methods used for the quantification of structural-carbohydrate-derived neutral monosaccharide-equivalents in biomass are not particularly well suited for the quantification of fructose equivalents due to the inherent instability of fructose in conditions commonly used for hemicellulose/cellulose hydrolysis (> 80% degradation of fructose standards treated at 4% sulfuric acid, 121oC, 1 hr). Alternative time, temperature and acid concentration combinations for fructan hydrolysis were considered using model fructans (inulin, β-2,1 and levan, β-2,6) and a grass seed straw (Tall Fescue, Festuca arundinacea) as representative feedstocks. The instability of fructose, relative to glucose and xylose, at higher acid/temperature combinations is demonstrated, all rates of fructose degradation being acid and temperature dependent. Fructans are shown to be completely hydrolyzed at acid concentrations well below that used for the structural carbohydrates, as low as 0.2%, at 121oC for 1 hr. Lower temperatures are also shown to be effective, with corresponding adjustments in acid concentration and time. Thus, fructans can be effectively hydrolyzed under conditions where fructose degradation is maintained below 10%. Hydrolysis of the β-2,1 fructans at temperatures ≥ 50oC, at all conditions consistent with complete hydrolysis, appear to generate difructose dianhydrides. These same compounds were not detected upon hydrolysis of levan, sucrose, or straw components. It is suggested that fructan hydrolysis conditions be chosen such that hydrolysis goes to completion, fructose degradation is minimized, and difructose dianhydride production is accounted for. / Graduation date: 2009

Excessive fructose consumption in Western diets correlates with increases in obesity, insulin resistance, kidney disease, and non-alcoholic fatty liver disease (NAFLD), collectively part of metabolic syndrome (MBS). Liver and kidneys metabolize 50-70% of ingested fructose, but the fate of remaining fructose remains poorly understood. Moreover, the correlation of fructose ingestion with MBS highlights the need for better understanding of whole-body fructose metabolism, in both health and disease. To that end, valid rodent models for fructose metabolism must reflect the same metabolism in humans. A serious autosomal recessive defect in fructose metabolism, called hereditary fructose intolerance (HFI), is caused by mutations in the aldolase B gene (ALDOB, human; Aldo2, mouse). With low levels of fructose exposure, HFI patients develop NAFLD and liver fibrosis, sharing pathologies with MBS. Targeting Aldo2 for deletion in mice (Aldo2-/-) provides a major step in validating that fructose metabolism in mice mimics that in humans. Like HFI patients, Aldo2-/- mice exposed to chronic, low-level dietary fructose show failure to thrive, liver dysfunction, and potential mortality. The fructose-induced symptoms of HFI and MBS result from flux through the ketohexokinase (KHK)-mediated pathway, and the metabolite Fru 1-P. Bioinformatic analysis reveals gene expression for this pathway is highest in liver, as expected; surprisingly, brain is predicted to have expression levels similar to kidney. This predicted gene expression is validated via RNA in situ hybridization, quantification of enzyme activities, presence of transport proteins, and measuring fructose oxidation rates in adult mice brains. Within the brain, regions of the cerebellum, hippocampus, cortex, and olfactory bulb show the highest population of cells expressing Fru-1-P pathway genes. In these regions, enzyme activities for both KHK and aldolase, and rates of fructolytic flux, are many times that seen in liver slices. Additionally, brains of mice on a high fructose diet show a three-fold increase in KHK activity. This suggests that not only are these regions of the brain capable of metabolizing fructose, but that they are also capable of responding to increases in dietary fructose. This work provides a foundation for research of long-term consequences of excessive fructose consumption in multiple organs. / 2017-06-21T00:00:00Z