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Structural carbohydrate availability with electrochemical ozonation and ammonia pressurization / depressurization pre-treatment technologies
Abstract
Experiments were conducted to determine the quantity and conditions of electrochemical ozonation (O₃) that maximize the dissolution of the lignin-cellulose complex. Combination treatments of anhydrous ammonia (NH₃) and O₃ were also assessed for possible additive affects. In experiment 1, samples of rice straw (RS) were hydrated to between 13 and 75% H₂O. Samples were then subjected to O₃ for 80 min at 2 L of O₃/min. Neutral detergent fiber (NDF), hemicellulose (HC) and lignin (LG) content were reduced (p < .05) to the greatest extent at H₂O concentrations of between 34.7 and 19.9%. In experiment 2, samples of RS were processed with O₃ at 20 min intervals yielding final O₃ concentrations of 5.2, 10.4, 15.6, 20.8 and 26.0 L of O₃/g of substrate. NDF and HC contents decreased linearly with increasing O₃ concentration. Effects on lignin content however were not observed until the 10.4 L O₃ treatment point. In situ dry matter digestibility (ISDMD) was increased (p < .05) with the 10.4 - 26.0 L O₃ treatments at all in situ times. In experiment 3, samples of triticale straw (TS), rice straw (RS), wheat straw (WS) and rice hulls (RH) were processed with O₃ using treatment conditions established in experiments 1 and 2. NDF, HC and LG contents were significantly decreased (p < .01) in O₃ treated samples. ISDMD for all substrates was significantly increased (p < .05) at all in situ times. In experiment 4, samples of RS were processed with both O₃ and NH₃ in alternate combination treatments. NDF, LG and HC contents were reduced (p < .05) to the greatest extent with the O₃ / NH₃ (ONH) combination treatment. ISDMD for ONH treated RS was increased (p < .05) over both O₃ and NH₃ treatments alone at all in situ times. Results of this study suggest the following. Moisture concentrations of between 20 and 35% are most effective in catalyzing ozonation processes. The quantity of O₃ required to significantly affect LG content and enhance ISDMD was shown to be greater than 15.6 L/g. Treatment with O₃ in combination with NH₃ proved to be more effective in increasing substrate quality over either treatment alone.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 83-88).
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Citation
Williams, James Jason (1999). Structural carbohydrate availability with electrochemical ozonation and ammonia pressurization / depressurization pre-treatment technologies. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1999 -THESIS -W554.
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