Conversion of bagasse and corn stover to mixed carboxylic acids using a mixed culture of mesophilic microorganisms /
This dissertation describes the operation of batch and countercurrent fermentations to anaerobically convert bagasse and corn stover to mixed carboxylic acids using a mixed culture of mesophilic microorganisms. The bagasse and corn stover, energy sources, were supplemented with chicken manure and p...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2003.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=726458361&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | This dissertation describes the operation of batch and countercurrent fermentations to anaerobically convert bagasse and corn stover to mixed carboxylic acids using a mixed culture of mesophilic microorganisms. The bagasse and corn stover, energy sources, were supplemented with chicken manure and pig manure, respectively, as nutrient sources. Biomass was treated with lime to increase digestibility before entering the fermentors. Continuum Particle Distribution Modeling (CPDM) was used to simulate continuous fermentors based on data collected from batch experiments. This model saves considerable time in determining optimum operating conditions. In the batch studies, the optimum combination of bagasse/chicken manure and corn stover/pig manure fermentation was 80/20. Subsequent studies revealed that the addition of urea and nutrients to the system also resulted in higher conversion and total acid produced. For corn stover/pig manure batch fermentation with sonication treatment, the optimum condition was power of 60 for 15 min (Fisher sonic dismembrator Model 300). The highest acid productivity for the bagasse/chicken manure countercurrent fermentation was 2.5 g/(L· d) with the highest acid selectivity (0.581 g acid/g VS digested) and highest yield (0.338 g acid/g VS fed). For the corn stover/pig manure countercurrent fermentation, the highest acid productivity was 1.81 g/(L· d). The highest acid selectivity and yield were 0.714 g acid/g VS digested and 0.550 g acid/g VS fed, respectively. CPDM for bagasse/chicken manure fermentation systems predicted the total acid concentration and conversion within 20.1% and 24.1%, respectively, of experimental results. CPDM for corn stover/pig manure fermentation systems predicted the total acid concentration and conversion within 13.4% and 11.6%, respectively, of experimental results. Regarding, the transfer procedure for both systems, the single-centrifuge transfer procedure is more time efficient than the double-centrifuge transfer procedure. To increase the acid productivity, yield, selectivity, and conversion, additional lime and sonication treatment between Fermentors 3 and 4 was beneficial. Also, air and lime pretreatment was found to be the most effective pretreatment method. Comparing between terrestrial and marine inocula, the acid productivity, selectivity, and yield in fermentation trains with marine inoculum were higher than fermentation trains with solely terrestrial inoculum for bagasse/chicken manure fermentation. |
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| Item Description: | Vita. "Major Subject: Chemical Engineering". |
| Physical Description: | xx, 321 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 169-171). |