Thesis
In situ extraction of biomass-derived lactic acid using sustainable technologies to enhance stable ruminal mixed culture
Washington State University
Master of Science (MS), Washington State University
2014
Handle:
https://hdl.handle.net/2376/105468
Abstract
Due to its functionality, lactic acid shows promise as a platform molecule for the production of fuels and chemicals from lignocellulosic biomasses to reduce petroleum dependence. However, product inhibition and purification costs associated with the typically-used biological production process reduce applicability for a bio refinery. During this work, these issues were remedied through implementation of a stable mixed ruminal culture capable of converting lignocellulosic sugars to lactic acid in non-sterile environments, followed by use of sustainable in situ extraction methods to reduce repressive effects from product accumulation. Fermentation studies showed pH 5.5 and 50° C to be optimal conditions for production of lactic acid from glucose, with high product yield (>90%) and minimal co-product generation. However, product inhibition decreased fermentation performance at concentrations higher than 20 g/L. Through literature review, carbon dioxide solvent extraction, and weak base ion exchange resin sorption were selected as plausible extractive fermentation methods to minimize inhibitory effects. Carbon dioxide, upon preliminary studies, showed minimal extraction efficiency for lactic acid, with a substantially higher capacity for acetic acid. Weak base ion exchange resin used in an extractive fermentation setup increased fed-batch culture productivity by 33%, and was shown to be stable over 100 days during fed-batch fermentation of real corn stover hydrolysate.
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Details
- Title
- In situ extraction of biomass-derived lactic acid using sustainable technologies to enhance stable ruminal mixed culture
- Creators
- Benjamin Garrett
- Contributors
- Birgitte K. Ahring (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525272701842
- Language
- English
- Resource Type
- Thesis