Thesis
Lipid production from xylose and inhibitory effects from lignocellulose hydrolysate using Mortierella isabellina
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/101041
Abstract
Microbial lipids from lignocellulosic biomass can be used as a source for advanced biofuel production. Efficient utilization of mixed sugars from lignocellulose is required for economical biofuel production. The oleaginous fungus Mortierella isabellina has been studied to produce lipid from cellulosic sugar. However, lipid yield from xylose by this strain was much lower than that from glucose. To address this problem, parameters including nitrogen source, xylose concentration, inoculum level and nitrogen concentration were evaluated for maximum cell growth and lipid production. Yeast extract and ammonium sulfate were found to be the best organic and inorganic nitrogen sources tested. Subsequent combination of these two nitrogen sources at a nitrogen ratio of 1:1 (mol mol-1) further enhanced lipid production. The highest cell biomass 28.8 g L-1 and lipid 18.5 g L-1 were obtained on a medium containing 100 g L-1 xylose and 50.4 mM nitrogen at a spore concentration of 108 mL-1. Specifically, nitrogen concentration and inoculum level were demonstrated to be important to obtain a high lipid yield on xylose consumed of 0.182 g g-1. In addition, the inhibitory effects to lipid production were evaluated through testing lignocellulose derived model compounds (lignin aldehydes, furan aldehydes and weak acid). Lignin derivatives were the compounds that inhibited cell growth most. Interestingly, instead of inhibition, acetic acid and formic acid at low concentration significantly improved the lipid production achieving to 6.81±0.07 g L-1 and 6.66±0.33 g L-1 that was twice as high as the control group. Our results demonstrate that M. isabellina holds great potential to be a candidate for biofuel production from lignocellulosic biomass.
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Details
- Title
- Lipid production from xylose and inhibitory effects from lignocellulose hydrolysate using Mortierella isabellina
- Creators
- Difeng Gao
- Contributors
- Shulin Chen (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525094101842
- Language
- English
- Resource Type
- Thesis