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Title: Application of metabolic controls for the maximization of lipid production in semicontinuous fermentation

We report that acetic acid can be generated through syngas fermentation, lignocellulosic biomass degradation, and organic waste anaerobic digestion. Microbial conversion of acetate into triacylglycerols for biofuel production has many advantages, including low-cost or even negative-cost feedstock and environmental benefits. The main issue stems from the dilute nature of acetate produced in such systems, which is costly to be processed on an industrial scale. To tackle this problem, we established an efficient bioprocess for converting dilute acetate into lipids, using the oleaginous yeast Yarrowia lipolytica in a semicontinuous system. The implemented design used low-strength acetic acid in both salt and acid forms as carbon substrate and a cross-filtration module for cell recycling. Feed controls for acetic acid and nitrogen based on metabolic models and online measurement of the respiratory quotient were used. The optimized process was able to sustain high-density cell culture using acetic acid of only 3% and achieved a lipid titer, yield, and productivity of 115 g/L, 0.16 g/g, and 0.8 g∙L -1∙h -1, respectively. No carbon substrate was detected in the effluent stream, indicating complete utilization of acetate. In conclusion, these results represent a more than twofold increase in lipid production metrics compared with the current best-performingmore » results using concentrated acetic acid as carbon feed.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Department of Chemical Engineering; Zhejiang Police College, Hangzhou (China). Department of Forensic Science and Technology
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Department of Chemical Engineering
Publication Date:
Grant/Contract Number:
SC0008744
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 114; Journal Issue: 27; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; lipid production; acetate; tangential filtration; dynamic modeling; exhaust gas analysis
OSTI Identifier:
1367775
Alternate Identifier(s):
OSTI ID: 1465958