Metabolic engineering of <em>Bacillus subtilis</em> for production of D-lactic acid.
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| Format: | eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. Department of Energy. Office of Energy Efficiency and Renewable Energy ; Distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2017.
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| Abstract: | Poly lactic acid (PLA) based plastics is renewable, bio?based, and biodegradable. Although present day PLA is composed of mainly L?LA, an L? and D? LA copolymer is expected to improve the quality of PLA and expand its use. To increase the number of thermotolerant microbial biocatalysts that produce D?LA, a derivative of Bacillus subtilis strain 168 that grows at 50ʻC was metabolically engineered. Since B. subtilis lacks a gene encoding D?lactate dehydrogenase (ldhA), five heterologous ldhA genes (B. coagulans ldhA and gldA101, and ldhA from three Lactobacillus delbrueckii) were evaluated. Corresponding D?LDHs were purified and biochemically characterized. Among these, D?LDH from L. delbrueckii subspecies bulgaricus supported the highest D?LA titer (about 1M) and productivity (2 g h<sup>?1</sup> g cells<sup>?1</sup>) at 37ʻC (B. subtilis strain DA12). The D?LA titer at 48ʻC was about 0.6 M at a yield of 0.99 (g D?LA g?1glucose consumed). Strain DA12 also fermented glucose at 48ʻC in mineral salts medium to lactate at a yield of 0.89 g g<sup>?1</sup> glucose and the D?lactate titer was 180 ł 4.5 mM. Furthermore, these results demonstrate the potential of B. subtilis as a platform organism for metabolic engineering for production of chemicals at 48ʻC that could minimize process cost. |
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| Item Description: | Published through Scitech Connect. 10/07/2017. "Journal ID: ISSN 0006-3592." Awasthi, Deepika ; Wang, Liang ; Rhee, Mun S. ; Wang, Qingzhao ; Chauliac, Diane ; Ingram, Lonnie O. ; Shanmugam, Keelnatham T. ; Univ. of Florida, Gainesville, FL (United States) |
| Physical Description: | Size: p. 453-463 : digital, PDF file. |