Metabolic engineering of Bacillus subtilis for production of D-lactic acid
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 50°C 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–1 g cells–1) at 37°C (B. subtilis strain DA12). The D–LA titer at 48°C was about 0.6 M at a yield of 0.99 (g D–LA g–1glucose consumed). Strain DA12 also fermented glucose at 48°C in mineral salts medium to lactate at a yield of 0.89 g g–1 glucose and the D–lactate titer was 180 ± 4.5 mM. Furthermore, these results demonstrate the potential of B. subtilis as a platform organism for metabolic engineering for production of chemicals at 48°C that could minimize process cost.
- Research Organization:
- Univ. of Florida, Gainesville, FL (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Grant/Contract Number:
- PI0000031
- OSTI ID:
- 1766311
- Alternate ID(s):
- OSTI ID: 1408188
- Journal Information:
- Biotechnology and Bioengineering, Vol. 115, Issue 2; ISSN 0006-3592
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Lactic acid production from sugarcane bagasse hydrolysates by Lactobacillus pentosus : Integrating xylose and glucose fermentation
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journal | October 2018 |
Co-culture of Lactobacillus delbrueckii and engineered Lactococcus lactis enhances stoichiometric yield of d-lactic acid from whey permeate
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journal | May 2019 |
Recent Advances in D-Lactic Acid Production from Renewable Resources
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journal | January 2019 |
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