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Abstract
BackgroundIntegrating waste management with fuels and chemical production is considered to address the food waste problem and oil crisis. Approximately, 600 million tonnes crude glycerol is produced from the biodiesel industry annually, which is a top renewable feedstock for succinic acid production. To meet the increasing demand for succinic acid production, the development of more efficient and cost-effective production methods is urgently needed. Herein, we have proposed a new strategy for integration of both biodiesel and SA production in a biorefinery unit by construction of an aerobic yeast Yarrowia lipolytica with a deletion in the gene coding succinate dehydrogenase subunit 5.ResultsRobust succinic acid production by an engineered yeast Y. lipolytica from crude glycerol without pre-treatment was demonstrated. Diversion of metabolic flow from tricarboxylic acid cycle led to the success in generating a succinic acid producer Y. lipolytica PGC01003. The fermentation media and conditions were optimized, which resulted in 43 g L−1 succinic acid production from crude glycerol. Using the fed-batch strategy in 2.5 L fermenter, up to 160 g L−1 SA was yielded, indicating the great industrial potential.ConclusionsInactivation of SDH5 in Y. lipolytica Po1f led to succinic acid accumulation and secretion significantly. To our best knowledge, this is the highest titer obtained in fermentation on succinic acid production. In addition, the performance of batch and fed-batch fermentation showed high tolerance and yield on biodiesel by-product crude glycerol. All these results indicated that PGC01003 is a promising microbial factorial cell for the highly efficient strategy solving the environmental problem in connection with the production of value-added product.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0597-8) contains supplementary material, which is available to authorized users.
Highlights
Integrating waste management with fuels and chemical production is considered to address the food waste problem and oil crisis
As an intermediate of tricarboxylic acid (TCA) cycle, succinic acid (SA) is formed from α-ketoglutaric acid through α-ketoglutarate dehydrogenase and from isocitric acid through isocitrate lyase, and subsequently depleted by the catalysis of succinate dehydrogenase complex (SDH)
The PUT cassette for homologous substitution onto SDH5 locus Ylsdh5 (YALI0F11957 g) of Y. lipolytica Po1f genome was obtained by PCR amplification and was transformed into the competent cell (Fig. 1a)
Summary
To meet the increasing demand for succinic acid production, the development of more efficient and cost-effective production methods is urgently needed. We have proposed a new strategy for integration of both biodiesel and SA production in a biorefinery unit by construction of an aerobic yeast Yarrowia lipolytica with a deletion in the gene coding succinate dehydrogenase subunit 5. Since fossil fuel resource is in the trend of depletion, it becomes apparent that a switch from petrochemicalbased chemical production industry toward a bio-based and carbon neutral process is inevitable. Robust and efficient microbes are urgently needed for the cost-effective biosynthesis of valuable chemicals. The total addressable market volume for bio-based SA is estimated to reach US$ 14.1 billion. Petroleum-based chemical production should be shifted to biotechnological processes for a long-term consideration of environment
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