Dataset Information

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) co-produced with L-isoleucine in Corynebacterium glutamicum WM001.

ABSTRACT: BACKGROUND:Co-production of polyhydroxyalkanoate (PHA) and amino acids makes bacteria effective microbial cell factories by secreting amino acids outside while accumulating PHA granules inside. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is one of the PHAs with biocompatibility and fine mechanical properties, but its production is limited by the low level of intracellular propionyl-CoA. RESULTS:L-Isoleucine producing Corynebacterium glutamicum strain WM001 were analyzed by genome and transcriptome sequencing. The results showed that the most over-expressed genes in WM001 are relevant not only to L-isoleucine production but also to propionyl-CoA accumulation. Compared to the wild-type C. glutamicum ATCC13869, the transcriptional levels of the genes prpC2, prpD2, and prpB2, which are key genes relevant to propionyl-CoA accumulation, increased 26.7, 25.8, and 28.4-folds in WM001, respectively; and the intracellular level of propionyl-CoA increased 16.9-fold in WM001. When the gene cluster phaCAB for PHA biosynthesis was introduced into WM001, the recombinant strain WM001/pDXW-8-phaCAB produced 15.0 g/L PHBV with high percentage of 3-hydroxyvalerate as well as 29.8 g/L L-isoleucine after fed-batch fermentation. The maximum 3-hydroxyvalerate fraction in PHBV produced by WM001/pDXW-8-phaCAB using glucose as the sole carbon source could reach 72.5%, which is the highest reported so far. CONCLUSIONS:Genome and transcriptome analysis showed that C. glutamicum WM001 has potential to accumulate L-isoleucine and propionyl-CoA pool. This was experimentally confirmed by introducing the phaCAB gene cluster into WM001. The recombinant strain WM001/pDXW-8-phaCAB produced high levels of PHBV with high 3-hydroxyvalerate fraction as well as L-isoleucine. Because of its high level of intracellular propionyl-CoA pool, WM001 might be used for producing other propionyl-CoA derivatives.

SUBMITTER: Ma W

PROVIDER: S-EPMC6004086 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) co-produced with L-isoleucine in Corynebacterium glutamicum WM001.

Ma Wenjian W Wang Jianli J Li Ye Y Yin Lianghong L Wang Xiaoyuan X

Microbial cell factories 20180615 1

<h4>Background</h4>Co-production of polyhydroxyalkanoate (PHA) and amino acids makes bacteria effective microbial cell factories by secreting amino acids outside while accumulating PHA granules inside. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is one of the PHAs with biocompatibility and fine mechanical properties, but its production is limited by the low level of intracellular propionyl-CoA.<h4>Results</h4>L-Isoleucine producing Corynebacterium glutamicum strain WM001 were analyzed by ...[more]

PMID: 29907151

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Project description:The effect of accelerated weathering on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV-based nanocomposites with rutile titanium (IV) dioxide (PHBV/TiO2) was investigated. The accelerated weathering test applied consecutive steps of UV irradiation (at 340 nm and 0.76 W m-2 irradiance) and moisture at 50 °C following the ASTM D4329 standard for up to 2000 h of exposure time. The morphology, chemical structure, crystallization, as well as the mechanical and thermal properties were studied. Samples were characterized after 500, 1000, and 2000 h of exposure time. Different degradation mechanisms were proposed to occur during the weathering exposure and were confirmed based on the experimental data. The PHBV surface revealed cracks and increasing roughness with the increasing exposure time, whereas the PHBV/TiO2 nanocomposites showed surface changes only after 2000 h of accelerated weathering. The degradation of neat PHBV under moisture and UV exposure occurred preferentially in the amorphous phase. In contrast, the presence of TiO2 in the nanocomposites retarded this process, but the degradation would occur simultaneously in both the amorphous and crystalline segments of the polymer after long exposure times. The thermal stability, as well as the temperature and rate of crystallization, decreased in the absence of TiO2. TiO2 not only provided UV protection, but also restricted the physical mobility of the polymer chains, acting as a nucleating agent during the crystallization process. It also slowed down the decrease in mechanical properties. The mechanical properties were shown to gradually decrease for the PHBV/TiO2 nanocomposites, whereas a sharp drop was observed for the neat PHBV after an accelerated weathering exposure. Atomic force microscopy (AFM), using the amplitude modulation-frequency modulation (AM-FM) tool, also confirmed the mechanical changes in the surface area of the PHBV and PHBV/TiO2 samples after accelerated weathering exposure. The changes in the physical and chemical properties of PHBV/TiO2 confirm the barrier activity of TiO2 for weathering attack and its retardation of the degradation process.

Dataset Information

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) co-produced with L-isoleucine in Corynebacterium glutamicum WM001.

Publications

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) co-produced with L-isoleucine in Corynebacterium glutamicum WM001.

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