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Recruiting a new strategy to improve levan production in Bacillus amyloliquefaciens.

Feng J, Gu Y, Quan Y, Zhang W, Cao M, Gao W, Song C, Yang C, Wang S - Sci Rep (2015)

Bottom Line: Microbial levan is an important biopolymer with considerable potential in food and medical applications.Furthermore, the NK-Q-7 strain also showed a 94.1% increase in α-amylase production compared with NK-ΔLP strain, suggesting a positive effect of extracellular protease genes deficient on the production of endogenously secreted proteins.This is the first report of the improvement of levan production in microbes deficient in extracellular proteases and TasA, and the NK-Q-7 strain exhibits outstanding characteristics for extracellular protein production or extracellular protein related product synthesis.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin 300071, China.

ABSTRACT
Microbial levan is an important biopolymer with considerable potential in food and medical applications. Bacillus amyloliquefaciens NK-ΔLP strain can produce high-purity, low-molecular-weight levan, but production is relatively low. To enhance the production of levan, six extracellular protease genes (bpr, epr, mpr, vpr, nprE and aprE), together with the tasA gene (encoding the major biofilm matrix protein TasA) and the pgsBCA cluster (responsible for poly-γ-glutamic acid (γ-PGA) synthesis), were intentionally knocked out in the Bacillus amyloliquefaciens NK-1 strain. The highest levan production (31.1 g/L) was obtained from the NK-Q-7 strain (ΔtasA, Δbpr, Δepr, Δmpr, Δvpr, ΔnprE, ΔaprE and ΔpgsBCA), which was 103% higher than that of the NK-ΔLP strain (ΔpgsBCA) (15.3 g/L). Furthermore, the NK-Q-7 strain also showed a 94.1% increase in α-amylase production compared with NK-ΔLP strain, suggesting a positive effect of extracellular protease genes deficient on the production of endogenously secreted proteins. This is the first report of the improvement of levan production in microbes deficient in extracellular proteases and TasA, and the NK-Q-7 strain exhibits outstanding characteristics for extracellular protein production or extracellular protein related product synthesis.

No MeSH data available.


Related in: MedlinePlus

Confirmation of gene deletions via PCR.Chromosomal DNA served as the template for amplification. Lane M: DNA marker III; Lane WT: strains amplified with relevant detection primers using B. amyloliquefaciens NK-1 chromosomal DNA as the template; Lane MT: strains amplified with the relevant detection primers using chromosomal DNA from the gene deletion strains’ as the template.
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f2: Confirmation of gene deletions via PCR.Chromosomal DNA served as the template for amplification. Lane M: DNA marker III; Lane WT: strains amplified with relevant detection primers using B. amyloliquefaciens NK-1 chromosomal DNA as the template; Lane MT: strains amplified with the relevant detection primers using chromosomal DNA from the gene deletion strains’ as the template.

Mentions: We constructed these gene deletion mutants via a marker-less knockout method. This method is based on using the upp gene, which encodes uracil-phosphoribosyl-transferase, as the counter-selectable marker. The upp cassette and 5-fluorouracil (5-FU) selection were used to identify marker-less gene deletions29. According to the PCR results shown in Fig. 2 and the DNA sequencing results, we confirmed that the gene mutant strains had been successfully constructed.


Recruiting a new strategy to improve levan production in Bacillus amyloliquefaciens.

Feng J, Gu Y, Quan Y, Zhang W, Cao M, Gao W, Song C, Yang C, Wang S - Sci Rep (2015)

Confirmation of gene deletions via PCR.Chromosomal DNA served as the template for amplification. Lane M: DNA marker III; Lane WT: strains amplified with relevant detection primers using B. amyloliquefaciens NK-1 chromosomal DNA as the template; Lane MT: strains amplified with the relevant detection primers using chromosomal DNA from the gene deletion strains’ as the template.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561895&req=5

f2: Confirmation of gene deletions via PCR.Chromosomal DNA served as the template for amplification. Lane M: DNA marker III; Lane WT: strains amplified with relevant detection primers using B. amyloliquefaciens NK-1 chromosomal DNA as the template; Lane MT: strains amplified with the relevant detection primers using chromosomal DNA from the gene deletion strains’ as the template.
Mentions: We constructed these gene deletion mutants via a marker-less knockout method. This method is based on using the upp gene, which encodes uracil-phosphoribosyl-transferase, as the counter-selectable marker. The upp cassette and 5-fluorouracil (5-FU) selection were used to identify marker-less gene deletions29. According to the PCR results shown in Fig. 2 and the DNA sequencing results, we confirmed that the gene mutant strains had been successfully constructed.

Bottom Line: Microbial levan is an important biopolymer with considerable potential in food and medical applications.Furthermore, the NK-Q-7 strain also showed a 94.1% increase in α-amylase production compared with NK-ΔLP strain, suggesting a positive effect of extracellular protease genes deficient on the production of endogenously secreted proteins.This is the first report of the improvement of levan production in microbes deficient in extracellular proteases and TasA, and the NK-Q-7 strain exhibits outstanding characteristics for extracellular protein production or extracellular protein related product synthesis.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin 300071, China.

ABSTRACT
Microbial levan is an important biopolymer with considerable potential in food and medical applications. Bacillus amyloliquefaciens NK-ΔLP strain can produce high-purity, low-molecular-weight levan, but production is relatively low. To enhance the production of levan, six extracellular protease genes (bpr, epr, mpr, vpr, nprE and aprE), together with the tasA gene (encoding the major biofilm matrix protein TasA) and the pgsBCA cluster (responsible for poly-γ-glutamic acid (γ-PGA) synthesis), were intentionally knocked out in the Bacillus amyloliquefaciens NK-1 strain. The highest levan production (31.1 g/L) was obtained from the NK-Q-7 strain (ΔtasA, Δbpr, Δepr, Δmpr, Δvpr, ΔnprE, ΔaprE and ΔpgsBCA), which was 103% higher than that of the NK-ΔLP strain (ΔpgsBCA) (15.3 g/L). Furthermore, the NK-Q-7 strain also showed a 94.1% increase in α-amylase production compared with NK-ΔLP strain, suggesting a positive effect of extracellular protease genes deficient on the production of endogenously secreted proteins. This is the first report of the improvement of levan production in microbes deficient in extracellular proteases and TasA, and the NK-Q-7 strain exhibits outstanding characteristics for extracellular protein production or extracellular protein related product synthesis.

No MeSH data available.


Related in: MedlinePlus