English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Background  Genome streamlining has emerged as an effective strategy to boost the production efficiency of bio-based products. Many efforts have been made to construct desirable chassis cells by reducing the genome size of microbes. It has been reported that the genome-reduced  Bacillus subtilis  strain MBG874 showed clear advantages for the production of several heterologous enzymes including alkaline cellulase and protease. In addition to enzymes,  B. subtilis  is also used for the production of chemicals. To our best knowledge, it is still unknown whether genome reduction could be used to optimize the production of chemicals such as nucleoside products.    Results  In this study, we constructed a series of genome-reduced strains by deleting non-essential regions in the chromosome of  B. subtilis  168. These strains with genome reductions ranging in size from 581.9 to 814.4 kb displayed markedly decreased growth rates, sporulation ratios, transformation efficiencies and maintenance coefficients, as well as increased cell yields. We re-engineered the genome-reduced strains to produce guanosine and thymidine, respectively. The strain BSK814G2, in which  purA  was knocked out, and  prs ,  purF  and  guaB  were co-overexpressed, produced 115.2 mg/L of guanosine, which was 4.4-fold higher compared to the control strain constructed by introducing the same gene modifications into the parental strain. We also constructed a thymidine producer by deleting the  tdk  gene and overexpressing the  prs ,  ushA ,  thyA ,  dut , and  ndk  genes from  Escherichia coli  in strain BSK756, and the resulting strain BSK756T3 accumulated 151.2 mg/L thymidine, showing a 5.2-fold increase compared to the corresponding control strain.    Conclusions  Genome-scale genetic manipulation has a variety of effects on the physiological characteristics and cell metabolism of  B. subtilis . By introducing specific gene modifications related to guanosine and thymidine accumulation, respectively, we demonstrated that genome-reduced strains had greatly improved properties compared to the wild-type strain as chassis cells for the production of these two products. These strains also have great potential for the production of other nucleosides and similar derived chemicals.    Electronic supplementary material  The online version of this article (doi:10.1186/s12934-016-0494-7) contains supplementary material, which is available to authorized users.

Characterization of genome-reduced Bacillus subtilis strains and their application for the production of guanosine and thymidine