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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  The filamentous ascomycete  Aspergillus niger  is used in many industrial processes for the production of enzymes and organic acids by batch and fed-batch cultivation. An alternative technique is continuous cultivation, which promises improved yield and optimized pipeline efficiency.    Results  In this work, we have used perfusion (retentostat) cultivation to validate two promoters that are suitable for  A. niger  continuous cultivation of industrially relevant products. Firstly, promoters of genes encoding either an antifungal protein ( Panafp ) or putative hydrophobin ( PhfbD ) were confirmed as active throughout retentostat culture by assessing mRNA and protein levels using a luciferase ( mluc ) reporter system. This demonstrated the  anafp  promoter mediates a high but temporally variable expression profile, whereas the  hfbD  promoter mediates a semi-constant, moderate-to-high protein expression during retentostat culture. In order to assess whether these promoters were suitable to produce heterologous proteins during retentostat cultivation, the secreted antifungal protein (AFP) from  Aspergillus giganteus , which has many potential biotechnological applications, was expressed in  A. niger  during retentostat cultivation. Additionally, this assay was used to concomitantly validate that native secretion signals encoded in  anafp  and  hfbD  genes can be harnessed for secretion of heterologous proteins.  Afp  mRNA and protein abundance were comparable to luciferase measurements throughout retentostat cultivation, validating the use of  Panafp  and  PhfbD  for perfusion cultivation. Finally, a gene encoding the highly commercially relevant thermal hysteresis protein (THP) was expressed in this system, which did not yield detectable protein.    Conclusion  Both  hfbD  and  anafp  promoters are suitable for production of useful products in  A. niger  during perfusion cultivation. These findings provide a platform for further optimisations for high production of heterologous proteins with industrial relevance.    Electronic supplementary material  The online version of this article (doi:10.1186/s12934-016-0543-2) contains supplementary material, which is available to authorized users.

Highly active promoters and native secretion signals for protein production during extremely low growth rates in Aspergillus niger