The forced activation of asexual conidiation in Aspergillus niger simplifies bioproduction

Aspergillus niger is an efficient cell factory for organic acids production, particularly L-malic acid, through genetic manipulation. However, the traditional method of collecting A. niger spores for inoculation is labor-intensive and resource-consuming. In our study, we used the CRISPR-Cas9 system to replace the promoter of brlA, a key gene in Aspergillus conidiation, with a xylose-inducible promoter in L-malic acid-producing A. niger strain RG0095, generating strain brlAxylP. When induced with xylose in submerged liquid culture, brlAxylP exhibited significant upregulation of conidiation-related genes. This induction allowed us to easily collect an abundance of brlAxylP spores (>7.1×106/mL) in liquid xylose medium. Importantly, these spores retained their ability to produce L-malic acid. In summary, our study offers a simplified submerged conidiation strategy to streamline the preparation stage and reduce labor and material costs for industrial organic acid production using Aspergillus species.