Heterologous expression of Thermomyces lanuginosus lipase in Aspergillus niger: enzyme characterization, optimization of fermentation conditions and transcriptomic analysis

Aspergillus niger serves as a cell factory for efficient enzyme production. The lipase derived from Thermomyces lanuginosus (TLL) is known for its remarkable thermal stability and is extensively utilized in various industrial fields. In this study, a heterologous expression strain Δ AnTll -11 of TLL was successfully constructed in A. niger . This strain achieved an enzyme activity of 520 U/ml during shake flask fermentation. Furthermore, the Δ AnTll -11 strain exhibited resistance to hypertonicity, oxidation, and heat shock. Analysis of its enzymatic properties revealed that this lipase exhibited optimal activity at pH 9.5 and 45℃. Ca²⁺, Ag⁺, Mg²⁺, and Cu²⁺ were found to enhance enzyme activity, with the enzyme displaying higher activity towards p -nitrophenyl palmitate (C16). By optimizing fermentation conditions, enzyme activity was increased to 4,547.95 U/mL, representing an 8.7-fold increase from the initial activity. Additionally, transcriptomic analysis of A. niger expressing TLL indicated that differentially expressed genes (DEGs) accounted for approximately 53.8% of the total gene (7199 genes). Among these, 66 genes were identified as playing a crucial role in lipase expression. These DEGs primarily participated in translation and signal transduction processes. The transcriptomic findings elucidated the regulatory mechanisms by which A. niger expresses foreign proteins and enzymes, establishing a groundwork for further enhancing A. niger as a cell factory for efficient enzyme and protein production.