Valorization of bioethanol by-products to produce unspecific peroxygenase with Agrocybe aegerita: Technological and proteomic perspectives

Unspecific peroxygenase (UPO) presents a wide range of biotechnological applications. This study targets the use of by-products from bioethanol synthesis to produce UPO by Agrocybe aegerita. Solid-state and submerged fer-mentations (SSF and SmF) were evaluated, achieving the highest titers of UPO and laccase in SmF using vinasse as nutrients source. Optimized UPO production of 331 U/L was achieved in 50% (v:v) vinasse with an inoculum grown for 14 days. These conditions were scaled-up to a 4 L reactor, achieving a UPO activity of 265 U/L. Fungal proteome expression was analyzed before and after UPO activity appeared by shotgun mass spectrometry pro-teomics. Laccase, dye-decolorizing peroxidases (DyP), lectins and proteins involved in reactive oxygen species (ROS) production and control were detected (in addition to UPO). Interestingly, the metabolism of complex sugars and nitrogen sources had a different activity at the beginning and end of the submerged fermentation.

Automated summary

This study focuses on the production of UPO by Agrocybe aegerita using by-products from bioethanol synthesis. Solid-state and submerged fermentations were compared, and the highest titers of UPO and laccase were achieved in submerged fermentation using vinasse as the nutrient source. Optimized UPO production of 331 U/L was obtained in 50% vinasse with a 14-day inoculum. These conditions were scaled-up to a 4 L reactor, resulting in a UPO activity of 265 U/L. Proteomic analysis revealed the expression of laccase, dye-decolorizing peroxidases, lectins, and proteins involved in reactive oxygen species production and control, in addition to UPO. Interestingly, the metabolism of complex sugars and nitrogen sources showed different activities at the beginning and end of submerged fermentation.