The flexible linker and CotG were more effective for the spore surface display of keratinase KERQ7

AbstractFeather, horn, hoof, and other keratin waste are protein-rich but limited by natural keratinase synthesis, activity, pH, and temperature stability. It is challenging to realize its large-scale application in industries.Bacillus subtilis spores are a safe, efficient, and highly resistant immobilized carrier, which can improve target proteins ’ resistance. In this research,KERQ7, the keratinase gene ofBacillus tequilensis strain Q7, was fused to theBacillus subtilis genes coding for the coat proteins CotG and CotB, respectively, and displayed on the surface ofB. subtilis spores. Compared with the free KERQ7, the immobilized KERQ7 showed a greater pH tolerance and heat resistance on the spore surface. The activity ofCotG-KERQ7 is 1.25 times that ofCotB-KERQ7, andCotG-KERQ7 is more stable. When the flexible linker peptide L3 was used to connectCotG and KERQ7, the activity was increased to 131.2  ± 3.4%, and the residual enzyme activity was still 62.5 ± 2.2% after being kept at 60 ℃ for 4 h. These findings indicate that the flexible linker andCotG were more effective for the spore surface display of keratinase to improve stress resistance and promote its wide application in feed, tanning, washing, and other industries.Graphic Abstract
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research