Modular Engineering to Enhance Keratinase Production for Biotransformation of Discarded Feathers.

Biotransformation of wasted feathers via feather-degrading enzyme has gained immense popularity, low conversion efficiency hinders its scale application, and the main purpose of this study is to improve feather-degrading enzyme production in Bacillus licheniformis. Firstly, keratinase from Bacillus amyloliquefaciens K11 was attained with the best performance for feather hydrolysis, via screening several extracellular proteases from Bacillus; also, feather powder was proven as the most suitable substrate for determination of feather-degrading enzyme activity. Then, expression elements, including signal peptides and promoters, were optimized, and the combination of signal peptide SP with promoter Pdual3 owned the best performance, keratinase activity aggrandized by 6.

Construction and Characterization of a Gradient Strength Promoter Library for Fine-Tuned Gene Expression in .

DW2 is an important industrial strain for bacitracin production, and it is also used for biochemical production, however, the lack of effective toolkit for precise regulation of gene expression hindered its application seriously. Here, a gradient strength promoter library was constructed based on bacitracin synthetase gene cluster promoter P. First, different P promoter variants were constructed via coupling P with various 5'-UTRs, and expression ranges of 32.