Whole Genome Regulator Mutant Library for Expedited Identification of Beneficial Mutations for Enhanced Tolerance Towards Environmental Stress

Use of E coli as an industrial strain entails tolerance to multiple environmental stresses. Resistance towards such stresses is a complex phenotype requiring modification of expression of multiple genes across the genome. In the past, mutations in regulatory proteins have enabled such complex modifications. Universal resources for rapid identification of such beneficial mutations are lacking. We propose the development of a library with single point mutations on functional sites of regulatory proteins across the E coli genome. The library was subject to multiple environmental stresses like presence of ethanol and isobutanol, low pH, high temperature and presence of antibiotics. From the selections, multiple novel beneficial mutations were identified with enhanced tolerance to these stresses. These mutations might enable better understanding of tolerance mechanisms towards these stresses. The library can act as a platform for expedited strain engineering for applications in metabolic engineering.