Pseudonocardia strain improvement for stimulation of the di-sugar heptaene Nystatin-like Pseudonocardia polyene B1 biosynthesis.

Pseudonocardia strain improvement for stimulation of the di-sugar heptaene Nystatin-like Pseudonocardia polyene B1 biosynthesis. J Ind Microbiol Biotechnol. 2019 Feb 23;: Authors: Han CY, Jang JY, Kim HJ, Choi S, Kim ES Abstract Pseudonocardia autotrophica was previously identified to produce a toxicity-reduced and solubility-improved disaccharide-containing anti-fungal compound belonging to the tetraene-family, Nystatin-like Pseudonocardia Polyene A1 (NPP A1). Subsequently NPP B1, a novel derivative harboring a heptaene core structure, was produced by a pathway-engineered Pseudonocardia strain through inactivation of the specific enoly reductase gene domain in the NPP biosynthetic gene cluster. Although in vitro and in vivo efficacy and toxicity studies indicate that NPP B1 is a promising lead antifungal compound, further improvement is required to increase the extremely low production yield in the pathway-engineered strain. To overcome this challenge, we performed the N-methyl-N'-nitro-N-nitrosoguanidine (NTG) iterative random mutagenesis, followed by zone-of-inhibition agar plug assay. After three rounds of the mutagenesis-and-screening protocol, the production yield of NPP B1 increased to 6.25 mg/L, which is more than an eightfold increase compared to the parental strain. The qRT-PCR analysis revealed that transcripts of the NPP B1 biosynthetic genes were increased in the mutant strain. Interestingly, an endogenous 125-kb plasmi...
Source: Journal of Industrial Microbiology and Biotechnology - Category: Microbiology Authors: Tags: J Ind Microbiol Biotechnol Source Type: research