Abstract

Streptomyces clavuligerus produces a number of β-lactam compounds, including clavulanic acid. Here, we describe an efficient procedure for creating clavulanic acid high producing S. clavuligerus mutant by using traditional UV light treatment method and PCR-targeting system. After inducing S. clavuligerus B71 with UV light S. clavuligerus B71-14 was selected for its 1.91-fold clavulanic acid production to the original strain. Then we applied polymerase chain reaction (PCR)-targeting system to mutate the lat gene of S. clavuligerus B71-14 to obtain lat gene knocked-out, unmarked mutant S. clavuligerus lat::scar. Through traditional UV light treatment and PCR-targeting system to knock out thelat gene of S. clavuligerus wild type strain, the clavulanic acid of the mutant S. clavuligerus lat::scar was 2.85-fold to the original strain S. clavuligerus B71. This procedure allows repeated use of the same resistance marker for making multiple knock-outs in the same strain.

Key words: Streptomyces clavuligerus, mutant, clavulanic acid, increase