Screening and identification of high gibberellin-producing strain from terbinafine resistant mutants

Abstract:

[Objective] The high gibberellins-producing strains were screened and identified. Meanwhile, studies on characterization of genetic stability and fermentation in the bioreactor were also carried out. [Methods] Used the NTG, 60Co-γ rays and composite mutagenesis methods, high-yield mutant strains were isolated directionally in the medium including the antifungal agents-terbinafine. The genetic stability of mutant strain was determined by the several generations on the agar slants. The part of its fermentation characteristics were studied in the fermentation tank. [Results] The strains suspension was treated with the mutagens including a final NTG concentration 200 mg/L for 30 min, followed by 60Co gamma ray (300 Gy). The mutant strains were isolated on the PDA plate containing 120 μg/L terbinafine. After further shaking flask experiments, potentials of the mutant strains were determined. The fermentation titer of strain ZNL13-3 was 2 245±35 mg/L, increased 11.87% compared with the primary strains. The ZNL13-3 has a good genetic stability and value of application. Fermentation performance of ZNL13-3 is better than the primary strains, compared with the time trends of mycelia concentration and gibberellin acid concentration in the 5 L bioreactor. [Conclusion] The high-yield strains of gibberellin acid could be found and its ability to produce gibberellin acid could be affected by the terbinafine resistance.