Mutagenesis, Screening and Industrialization of High Avermectin B1a Producing Strains from Streptomyces Avermitilis Irradiated by ¹²C ⁶⁺ Ion Beam

Abstract

Heavy ion irradiation induced mutation is a unique method of physical mutation, with various parameters, high LET and RBE characteristic. The spore suspension of streptomyces avermitilis were irradiated by carbon ions with doses of 0、30、40、50、60 and 70 Gy. The high avermectin producing strain was successfully obtained after the mutagenesis processing by heavy ion beam and the screening of orthomutation strains. Two strains(No.203 and No.148) which potency was 5200μg/ml was sieved and its potency increased 38.64% than the original strain. The obtained strains were used for 1 ton fermentation tank and the pilot 5-ton fermentation tank amplification tests.

Raising the avermectins production in Streptomyces avermitilis by utilizing nanosecond pulsed electric fields (nsPEFs)

“…Basically, there are three conventional approaches to improve the fermentation efficiency of avermectins in S. avermitilis : utilization of mutagens (such as ultraviolet, atmospheric pressure cold plasma, lithium chloride and nitrosoguanidine) 4 5 , genetic engineering technology 6 7 , and optimization of fermentation conditions 8 9 . In fact, each technique has its disadvantages.…”