Breeding Strains Producing Coenzyme Q₁₀

Based on the determination results of original CoQ₁₀’s yield of five Agrobacterium tumefaciens strains, strain C58 was selected as the original strain for breeding the CoQ₁₀ producing strain, of which CoQ₁₀’s original yield is 3.56mg/L, higher than other strains. The methods of NTG（400μg/mL, pH8.0） was used to mutate the C58 strain. After three rounds of mutagenesis screenings, mutant C58-44-100-36 with a yield of 65.78 mg/L CoQ₁₀ was obtained, with 17.48 times increased than the original strain C58.After the treatment of NTG mutagenesis and 2μg/mL ActD plate screening,48 strains of ActD resistant mutant （ActD^r） were obtained from strain C58. Then a resistance screening of the ActD^r was carried out by using 2μg/mL,3μg/mL,4μg/mL,5μg/mL ActD viability of this concentration gradient plate. Mutant C58-44 with CoQ₁₀ yield of 19.60 mg/L was obtained, which was increased stably by 450.67% than original strain C58.Using C_58-44 as the original strain, after NTG mutagenesis treatment and 5μg/mL ActD plate screening, we got 38 ActD resistant mutant strains. Mutant C_58-44-1 was obtained by dilute seeding them on 10μg/mL,20μg/mL,30μg/mL,40μg/mL,50μg/mL ActD plates. And the CoQ₁₀ yield of strain C_58-44-1 reached 43.85 mg/L, which was increased stably by 123.68% than the original strain C58-44.Using C_58-44-1 as the original strain, after NTG mutagenesis treatment and 50μg/mL ActD plate screening, we got 43 ActD resistant mutant strains. Mutant C58-44-100-36 was obtained by dilute seeding them on 60μg/mL,70μg/mL,80μg/mL,90μg/mL, 100μg/mL ActD plates. And the CoQ₁₀ yield of strain C_58-44-100-36 reached 65.78 mg/L, which was increased stably by 17.48 times than the original strain.Through genetic experiment, the strain was proved to have good genetic stability.