Monday, August 11, 2008
P100
High Yield Avermectin B1a Production of Streptomyces avermitils
Avermectins, produced by Streptomyces avermitilis, are major commercial antiparasitic agents in the fields of animal health, agriculture, and human infections. Avermectin is produced into eight derivatives which are A1a, A2a, B1a, B2a, A1b, A2b, B1b and B2b. We used random mutation system to develop a strain that has high yield of avermectin B1a as a target, because avermectin B1a has the most effective anthelmintic and insecticidal activities.
Mutant strain of S. avermitilis ATTC 31271(KCCM 40226) was obtained via random mutation using NTG (3 mg/ml, 60 minutes). This mutant strain shows 8 times higher avermectin B1a production (1.6 mg/L) than wild type strain (0.2 mg/L). For further improvement of avermectin B1a production from mutant strain, optimization of current avermectin B1a production medium was studied. Results of media optimization was carbon source, fructose 70 g/L, nitrogen source, soy peptone 12 g/L, yeast extract 2 g/L and showed productivity of 475.6 mg/L which is about 300 times greater than before medium optimization.
Soytone peptone selected as nitrogen source is known to have effect on pyruvate, which is a precursor for CoA such as acetyl-CoA, malonyl-CoA, during metabolic process. Few CoAs are used as precursor for avermectin and soytone peptone is expected to have relation with improving avermectin productivity. Soytone peptone affects genes and pathways related to avermectin production of mutants. Therefore through analysis of relationship between soytone peptone components and the mutant, it is expected to figure out the mutant's avermectin production pathway and why the avermectin production has risen.
Mutant strain of S. avermitilis ATTC 31271(KCCM 40226) was obtained via random mutation using NTG (3 mg/ml, 60 minutes). This mutant strain shows 8 times higher avermectin B1a production (1.6 mg/L) than wild type strain (0.2 mg/L). For further improvement of avermectin B1a production from mutant strain, optimization of current avermectin B1a production medium was studied. Results of media optimization was carbon source, fructose 70 g/L, nitrogen source, soy peptone 12 g/L, yeast extract 2 g/L and showed productivity of 475.6 mg/L which is about 300 times greater than before medium optimization.
Soytone peptone selected as nitrogen source is known to have effect on pyruvate, which is a precursor for CoA such as acetyl-CoA, malonyl-CoA, during metabolic process. Few CoAs are used as precursor for avermectin and soytone peptone is expected to have relation with improving avermectin productivity. Soytone peptone affects genes and pathways related to avermectin production of mutants. Therefore through analysis of relationship between soytone peptone components and the mutant, it is expected to figure out the mutant's avermectin production pathway and why the avermectin production has risen.
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