Enhanced Production of Avermectin B1a with Streptomyces avermitilis

It has been reported that Streptomyces avermitilis is able to produce a number of potent anthelmintic and insecticidal agents known as the avermectins. Among those compounds, avermectin B1a has the most effective antiparasitic activity, and has been successfully commercialized as a powerful agricultural pesticide and antiparasitic agent.Mutant strain of S. avermitilis ATTC 31271(AJ-7) was obtained via random mutation using NTG (3 mg/ml, 60 minutes). For further improvement of avermectin B1a production from AJ-7, optimization of current avermectin B1a production medium was studied. Result of medium optimization was showed productivity of 475.6 mg/L which is about 300 times greater than before medium optimization. Cobalt and vitamin B12 are believed to be the most critical elementsin secondary metabolism. Furthermore attempts were made to increase avermectin B1a production using Co2+ and Vitamin B12. As a result, avermectin B1a production decreased with higher concentration of CoCl2 and vitamin B12.The results indicated that two substances are not required for increasing production of avermectin B1a in AJ-7. Using these results currently, fermentation using bioreactor to achieve scale up is underway.