Identification of avermectin-high-producing strains by high-throughput screening methods.

Avermectins produced by Streptomyces avermitilis are potent against a broad spectrum of nematode and arthropod parasites with low-level side effects on the host organisms. This study was designed to investigate a high-throughput screening strategy for the efficient identification of avermectin high-yield strains. The production protocol was miniaturized in 96 deep-well microplates. UV absorbance at 245 nm was used to monitor avermectin production. A good correlation between fermentation results in both 96 deep-well microplates and conventional Erlenmeyer flasks was observed. With this protocol, the production of avermectins was determined in less than 10 min for a full plate without compromising accuracy. The high-yield strain selected through this protocol was also tested in 360 m(3) batch fermentation with 1.6-fold improved outcome. Thus, the development of this protocol is expected to accelerate the selection of superior avermectin-producing strains.