2017 ASHS Annual Conference

There are various types of limitations for the mass production of the biocontrol agents such as the expensive incubating facilities and media. In this study, the cost-effective incubator for the mass production of bacteria was considered to replace the expensive incubating facilities. The low-cost BB medium treated with 2% H₂O₂ which had been previously developed and optimized for mass cultivation was used throughout this study. 5g of soil was inoculated in 100ml of the non-autoclaved BB medium for 3h and then treated with 30 ppm of Ca(ClO)₂. After 12hours, a thermophilic strain, Bacillus amyloliquefaciens Y1 was inoculated. At 2 days after inoculation, only Y1 was observed, which means that Ca(ClO)₂ completely sterilized any contaminated microbes in the medium. When Y1 was cultured in the plastic incubator containing 500L of BB medium with tap water at 40ºC for 3 days, Y1 was mainly observed with 1.07x10⁵CFU/mL. However, small portion of other microbes was also found with 0.91x10⁴CFU/mL. This experiment was repeated at the different fields, Hwasun and Yeonggwang, Jeonnam Province, South Korea. The population of Y1 in Hwasun was examined 4.2x10⁵ CFU/mL together with 1.0x10⁴CFU/mL of other contaminated microbes. At Yeonggwang, the population of Y1 and contaminated microbes were detected 2.06x10⁵CFU/mL and 1.36x10⁵CFU/mL, respectively. Y1 was cultured in the iron incubator containing 15,000L of BB medium with tap water at 40ºC for 8 days in Gwangju Agricultural Technology Center, Gwangju city, South Korea. In this experiment, the population of Y1 was examined with 1.7x10⁷ CFU/mL, which was the highest value among the experiment trials. The results of our study demonstrated that the low-cost incubator and medium can be used for Y1 culture without autoclaving at the agricultural fields.