Bacillus subtilis ESU181 suşunda indol-3-asetik asit biyosentezinin optimizasyonu

Biofertilizers are produced as an alternative to chemical fertilizers and pesticides to ensure sustainability in agriculture, which has gained importance especially in recent years. It is necessary to investigate the native bacterial species in the production of biofertilizers, to determine the mechanisms that affect plant growth in the detected species, and to investigate the conditions under which these mechanisms should be activated to obtain the highest possible crop. Indole-3-acetic acid (IAA) is a hormone that has a significant effect on plant growth. There are few optimization studies in Bacillus subtilis species, which can synthesize this hormone. The main purpose of this thesis is to optimize the ambient conditions for IAA synthesis in B. subtilis strain ESU181 isolated from local einkorn roots. IAA production was observed for 96 hours at three different pH (6.5, 7.5, 8.5) and two different temperatures (30°C and 37°C). IAA measurements were made in 24-hour periods. Since IAA production can occur in two known ways, tryptophan dependent and independent, in the experiment, the medium was arranged in two sets with and without the addition of tryptophan, while keeping the other nutrient types and amounts constant. According to the data, it was observed that the highest IAA production was at the end of 96 hours incubation period at pH 6.5, 37 °C and tryptophan added medium. In addition, it was observed that a significant amount of IAA was produced in the medium without tryptophan addition and the addition of tryptophan did not have as high an effect as expected on this strain. As the reason for the decrease in the amount of IAA observed in the data, storage of IAA in cells was put forward as an intermediate hypothesis and it was observed that no significant amount of IAA was found in cells. The data presented in this study offer the possibility of activating bacterial IAA production in agricultural applications and adaptability for large-scale production of IAA.