Physicochemical and microbial responses of Streptomyces natalensis HW-2 to fungal elicitor

The effects of fungal elicitor on the physicochemical and microbial responses of Streptomyces natalensis HW-2 were investigated. The results showed that the elicitor could decrease dry cell weight (DCW) by 17.7% and increase the utilization of glucose, while the curve of pH was not obviously altered. The elicitor enhanced the yield of natamycin from 1.33 to 2.49 g/L. The morphology of the colony and the mycelium treated with elicitor showed significant differences from that of control. The level of intracellular reactive oxygen species (ROS) increased to 333.8 ng/L, which was a twofold increase comparing with the control. The concentration of Ca 2+ reached 421.1 nmol/L, which increased by 32.8% after the addition of the elicitor. The activities of pyruvic carboxylase and phosphoenol pyruvate carboxylase were enhanced by 27.8 and 11.9%, respectively, while citrate synthase activity decreased by 23.1% in comparison with the control.