Enhancement of botrallin and TMC-264 production in liquid culture of endophytic fungus Hyalodendriella   sp. Ponipodef12 after treatments with metal ions

Background: Hyalodendriella sp. Ponipodef12, an endophytic fungus from a poplar hybrid, was a high producer of botrallin and TMC-264 with various bioactivities. In this study, the influences of eight metal ions (i.e., Mn²⁺, Na⁺, Mg²⁺, Zn²⁺, Cu²⁺, Fe²⁺, Fe³⁺ and Al³⁺) on botrallin and TMC-264 production in liquid culture of the endophytic fungus Hyalodendriella sp. Ponipodef12 were investigated.
Results: Three most effective metal ions (Zn²⁺, Cu²⁺ and Mg²⁺) along with their optimum concentrations were screened. The optimum addition time and concentrations of Zn²⁺, Cu²⁺ and Mg²⁺ were further obtained respectively for improving botrallin and TMC-264 production. The combination effects of Zn²⁺, Cu²⁺ and Mg²⁺ on the production of botrallin and TMC-264 by employing statistical method based on the central composite design (CCD) and response surface methodology (RSM) were evaluated, and two quadratic predictive models were developed for botrallin and TMC-264 production. The yields of botrallin and TMC-264, which were predicted as 144.12 mg/L and 36.04 mg/L respectively, were validated to be 146.51 mg/L and 36.63 mg/L accordingly with the optimum concentrations of Zn²⁺ at 0.81 mmol/L, Cu²⁺ at 0.20 mmol/L, and Mg²⁺ at 0.13 mmol/L in medium.
Conclusion: The results indicated that the enhancement of botrallin and TMC-264 accumulation in liquid culture of the endophytic fungus Hyalodendriella sp. Ponipodef12 by the metal ions and their combination should be an effective strategy.

Keywords
Combination effects; Production; Microbial biotechnology; Process biotechnology; Bioactivities; Central composite design; Response surface methodology