[Induced synthesis of hydroxyapatite by Aspergillus niger].

Objective: The research objective is to induce hydroxyapatite (HAP) synthesis by using fungus.

Methods: We used the PDA (Potato Dextrose Agar Medium) liquid medium containing different concentrations of Na2HPO4 and CaCO3 to study the way Aspergillus niger synthesize HAP, to observe the induced mineral crystal structure and to analyze the induced mineral type with transmission electron microscopy (TEM) and X-ray diffraction (XRD).

Results: The main results are as follows: (1) A. niger can induce HAP synthesis in PDA liquid medium with the proper concentration of Na2HPO4 and CaCO3. (2) The reaction of A. niger inducing HAP synthesis depends on the time of the response system. Longer time is more advantageous in producing HAP. The main reason for A. niger inducing HAP crystals formation are as follows: fungal metabolism produces the acidic substances to dissolve CaCO, and the growth mycelia absorbing Ca2+ lead to Ca2+ enriched on the surface, to promote the production of secondary mineral apatite and further transform into HAP in the mycelia spheres.

Conclusion: A. niger can inducing HAP crystals formation in PDA liquid medium containing Na2HPO4 and CaCO3. Considering the importance of HAP in bio-medicine materials and its costly prices, our method for HAP bio-induction is of the temperate response condition, simple preparation craft, and lower cost, which has the potential application prospect.