Anita Khanafari - Microbiology Department, North Tehran Branch, Islamic Azad University, Tehran, Iran
Tayebeh Akbari - Microbiology Department, North Tehran Branch, Islamic Azad University, Tehran, Iran
Mahmoud Reza Sohrabi - Chemistry Department, North Tehran Branch, Islamic Azad University, Tehran, Iran

Objective(s):   The production of nano-hydroxyapatite by two encapsulated bacterial strains was the goal of current research.  Materials and Methods:   Serratia marcscens ATCC 14756 and Pseudomonas aeruginosa PTCC 1570 were used by two methods including encapsulated form in 2% (w/v) alginate sodium powder and inoculated form (10%) in nutrient broth medium containing alginate sodium blank beads. In both cases alginate beads transferred to calcium and phosphorus precursors mineral medium for 48 h and were incubated at 32-35 °C for 14 days. To obtain hydroxyapatite powder, alginate beads were dried at 60 °C and rubbed. Sol-gel as chemical method was used for comparing with microbial analysis. The nature of produced powders was evaluated in each step by XRD, FTIR and scanning electron microscopy.  Results:   The results showed that the yield rate of sol-gel method was 18.3% and it was much more than encapsulated method (3.032 and 3.203 w/w dried alginate bead). The size of the particles in microbial method were smaller (8-68 nm cylindrical particles and 12-55 and 15-37 nm spherical particles) than chemical method (350-880 nm of cylindrical and 34-67 nm of spherical particles).  Conclusion:   Nanoparticle sizes and distribution of microbial nano-hydroxyapatite powder samples shows that it has excellent physical properties similar to natural bone and may be to produce dense and porous bioactive bone implants with desired properties.

Alginate beads, Hydroxylapatite, Nanoscale, Pseudomonas aeruginosa, Serratia marcescens