Isolation and identification of phosphate solubilizing bacteria from warm-water fish farms as phosphate biofertilizer candidates

The bio-availability of phosphorus for primary producers is reduced mainly due to the formation of complex with cations and organic matter in warm-water fish ponds. Therefore, the most important new approaches for increasing water-soluble phosphate that are consistent with the principles of sustainable agriculture are the use of phosphate solubilizing and mineralizing bacteria (PSB). For this purpose, sampling of the sediment of warm-water fish ponds in central regions of Mazandaran province was carried out. Isolation and identification of bacteria were performed using by National Botanical Research Institute (NBRIP) medium and 16s rRNA gene sequence. The ability of strains to grow in the range of environmental parameters of warm-water fish ponds was also evaluated. In the present study, a total of 64 PSB strains were isolated, among these, 11 stronger PSBs were including Pseudomonas taiwanensis (Persian1 and Persian2), P. putida (Persian3), P. umsongensis (Persian4 and Persian5), P. kilonensis (Persian6), P. frederiksbergensis (Persian7, Persian8 and Persian9), P. deceptionensis (Persian10) and Acinetobacter lactucae (Persian11) had the best performance in solubilizing insoluble phosphates. The results showed that these strains have a high ability to dissolve insoluble phosphate compounds and grow well under the environmental parameter of warm-water fish ponds.