Abstract:
Low efficiency of P chemical fertilizers absorbed by plant raises the idea of using
phosphate solubilizing bacteria as biofertilizer agent. Phosphate solubilizing bacteria (PSB)
is a group of bacteria that able to transform insoluble P into soluble P that available for
plants. The purpose of this study was to produce powder-biofertilizer using peat soil
moistured for 10% as a carrier material and to compare the quality of both biofertilizer
produced for a period of 3 months based on shelf life of PSB. Four potentially PSB isolates
were chosen as biofertilizer agents and subcultured on agar slant Pikovskaya. The isolates
were used as a starter and inoculated into liquid pikovskaya medium to produce starter I
that consists of four isolates (BB_UB6, BB_K2, BB_K9 and BB_HS13), starter II that
consists of three isolates (BB_UB6, BB_K2 and BB_K9), and starter III that consists of
two isolates (BB_UB6 and BB_K9). Each of the log phase of starter was inoculated into
sterilized peat carrier materials and fermented for four days at room temperature due to
powder-biofertilizer production. At the end of fermentation process, the biofertilizer was
directly packaged and stored in the refrigerator for 0, 1 and 3 months. Biofertilizer quality
was analyzed by quantifying the PSB population and biofertilizer pH. The treatment of peat
carrier moistured at 10% was able to maintain the viability of the PSB in period of 3
months strorage ranging 6.6 x 1010-2.09 x 1011CFU/gr and pH range 5.1-6.9. The value is
still in accordance with the quality standards the population of biofertilizer agent
≥107CFU/gr.
