Characterization of phosphate solubilizing bacteria and nitrogen fixing bacteria from limestone mining region
- Author:
Dini Fitriyanti
;
Nisa Rachmania Mubarik
- Publication Type:Original Article
- Keywords:
16S rRNA, nitrogen fixing bacteria, limestone soil, phosphate solubilizing bacteria
- From:Malaysian Journal of Microbiology
2017;13(3):147-155
- CountryMalaysia
- Language:English
-
Abstract:
Aims: Phosphate and nitrogen are major macronutrients needed by plants. Phosphates in the soil are present in the
organic and inorganic form. The amounts of phosphate and nitrogen in marginal soil can be increased by plant growth
promoting rhizobacteria (PGPR). The aim of this study was to isolate and characterize phosphate solubilizing bacteria
which has ability to fix nitrogen from the soil around limestone mining area.
Methodology and results: There were 22 isolates that could solubilize phosphate and fix nitrogen. There were 9
isolates that could not cause hypersensitivity symptoms (necrotic) on tobacco leaf. Quantitative assay of phosphate
solubilizing was done by colorimetric method. Quantitative assay of phosphate showed that isolate GPC1.7 had the
highest phosphate solubilizing activity on Pikovskaya broth (450 mg/L) on the 6th and 7th day of incubation whereas
isolate GPA2.2 had the highest nitrogen fixing activity (0.162 ppm/h), measured with Acetylene Reduction Assay
whereas nitrogenase activity of GPC1.7 was unidentified. Isolate GPA2.1 and GPA2.2 were Gram negative bacteria
whereas isolate GPC1.7 was Gram positive bacteria. Identification based on 16S rRNA gene showed that GPA2.1 was
closely related to Pseudomonas psychrotolerans, GPA2.2 was closely related to Stenotrophomonas maltophilia, GPC1.7
was closely related to Bacillus megaterium and B. aryabhattai.
Conclusion, significance and impact of study: Phosphate solubilizing bacteria and nitrogen fixing bacteria isolate
could be further used for revegetation process of the ex-limestone mining area.
