Pseudomonas Otitidis and Bacillus Subtilis from Saline Soil of Pakistan Exhibiting a Potential for Calcium Precipitation

Abstract

Biomineralization is an important phenomenon reported in microbes of different environments. Present
study deals with the analysis of mineralization potential of two salt tolerant species named IQ (Pseudomonas otitidis)
and NAY (Bacillus subtilis) isolated from rhizosphere soil. These strains have the ability to show precipitation in
acetate supplemented culture medium incubated for 21 days and showed positive results for urease tests. Increase in
microbial precipitation was recorded in both strains. However, strain NAY (Bacillus subtilis) showed more
precipitation as compared to other IQ (Pseudomonas otitidis). It was also observed that this precipitation was associated
with increase in pH of the medium from 7.0 to 8.0 that started to increase on 4th day of culture incubation and
increased slightly till 15 days. The FTIR analysis of the calcite crystals showed visible peaks at 711-1400 cm-1
wavelength. The visible bubbling appeared in acid test assay further confirmed the calcite precipitation. The mineral
precipitation in both species under salt stress is significant for soil consolidation as well as adjusting soil pH under
acidic conditions.