Characterization and comparison of phytase production by Bacillus and Paenibacillus strains from Thai soils

ABSTRACT

Aims: The objective of this research was to isolate, screen and identify phytase-producing bacteria from soils and a potent isolate was selected for its phytase production. Methodology and results: Eight spore-forming bacteria isolated from agricultural soils in Thailand were screened for their phytase production. They were identified as Bacillus and Paenibacillus strains based on their phenotypic characteristics and 16S rRNA gene sequence analyses. The phytase production by Bacillus amyloliquefaciens CH3-1 [Group I(a)] was 20.956 ± 0.099 U/mL, while Bacillus subtilis SR9-3 [Group I(b)] produced 20.588 ± 0.099 U/mL. Five isolates in Group I(c), identified as Bacillus aryabhattai, produced phytase at levels ranging from 2.436 ± 0.116 to 20.910 ± 0.000 U/mL, while Paenibacillus cineris CM5-3 (Group II) produced 1.261 ± 0.111 U/mL. A potent strain, CH3-1, produced the highest phytase when cultivated in Phytate Specific Medium (PSM) supplemented with 1% glucose, at pH 7.0 and incubated at 45 °C. Additionally, wheat bran and sorghum seed (0.5%) substrates were used to induce phytase production by replacing Na-phytate. Conclusion, significance and impact of study: Phytase producing bacteria were isolated from soils in Thailand. Gram-positive spore forming thermotolerant Bacillus strains displayed higher phytase activity than a Paenibacillus strain. A potent strain, CH3-1, could utilize agricultural waste as a substrate, which may be useful for animal feed supplementation.