Cellular fatty acid profile and H⁺-ATPase activity to assess acid tolerance of Bacillus sp. for potential probiotic functional attributes
2014
Shobharani, P. | Halami, Prakash M.
The present study has been focused widely on comparative account of probiotic qualities of Bacillus spp. for safer usage. Initially, 170 heat resistant flora were isolated and selected for non-pathogenic cultures devoid of cytK, hblD, and nhe1 virulence genes. Subsequently, through biochemical tests along with 16S rRNA gene sequencing and fatty acid profiling, the cultures were identified as Bacillus megaterium (AR-S4), Bacillus subtilis (HR-S1), Bacillus licheniformis (Csm1-1a and HN-S1), and Bacillus flexus (CDM4-3c and CDM3-1). The selected cultures showed 70–80 % survival under simulated gastrointestinal condition which was also confirmed through H⁺-ATPase production. The amount of H⁺-ATPase increased by more than 2-fold when grown at pH 2 which support for the acid tolerance ability of Bacillus isolates. The study also examined the influence of acidic pH on cellular fatty acid composition of Bacillus spp. A remarkable shift in the fatty acid profile was observed at acidic pH through an increased amount of even numbered fatty acid (C16 and C18) in comparison with odd numbered (C15 and C17). Additionally, the cultures exhibited various probiotic functional properties. Overall, the study increases our understanding of Bacillus spp. and will allow both industries and consumers to choose for well-defined probiotic with possible health benefits.
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