An in vitro chicken gut model for the assessment of phytase producing bacteria.

Abstract

An in vitro simulated chicken gut model was proposed for studying the phytase activity of selected bacteria such as Streptococcus thermophilus, Sporosarcina pasteurii, Sporosarcina globispora, and Sporosarcina psychrophila using known probiotic bacterium, Lactobacillus helveticus as a control. The selected bacteria were viable in the intestinal lumen and produced extracellular phytase at optimal phytate concentration of 6.25mM when compared to 3.125mM and 12.5mM. These bacteria demonstrated significantly higher (p < 0.05) phosphate liberation (up to 387µM) due to better phytase activity in the production medium, when compared to the growth medium (339µM). The phytase activity showed a steady increase in phosphate liberation up to 150min after which it became constant. This trend is observed for the selected bacteria at pH 5, 6 and 7. However, the liberation of phosphates showed no significant difference (p > 0.05) at the tested pH. Among the analyzed bacteria, the members of the genus Sporosarcina showed better phytate degradation when compared to S. thermophilus. The proposed model can be extended to analyze any extracellular enzymes produced by gut microbes.