Growth Optimisation of Bacillus subtilis in medium supplemented with prebiotic gum Arabic

Bacillus subtilis is a type of gastrointestinal bacteria that build up a healthy gut microbiota. The bacterial species has been well documented to involve in maintaining a healthy gut homeostasis in which disruption in it's microbial composition or "dysbiosis" has recently been linked to obesity. Probiotic in vivo restoration of dysbiosed microbiota have been proved successful in obese CD-1 mice model. However, prebiotic study using Gum Arabic (GA) assessing to optimise an in vitro lumen system specifically targeting to enhance the growth of B. subtilis are still lacking since this bacteria are depleted in obese individuals. Thus, this study aimed to establish the optimal growth conditions in simulated in vitro lumen system and to the best of our knowledge, this is the first in vitro study attempted to optimize the growth of B. subtilis in medium supplemented with prebiotic GA. Growth screening analysis suggested an optimal dosage of 1.0% and 0.5% glucose and GA, respectively. The highest growth rate was recorded at 0.7995 hours⁻¹ with doubling time of 52.02 minutes with extended period of stationary phase. The optimal GA concentration and fermentation conditions were determined at 0.67%, pH 7.4 and temperature of 37°C. The validated suggested model indicates that the supplementation of GA into an optimal fermentation systems is promising to enhance the growth of gut microflora Bacillus subtilis, for restoration of a dysbiosed gut microbiota in vitro.