نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 گروه میکروبیولوژی، دانشکدۀ علوم زیستی، دانشگاه آزاد اسلامی، واحد تهران شمال، تهران، ایران
2 گروه میکروبیولوژی، دانشکدۀ علوم زیستی، دانشگاه آزاد اسلامی، واحد تهران مرکزی، تهران، ایران
3 گروه زیست شناسی، دانشکدۀ علوم زیستی، دانشگاه آزاد اسلامی، واحد تهران شمال، تهران، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective: Prebiotics are indigestible compounds that pass through the gastrointestinal tract without degradation and selectively stimulate the growth and activity of beneficial or probiotic bacteria in the host gut. These compounds, by enhancing beneficial microbial populations, contribute to maintaining microbial balance and improving gastrointestinal health. The present study investigates the innovative role of plant-derived prebiotic compounds in optimizing the growth of probiotics recovered from the wastewater from food-processing factories.
Materials and Methods: The chicory root and wheat bran were prepared, and inulin and arabinoxylan were extracted from chicory root and wheat bran, respectively, using an extraction method. The mean degree of polymerization and the total and reducing sugar contents of inulin and arabinoxylan were determined using the phenol–sulfuric acid method. Sampling from food-processing factories was carried out at the wastewater outlet based on Standard No. 2440, followed by the isolation of yeast and bacterial strains. Diagnostic, biochemical, molecular, and probiotic potential tests, including heat resistance, acid resistance, antibiogram, and bile tolerance, were performed to identify the strain. The similarity of the studied strains was evaluated by constructing a phylogenetic tree using MEGA X software. Four selected strains were treated with different concentrations of inulin and arabinoxylan for 24 hours, both individually and in dual and triple synergistic combinations with inulin and arabinoxylan. To evaluate the effects of plant extracts on probiotic growth, a factorial experimental design was applied, and the results were compared with those of a purchased standard strain. Finally, growth curves of the strains in the presence of prebiotics were plotted, and the results were statistically analyzed using ANOVA (P> 0.05).
Results: Overall, Lactobacillus plantarum, Lactobacillus brevis, and two strains of Saccharomyces cerevisiae (phylogenetic similarity of 97.35-99.31% with standard strains) were identified. Chicory inulin (degree of polymerization = 38.45, carbohydrate = 81.276%, reducing sugar = 1.79%, dry matter = 96.24%) and wheat bran arabinoxylan (degree of polymerization = 41.39, carbohydrate = 88.237%, reducing sugar = 2.14%, dry matter = 96.45%) were superior to the standards. The isolated strains showed desirable growth at 25-42 °C, bile tolerance up to 2%, tolerance to pH 2.5-4, sensitivity to ciprofloxacin (>25 mm), erythromycin (20-30 mm), and vancomycin (>18 mm), and PCR results exhibited bands within the correct range. ANOVA and Tukey tests showed that the mean growth of all four samples treated with inulin and arabinoxylan was higher than that of the control group. Under synergistic conditions, the combination of inulin and arabinoxylan had a greater effect on strain growth compared with other plant extracts.
Conclusion: The chicory inulin (degree of polymerization = 38.45) and wheat bran arabinoxylan (degree of polymerization = 41.39) enhanced the growth of Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus brevis strains under synergistic conditions and improved their stability; therefore, these compounds have high potential for application in the food, livestock, and aquaculture industries.
کلیدواژهها [English]
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