Nutrient consumption patterns of Lactobacillus acidophilus

Abstract BACKGROUND One of the greatest challenges in using Lactobacillus acidophilus as a probiotic is acid stress. The current research aimed to identify substances that help L. acidophilus resist acid stress; this was achieved through assessing its nutrient consumption patterns under various pH conditions. RESULTS The consumption rates of alanine, uracil, adenine, guanine, niacin, and manganese were consistently higher than 60% for L. acidophilus LA‐5 cultured at pH 5.8, 4.9, and 4.4. The consumption rates of glutamic acid + glutamine and thiamine increased with decreasing pH and were higher than 60% at pH 4.9 and 4.4. The viable counts of L. acidophilus LA‐5 were significantly increased under the corresponding acidic stress conditions (pH 4.9 and 4.4) through the appropriate addition of either alanine (3.37 and 2.81 mmol L −1 ), glutamic acid + glutamine (4.77 mmol L −1 ), guanine (0.13 and 0.17 mmol L −1 ), niacin (0.02 mmol L −1 ), thiamine (0.009 mmol L −1 ), or manganese (0.73 and 0.64 mmol L −1 ) ( P < 0.05). The viable counts of L. acidophilus LA‐5 cultured in a medium supplemented with combined nutritional factors was 1.02–1.03‐fold of the counts observed in control medium under all acid conditions ( P < 0.05). CONCLUSION Alanine, glutamic acid + glutamine, guanine, niacin, thiamine, and manganese can improve the growth of L. acidophilus LA‐5 in an acidic environment in the present study. The results will contribute to optimizing strategies to enhance the acid resistance of L. acidophilus and expand its application in the fermentation industry. © 2024 Society of Chemical Industry.