• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.133-143
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• 2014

The development of the gut is controlled and modulated by different interacting mechanisms, such as genetic endowment, intrinsic biological regulatory functions, environment influences and last but no least, the diet influence. In this work, we compared the fecal microbiota of breast-fed (BF), formula-fed (FF), and mixed-fed (MF) infants from Hebei Province, China. By using high-throughput 16S rDNA sequencing analyses, we found some differences in gut microbiota in the three groups. Firmicutes and Proteobacteria were the dominant bacteria at the phylum level in the three groups, where FF infants showed a significant depletion in Bacteroidetes (p < 0.001) and Actinobacteria (p < 0.05). Enterobacteriaceae was the dominant bacteria at the family level in the three groups, but FF infants showed higher Enterobacteriaceae enrichment than BF and MF infants (p < 0.05); the abundance of the Bifidobacteriaceae was only 8.16% in the feces of BF infants, but higher than in MF and FF infants (p < 0.05). The number of genera detected (abundance >0.01%) in BF, MF, and FF infants was only 15, 16, and 13, respectively. This study could provide more accurate and scientific data for the future study of infant intestinal flora.

• Journal of Dairy Science and Biotechnology
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• v.30 no.1
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• pp.45-53
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• 2012

Lactobacillus acidophilus isolated from the feces of a 7-day-old breast-fed infant was characterized to examine the scope of its commercial use. Forty-three Lactobacillus strains, which could grow at pH 5.5, were isolated. From these Lactobacillus isolates, 14 Lactobacillus strains were selected, which demonstrated more than 80% viability and homofermentative lactic fermentation. Finally, 9 L. acidophilus strains (NB 201~NB 209) were identified as candidate strains based upon biochemical properties, carbohydrate utilization, and cellular fatty acid composition. L. acidophilus isolates demonstrated a survival rate of more than 80% when exposed to pH 2.5 for 2 h. In particular, L. acidophilus NB 204 showed a strong acid tolerance, with a 71% survival rate even at pH 2.0. L. acidophilus isolates also manifested high bile acid tolerance; more than 87% of the cells survived on agar containing 1% bile extract, except for L. acidophilus NB 206, which showed a 73% survival rate. All L. acidophilus isolates were confirmed to have proteolytic activity; L. acidophilus NB 204 and NB 209 yielded higher levels of TCA-soluble peptides and free amino acids. The ${\beta}$-galactosidase activity of the L. acidophilus isolates was in the range of 1.97~2.45 units/mL.

• Preventive Nutrition and Food Science
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• v.10 no.4
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• pp.333-339
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• 2005

Three lactobacillus strains, two from infant feces, and one from cow's milk, were selected among 172 isolates, from multiple sources, for further study based on the antimicrobial activities against six strains of pathogenic bacteria and identified as Lactobacillus acidophilus. The strains revealed a wide scope of spectrum against pathogenic bacteria. Viable Lactobacillus acidophilus KH-l cell counts at pH 2.0 were slightly decreased to $1.42\times10^7$ CFU/mL from $4.18\times10^7$ CFU/mL, while remaining at $3.42\times10^7$ CFU/mL at pH 4.0 with the survival rate of $33.97\%\;and\;81.82\%$, respectively. At the concentration of $0.1\%$ oxgall, L acidophilus KH-l kept growing up to $3.12\times10^7$ CFU/mL with a mean growth rate constant (k) of 0.25, and cell number was slightly decreased to $1.21\times10^7$ CFU/mL (k=0.19) with $0.3\%$ oxgall, but remained at $7.6\times10^6$ CFU/mL (k=0.17) with $0.5\%$ oxgall. L. acidophilus KH-l had a $D_{60}$ value of 7.14, with viable cell numbers $1.4\times10^5$ CFU/mL after heat treatment at $60^{\circ}C$ for 30 minutes. Stability of L acidophilus KH-l at $-20^{\circ}C$ was significantly higher, when the strain was cultivated under the optimum growth temperature $(54.41\%\;and\;54.35\%)$ than at the temperature $(13.53\%)$.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1244-1247
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• 2003

The purpose of this study was to isolate lactic acid bacteria that produced L(+) lactic acid from infant feces. Thirteen colonies were isolated with a MRS-plate containing 0.5% $CaCO_3$ to determine their ability to produce lactic acid. Based on their lactic acid production, 10 strains of Lactobacillus were identified to assess the ratio of lactate isomer using HPLC. A strain producing L-lactic acid was identified as Lactobacillus acidophilus, using API carbohydrate fermentation patterns and physiological tests, and named KY1909. The strain exhibited good acid tolerance in an artificial gastric juice as well as high bile resistance in MRS containing 0.5% bile acids. L. acidophilus KY1909 produced D(-) and L(+) lactic acid at a ratio of 6 : 94; whereas commercial strains of Lactobacillus acidophilus produced D(-) and L(+) lactic acid at a ratio of 1 : 1. These results demonstrate the L. acidophilus KY1909 can be utilized in fermented milk products and dietary supplements as a probiotic culture.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.596-603
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• 2008

Lactobacillus acidophilus is a normal inhabitant of the human intestine and its numerous health benefits have been reported. This organism is referred to as a "starter culture". This study was conducted to verify that the production of flavor compounds in fermented milk was obtained using a good probiotic strain of L. acidophilus from breast-fed infant feces. The bitter-tasting amino acids, such as arginine and histidine were produced in larger amounts than other free amino acids when L. acidophilus strains were inoculated in skim milk. The lactic acid was the major acid produced from glucose. L. acidophilus NB 209 was the best producer of lactic acid. This L. acidophilus NB 209 produced higher amounts of acetaldehyde than other L. acidophilus strains. L. acidophilus NB 209 gave higher flavor and taste score of the yogurt produced than other L. acidophilus strains in sensory evaluation. These results indicate that L. acidophilus NB 209 has the potential to be developed as a starter culture for fermented milk products.