Abstract:The growth of Bifidobacterium animalis was tested, under batch and continuous culture conditions, for dependence upon specific nitrogen compounds. The addition of nitrogen bases (adenine, xantine, and guanine) to the medium containing acid-hydrolyzed casein significantly affected the growth of B. animalis, whereas no significant growth was reported when those bases were added to the medium containing only free amino acids; B. animalis was characterized by a max of 0.16/h when growth took place in PROLAB medium… Show more
“…In vivo, the activity of DNA-cytosine methyltransferase (EC 2.1.1.37) may contribute to the formation of S-adenosyl-L-homocysteine. Besides cysteine and methionine, in silico predictions further suggested that BB-12 and BB-46 can use peptides as an organic sulfur source, which agrees with former studies demonstrating the ability of bifidobacteria to grow in a medium containing hydrolyzed casein instead of free amino acids 38 , 39 . Fig.…”
Section: Resultssupporting
confidence: 87%
“…No CDM reported in literature for bifidobacteria contained the combination of pantethine, menaquinone-4, and nicotinic acid 38 – 41 , which explains their inability to sustain reproducible growth of BB-12 and BB-46 in this study for multiple subcultures. Even though early publications described pantethine as an essential growth factor for Bifidobacterium strains 36 , 44 , 47 , 48 , several newer studies on medium development for bifidobacteria have ignored this finding 39 – 41 . For example, a previously developed CDM for a B. animalis strain lacked pantethine and nicotinic acid 39 .…”
Although bifidobacteria are widely used as probiotics, their metabolism and physiology remain to be explored in depth. In this work, strain-specific genome-scale metabolic models were developed for two industrially and clinically relevant bifidobacteria, Bifidobacterium animalis subsp. lactis BB-12® and B. longum subsp. longum BB-46, and subjected to iterative cycles of manual curation and experimental validation. A constraint-based modeling framework was used to probe the metabolic landscape of the strains and identify their essential nutritional requirements. Both strains showed an absolute requirement for pantethine as a precursor for coenzyme A biosynthesis. Menaquinone-4 was found to be essential only for BB-46 growth, whereas nicotinic acid was only required by BB-12®. The model-generated insights were used to formulate a chemically defined medium that supports the growth of both strains to the same extent as a complex culture medium. Carbohydrate utilization profiles predicted by the models were experimentally validated. Furthermore, model predictions were quantitatively validated in the newly formulated medium in lab-scale batch fermentations. The models and the formulated medium represent valuable tools to further explore the metabolism and physiology of the two species, investigate the mechanisms underlying their health-promoting effects and guide the optimization of their industrial production processes.
“…In vivo, the activity of DNA-cytosine methyltransferase (EC 2.1.1.37) may contribute to the formation of S-adenosyl-L-homocysteine. Besides cysteine and methionine, in silico predictions further suggested that BB-12 and BB-46 can use peptides as an organic sulfur source, which agrees with former studies demonstrating the ability of bifidobacteria to grow in a medium containing hydrolyzed casein instead of free amino acids 38 , 39 . Fig.…”
Section: Resultssupporting
confidence: 87%
“…No CDM reported in literature for bifidobacteria contained the combination of pantethine, menaquinone-4, and nicotinic acid 38 – 41 , which explains their inability to sustain reproducible growth of BB-12 and BB-46 in this study for multiple subcultures. Even though early publications described pantethine as an essential growth factor for Bifidobacterium strains 36 , 44 , 47 , 48 , several newer studies on medium development for bifidobacteria have ignored this finding 39 – 41 . For example, a previously developed CDM for a B. animalis strain lacked pantethine and nicotinic acid 39 .…”
Although bifidobacteria are widely used as probiotics, their metabolism and physiology remain to be explored in depth. In this work, strain-specific genome-scale metabolic models were developed for two industrially and clinically relevant bifidobacteria, Bifidobacterium animalis subsp. lactis BB-12® and B. longum subsp. longum BB-46, and subjected to iterative cycles of manual curation and experimental validation. A constraint-based modeling framework was used to probe the metabolic landscape of the strains and identify their essential nutritional requirements. Both strains showed an absolute requirement for pantethine as a precursor for coenzyme A biosynthesis. Menaquinone-4 was found to be essential only for BB-46 growth, whereas nicotinic acid was only required by BB-12®. The model-generated insights were used to formulate a chemically defined medium that supports the growth of both strains to the same extent as a complex culture medium. Carbohydrate utilization profiles predicted by the models were experimentally validated. Furthermore, model predictions were quantitatively validated in the newly formulated medium in lab-scale batch fermentations. The models and the formulated medium represent valuable tools to further explore the metabolism and physiology of the two species, investigate the mechanisms underlying their health-promoting effects and guide the optimization of their industrial production processes.
“…Bifidobacterium breve UCC2003 (previously designated NCIM B8807), originally isolated from an infant nursing stool (Ventura et al, 2004b), was routinely cultured in reinforced clostridial medium (RCM) at 37 uC in an anaerobic chamber (Don Whitley Scientific). Where mentioned, a defined medium (DM) based on that described by Kongo et al (2003) was used to culture B. breve, with glycine betaine (Sigma) being added as a filter-sterilized solution. Escherichia coli MKH13 was grown in Luria-Bertani (LB) medium at 37 uC with agitation.…”
“…animalis in small ruminant milk media (Gomes and Malcata 1998a,b), in cow milk (Gomes et al. 1995, 1998) and in artificial medium (Kongo et al. 2003) have been undertaken.…”
Section: Introductionmentioning
confidence: 99%
“…acidophilus and Bif. animalis in small ruminant milk media (Gomes and Malcata 1998a,b), in cow milk (Gomes et al 1995(Gomes et al , 1998 and in artificial medium (Kongo et al 2003) have been undertaken. Other studies within our group (not published) have also shown a commensalistic growth relation in mixed cultures of Lact.…”
Aims: This work was undertaken to study the feasibility and the characteristics of a fermented product made of goat milk, using a mixed starter culture of Bifidobacterium animalis and Lactobacillus acidophilus under controlled conditions, and to determine their survival in the fermented milk during refrigerated storage.
Methods and Results: Goat milk was inoculated with Lact. acidophilus and Bif. animalis mixed starter, fermented in a glass bioreactor with controlled temperature (37°C) and anaerobiosis, and monitored for growth and acidification. The fermented milk was then stored for 10 days under refrigeration, and monitored daily for starter microflora survival and pH changes. Lact. acidophilus viable counts reached a maximum of 7·1 × 108 colony‐forming units (CFU) ml−1, and Bif. animalis a maximum of 6·3 × 107 CFU ml−1 by 20 h of fermentation. During refrigerated storage, both strains exhibited a good survival, with viable numbers remaining essentially constant throughout the experiment, whereas the pH of the fermented milk dropped slightly.
Conclusions: Mixed cultures of Bif. animalis and Lact. acidophilus may be used to produce fermented goat milk with high counts of both probiotic strains.
Significance and Impact of the Study: Goat milk fermented with Bif. animalis and Lact. acidophilus can be manufactured as an alternative probiotic dairy product.
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