Lactobacillus Acidophilus Oxygen Requirements
The lactobacillus acidophilus is a non flagellated, nonmotile, and non-spore-forming microorganism that metabolizes carbohydrates through homolactic fermentation. The organism also has a low citrate synthase level, making it resistant to antibiotics. Read on to learn about the oxygen requirements of this type of bacteria and the conditions it can thrive.
This study provides new insights into the role of commensal Lactobacilli in maintaining the homeostasis of the host intestinal tract. The researchers found that L. acidophilus reduced the adherence and invasion of enteropathogenic bacteria to Caco-2 cells. The findings suggest that this bacterium’s anti-inflammatory properties may contribute to the protective effect of L. acidophilus on intestinal epithelial cells and may also affect bacterial cell viability.
The original M92 strain of Lactobacillus acidophilus has a morphology resembling a lactobacillus colony. However, new strains of this species have been isolated, which adhere to the tissues of various animals and are resistant to streptomycin and erythromycin. It has been noted that Lactobacillus acidophilus species are occasional human pathogens. These bacteria are classified based on their morphological characteristics.
The bacterium is Gram-positive and anaerobic. It plays an important role in human and animal foodborne diseases. Although it is not a spore-forming microorganism, it is a key agent in treating many human and animal diseases. Because it is resistant to TSI slants and 0.4 mM teepol, it is a vital part of the food chain.
It metabolizes carbohydrates by homolactic fermentation.
When you make beer, Lactobacillus acidophilus is a popular choice because it can ferment many types of sugar and produce several secondary metabolites. Lactobacillus produces lactic acid, an essential component of beer, but not butyric acid or isovaleric acid, which are off-flavors. Some strains of Lactobacillus produce these compounds as a byproduct.
These organisms produce lactic acid, which is a product of homolactic fermentation. Lactobacillus species also produce ethanol/acetate (acetic acid). Acid production is greatest in the exponential growth phase and continues into the stationary and decomposition phases. During growth, only a small fraction of the lactic acid is L-lactic acid, and the remainder is D-lactic acid. Different species produce lactic acid differently. L. Plantarum produces more than twice as much L-lactic acid as L. brevis, and L. reuteri produces slightly more.
Some strains of Lactobacillus can break down starch and polysaccharides. These are called amylolytic LABs. Lb. Plantarum and Lb. paracasei are also amylolytic. Amylolytic LABs can break down starch and polysaccharides. This enzyme is responsible for a distinct flavor in beer.
It has a low citrate synthase.
The synthesis of citrate plays a major role in the biosynthesis of fatty acids and membrane lipids. However, the precise pathways governing the intracellular citrate concentration remain elusive. Interestingly, STAT3 is a key regulator of intracellular citrate levels. Inhibition of STAT3 decreases intracellular citrate, which is crucial for responding to extracellular growth factors. Hence, exogenous citrate restores fatty acid synthesis, cell proliferation, and growth.
It is the first step in the citric acid cycle, the Krebs cycle. In eukaryotic cells, citrate synthase is located in the mitochondrial matrix. It is encoded by nuclear DNA and synthesized by cytoplasmic ribosomes. The resulting product is released into the cytoplasm and enters the mitochondrial matrix through a tricarboxylate carrier.
In the context of human health, cyanobacterial CSS is important for the synthesis of fatty substrates and carbohydrates—the cyanobacteria Synechocystis sp. PCC 6803 has been extensively studied for the production of metabolites. Its biosynthesis and metabolic engineering methods have been used in many applications. However, further research is needed to determine whether or not this enzyme is essential for synthesizing fatty metabolites.
It is resistant to antibiotics.
Lactobacillus acidophilus’s antibiotic resistance may have more to do with the antimicrobials than with its genetic makeup. Certain bacterial strains have different levels of antibiotic resistance, and these differences are often related to antibiotic-resistant genes. Furthermore, there may be transferable resistance genes. Therefore, additional studies of Lactobacillus acidophilus and its antibiotic resistance should be done.
This research reveals that LAB resistance is linked to increased survival rates in antimicrobial environments. Bacterial strains were selected based on their susceptibility to specific antibiotics. The bacteria were isolated from different cultures and then classified using the microdilution method. The MICs of each strain are reliable predictors of antibiotic behavior and should be used to select probiotic adjunct cultures.
The antibiotics that LAB was most susceptible to were clindamycin, amoxicillin, and gentamycin. However, L. curvatus was more resistant to vancomycin, sulphamethoxazole, and chloramphenicol. In addition to these antibiotics, lactobacilli in two hard Italian kinds of cheese were resistant to penicillin, erythromycin, and streptomycin.
It is used as a food ingredient.
Several types of research have supported the safe use of Lactobacillus acidophilus in conventional food. Most strains of this beneficial bacterium are nonpathogenic and non-toxic. The International Dairy Federation has compiled a list of organisms that meet safety criteria for use in the food supply. These organisms may be starter cultures or autochthonous to raw materials. Regardless of their source, however, they must be characterizing.
According to the European Food Safety Authority, a comprehensive safety evaluation was carried out on the species of L. acidophilus listed on the IDF. It incorporated several scientific journals, governmental reviews, and in-house safety studies. The results showed that all strains of L. acidophilus are considered safe for use in foods, and the ingredient is GRAS-approved for use in dairy products.
While most strains of Lactobacillus acidophilus are nonpathogenic, some may be associated with bacteremia, especially those with poor adhesion properties. The risk of bacteremia is minimal, but certain strains may be dangerous for immunocompromised individuals. This is large because most Lactobacillus species are nonpathogenic in humans. However, certain strains of L. rhamnosus may be dangerous for immunocompromised individuals or those with a history of rheumatic endocarditis.
It is resistant to H2O2 decomposing.
This study examined the effect of inoculation methods and cultivation conditions on the growth of L. acidophilus. The isolated strain is nonmotile, catalase-negative, and capable of fermenting glucose, maltose, and sucrose. However, it was not able to ferment arabinose. The strain’s phenotype was further characterized by SEM examination.
The resistance to H2O2 was associated with the presence of the Ohr family, a group of enzymes involved in maintaining intracellular redox balance. Bacillus subtilis possesses OhrA, which induces H2O2 tolerance, and Ohr, which represses the expression of OhrA. However, it is unknown whether this family is found in lactic acid bacteria. Similarly, deletion of the Ohr gene in L. casei IGM394 results in greater H2O2 resistance and increased expression of NADH peroxidase.
Interestingly, these lactic acid bacteria also provide extra benefits in polyphenol metabolism. This process may be an intermediate in the reoxidation of reduced NADH cofactor. In addition, it provides an energy benefit through NAD+ regeneration. However, the specific mechanism is not yet known. Researchers from the University of Florida, Orlando, and the University of Washington in Orlando, Florida, have shown that Lactobacillus acidophilus is resistant to H2O2 decomposing under anaerobic conditions.
It is a nontraditional product.
The bacteria in the lactobacillus acidophilus strain are known as probiotics. They naturally occur in the human gastrointestinal tract, mouth, and vagina and are used in food and dietary supplements. Their ability to survive in the intestinal tract is because they are bile-tolerant. In addition, they can adhere to the mucosal surfaces of the intestine.
The organisms produce lactic acid from various substrates, including sugar. However, the most common byproduct is lactate, accounting for at least 85 percent of the organism’s end product. In contrast, some species are heterofermentative and derive most of their energy from other organic compounds. This means that they may not be as efficient at producing lactate.
While the mechanism of methyl ketone production in L. acidophilus is not clear, the methyl ketone production mechanism is well known in eukaryotic microbes. Methyl ketones are produced through decarboxylation and b-oxidation of fatty acids. On the other hand, Lactones are formed via intramolecular esterification of hydroxy acids. Thus, the lactobacilli may have similar mechanisms.