Metabolic Engineering of Bacteria for Food Ingredients

Bacteria produces metabolites and their metabolic pathway can be manipulated to produce good food ingredients. These ingredients includes different amino acids, vitamins, carbohydrates, organic acids aroma compounds and bacteriocins. Different genes in different strains of bacteria are identified and harnessed to attain food ingredients and results of manipulation were satisfying. The metabolic pathway of lactic acid bacteria is manipulated to produce amino acids such as L-alanine was produced by silencing the gene that encodes alanine racemase. Moreover, low calorie sugars such as mannitol and tagatose were produced. Lac-lactis is engineered by silencing lacC and lacD genes for the production of tagatose.

Download Full-text

Products of Metabolism and Processing of Lactic Acid Bacteria as Functional Ingredients

Food Science and Applied Biotechnology ◽

10.30721/fsab2018.v1.i1.13 ◽

2018 ◽

Vol 1 (1) ◽

pp. 47 ◽

Cited By ~ 1

Author(s):

Antonina Ivanovna Kapustian ◽

Natalia Cherno ◽

Alexei Kovalenko ◽

Kristina Naumenko ◽

Igor Kushnir

Keyword(s):

Amino Acids ◽

Molecular Weight ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Organic Acids ◽

Cell Walls ◽

Degradation Products ◽

Lactobacillus Delbrueckii ◽

Low Molecular Weight ◽

Gel Chromatography

Lactic acid bacteria (LAB) and bifidobacteria (BB) are unique substances that have a lot of biological and physiological effects. Structural components of LAB and BB – peptidoglycans, compounds of the muramylpeptide series, teichoic acids – have powerful immunological properties. Metabolites of LAB and BB – organic acids, hydrogen peroxide, bacteriocins, etc. – provide antagonistic activity, have an indirect impact on the immune system, reducing the antigenic load caused by pathogenic microorganisms. The expediency of peptidoglycans degradation of LAB and BB cell walls is substantiated. Low molecular weight products of the degradation can easily be absorbed and enter into biochemical processes, accelerating the expected functional-physiological effect. To obtain low-molecular products of peptidoglycans degradation, a combination of LAB and BB was used. The combination of LAB and BB is the sum of the test cultures of Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. Bulgaricus, Bifidobacterium bifidum, Lactococcus cremoris, Streptococcus termophilus. Destruction of peptidoglycans of bacterial cell walls was carried out using a combination of disintegrating factors. The efficiency of destruction was determined by the accumulation of low molecular weight peptides (with molecular weight up to 1500 Da), amino acids and soluble protein in the disintegrate. It has been established that the highest accumulation of low molecular weight degradation products occurs when using autolysis followed by enzymatic hydrolysis during 180 min with the ratio of the enzyme : substrate 1 : 100. At the same time ≈ 53% of protein substances pass from insoluble to soluble state. The molecular weight of the obtained products is determined by the gel chromatography method. The qualitative and quantitative content of organic acids, amino acids and vitamins of group В in the hydrolysis products composition was investigated. It was shown that the obtained product possesses high biological effect in the experiment on animals.

Download Full-text