lactobacilli : Their Role and Importance
in Contemporary Food and
Pharmaceutical Industry
Past-Present-Future
Dr. Myrto -Panagiota Zacharof ¹
Dr. Robert W. Lovitt²
¹Multidisciplinary Nanotechnology Center,
Swansea University, Swansea, SA2 8PP, UK
² College of Engineering, Multidisciplinary
Nanotechnology Center, Swansea University,
Swansea, SA2 8PP, UK
lactobacilli and their Industrial
Importance
• lactobacilli are Gram positive (+) bacteria, shaped
as rods which belong to the group of LAB.
• They are natural habitants, rapidly colonising
mammalian mucosal membranes such as oral
cavity, intestine and vagina.
• They are found where rich carbohydrate sources
are available such as plants and materials of plant
origin for example sewage and fermenting or
spoiled food (Bernardeau et al., 2006).
lactobacilli and their Industrial
Importance
• lactobacilli may affect the quality, flavour, odour and
texture of the final product in either a favourable or a
detrimental way (Cutting, Carr, & Whiting, 1975).
• The genera important members of this group are
Lactobacillus, Leuconostoc, Pediococcus and
Streptococcus.
• lactobacilli are also considered to be probiotic
bacteria. Probiotics are live microorganisms that
exhibit beneficial effects on the host’s health beyond
inherent basic nutrition (Rose, 1978).
lactobacilli and their Industrial
Importance
• lactobacilli fill in the major criteria that a
microorganism should meet to be considered as a
probiotic.
• lactobacilli have proven to be effective against
intestinal
inflammation,
maintenance
of
remission in Chron’s disease, treatment of
infections during pregnancy, prevention of
urinary tract infections (Ahrne et al., 2005).
lactobacilli and their Industrial
Importance
• lactobacilli distinctive ability is to produce lactic acid
from carbohydrate sources, especially from lactose and
glucose.
• Many of them have been found to produce
antimicrobial activity possessing molecules called
bacteriocins.
Application of lactobacilli in the
Contemporary Food industry
Starter Cultures of Lactic Acid Bacteria (LAB)
• Nowadays, LAB are constantly used in the food
process industry in the form of starter cultures
(Ross et al., 2005).
• lactobacilli are widely applied in the food industry
as the acids they produce suppress pH below the
growth range causing metabolic inhibition of most
pathogenic bacteria (Gruger& Gruger, 1989).
Application of lactobacilli in Dairy
Industry
• Lactic Acid Bacteria (LAB) especially lactobacilli are
responsible for the formation of the microflora of most
dairy products especially of cheese and fermented
milk.
• lactobacilli are important for flavour, colour and
texture of dairy products through acidification due to
lactic acid and of the metabolism of milk proteins.
• The most commonly used species in dairy products are
L.casei,
L.helveticus,
L.rhamnosus,
L.lactis,
L.curvatus and L.plantarum (Jack et al., 1995).
Application of lactobacilli on Wine
Industry
• lactobacilli are also applied in wine industry both
for grape and fruit wines, such as cider.
• The organic acids existing in wine which are mainly
malic and tartaric acid can be easily metabolised by
lactobacilli (Board, 1983).
• Malic acid is converted to lactic acid and carbon
dioxide, this phenomenon is called malolactic
fermentation which is extensively used for fruit
wines maturation (Liu et al., 2003).
Application of lactobacilli on nonbeverage food products of plant
origin
• lactobacilli are applied in the fermentation of
sauerkraut that is the product of fresh cabbage,
pickles and olive fermentation.
• The starter culture for sauerkraut or pickles or
olives production is the normal flora of cabbage or
any of the other plants, in addition with
L.plantarum and an amount of NaCl so to avoid the
growth of pathogenic bacteria (Miller & Litsky,
1976).
Application of lactobacilli on
Pharmaceutical Industry Production of
Lactic acid
• lactobacilli catabolise glucose to pyruvate acid by
the Embden-Meyerhof (EMP) glycolytic pathway
and galactose by the Leloir pathway.
• The pathways are connected via phosphate-6glucose which is the final end product in the Leloir
pathway and through this form can enter the
glycolysis pathway and be further converted to
pyruvate acid (Davidson & Sittman, 1999).
Application of lactobacilli on
Pharmaceutical Industry Production
of Lactic acid
• Lactic acid or 2-hydroxypropanoic acid is an
important chemical substance widely used in
food industry and in pharmaceutical and
cosmetics industry.
• Another modern application is the use of lactic
acid as a monomer participating in the synthesis
of biodegradable homopolymers and copolymers, such as polylactide (Choi & Hong,
1999).
Industrial Importance of Lactic Acid
• Lactic acid can be produced into large amounts,
biotechnologically, through fermentation process
performed by bacteria such lactobacilli. The
fermentation can be carried out in a variety of liquid or
solid media.
• Usually, the product of fermentation is a racemic
mixture conglomerate mixture of D (-) - and L (+) –
isomers but there are also strains which produce
optically pure forms of one of the stereoisomer’s.
(Martak et al., 2003).
Application of lactobacilli on
Pharmaceutical Industry The
Production of Bacteriocins
• Among the Gram positive (+) bacteria, the Lactic
Acid Bacteria (LAB) have gained particular
attention nowadays, due to the production of
bacteriocins (Ross, Morgan &Hill, 2002).
Application of lactobacilli on
Pharmaceutical Industry: The
Production of Bacteriocins
• The use of bacteriocins in food industry
especially on dairy, egg, vegetable and meat
products has been extensively investigated.
• Among the LAB bacteriocins Nisin A and its
natural variant Nisin Z has been proven to be
highly effective against microbial agents causing
food poisoning and spoilage.
Conclusions
• lactobacilli are an important microbial group for
the productions of numerous compounds. The bulk
quantities of their biomass are needed in dairy
industry and further research has to be performed
so to enhance their potential use as natural
bioreactor which can produce efficiently many
products of commercial usage.
References
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Board, R. G., A Modern Introduction to Food Microbiology. 1st ed.; Blackwell Scientific Publications: 1983; p 150.
Choi, J. H., Ng, H.Y., Effect of Membrane type and material on performance of a submerged membrane
bioreactor. Chemosphere Journal 2007, 11, 1-7.
Bernadeau M. Vernoux, J. P., ,Henri-Dubernet, S., Gueguen M.,, The Lactobacillus genus. International Journal
of Food Microbiology 2007, 41, 103-125.
Liu, S.Q. (2003). Practical implications of lactate and pyruvate metabolism by lactic acid bacteria in food and
beverage fermentations. International Journal of Food Microbiology, 83, 115-131 Stanier, R.Y., Adelberg, E.A., &
Ingraham, J.L. (1977). General Microbiology (4th ed.): Oxford, Macmillan Press pp:496-504.
Gruger, A.; Gruger, W., Biotechnology, A Textbook of Industrial Microbiology. 1st ed.; Sunderland,Mass Sinauer
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Jack R.W. Tagg, J. R., Ray B. , Bacteriocins of Gram-positive bacteria. Microbiological Reviews 1995, 3, 171-200
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Ross, R. P.; Desmond, C.; Fitzerald, G. F.; Stantch, C., Overcoming the technological hurdles in the development
of probiotic foods. Journal of Applied Microbiology 2005, 98, 1410-1417.
Ahrne S. et al., lactobacilli in the intestinal microbiota of Swidish infants. Microbes and Infection Journal 2005,
7, 1256-1262.
Miller, B. M. and Litsky, W. (1976) Industrial Microbiology, McGraw-Hill, NY.
Liu X., Chung Y. K., Yang S.T. , Yousef A.G., Continuous nisin production in laboratory media and whey
permeate by immobilized Lactococcus lactis. Process Biochemistry Journal 2005, 40, 13-24.
Martak, J.; Schlosser, S.; Sabalova, E.; Kristofikova, L.; Rosenberg, M., Fermentation of lactic acid with Rhizopus
arrhizus in a stirred tank reactor with a periodical feed and bleed operation. Process Biochemistry Journal 2003,
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Davidson V. L., Sittman D. B., Biochemistry, NMS Series. 4th ed., Lippincott Williams and Wilkins: 1999, p 280285.
Aknowledgments
Questions
Email:
M.Zacharof@swansea.ac.uk
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