Role of lactic acid bacteria in food biotechnology

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lactic acid bacteria-food biotechnology

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Role of lactic acid bacteria in food biotechnology:

Role of lactic acid bacteria in food biotechnology Sajad sarvari

Introduction :

Introduction Gram positive Rods or cocci , or tetrad formation Non‐spore forming Catalase negative Acid tolerant Fastidious Non motile Low mol % G+C Facultative anaerobes / Micro‐aero‐tolerant

Chemical synthesis vs. biological synthesis:

Chemical synthesis vs. biological synthesis There are two optical isomers of lactic acid: L(+)-lactic acid and D(-)-lactic acid. Although L(+)-lactic acid is known GRAS(generally recognized as safe) by US FDA for addition to foods,D (-)-lactic acid is sometimes harmful to human metabolism and can result in acidosis and decalcification! Petrochemical methods always products racemic lactic acid while by microbial fermentation it can be pure L(+) or D(-) lactic acid.

Chemical synthesis vs. microbial fermentation:

Chemical synthesis vs. microbial fermentation

Importance of lactic acid :

Importance of lactic acid In chemical industry ,it is used a raw material for production of lactate ester, propylene glycol, 2,3-pentanedione,propanoic acid ,acrylic acid , acetaldehyde, and dilactide . In food industry as preservative , acidulant ,and flavouring . in the textile and pharmaceutical industry. The world wide demand is 130000 to 150000 tone per year.

Lactic acid-producing microorganism:

Lactic acid-producing microorganism

Homofermentative vs. hetrofermentative:

Homofermentative vs. hetrofermentative

Raw materials for biotechnological production of lactic acid:

Raw materials for biotechnological production of lactic acid

Engineered approaches to lactic acid production:

Engineered approaches to lactic acid production Higher lactic acid concentrations may be obtained in batch and fed-batch cultures than in continuous cultures, whereas higher productivity may be achieved by the use of continuous cultures . Another advantage of the continuous culture compared to the batch culture, is the possibility to continue the process for a longer period of time. The cell-recycle system, together with repeated batch and continuous processes, enables the achievement of a higher cell concentration and product productivity in the process.

Engineered approaches to lactic acid production:

Engineered approaches to lactic acid production

Engineered approaches to lactic acid production:

Engineered approaches to lactic acid production Lactic acid production processes traditionally suffer from end-product inhibition. An undissociated lactic acid passes through the bacterial membrane and dissociates inside the cell. The inhibition mechanism of lactic acid is probably related to the solubility of the undissociated lactic acid within the cytoplasmic membrane and the insolubility of dissociated lactate, which causes acidification of cytoplasm and failure of proton motive forces.

Engineered approaches to lactic acid production:

Engineered approaches to lactic acid production In situ extraction was possible with the use of di -n- octylamine and with adjustment of the fermentation broth to a pH=5.0 by ammonia. Electrodialysis fermentation with ion exchange membranes was often used for in situ removal of lactic acid. extract lactic acid simultaneously with the use of a two-zone fermentor -extractor system

Role of lactic acid bacteria in food biotechnology:

Role of lactic acid bacteria in food biotechnology functional starter cultures for the food fermentation Bio‐preservative Additive in foods Mannitol production

Bio‐preservative :

Bio‐preservative LAB display a wide range of antimicrobial activities. Many strains produce bacteriocins and bacteriocin - like molecules that display antibacterial activity. some LAB are able to synthesize other antimicrobial peptides that may also contribute to food preservation and safety. strains of Lactobacillus plantarum , isolated from sourdough and grass silage, display antifungal activity, due to the production of organic acids, other low-molecular-mass metabolites, and/or cyclic dipeptides .

Bio‐preservative :

Bio‐preservative

Additive to foods:

Additive to foods Since lactic acid is classified as GRAS for use as a food additive by the US FDA , it is widely used in almost every segment of the food industry, where it serves in a wide range of functions, such as flavouring , pH regulation, improved microbial quality, and mineral fortification.

functional starter cultures for the food fermentation:

functional starter cultures for the food fermentation Functional starter cultures are starters that possess at least one inherent functional property. The latter can contribute to food safety and/or offer one or more organoleptic , technological, nutritional, or health advantages. LAB are able to produce antimicrobial substances, sugar polymers, sweeteners, aromatic compounds, useful enzymes, or nutraceuticals , or health-promoting properties, so called probiotic features.

Mannitol production:

Mannitol production Mannitol production by lactic acid bacteria and other food-grade microorganisms offer several important advantages. Firstly, food-grade microorganisms and their products are directly applicable in food products, without any restriction. Secondly, there is no need for a careful separation of products and microorganisms, which would be the case if microorganisms are not of food grade. Thirdly, some lactic acid bacteria are claimed as beneficial in the gastrointestinal tract. Mannitol production by those bacteria may strengthen their health-promoting ability.

Mannitol production:

Mannitol production

Mannitol production:

Mannitol production

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