Gamma-aminobutyric acid is a non-protein amino acid that is widely present in organisms. Several important physiological functions of gamma-aminobutyric acid have been characterized, such as neurotransmission, induction of hypotension, diuretic effects, and tranquilizer effects. Many microorganisms can produce gamma-aminobutyric acid including bacteria, fungi and yeasts. Among them, gamma-aminobutyric acid-producing lactic acid bacteria have been a focus of research in recent years, because lactic acid bacteria possess special physiological activities and are generally regarded as safe. They have been extensively used in food industry. The production of lactic acid bacterial gamma-aminobutyric acid is safe and eco-friendly, and this provides the possibility of production of new naturally fermented health-oriented products enriched in gamma-aminobutyric acid. The gamma-aminobutyric acid-producing species of lactic acid bacteria and their isolation sources, the methods for screening of the strains and increasing their production, the enzymatic properties of glutamate decarboxylases and the relative fundamental research are reviewed in this article. And the potential applications of gamma-aminobutyric acid-producing lactic acid bacteria were also referred to.

Lactic acid bacterial cell factories for gamma-aminobutyric acid.

Class IIa bacteriocins from lactic acid bacteria are small, cationic proteins with antilisterial activity. Within this class, the pediocins are those bacteriocins that share a highly conserved hydrophilic and charged N-terminal part harboring the consensus sequence -YGNGV- and a more variable hydrophobic and/or amphiphilic C-terminal part. Several pediocins have been isolated and characterized. Despite the structural similarities, their molecular weight varies, as well as their spectrum of antimicrobial activity. They exhibit important technological properties, e.g. thermostability and retaining of activity at a wide pH range, which along with the bactericidal action against Gram-positive food spoilage and pathogenic bacteria, make them an important class of biopreservatives. Much new information regarding the pediocins has emerged during the last years. In this review, we summarize and discuss all the available information regarding the sources of pediocins, the characteristics of their biosynthesis and production in fermentation systems, the characteristics of the known pediocin molecules, and their antibacterial action. The advances made by genetic engineering in improving the features of pediocins are also discussed, as well as their perspectives for future applications.

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Pediocins: The bacteriocins of Pediococci. Sources, production, properties and applications.

Bacterial community structure in kimchi, a Korean fermented vegetable food, as revealed by 16S rRNA gene analysis

Functional and Safety Aspects of Enterococci Isolated from Different Spanish Foods

Molecular quantification of lactic acid bacteria in fermented milk products using real-time quantitative PCR.

Molecular diversity of lactic acid bacteria from cassava sour starch (Colombia).

The preparation of lactic flour (i.e. fermentation product) from lactic bacteria comprises: (1) fermenting an aqueous suspension of starchy products with amylolytic lactic bacteria in a fermentation medium; and (2) recovering the fermented biomass to obtain a crude lactic flour, optionally followed by fractionation. The preparation of lactic flour (i.e. fermentation product) from lactic bacteria comprises: (1) fermenting an aqueous suspension of starchy products with amylolytic lactic bacteria in a fermentation medium (with a dry solids content of 175 g/l) comprising an inducer of alpha -amylase biosynthesis (at least 75 g/l) and a starchy product (at least 100 g/l) at pH 4-6.5; and (2) recovering the fermented biomass to obtain a crude lactic flour, optionally followed by fractionation. Independent claim are also included for: (1) lactic powders comprising alpha -amylase (more than 50, preferably 70-80, enzymes units/g) and bacteria (10 , preferably 1.5 x 10 , viable cells/g of powder); (2) alpha -amylases obtained by the above preparation; and (3) a bacterial stock of Lactobacillus paracasei paracasei species, R10107 (registered under number I-2030 at CNCM (27/05/1998)).

Maurice Raimbault

Papers

Molecular diversity of lactic acid bacteria from cassava sour starch (Colombia).

Process for the valorization of starch into lactic acid-containing products, and obtained products

Procede de production de farines lactiques et produits obtenus