Produção de ácido L-glutâmico por bactérias do ácido lático

Abstract

L-glutamic acid is one of the main amino acids that is present in a wide variety of foods. It is mainly used as a food additive in the form of monosodium glutamate and is produced almost exclusively by fermentation. Considering the great commercial interest of L-glutamic acid, the discovery of strains with desirable biochemical and physicochemical characteristics, from diverse substrates, such as fermented foods and beverages, is extremely important for the amino acid market. The discovery of new species and strains producing L-glutamic acid with new attributes such as safety and probiotic potential provide the possibility of new applications, as well as obtaining the amino acid more effectively, safely and cheaply. Thus, the objective was to select lactic acid bacteria isolated from fermented foods with the capacity to produce glutamic acid, as well as to verify some probiotic attributes in vitro and to verify the best parameters of production of the amino acid. The bacteria from the agricultural microbiology culture collection (ACC) were qualitatively evaluated for their ability to synthesize L-glutamic by thin layer chromatography ( TLC ) and quantitatively by spectrophotometry using a standard curve. As for the probiotic potential, safety features were verified, as well as hydrophobicity, autoaggregation and coaggregation. The intracellular and extracellular production of the amino acid was quantified by High Performance Liquid Chromatography-HPLC. The lactic acid bacteria isolated from the Brazilian indigenous drink “Yakupa” belonging to the species Limosilactobacillus fermentum CCMA 0209 and CCMA 0205 showed greater potential in the production of L-glutamic acid, intracellular and extracellular, respectively. The empirical prediction models developed were considered adequate (p<0.05) to describe the extracellular and intracellular production of L-glutamic acid from the CCMA 0205 strain (R2 = 0.83 and 0.84). The optimal conditions established for the production of L-glutamic acid by the strain were pH 4.5; temperature of 35°C and time of 72 hours. The study presents the promising potential of lactic acid bacteria isolated from a Brazilian indigenous drink in the production of L-glutamic acid and provides relevant information for the production of the amino acid by L. fermentum (strain CCMA 0205).