Cultive of lactic acid bacteria in coffee residues elaborated media and obtention of antimicrobial compounds of food and pharmaceutical interest

• Ano de defesa: 2022
• Autor(a) principal: Piazentin, Anna Carolina Meireles
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Bactérias ácido-láticas; BLIS; Coffee silverskin; Enterococcus faecium; Lactic acid bacteria; Potencial probiótico; Probiotic potential; Spent coffee grounds
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/9/9134/tde-25082022-171120/

The objective of this study was to evaluate the potential of lactic acid bacteria (LAB) to produce BLIS (Bacteriocin Like Inhibitory Substances) with activity against pathogenic bacteria of food interest and clinical importance, in addition to developing an alternative culture media based on waste from the coffee industry, such as coffee silverskin (CS) and spent coffee grounds (SCG) where BAL could be able to grow and produce BLIS. Enterococcus faecium 135, which was isolated from the intestine of a starfish (Order Forcipulatida), stood out as a producer of BLIS with anti-listeric activity. However, its activity was reduced when cultured with the bacteria Ligilactobacillus salivarius and Limosilactobacillus reuteri. For the elaboration of the alternative media containing the CS and SCG residues, they were subjected to an acid pretreatment with 120 and 100 mg of H2SO4/g, for 75 and 45 minutes at 140 ºC in an autoclave. For CS and SCG, the hydrolysates passed through a post-hydrolysis with 4% (v/v) H2SO4 at 121ºC for 60 min, after which the hydrolysates were detoxified using a C-18 silica column and the pH was adjusted to 6. The media was prepared based on the commercial MRS medium (by Man, Rogosa and Sharp), and the hydrolyzate concentrations used for the preparation of the media were 0, 25, 50 and 100 % (v/v) in addition to the detoxified hydrolysate. The media was supplemented with sources of nitrogen and salts equal to the commercial MRS, and also sugars for the diluted media, so the concentration of sugars was equal to the 100% hydrolysate. The supplemented detoxified SCG and CS 25% medium stood out from the others, because E. faecium 135 obtained a growth of ~ 1.9 log CFU/mL. In addition the antimicrobial activity was superior to the control, being 480 AU/mL for CS 25 % and 428 AU/mL for supplemented detoxified SCG, in addition to lactic acid production, which was 10.51 g/L for 25% CS. The probiotic potential of E. faecium 135 was also tested and it showed resistance to low pH (2.5 and 3.0). Apart from resistance to 3% (w/v) bile salts, the strain was able to adhere to Caco-2 cells, and presented negative results for virulence factors. The presence of some genes responsible for the production of enterocins was also observed in the DNA of the bacterium. E. faecium 135 was a lactic acid bacterium that could be good candidate as a probiotic, and it can make BLIS, even in an alternative media made with CS and SCG coffee residues. These residues were interesting carbon sources for the growth of the bacterium, and they could be used as an alternative to traditional culture medium.