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Compr Rev Food Sci Food Saf ; 20(1): 863-899, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33443793


Bacteriocins are generally considered as low-molecular-weight ribosomal peptides or proteins synthesized by G+ and G- bacteria that inhibit or kill other related or unrelated microorganisms. However, low yield is an important factor restricting the application of bacteriocins. This paper reviews mining methods, heterologous expression in different systems, the purification technologies applied to bacteriocins, and identification methods, as well as the antibacterial mechanism and applications in three different food systems. Bioinformatics improves the efficiency of bacteriocins mining. Bacteriocins can be heterologously expressed in different expression systems (e.g., Escherichia coli, Lactobacillus, and yeast). Ammonium sulfate precipitation, dialysis membrane, pH-mediated cell adsorption/desorption, solvent extraction, macroporous resin column, and chromatography are always used as purification methods for bacteriocins. The bacteriocins are identified through electrophoresis and mass spectrum. Cell envelope (e.g., cell permeabilization and pore formation) and inhibition of gene expression are common antibacterial mechanisms of bacteriocins. Bacteriocins can be added to protect meat products (e.g., beef and sausages), dairy products (e.g., cheese, milk, and yogurt), and vegetables and fruits (e.g., salad, apple juice, and soybean sprouts). The future research directions are also prospected.

Bacteriocinas , Animais , Antibacterianos/farmacologia , Bacteriocinas/genética , Bovinos , Escherichia coli/genética , Lactobacillus , Leite
Int J Biol Macromol ; 128: 480-492, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30682478


A novel crude exopolysaccharide (EPS) produced by Lactobacillus plantarum KX041 possessed prominent antioxidant activity which was proved in our previous study. In our present study, the further purifications were conducted to obtain EPS fractions, which were called as EPS-1-1, EPS-2-1 and EPS-3. The structures and conformational characterizations were determined through FT-IR, UV, GC, HPLC, NMR, SEM and Congo red test analysis. The Mw of EPS-1-1, EPS-2-1 and EPS-3 were estimated to be 57,201, 70,734, and 26,387 Da, respectively. EPS-1-1 and EPS-2-1 had the similar structure, composed of arabinose, mannose, glucose and galactose with a ratio of 1.09:88.53:3.99:6.39 and 0.58:94.11:3.55:1.76, and both were α-type configurations. Whereas EPS-3 contained rhamnose, fucose, arabinose, xylose, mannose, glucose, galactose and galacturonic acid in a molar ratio of 2.01:2.65:10.95:4.62:4.07:27.81:44.16:3.73 and possessed a triple helical structure. SEM results indicated EPS-1-1 and EPS-2-1 appeared flake shapes piling up into compact structures with a rough surface. In addition, these purified EPS fractions all possessed the immune activity, DPPH/ABTS radicals scavenging activities and DNA damage protective effect.

Lactobacillus plantarum/química , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Benzotiazóis/química , Compostos de Bifenilo/química , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA , Células HT29 , Humanos , Camundongos , Fagocitose/efeitos dos fármacos , Picratos/química , Polissacarídeos Bacterianos/isolamento & purificação , Células RAW 264.7 , Ácidos Sulfônicos/química
J Ind Microbiol Biotechnol ; 45(10): 913-927, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30051274


Lignin valorization can be obtained through cleavage of selected bonds by microbial enzymes, in which lignin is segregated from cellulose and hemicellulose and abundant phenolic compounds can be provided. In this study, Pseudomonas sp. Q18, previously isolated from rotten wood in China, was used to degrade alkali lignin and raw lignocellulosic material. Gel-permeation chromatography, field-emission scanning electron microscope, and GC-MS were combined to investigate the degradation process. The GC-MS results revealed that the quantities of aromatic compounds with phenol ring from lignin increased significantly after incubation with Pseudomonas sp. Q18, which indicated the degradation of lignin. According to the lignin-derived metabolite analysis, it was proposed that a DyP-type peroxidase (PmDyP) might exist in strain Q18. Thereafter, the gene of PmDyP was cloned and expressed, after which the recombinant PmDyP was purified and the enzymatic kinetics of PmDyP were assayed. According to results, PmDyP showed promising characteristics for lignocellulosic biodegradation in biorefinery.

Bactérias/enzimologia , Biodegradação Ambiental , Celulose/metabolismo , Corantes/metabolismo , Lignina/metabolismo , Peroxidases/metabolismo , Pseudomonas/enzimologia , China , Biologia Computacional , Engenharia Genética/métodos , Microscopia Eletrônica de Varredura , Fenol/química , Filogenia , Polissacarídeos , Madeira/metabolismo