Background:Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets.However,the current technologies rely heavily on non-food grade mi...Background:Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets.However,the current technologies rely heavily on non-food grade microorganism and chemical synthesis for the production of AA.Several studies reported that lactic acid bacteria (LAB) have the capability of producing AA owing to their well-established proteolytic system and amino acid biosynthesis genes.Hence,the objectives of this study were to explore the extracellular proteolytic activity of LAB isolated from various Malaysian fermented foods and their potential to produce AA extracellularly as feed supplements.Results:All the studied LAB isolates were versatile extracellular protease producers,whereby extracellular protease activities were detected from acidic to alkaline pH (pH 5,pH 6.5,pH 8) using qualitative and quantitative proteolytic assays.The highest proteolytic activity at pH 5 (15.76 U/mg) and pH 8 (19.42 U/mg) was achieved by Lactobacillus plantarum RG14,while Lactobacillus plantarum RS5 exhibited the highest proteolytic activity of 17.22 U/mg at pH 6.5.As for the results of AA production conducted in de Man,Rogosa and Sharpe medium and analysed by high pressure liquid chromatography system,all LAB isolates were capable of producing an array of AA.Generally,Pediococcus sp.showed greater ability for AA production as compared to Lactobacillus sp.Moreover,the studied LAB were able to produce a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.P.pentosaceus TL-3 recorded the highest methionine and threonine productivity of 3.72 mg/L/h and 5.58 mg/L/h respectively.However,L.plantarum I-UL4 demonstrated a lysine productivity of 1.24 mg/L/h,while P.acidilactici TP-6 achieved up to 1.73 mg/L/h of tryptophan productivity.Conclusion:All the 17 studied LAB isolates possessed versatile extracellular proteolytic system and have vast capability of producing various amino acids including a few major feed supplement AA such as methionine展开更多
Objective: Evaluating the bio-reducing activity and various potential, annotates the biological entitties of Fagonia cretica. Method: By fractionating the crude extract with different ethanol-water fraction mixture. T...Objective: Evaluating the bio-reducing activity and various potential, annotates the biological entitties of Fagonia cretica. Method: By fractionating the crude extract with different ethanol-water fraction mixture. This substantiates the reduction potential for the biological synthesis of AgNPs, its antioxidant, anti-urease and anti-Tyrosinase activity. Results: UV-visible spectra confirm the bio-reducing potential for Ag NPs with the optimized 50% ethanol-water fraction mixture. Transmission electron microscopy (TEM) confirmed the round shaped AgNPs with an average size of 16 nm in optimized 50% fraction mixture. Further evaluating Ethanol-water fraction with 90% and 70% of plant extract showed more potentials for Anti-Tyrosinase and Anti-urease activity. Moreover, diluted 30% fraction exhibits two folds higher Anti-oxidant and Anti urease activity. Conclusion: Overall, this work showed that 50% Ethanol-water fraction has potentially active molecules (among all fractions) primarily involved in bio-reducing potential of Ag NPs and enzymatic assay while 90% mixture proved to be least active. This study suggested electing the optimum mixture fraction of 50% ethanol-water in order to screen the bioactive compounds and to inculcate their activity status for clinical trials.展开更多
基金The Long-Term Research Grant(LRGS)of the Ministry of Education of Malaysia supported this work
文摘Background:Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets.However,the current technologies rely heavily on non-food grade microorganism and chemical synthesis for the production of AA.Several studies reported that lactic acid bacteria (LAB) have the capability of producing AA owing to their well-established proteolytic system and amino acid biosynthesis genes.Hence,the objectives of this study were to explore the extracellular proteolytic activity of LAB isolated from various Malaysian fermented foods and their potential to produce AA extracellularly as feed supplements.Results:All the studied LAB isolates were versatile extracellular protease producers,whereby extracellular protease activities were detected from acidic to alkaline pH (pH 5,pH 6.5,pH 8) using qualitative and quantitative proteolytic assays.The highest proteolytic activity at pH 5 (15.76 U/mg) and pH 8 (19.42 U/mg) was achieved by Lactobacillus plantarum RG14,while Lactobacillus plantarum RS5 exhibited the highest proteolytic activity of 17.22 U/mg at pH 6.5.As for the results of AA production conducted in de Man,Rogosa and Sharpe medium and analysed by high pressure liquid chromatography system,all LAB isolates were capable of producing an array of AA.Generally,Pediococcus sp.showed greater ability for AA production as compared to Lactobacillus sp.Moreover,the studied LAB were able to produce a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.P.pentosaceus TL-3 recorded the highest methionine and threonine productivity of 3.72 mg/L/h and 5.58 mg/L/h respectively.However,L.plantarum I-UL4 demonstrated a lysine productivity of 1.24 mg/L/h,while P.acidilactici TP-6 achieved up to 1.73 mg/L/h of tryptophan productivity.Conclusion:All the 17 studied LAB isolates possessed versatile extracellular proteolytic system and have vast capability of producing various amino acids including a few major feed supplement AA such as methionine
文摘Objective: Evaluating the bio-reducing activity and various potential, annotates the biological entitties of Fagonia cretica. Method: By fractionating the crude extract with different ethanol-water fraction mixture. This substantiates the reduction potential for the biological synthesis of AgNPs, its antioxidant, anti-urease and anti-Tyrosinase activity. Results: UV-visible spectra confirm the bio-reducing potential for Ag NPs with the optimized 50% ethanol-water fraction mixture. Transmission electron microscopy (TEM) confirmed the round shaped AgNPs with an average size of 16 nm in optimized 50% fraction mixture. Further evaluating Ethanol-water fraction with 90% and 70% of plant extract showed more potentials for Anti-Tyrosinase and Anti-urease activity. Moreover, diluted 30% fraction exhibits two folds higher Anti-oxidant and Anti urease activity. Conclusion: Overall, this work showed that 50% Ethanol-water fraction has potentially active molecules (among all fractions) primarily involved in bio-reducing potential of Ag NPs and enzymatic assay while 90% mixture proved to be least active. This study suggested electing the optimum mixture fraction of 50% ethanol-water in order to screen the bioactive compounds and to inculcate their activity status for clinical trials.
