“…Pailin et al [39] reported similar finding, where all studied LAB isolates demonstrated ability to form clear zone on skim milk. Likewise, majority of the LAB isolated from Algerian goat’s milk [40] and Egyptian Ras cheese [41] have demonstrated the ability to produce clear hydrolysis zone on skim milk agar. This implied that majority of LAB possessed extracellular proteolytic activity.Fig.…”
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, lysine, threonine and tryptophan. Despite AA production was strain dependent, the studied LAB isolates possessed vast potential and can be exploited further as a bio-agent or an alternative amino acids and bioactive peptide producers.
“…Pailin et al [39] reported similar finding, where all studied LAB isolates demonstrated ability to form clear zone on skim milk. Likewise, majority of the LAB isolated from Algerian goat’s milk [40] and Egyptian Ras cheese [41] have demonstrated the ability to produce clear hydrolysis zone on skim milk agar. This implied that majority of LAB possessed extracellular proteolytic activity.Fig.…”
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, lysine, threonine and tryptophan. Despite AA production was strain dependent, the studied LAB isolates possessed vast potential and can be exploited further as a bio-agent or an alternative amino acids and bioactive peptide producers.
“…2B, reached a final viable count of more than 10 7 CFU per gram, which can be considered satisfactory for a potential probiotic in cheeses (Karimi, Mortazavian, & Da Cruz, 2011). To the best of the authors' knowledge, although L. plantarum strains have been used successfully as adjunct cultures in other semi-hard and semi-ripened cheeses (Milesi, McSweeney, & Hynes, 2008;Milesi, Vinderola, Sabbag, Meinardi, & Hynes, 2009;Minervini et al, 2012;Ortigosa, Arizcun, Torre, & Izco, 2005;Songisepp et al, 2012), few studies have been carried out concerning the possible use of L. pentosus strains as adjunct cultures in dairy products, especially those isolated from fermented vegetables (Ciocia et al, 2013;Marroki & Bousmaha-Marroki, 2014). Another fundamental feature that a probiotic added to a food matrix has to possess is the capability of overcoming the conditions found in the digestive tract and of reaching the intestine in adequate amounts.…”
Available online A B S T R A C TTwo strains of Lactobacillus plantarum (Lp S11T3E and Lp S2T10D) and one of Lactobacillus pentosus (Lps S3T60C), originally isolated from table olive fermentations, and previously characterized for their probiotic properties, have been added as adjunct cultures to Toma Piemontese Protected Denomination of Origin (PDO) cheese, in order to develop a functional dairy product. The cheeses were sampled throughout their manufacturing process and during the two months of ripening. Moreover, they were also subjected to in vitro human digestion, followed by microbiological analysis. Monitoring of the inoculated strains was performed through molecular identification and biotyping. The organic acid and sugar contents of the cheeses were determined at each sampling point, while the organoleptic features were assessed by sensory evaluation. All isolated lactobacilli, during ripening and after digestion of the cheeses, were recognized as putative probiotics, and demonstrated to be well adapted to the food matrix investigated. The organic acid composition of the cheeses with the adjunct culture differed from the control, but this difference did not negatively affect the organoleptic profiles of the final product. Therefore, all the strains tested were to be usable as adjunct cultures in Toma Piemontese PDO production to develop a new functional food.
“…Positive hemolytic activity (ability to breakdown red blood cells) halt the underlying epithelial layer whereas positive gelatinase activity (ability to hydrolyse gelatin) breakdown the protective lining of the GIT. Absence of hemolytic, gelatinase and lipase activity makes a strain non-virulent, indicating its selection for probiotic strain 30 .…”
Section: Safety Assessment Of Selected Isolatesmentioning
Recently, probiotic lactic acid bacteria have been utilized as therapeutic supplements and food additives. Nowadays, the interest has been increased regarding the commercial utilization of probiotic LAB strains isolated from traditional fermented food products. Therefore, the present study was aimed to investigate the probiotic properties of lactic acid bacteria isolated from traditional food sources viz. dosa batter and sauerkraut. Total 7 lactic acid bacteria were obtained, 4 from dosa batter and 3 from sauerkraut, out of which one isolate from each food source were selected based on their broadest antagonistic spectrum. These strains were identified using 16S r RNA technique as Lactobacillus plantarum DB-2 (isolated from dosa batter) and Lactobacillus plantarum SK-3 (isolated from sauerkraut). The investigation of acid-bile tolerance, antibiotic sensitivity, auto-aggregation, co-aggregation, bacterial adhesion to hydrocarbons were confirmed. The results revealed normal growth of L. plantarum DB-2 and L. plantarum sK-3 in the presence of low pH, high bile salt concentration and ability to produce antimicrobial compounds viz. bacteriocin and h 2 O 2. No gelatinase, lipase and hemolytic activity were observed. Natural susceptibility to the tested antibiotics was investigated. Thus, according to these results, L. plantarum DB-2 and sK-3 proved the good probiotic candidates as they survived during stress conditions posing to them and can be exploited for the preparation of nutraceutical products. This study also revealed the potential of using LAB and /or bacteriocin produced by them as food bio preservative to control food borne pathogenic bacteria in near future.
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