Associative Growth and Proteolysis of Streptococcus thermophilus and Lactobacillus bulgaricus in Skim Milk

Rajagopal, Sreenath; Sandine, W. E.

doi:10.3168/jds.s0022-0302(90)78745-0

Cited by 105 publications

(71 citation statements)

References 14 publications

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“…Other literature indicated that the assossiative growth affects the proteolytic activity owing to corresponding alteration of pH. It was found that mixed cultures of Streptococcus thermophilus and L. bulgaricus cultures in one combination was less proteolytic than the corresponding L. bulgaricus strain in pure culture that was combined with lowering in pH [42]. Lowering in pH and correspondingly lowering in proteolytic activity agree with our study observations.…”

Section: E Phsupporting

confidence: 83%

Chemically Defined Medium for Optimization of Proteolytic Activity of Lactobacillus bulgaricus 761N

Nour¹,

Fattouh²,

El-Adawi³

2014

LSMR

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Abstract-Subcellular fractions of Lactobacillus bulgaricus 761N were investigated for their proteolytic activity that results in production of bioactive peptides in the cell-free supernatant. It was observed that the extracellular extract of L. bulgaricus 761N possessed the highest proteolytic activity of about 63.1 U/ml/min. Consequently, the extracellular fraction was chosen for assessing the proteolytic activity after each step of the optimization process was carried out. The factors of the optimization process involve the incubation period, temperature, pH, salinity (expressed by NaCl concentration), casein content, trace element concentration. The trace elements include cobalt chloride, copper sulphate, calcium chloride and ferrous sulphate. The basal medium used was skim milk agar. The other constituents of the chemically synthesized medium, that would optimize the proteolytic activity that in turn elevate the bioactive peptides production, are determined upon the results of the optimization process. The preferred conditions for maximal activity occurrence was after 48h incubation period, at pH 7, 37 o C, brackish environment at 5gl -1 NaCl content and 5gl -1 casein content. CaCl 2 and CoCl 2 were found to enhance the proteolytic activity at 1mM, while CuSO 4 and FeSO 4 were found to be needed in fewer amounts at 0.5mM and 0.1mM, respectively. The antibacterial activity of these bioactive peptides produced in the cell free supernatant was investigated against some human pathogenic bacteria. It was found that it impose a high antibacterial capacity on tested pathogens reaching 89% inhibition.

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Section: E Phsupporting

confidence: 83%

Chemically Defined Medium for Optimization of Proteolytic Activity of Lactobacillus bulgaricus 761N

Nour¹,

Fattouh²,

El-Adawi³

2014

LSMR

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“…II). These stronger proteolytic activities of Lactobacillus compared with S. thermophilus were in line with the findings of previous studies where proteolysis had been evaluated globally by measuring tyrosine release [8,21,24].…”

Section: Proteolysis In Pure Culturessupporting

confidence: 79%

Article

Courtin

Rul

2003

Lait

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-Yogurt is a simple ecosystem whose successful manufacture relies on interactions between two thermophilic lactic acid bacteria, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (Lb. bulgaricus). The present work studied the impact of co-culturing S. thermophilus with Lb. bulgaricus on bacterial growth in milk. To achieve this, we considered both sides of the bacterial association, by characterising proteolysis and quantifying formic acid in pure and mixed cultures of S. thermophilus and Lb. bulgaricus. In pure cultures, S. thermophilus CNRZ385 exhibited better growth than the two Lb. bulgaricus strains (1038 and CNRZ397). The S. thermophilus/Lb. bulgaricus association was positive for S. thermophilus growth with strain 1038, contrary to the association with strain 397. These effects were correlated with the different proteolytic capacities of the two Lb. bulgaricus strains. In contrast, the bacterial association had no significant effect on Lb. bulgaricus growth, possibly because of an insufficient production of formic acid by the S. thermophilus strain. We also showed that the S. thermophilus/Lb. bulgarius association affected the production of volatile molecules involved in flavour development.Streptococcus thermophilus / Lactobacillus delbrueckii subsp. bulgaricus / milk co-cultures / proteolysis / formic acid / flavour Résumé -Interactions entre microorganismes dans un écosystème simple : les bactéries du yaourt comme modèle d'étude. Le yaourt constitue un écosystème simple dont la fabrication repose sur les interactions prenant place entre les deux espèces de bactéries lactiques Streptococcus thermophilus et Lactobacillus delbrueckii subsp. bulgaricus (Lb. bulgaricus). Au cours de ce travail, nous avons étudié l'impact de la co-culture de S. thermophilus avec Lb. bulgaricus sur la croissance bactérienne dans le lait. Pour cela, nous nous sommes intéressés aux deux aspects de l'association, en caractérisant la protéolyse et en quantifiant l'acide formique dans des cultures pures et mixtes de S. thermophilus et Lb. bulgaricus. En culture pure, S. thermophilus CNRZ385 se développait mieux que les deux souches de Lb. bulgaricus (1038 et CNRZ397). L'association S. thermophilus/Lb. bulgaricus avait un effet bénéfique sur la croissance de S. thermophilus avec la souche 1038 contrairement à l'association avec la souche CNRZ397. Ces effets étaient corrélés à des capacités protéolytiques différentes des deux souches de Lb. bulgaricus. Par ailleurs, l'association bactérienne n'avait pas d'effet significatif sur la croissance de Lb. bulgaricus possiblement en raison d'une production insuffisante d'acide formique par la souche de S. thermophilus. Nous avons également montré que l'association S. thermophilus/Lb. bulgaricus affectait la production de molecules volatiles impliquées dans le développement de la flaveur.Streptococcus thermophilus / Lactobacillus delbrueckii subsp. bulgaricus / co-culture en lait / protéolyse / acide formique / flaveur

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“…Ketika digunakan sebagai kultur campuran, kedua bakteri ini bersimbiosis mutualisme, dimana L. bulgaricus dilaporkan menghasilkan asam amino dan peptida pendek yang menstimulasi pertumbuhan S. thermophilus. Sedangkan S. thermophilus menghasilkan asam format yang menunjang pertumbuhan L. bulgaricus (El-Abbassy & Sitohy, 1993;Rajagopal & Sandine, 1990).…”

Section: Kualitas Yoghurt Yang Dibuat Dengan Kultur Dua (Lactobacilluunclassified

KUALITAS YOGHURT YANG DIBUAT DENGAN KULTUR DUA (Lactobacillus bulgaricus DAN Streptococcus thermophilus) DAN TIGA BAKTERI (Lactobacillus bulgaricus, Streptococcus thermophilus DAN Lactobacillus acidophilus)

et al. 2015

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Abstrak: Yoghurt merupakan produk susu terfermentasi yang dibuat dengan menambahkan kultur bakteri asam laktat (BAL) ke dalam susu. Kultur BAL yang ditambahkan dapat berupa kultur bakteri tunggal ataupun campuran. Pada umumnya, kultur campuran yang biasa digunakan untuk membuat yoghurt adalah campuran antara Lactobacilus bulgaricus (Lb) dan Streptococcus thermophilus (St). Namun berdasarkan beberapa penelitian kedua bakteri ini tidak bertahan lama pada saluran pencernaan. Oleh karena itu pada penelitian ini dilakukan penambahan Lactobacillus acidophilus (La) untuk memperbaiki sifat probiotik dari produk yoghurt. Pada pembuatan kultur starter, kultur tunggal bakteri ditumbuhkan pada media susu skim 10%. Kemudian susu sapi hasil pasteurisasi diinokulasi dengan kultur starter dengan perbandingan kultur yang berbeda-beda yaitu 1:1, 1:4 dan 4:1 (Lb:St) untuk kultur dua bakteri serta 1:1:1, 1:4:1 dan 4:1:1 (Lb:St:La) untuk kultur tiga bakteri. Susu yang telah diinokulasi kemudian diinkubasi pada suhu 40°C selama 12 jam. Analisis terhadap produk yoghurt meliputi pengukuran pH, kadar laktosa, kadar asam laktat dan kadar protein. Hasil analisis menunjukkan bahwa penambahan L. acidophilus cenderung memberikan efek penghambatan pembentukan asam laktat, seperti ditunjukkan oleh pH yang lebih tinggi, kadar asam laktat yang lebih rendah serta kadar laktosa sisa yang lebih tinggi pada yoghurt yang menggunakan kultur tiga bakteri. Kata kunci: Yoghurt, Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus Abstract: Yoghurt is fermented milk product that is made by addition of lactic acid bacteria (LAB) into

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Associative Growth and Proteolysis of Streptococcus thermophilus and Lactobacillus bulgaricus in Skim Milk

Cited by 105 publications

References 14 publications

Chemically Defined Medium for Optimization of Proteolytic Activity of Lactobacillus bulgaricus 761N

Chemically Defined Medium for Optimization of Proteolytic Activity of Lactobacillus bulgaricus 761N

Article

KUALITAS YOGHURT YANG DIBUAT DENGAN KULTUR DUA (Lactobacillus bulgaricus DAN Streptococcus thermophilus) DAN TIGA BAKTERI (Lactobacillus bulgaricus, Streptococcus thermophilus DAN Lactobacillus acidophilus)

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