scholarly journals Growth of the Bacteriocin-ProducingLactobacillus sakei Strain CTC 494 in MRS Broth Is Strongly Reduced Due to Nutrient Exhaustion: a Nutrient Depletion Model for the Growth of Lactic Acid Bacteria

2001 ◽  
Vol 67 (10) ◽  
pp. 4407-4413 ◽  
Author(s):  
Frédéric Leroy ◽  
Luc De Vuyst

ABSTRACT Although commercial MRS broth has been designed to allow excellent growth of lactobacilli, most of these bacteria are still subjected to a self-inhibiting process. The most likely explanation is the accumulation of lactic acid or other toxic end products and the depletion of nutrients. In this study, the self-inhibition ofLactobacillus sakei CTC 494 was analyzed in a kinetic way, and a nutrient depletion model was set up to describe the growth inhibition process. This simple model has considerable advantages compared to commonly used descriptive models such as the logistic growth equation. It offers a better fit and a more realistic description of the growth data by taking into account both growth inhibition due to lactic acid production and changes in growth rates due to nutrient depletion. Depending on the fermentation conditions, in MRS broth there appears to be a strong decrease of the specific growth rate over time. Some undefined compounds present in the complex nitrogen source of MRS broth appear to be of crucial importance because of their limited availability. Moreover, nutrient availability affects bacteriocin production through its effect on cell growth as well as on the bacteriocin production per cell. A plateau value for the bacteriocin production by L. sakei CTC 494 was observed.

2018 ◽  
Vol 37 (4) ◽  
pp. 437
Author(s):  
Zulafa Noor ◽  
Muhammad Nur Cahyanto ◽  
Retno Indrati ◽  
Sardjono Sardjono

This study was aimed to select the best isolates of Lactobacillus plantarum from 6 (six) of local isolates obtained from culture collections isolated from traditional foods. Selection of isolates was based on the growth rate, the number of cells, changes in pH and lactic acid production during cell growth on the MRS-broth at 37 °C for 24 hours. The results showed that the growth rate of each isolate varied, as measured by the length of the log phase, ranging from 8-20 h. It showed that some isolates quite fast towards a stationary phase and some quite slow. The number of cell ranged from 8.81 to 9.74 log CFU/mL, while the pH at the beginning of cell growth from 5.2 to 5.8, and at the end of growth from 3.4 to 3.7. Lactic acid production by the end of the growth (24 h) is 0.76 to 0.98%. The results showed isolate of L. plantarum UA3 was best having the fastest growth rate (8 h of log phase), the highest cell number (9.74 log CFU/mL), and the highest lactic acid produced (0.92 %) for 14 h incubation on MRS-broth at 37 °C. Application of selected isolate of L. plantarum UA3 on solid substrate fermentation using media grated cassava yield in 0.92% lactic acid after fermentation for 60 h, with a cell number of 9.54 log CFU/mL. ABSTRAKPenelitian ini bertujuan untuk memilih isolat Lactobacillus plantarum terbaik dari 6 (enam) macam isolat lokal yang diperoleh dari koleksi kultur yang berasal dari makanan tradisional. Pemilihan isolat didasarkan pada kecepatan pertumbuhan, jumlah sel, perubahan pH dan produksi asam laktat selama pertumbuhan pada media MRS-broth pada suhu 37 °C selama 24 jam. Hasil penelitian menunjukkan bahwa kecepatan pertumbuhan setiap isolat bervariasi, yang diukur dari lamanya fase log, yaitu berkisar antara 8–20 jam. Ini memperlihatkan bahwa beberapa isolat cukup cepat menuju fase stasioner dan beberapa lagi cukup lambat. Jumlah sel berkisar antara 8,81–9,74 log CFU/mL, sedangkan pH pada awal pertumbuhan sekitar 5,2–5,8, dan pada akhir pertumbuhan 3,4–3,7. Produksi asam laktat pada akhir pertumbuhan (24 jam) adalah 0,76–0,98%. Dari hasil tersebut isolat L. plantarum UA3 merupakan isolat terbaik dengan fase pertumbuhan log yang tercepat (8 jam), jumlah sel tertinggi (9,74 log CFU/mL), dan menghasilkan asam laktat paling tinggi (0,92%) pada inkubasi selama 14 jam dalam media MRS-broth suhu 37 °C. Aplikasi dari isolat terpilih L.plantarum UA3 dalam fermentasi substrat padat menggunakan media kasava parut menghasilkan asam laktat sebesar 0,92% setelah fermentasi selama 60 jam, dengan jumlah sel 9,54 logCFU/mL.


2016 ◽  
Vol 60 (2) ◽  
pp. 129-140 ◽  
Author(s):  
Metin Guldas

AbstractIn this research article, the effects of bee pollen and royal jelly on the selected probiotic bacteria, as growth factors, were investigated. The probiotic cultures were activated in MRS broth at 37°C. Then, bee pollen and royal jelly (10 mg/100 μL, 25 mg/250 μL, 50 mg/500 μL, 75 mg/750 μL, and 100 mg/1000 μL) were added on the probiotic cultures in MRS broth and sampled at 0, 24, and 48 hours of incubation. The medias used for enumeration of the probiotic cultures were RCA (Reinforced Clostridial Agar) forBf. animalisspp.lactis, MRS (deMann, Rogosa and Sharpe) Agar with D-sorbitol forLb. acidophilusand MRS-Vancomycine Agar forLb. casei. The lactic acid production byLb. acidophilus,Lb. casei, andBf. animalisspp.lactis, and acetic acid production byBf. animalisspp. lactis, were determined to compare the bacterial proliferation. The probiotic cultures were mainly affected by the bee pollen and royal jelly during the first 24 hours. The changes observed in the number of probiotic counts between 24 and 48 hours were not significant, statistically (P<0.05). Generally, the probiotic bacterial counts increased parallel to the concentration of bee pollen or royal jelly up to 75mg, and remained unchanged above this concentration. In terms of lactic acid production and bacterial growth, the most significant growth was observed onLb. acidophiluswhen bee pollen or royal jelly was added.


Food Research ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 331-339
Author(s):  
J.G.B. Peralta ◽  
F.B. Elegado ◽  
J.F. Simbahan ◽  
I.G. Pajares ◽  
E.I. Dizon

The succession of the dominant microbial population during cacao fermentation with or without adjunct inoculation of yeast and lactic acid bacteria (LAB) were monitored on a laboratory scale using culture-dependent and culture-independent methods. Yeasts and acetic acid bacteria (AAB) population throughout a five-day fermentation process showed no significant differences but the LAB population increased through adjunct inoculation. Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) identification method showed the dominance of only Lactobacillus plantarum, one of the species used as the adjunct inoculum, which resulted in higher lactic acid production. On the other hand, Acetobacter spp. and Gluconobacter spp. were markedly observed in the spontaneously fermented set-up resulting in increased acetic acid production, significantly different (p>0.05) at three to five days of fermentation. LAB and yeast inoculation resulted in a more desirable temperature and pH of the fermenting mash which may result in better product quality.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Beatriz Martines de Souza ◽  
Mayara Souza Silva ◽  
Aline Silva Braga ◽  
Patrícia Sanches Kerges Bueno ◽  
Paulo Sergio da Silva Santos ◽  
...  

AbstractThis in vitro study evaluated the protective effect of titanium tetrafluoride (TiF4) varnish and silver diamine fluoride (SDF) solution on the radiation-induced dentin caries. Bovine root dentin samples were irradiated (70 Gy) and treated as follows: (6 h): 4% TiF4 varnish; 5.42% NaF varnish; 30% SDF solution; placebo varnish; or untreated (negative control). Microcosm biofilm was produced from human dental biofilm (from patients with head-neck cancer) mixed with McBain saliva for the first 8 h. After 16 h and from day 2 to day 5, McBain saliva (0.2% sucrose) was replaced daily (37 °C, 5% CO2) (biological triplicate). Demineralization was quantified by transverse microradiography (TMR), while biofilm was analyzed by using viability, colony-forming units (CFU) counting and lactic acid production assays. The data were statistically analyzed by ANOVA (p < 0.05). TiF4 and SDF were able to reduce mineral loss compared to placebo and the negative control. TiF4 and SDF significantly reduced the biofilm viability compared to negative control. TiF4 significantly reduced the CFU count of total microorganism, while only SDF affected total streptococci and mutans streptococci counts. The varnishes induced a reduction in lactic acid production compared to the negative control. TiF4 and SDF may be good alternatives to control the development of radiation-induced dentin caries.


Heliyon ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. e07079
Author(s):  
Joel Romial Ngouénam ◽  
Chancel Hector Momo Kenfack ◽  
Edith Marius Foko Kouam ◽  
Pierre Marie Kaktcham ◽  
Rukesh Maharjan ◽  
...  

2009 ◽  
Vol 17 (1) ◽  
pp. 32-45 ◽  
Author(s):  
KAOUTAR YAAKOUBI ◽  
NOREDDINE BENKERROUM ◽  
FLORENT WIOROWSKI ◽  
FRANÇOISE SANSON ◽  
JULIEN HAYDERSAH ◽  
...  

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