scholarly journals The Effect of Salt and Temperature on the Growth of Fresco Culture

Fermentation ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 2 ◽  
Author(s):  
Alžbeta Medveďová ◽  
Petra Šipošová ◽  
Tatiana Mančušková ◽  
Ľubomír Valík
Keyword(s):  
Incubation Temperature ◽  
Growth Parameters ◽  
Bacterial Species ◽  
Growth Dynamics ◽  
Optimal Temperature ◽  
Considerable Impact ◽  
Culture Growth ◽  
Cardinal Temperature ◽  
Cardinal Temperatures ◽  
Fermented Dairy

The effect of environmental factors, including temperature and water activity, has a considerable impact on the growth dynamics of each microbial species, and it is complicated in the case of mixed cultures. Therefore, the aim of this study was to describe and analyze the growth dynamics of Fresco culture (consisting of 3 different bacterial species) using predictive microbiology tools. The growth parameters from primary fitting were modelled against temperature using two different secondary models. The intensity of Fresco culture growth in milk was significantly affected by incubation temperature described by Gibson’s model, from which the optimal temperature for growth of 38.6 °C in milk was calculated. This cardinal temperature was verified with the Topt = 38.3 °C calculated by the CTMI model (cardinal temperature model with inflection), providing other cardinal temperatures, i.e., minimal Tmin = 4.0 °C and maximal Tmax = 49.6 °C for Fresco culture growth. The specific growth rate of the culture under optimal temperature was 1.56 h−1. The addition of 1% w/v salt stimulated the culture growth dynamics under temperatures down to 33 °C but not the rate of milk acidification. The prediction data were validated and can be used in dairy practice during manufacture of fermented dairy products.

Evaluation of temperature effect on growth rate of Lactobacillus rhamnosus GG in milk using secondary models

2013 ◽  
Vol 67 (7) ◽  
Author(s):  
Ľubomír Valík ◽  
Alžbeta Medveďová ◽  
Michal Čižniar ◽  
Denisa Liptáková
Keyword(s):  
Growth Rate ◽  
Growth Parameters ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Bacterium ◽  
Extended Model ◽  
Temperature Model ◽  
Lactobacillus Rhamnosus Gg ◽  
Model Application ◽  
Cardinal Temperature ◽  
Cardinal Temperatures

AbstractThe application of secondary temperature models on growth rates of Lactobacillus rhamnosus GG, the much studied probiotic bacterium, is investigated. Growth parameters resulting from a primary fitting were modelled against temperature using the following models: Hinshelwood model (H), Ratkowsky extended model (RTK2), Zwietering model (ZWT), and cardinal temperature model with inflection (CTMI). As experienced by other authors, the RTK2, ZWT, and CTMI models provided the best statistical indices related to fitting the experimental data. Moreover, with the biological background, the following cardinal temperatures of L. rhamnosus GG resulted from the study by the model application: t min = 2.7°C, t opt = 44.4°C, t max = 52.0°C. The growth rate of the strain under study at optimal temperature was 0.88 log10(CFU mL−1 h−1).

scholarly journals Quantitative Characterization of Geotrichum candidum Growth in Milk

2021 ◽  
Vol 11 (10) ◽  
pp. 4619
Author(s):  
Petra Šipošová ◽  
Martina Koňuchová ◽  
Ľubomír Valík ◽  
Monika Trebichavská ◽  
Alžbeta Medveďová
Keyword(s):  
Growth Parameters ◽  
Mechanistic Model ◽  
Geotrichum Candidum ◽  
Activity Level ◽  
Effect Of Temperature ◽  
Operational Parameters ◽  
Quantitative Characterization ◽  
Essential Knowledge ◽  
Cardinal Temperatures

The study of microbial growth in relation to food environments provides essential knowledge for food quality control. With respect to its significance in the dairy industry, the growth of Geotrichum candidum isolate J in milk without and with 1% NaCl was investigated under isothermal conditions ranging from 6 to 37 °C. The mechanistic model by Baranyi and Roberts was used to fit the fungal counts over time and to estimate the growth parameters of the isolate. The effect of temperature on the growth of G. candidum in milk was modelled with the cardinal models, and the cardinal temperatures were calculated as Tmin = −3.8–0.0 °C, Topt = 28.0–34.6 °C, and Tmax = 35.2–37.2 °C. The growth of G. candidum J was slightly faster in milk with 1% NaCl and in temperature regions under 21 °C. However, in a temperature range that was close to the optimum, its growth was slightly inhibited by the lowered water activity level. The present study provides useful cultivation data for understanding the behaviour of G. candidum in milk and can serve as an effective tool for assessing the risk of fungal spoilage, predicting the shelf life of dairy products, or assessing the optimal conditions for its growth in relation to the operational parameters in dairy practices.

scholarly journals Impact of Different Carbon Sources on the in vitro Growth and Viability of Escherichia coli (SUBE01) and Salmonella spp. (SUBS01) Cells

2016 ◽  
pp. 39-44
Author(s):  
Ifra Tun Nur ◽  
Jannatun Tahera ◽  
Md Sakil Munna ◽  
M Majibur Rahman ◽  
Rashed Noor
Keyword(s):  
Escherichia Coli ◽  
Bacterial Growth ◽  
Culture Media ◽  
Bacterial Species ◽  
Carbon Sources ◽  
Growth Dynamics ◽  
Luria Bertani ◽  
Tween 20 ◽  
Salmonella Spp

With a previous observation of Escherichia coli growth cessation along with temperature variation within three different bacteriological culture media (nutrient agar, Luria-Bertani agar and minimal agar), current investigation further depicted on the possible growth dynamics of Escherichia coli (SUBE01) and Salmonella (SUBS01) growth and viability upon supplementation of different carbon sources (dextrose, sucrose, lactose, glycerol and tween 20) at 37°C under the aeration of 100 rpm. Viability of the tested bacterial species was assessed through the enumeration of the colony forming unit (cfu) appeared upon prescribed incubation for 12-24 hours on different agar plates consisting of the above mentioned carbon sources. Besides, to inspect the cellular phenotypic changes, morphological observations were conducted under the light microscope. Variations in bacterial growth (either growth acceleration or cessation) were further noticed through the spot tests on the agar plates. Considerable shortfalls in the culturable cells of E. coli and Salmonella spp. were noted in the minimal media separately consisting of sucrose, lactose, glycerol or tween 20 while an opposite impact of accelerated growth was noticed in the media supplied with dextrose. The data revealed a hierarchy of consequence of carbon sources as nutrient generators whereby the favourable bacterial growth and survival order of the carbon sources was estimated as dextrose > glycerol > lactose > tween 20 > sucrose.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 39-44

scholarly journals Environmental stress responses in yeasts and lactic acid bacteria strains isolated from dairy traditional Romanian fermented products

2021 ◽  
Vol 26 (2) ◽  
pp. 2548-2559
Author(s):  
VIORICA CORBU ◽  
◽  
STEFANA PETRUT ◽  
TATIANA VASSU ◽  
DIANA PELINESCU ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Cell Growth ◽  
Lactic Acid Bacteria ◽  
Environmental Stress ◽  
Stress Responses ◽  
Dairy Products ◽  
Growth Parameters ◽  
Great Opportunity ◽  
Fermented Dairy Products ◽  
Fermented Dairy

During last decades, there is a growing interest for characterizing new microbial strains isolated from various sources (plants, soil and natural fermentative processes), in order to enhance industrial productivity. The aim of the present study was to assess the profile of cell growth parameters and biomass accumulation of 15 newly isolated yeast and lactic acid bacteria (LAB) strains from Romanian spontaneous fermented dairy products under different environmental stress conditions (chemical and physical). On this purpose, the yeast and LAB strains were characterized and identified using MALDI-TOF MS and selected for their biotechnological potential. Cell growth was evaluated in presence of extreme pH values, temperatures and different NaCl concentrations. All strains included in this study grew well under their optimal conditions; some of them preferred extreme parameters: acid / very alkaline pH, high temperatures or NaCl concentration The characterization of microbiota from Romanian spontaneous fermented dairy products might represent a great opportunity for the development of dairy industry using native microorganisms, preserving thus the Romanian biodiversity and cultural heritage.

scholarly journals Pollutant removal and growth dynamics of macrophyte species for faecal sludge treatment with constructed wetland technology

2019 ◽  
Vol 80 (6) ◽  
pp. 1145-1154
Author(s):  
Agyemang Richard Osei ◽  
Yacouba Konate ◽  
Felix Kofi Abagale
Keyword(s):  
Constructed Wetland ◽  
Growth Parameters ◽  
Oxygen Demand ◽  
Growth Dynamics ◽  
Pilot Scale ◽  
Pollutant Removal ◽  
Local Context ◽  
Organic Chemical ◽  
Bambusa Vulgaris ◽  
Faecal Sludge

Abstract Constructed wetland technology is an innovative engineering technique for faecal sludge (FS) management. The presence of emergent macrophytes enhances the important processes of evapotranspiration, sludge mineralisation, and contaminant reduction. Consequently, selecting a species that can withstand the difficult sludge contaminated conditions within a local context is vital. This study monitored the pollutant removal potentials and growth dynamics of Bambusa vulgaris and Cymbopogon nardus as promising macrophytes for the constructed wetland technology in the Sudano-Sahelian context. The experiment, at pilot scale, consisted of plastic reactors (27 litre) filled with filter media of sand and fine gravels at the base, and planted with the selected species. Pollutant removal efficiencies were evaluated based on differences between influent and effluent concentrations, and physiological growth parameters of plant height, number of leaves and number of plants were monitored monthly. Total annual sludge loading rate of 31.4 and 103.4 kg TS/(m2·yr) (TS: total solids) were determined for FS + wastewater (acclimatisation phase) and FS load respectively. Both species recorded appreciable pollutant removal efficiency >80% for the organic (chemical oxygen demand), nutrients (PO43_P and NH4-N) and solid (total suspended solids and total volatile solids) contents. The species thus demonstrated satisfactory performance of resistance for faecal polluted wetland conditions.

Analysis of the effect of n fertilisation on the growth dynamics of winter wheat varieties using the hunt-parsons model

2011 ◽  
Vol 59 (1) ◽  
pp. 35-45
Author(s):  
E. Sugár ◽  
Z. Berzsenyi
Keyword(s):  
Winter Wheat ◽  
Leaf Area ◽  
Dry Matter ◽  
Growth Parameters ◽  
Growth Dynamics ◽  
Dry Matter Accumulation ◽  
Wheat Varieties ◽  
Mean Values ◽  
N Treatment ◽  
Winter Wheat Varieties

The effect of nitrogen (N) fertilisation on the growth of winter wheat varieties was examined in three diverse years using the functional method of growth analysis. The main plot in the two-factorial, split-plot experiment was the N treatment and the subplot the variety. The wheat varieties Mv Toborzó (extra-early), Mv Palotás (early) and Mv Verbunkos (mid-early) were treated with N rates of 0, 80, 160 and 240 kg N ha−1 (N0, N80, N160, N240). The Hunt-Parsons (HP) program fitted a third-degree exponential function to the dry matter and leaf area data. In 2007 and 2008 dry matter accumulation continued up to the N240 rate and in 2009 to the N160 rate. In all three years the highest value was recorded for Mv Verbunkos (4.62 g plant−1 in 2007, 4.63 g in 2008 and 4.51 g in 2009). The highest value of maximum leaf area (237.5 cm2) was found for Mv Verbunkos in the N240 treatment. The maximum values of leaf area in each N treatment, averaged over years and varieties (cm2 plant−1), were as follows: N0: 86.2; N80: 141.0; N160: 164.0; N240: 173.1. The parameter AGRmean exhibited the highest value (8.04 g day−1 102) in the N160 treatment, while among the varieties Mv Verbunkos had the highest mean value (7.18 g day−1 102). The highest value of RGRmean was achieved by Mv Toborzó in the N160 treatment in 2009 (3.94 g g−1 day−1 102). The value of NARmean increased up to fertiliser rates of N160 and N240, with mean values (g m−1 day−1) of N0: 2.35, N80: 2.44, N160: 2.53 and N240: 2.47. The highest value of NAR (3.29 g m−1 day−1) was obtained for Mv Palotás in the N160 treatment in 2008. On average the greatest value of LARmax was recorded in the N160 treatment (172.8 cm2 g−1), while the highest absolute value (213.6 cm2 g−1) was achieved by Mv Toborzó in 2008. The unfavourable effect of the drought in 2007 was clearly reflected in the values of the growth parameters.

Growth dynamics of cyclomaltodextrin glucanotransferase producing Bacillus circulans var. alkalophilus

1990 ◽  
Vol 36 (3) ◽  
pp. 176-182 ◽  
Author(s):  
Mauri J. Mäkelä ◽  
Sari K. Paavilainen ◽  
Timo K. Korpela
Keyword(s):  
Time Course ◽  
Growth Parameters ◽  
Growth Dynamics ◽  
Point Of View ◽  
Bacillus Circulans ◽  
Amylolytic Enzyme ◽  
Bulk Growth ◽  
Atcc Strain ◽  
Total Carbohydrates ◽  
Cyclomaltodextrin Glucanotransferase

The time course of the growth of cyclomaltodextrin glucanotransferase (EC 2.4.1.19; CGTase) producing Bacillus circulans var. alkalophilus (ATCC 21783) was studied using shaking-flask cultivations. The growth curve was diauxic and during the initial phase the pH decreased sharply by 1.3–1.5 units. Most of the total carbohydrates disappeared prior to the bulk growth, which corresponded to a transient peak of amylolytic enzyme activity and of reducing sugars followed by acid production. During active cell growth the pH recovered by about 0.5 units and 65% of the final CGTase appeared in the medium. Another 20% was produced during the stationary phase and 15% was produced in the death phase. The growth dynamics of two randomly selected alkalophilic Bacillus strains (ATCC 27647 and 27557) were compared with those of ATCC-strain 21783. The reference strains showed related growth behavior with the exception that the timing and magnitudes of the changes in the growth parameters measured were different. The effects of carbon source (starch), nitrogen source (yeast extract plus Bacto-pantone), sodium carbonate, and temperature were studied from the point of view of CGTase production. Key words: cyclomaltodextrin glucanotransferase; alkalophilic bacilli; cyclodextrins.

scholarly journals Two resistance nodulation division-family efflux pumps inChromobacteriumspecies and their role in antibiotic resistance and tolerance

2019 ◽  
Author(s):  
Saida Benomar ◽  
Kara C Evans ◽  
Robert L Unckless ◽  
Josephine R Chandler
Keyword(s):  
Antibiotic Resistance ◽  
Efflux Pump ◽  
Bacterial Species ◽  
Efflux Pumps ◽  
Resistance Mechanisms ◽  
Antibiotic Resistant ◽  
Burkholderia Thailandensis ◽  
New Information ◽  
Resistance Nodulation Division ◽  
Culture Growth

ABSTRACTVery little is known of the antibiotic resistance mechanisms of members of theChromobacteriumgenus. In previous studies ofChromobacterium subtsugae(formerlyC. violaceum) strain CV017, we identified a resistance nodulation division (RND)-family efflux pump (CdeAB-OprM). Here, we show thecdeAB-oprMgenes are widely distributed in members of theChromobacteriumgenus. We use antimicrobial susceptibility testing with a CV017cdeAB-oprMmutant to show the products of these genes confers resistance to a variety of antibiotics including ciprofloxacin, a clinically important antibiotic. We also identified a related RND-family pump,cseAB-oprN, in the genome of CV017 and otherC. subtsugaespecies, that is not present in other members of theChromobacteriumgenus. We demonstrate that CdeAB-OprM and CseAB-OprN are both transcriptionally induced in CV017 cells treated with sub-lethal antibiotic concentrations and they are important for induction of tolerance to different antibiotics. While CdeAB-OprM has a broad antibiotic specificity, the CseAB-OprN system is highly specific for a ribosome-targeting antibiotic produced by the saprophytic bacteriumBurkholderia thailandensis,bactobolin. Finally, we use a previously developedB. thailandensis-C. subtsugaeCV017 co-culture model to demonstrate that adding sub-lethal bactobolin at the beginning of co-culture growth increases the ability of CV017 to compete withB. thailandensisin a manner that is dependent on the CseAB-OprN system. Our results provide new information on the antibiotic resistance mechanisms ofChromobacteriumspecies and highlight the importance of efflux pumps during competition with other bacterial species.IMPORTANCEThis study describes two closely related efflux pumps in members of theChromobacteriumgenus, which includes opportunistic but often-fatal pathogens and species with highly versatile metabolic capabilities. Efflux pumps remove antibiotics from the cell and are important for antibiotic resistance. One of these pumps is broadly distributed in theChromobacteriumgenus and increases resistance to clinically relevant antibiotics. The other efflux pump is present only inChromobacterium subtsugaeand is highly specific for bactobolin, an antibiotic produced by the soil saprophyteBurkholderia thailandensis. We demonstrate these pumps can be activated to increase resistance by their antibiotic substrates, and that this activation is important forC. subtsugaeto survive in a laboratory competition experiment withB. thailandensis.These results have implications for managing antibiotic-resistantChromobacteriuminfections, bioengineering ofChromobacteriumspecies, and for understanding the evolution of efflux pumps.

scholarly journals Dynamic interspecies interactions and robustness in a four-species model biofilm

2021 ◽  
Author(s):  
Aurélie Baliarda ◽  
Michèle Winkler ◽  
Laurent Tournier ◽  
Colin Tinsley ◽  
Stéphane Aymerich
Keyword(s):  
Mutational Analysis ◽  
Interspecific Interactions ◽  
Bacterial Species ◽  
Species Abundance ◽  
Growth Dynamics ◽  
Equilibrium Composition ◽  
Interspecies Interactions ◽  
Molecular Determinant ◽  
And Function ◽  
Final Composition

Interspecific interactions within biofilms determine relative species abundance, growth dynamics, community resilience, and success or failure of invasion by an extraneous organism. However, deciphering interspecific interactions and assessing their contribution to biofilm properties and function remain a challenge. Here, we describe the constitution of a model biofilm composed of four bacterial species belonging to four different genera (Rhodocyclus sp., Pseudomonas fluorescens, Kocuria varians, and Bacillus cereus), derived from a biofilm isolated from an industrial milk pasteurization unit. We demonstrate that the growth dynamics and equilibrium composition of this biofilm are highly reproducible. Based on its equilibrium composition, we show that the establishment of this 4-species biofilm is highly robust against initial, transient perturbations but less so towards continuous perturbations. By comparing biofilms formed from different numbers and combinations of the constituent species and by fitting a growth model to the experimental data, we reveal a network of dynamic, positive, and negative interactions that determine the final composition of the biofilm. Furthermore, we reveal that the molecular determinant of one negative interaction is the thiocillin I synthesized by the B. cereus strain, and demonstrate its importance for species distribution and its impact on robustness by mutational analysis of the biofilm ecosystem.

scholarly journals Advances in role of organic acids in poultry nutrition: A review

2017 ◽  
Vol 9 (4) ◽  
pp. 2152-2157 ◽  
Author(s):  
Zulfqarul Haq ◽  
Ankur Rastogi ◽  
R. K. Sharma ◽  
Nazim Khan
Keyword(s):  
Drug Resistance ◽  
Organic Acids ◽  
Growth Parameters ◽  
Bacterial Species ◽  
Nutrient Digestibility ◽  
Feed Additives ◽  
Microbial Drug Resistance ◽  
Pathogenic Microbes ◽  
Poultry Nutrition ◽  
Poultry Diets

Anti microbial drug resistance concerns scientists all around the world epically one used as livestock feed additives. Feed grade antibiotics are given in non therapeutic doses which lead to survival of pathogenic microbes which in turn develop drug resistance, thus necessitating researchers to search for alternative ways to feed grade antibiotics besides doing least compromise on growth parameters. Organic acids are used in poultry to lower the pH of intestinal tract which favours good microbes which in turn suppress pathogenic microbes thus evicting the use of antibiotics. They are used in poultry diets and drinking water to elicit a positive growth response, improving nutrient digestibility, performance and immunity in poultry. Literature shows that organic acids have more or less pronounced antimicrobial activity, depending on both the concentration of the acid and the bacterial species that is exposed to the acid. The variability in response of organic acids and its possible mechanisms are discussed. Scope of this paper is to provide a view of the use of organic acids in the prevention of enteric disease in poultry, the effect on the gastrointestinal tract (GIT), immunity and performance of broiler or laying hens. In the current review beneficial as-pects of organic acids along with different dose combinations are discussed to promote its optimum utilization in poultry nutrition and production.

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