Lactobacillus reuteri β-galactosidase activity and low milk acidification ability

2005 ◽  
Vol 51 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Madeleine Hidalgo-Morales ◽  
Victor Robles-Olvera ◽  
Hugo S García
Keyword(s):  
Lactobacillus Reuteri ◽  
Specific Growth ◽  
Cell Concentration ◽  
Growth Parameters ◽  
Skim Milk ◽  
Nitrogen Sources ◽  
Broth Culture ◽  
Galactosidase Activity ◽  
Carbon And Nitrogen ◽  
Specific Growth Rates

β-galactosidase activity was studied as a possible cause of the low milk acidification ability observed in Lactobacillus reuteri NRRL 14171. Enzymatic activity was determined in MRS broth supplemented with either glucose or lactose and milk at the middle and final stage of the exponential phase, as well as at the stationary phase. Results were compared with β-galactosidase activity in Lactobacillus casei NRRL-B1922, a strain that shows the milk acidification ability. The effects of the types of carbon and nitrogen sources were established by comparison of growth parameters (higher maximum cell concentration and specific growth rate) in broth culture and skim milk supplemented with 2% glucose or 1% casein peptone. In milk, L. reuteri showed higher β-galactosidase activity in all growth phases compared with L. casei. Greater cell concentration maxima, specific growth rates, and acidification abilities were observed in L. reuteri when it was cultured in milk supplemented with 1% casein peptone compared with non-supplemented milk cultures. Results suggest that the poor milk acidification ability observed in L. reuteri may be more related to a weak proteolytic system than to deficient β-galactosidase activity.Key words: Lactobacillus reuteri, growth parameters, β-galactosidase, acidification.

scholarly journals Isolation of A Molybdenum-reducing Bacillus sp. strain Zeid 15 and Modeling of its Growth on Amides

2021 ◽  
Vol 5 (2) ◽  
pp. 19-27
Author(s):  
I.M. Abu Zeid ◽  
M.F. Rahman ◽  
Mohd Yunus Shukor
Keyword(s):  
Heavy Metals ◽  
Specific Growth ◽  
Growth Parameters ◽  
Gompertz Model ◽  
Electron Donors ◽  
Bacillus Sp ◽  
Aquatic Life ◽  
Molybdenum Blue ◽  
Specific Growth Rates ◽  
Modified Gompertz Model

More and more people are looking at bioremediation as a cheaper option to physhiochemical techniques for cleaning up pollution from farming, mines, and other chemical industries. Toxic effects of molybdenum on spermatogenesis harm not only humans but also livestock and aquatic life. As a result, efforts are being made to remove it from the ecosystem. A microorganism that can convert soluble molybdenum into colloidal molybdenum blue has been discovered. Phosphate concentrations were optimum between 2.5 and 5, molybdate concentrations between 15 and 20, pH between 6, and temperature between 25 and 34 degrees Celsius for the bacteria to thrive. Absorption spectrum of Mo-blue shows a peak at 865 nm and a shoulder at 700 nm, which indicates that it is in fact reduced phosphomolybdate. Copper, mercury, silver, copper, and chromium are all hazardous heavy metals that hinder the synthesis of Mo-blue. Bacillus sp. strain Zeid 15 is the most likely candidate for the bacterium's identity. As part of our screening, we look for the bacterium's capacity to employ different nitriles and amides as potential electron donors for molybdenum reduction or as substrates for growth. A microplate format was used for the screening. The bacterium was able to use the amides acrylamide and propionamide as sources of electron donor for reduction. Mo-blue production was best supported by acrylamide between 750 and 1250 mg/L, and propionamide between 750 and 1000 mg/L. In addition, these amides including acetamide could support the growth of the bacterium. The modified Gompertz model was utilized to model the growth of this bacterium on amides. The model’s growth parameters obtained were lag periods of 1.372, 1.562 and 1.639 d and maximum specific growth rates of 1.38, 0.95 and 0.734 d-1, for acrylamide, acetamide and propionamide, respectively. The capacity of this bacterium to decontaminate simultaneously amides and molybdenum is a novel characteristic that will be very beneficial in bioremediation.

One-Step Analysis for Listeria monocytogenes Growth in Ready-to-Eat Braised Beef at Dynamic and Static Conditions

2019 ◽  
Vol 82 (11) ◽  
pp. 1820-1827 ◽  
Author(s):  
YANGTAI LIU ◽  
XIANG WANG ◽  
BAOLIN LIU ◽  
QINGLI DONG
Keyword(s):  
Listeria Monocytogenes ◽  
Specific Growth ◽  
Growth Parameters ◽  
Dynamic Condition ◽  
Physiological State ◽  
External Validation ◽  
One Step ◽  
Lag Period ◽  
Specific Growth Rates ◽  
Static Conditions

ABSTRACT This study aimed to estimate the growth parameters of Listeria monocytogenes growth in ready-to-eat (RTE) braised beef by one-step dynamic and static kinetic analysis. The Baranyi model and cardinal parameters model were integrated into a dynamic and static model to estimate the kinetic parameters under one dynamic condition (−20 to 40.0°C) and eight static conditions (4, 8, 15, 20, 30, 35, 37, and 40°C). Based on the dynamic and static methods, the respective dynamic and static results for estimated growth boundaries of L. monocytogenes in RTE braised beef were from −2.5 and −2.7°C to 40.5 and 40.7°C with optimal specific growth rates of 1.078 and 0.913 per h at temperatures of 35.7 and 35.0°C. Temperature effects on the specific growth rate and lag period were developed and used to simulate the change of the physiological state of inocula during the bacterial growth. Subsequently, three additional dynamic temperature profiles were implemented for external validation. The root mean square error of the model developed by dynamic regression (0.19 log CFU/g) is slightly better than that of the model developed by static regression (0.23 log CFU/g). Comparing the validation results, one-step dynamic analysis might be a preferable method for prediction, especially when the growth approaches the stationary phase. Generally, both one-step dynamic and static analyses could be used to accurately predict L. monocytogenes growth in RTE braised beef under fluctuating temperatures.

scholarly journals Optimization of Culture Conditions for Protease Production using Three Strains of Bacillus

2021 ◽  
Author(s):  
Cyr Jonas Morabandza ◽  
Valentin Dibangou ◽  
Faly Armel Soloka Mabika ◽  
Elgie Viennechie Gatse ◽  
Tarcisse Baloki Ngoulou ◽  
...  
Keyword(s):  
Enzyme Production ◽  
Skim Milk ◽  
Nitrogen Sources ◽  
Petri Dish ◽  
Culture Conditions ◽  
Luria Bertani ◽  
Protease Production ◽  
Carbon And Nitrogen ◽  
Cassava Leaves ◽  
Milk Casein

The aim of this work was to determine the effect of a few external factors on bacterial growth and the production of enzymes with a proteolytic effect in three strains of Bacillus: CMS5 (Bacillus subtilis), CMS4 (Bacillus sp.) and SPo5 14′ (Bacillus velenzensis) isolated from squashes packed in traditionally prepared cassava leaves, but also to determine the best source of carbon and nitrogen. All three strains have the ability to actively degrade milk casein. The strains were grown in Luria Bertani medium and the suspension from the cell culture was used to measure optical density and demonstrate enzyme activity on a petri dish containing skim milk. Several parameters were verified including the influence of temperature, pH, and carbon and nitrogen source on growth and enzyme production. Growth was possible from 25 to 60°C with an optimal temperature of 30°C after 24 hours. Enzyme production was observed from 25 to 55°C with an optimum at 37°C. For pH, growth and enzyme production was possible from pH 5.7 and 9 with an optimum of 7 in all three strains. Among the sources of carbons used, galactose is the best source for growth after 24 h in all three strains, and starch for production. Among nitrogen sources, Bacto-peptone is best for growth as well as production.

Effect of ammonium on chloramphenicol production by Streptomyces venezuelae in batch and continuous cultures

1985 ◽  
Vol 31 (2) ◽  
pp. 119-123 ◽  
Author(s):  
S. Shapiro ◽  
L. C. Vining
Keyword(s):  
Nitrogen Assimilation ◽  
Specific Growth ◽  
Antibiotic Production ◽  
Nitrogen Sources ◽  
Streptomyces Venezuelae ◽  
Continuous Cultures ◽  
Limiting Nutrient ◽  
Nitrogen Repression ◽  
Specific Growth Rates ◽  
Temporary Inhibition

Cultures of Streptomyces venezuelae presented with a mixture of ammonium and an amino acid as nitrogen sources used both compounds together. Absence of ammonium repression of alternative nitrogen assimilation pathways was also observed when ammonium was added to cultures already growing on proline. The presence of ammonium in the medium ab initio depressed the yield of chloramphenicol. However, its addition to a culture growing on proline caused only a temporary inhibition of antibiotic synthesis, even when sufficient ammonium was added to create an excess. Continuous cultures supplied with ammonium as the growth-limiting nutrient showed no significant change in specific antibiotic production at different specific growth rates. The overall results indicate that in S. venezuelae neither nitrogen utilization pathways nor chloramphenicol biosynthesis is controlled by nitrogen repression.

scholarly journals Influence of Culture Conditions and Medium Compositions on the Production of Bacteriocin-Like Inhibitory Substances by Lactococcus lactis Gh1

2020 ◽  
Vol 8 (10) ◽  
pp. 1454
Author(s):  
Roslina Jawan ◽  
Sahar Abbasiliasi ◽  
Joo Shun Tan ◽  
Shuhaimi Mustafa ◽  
Murni Halim ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Lactococcus Lactis ◽  
Organic Nitrogen ◽  
Specific Growth ◽  
Cell Concentration ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Culture Conditions ◽  
Initial Ph

Antibacterial peptides or bacteriocins produced by many strains of lactic acid bacteria have been used as food preservatives for many years without any known adverse effects. Bacteriocin titres can be modified by altering the physiological and nutritional factors of the producing bacterium to improve the production in terms of yield and productivity. The effects of culture conditions (initial pH, inoculum age and inoculum size) and medium compositions (organic and inorganic nitrogen sources; carbon sources) were assessed for the production of bacteriocin-like inhibitory substances (BLIS) by Lactococcus lactis Gh1 in shake flask cultures. An inoculum of the mid-exponential phase culture at 1% (v/v) was the optimal age and size, while initial pH of culture media at alkaline and acidic state did not show a significant impact on BLIS secretion. Organic nitrogen sources were more favourable for BLIS production compared to inorganic sources. Production of BLIS by L. lactis Gh1 in soytone was 1.28-times higher as compared to that of organic nitrogen sources ((NH4)2SO4). The highest cell concentration (XmX = 0.69 ± 0.026 g·L−1) and specific growth rate (μmax = 0.14 h−1) were also observed in cultivation using soytone. By replacing carbon sources with fructose, BLIS production was increased up to 34.94% compared to BHI medium, which gave the biomass cell concentration and specific growth rate of 0.66 ± 0.002 g·L−1 and 0.11 h−1, respectively. It can be concluded that the fermentation factors have pronounced influences on the growth of L. lactis Gh1 and BLIS production. Results from this study could be used for subsequent application in process design and optimisation for improving BLIS production by L. lactis Gh1 at larger scale.

scholarly journals Studies on Optimization of Growth Parameters for L-Asparaginase Production byStreptomyces ginsengisoli

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Neelima Deshpande ◽  
Prachi Choubey ◽  
Manasi Agashe
Keyword(s):  
Anticancer Activity ◽  
Submerged Fermentation ◽  
Shake Flask ◽  
Growth Parameters ◽  
Nitrogen Sources ◽  
Culture Conditions ◽  
Carbon And Nitrogen Sources ◽  
Multiple Functions ◽  
Carbon And Nitrogen ◽  
Maximal Production

A species ofStreptomyces,Streptomyces ginsengisoli, a river isolate, was evaluated for production of an enzyme, L-asparaginase, with multiple functions mainly anticancer activity. The actinomycete was subjected to submerged fermentation by “shake flask” method. The quantity of L-asparaginase produced was estimated as 3.23 μmol/mL/min. The effect of various culture conditions on L-asparaginase production was studied by adopting a method of variation in one factor at a time. Of the various conditions tested, glucose (followed by starch) and peptone served as good carbon and nitrogen sources, respectively, for maximal production of enzyme at pH 8. The temperature of 30°C and an incubation period of 5 days with 0.05 g% asparagine concentration were found to be optimum for L-asparaginase production.

scholarly journals Poly-3-Hydroxybutyrate Metabolism in the Type II Methanotroph Methylocystis parvus OBBP

2011 ◽  
Vol 77 (17) ◽  
pp. 6012-6019 ◽  
Author(s):  
Allison J. Pieja ◽  
Eric R. Sundstrom ◽  
Craig S. Criddle
Keyword(s):  
Suspended Solids ◽  
Specific Growth ◽  
Carbon Assimilation ◽  
Reducing Power ◽  
Type Ii ◽  
Growth Substrate ◽  
Content Type ◽  
Carbon And Nitrogen ◽  
Specific Growth Rates

ABSTRACTDifferences in carbon assimilation pathways and reducing power requirements among organisms are likely to affect the role of the storage polymer poly-3-hydroxybutyrate (PHB). Previous researchers have demonstrated that PHB functions as a sole growth substrate in aerobic cultures enriched on acetate during periods of carbon deficiency, but it is uncertain how C1metabolism affects the role of PHB. In the present study, the type II methanotrophMethylocystis parvusOBBP did not replicate using stored PHB in the absence of methane, even when all other nutrients were provided in excess. When PHB-rich cultures ofM. parvusOBBP were deprived of carbon and nitrogen for 48 h, they did not utilize significant amounts of stored PHB, and neither cell concentrations nor concentrations of total suspended solids changed significantly. When methane and nitrogen both were present, PHB and methane were consumed simultaneously. Cells with PHB had significantly higher specific growth rates than cells lacking PHB. The addition of formate (a source of reducing power) to PHB-rich cells delayed PHB consumption, but the addition of glyoxylate (a source of C2units) did not. This and results from other researchers suggest that methanotrophic PHB metabolism is linked to the supply of reducing power as opposed to the supply of C2units for synthesis.

scholarly journals Phosphorus Solubilization by Bacillus Species

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2897 ◽  
Author(s):  
Agnieszka Saeid ◽  
Ewelina Prochownik ◽  
Justyna Dobrowolska-Iwanek
Keyword(s):  
Organic Acids ◽  
Specific Growth ◽  
Raw Materials ◽  
Total Concentration ◽  
Broth Culture ◽  
Bacillus Species ◽  
Phosphorus Concentration ◽  
Fish Bones ◽  
Specific Growth Rates ◽  
Acetic Acids

Microbial solubilization applies the natural ability of a microorganism to liberate phosphorus from unavailable structures. The main mechanism recognized to be responsible for the solubilization of phosphorus is the production of different types of organic acids. Three kinds of Bacillus species and three types of raw materials (poultry bones, fish bones, and ash) were tested for solubilization. The following parameters were compared for all discussed cases: pH, specific growth rate, solubilization factor, released phosphorus concentration, and total and individual concentration of organic acids. Utilization of ash brought about the highest specific and maximum specific growth rates. A decrease in pH was observed in most of the discussed cases with the exception of fish bones. At the same time, fish bones had the highest concentration of released P2O5 and the highest total concentration of produced organic acids (gluconic, lactic, acetic, succinic, and propionic) in all discussed cases. The tested Bacillus species produced the mentioned acids with the exception of B. megaterium, where propionic acid was not present. The lactic and acetic acids were those produced in the highest amount. The kind of raw materials and type of Bacillus species used in solubilization had a strong influence on the kind of organic acids that were detected in the broth culture and its total concentration, which had a direct influence on the amount of released phosphorus. The combination of Bacillus megaterium with the fish bones at 5 g/L is proposed as the pair that gives the highest concentration of released phosphorus (483 ± 5 mg/L).

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