scholarly journals The Joint Effect of pH Gradient and Glucose Feeding on the Growth Kinetics of Lactococcus lactis CECT 539 in Glucose-Limited Fed-Batch Cultures

2019 ◽  
Vol 68 (2) ◽  
pp. 269-280
Author(s):  
MÓNICA COSTAS MALVIDO ◽  
ELISA ALONSO GONZÁLEZ ◽  
RICARDO J. BENDAÑA JÁCOME ◽  
NELSON PÉREZ GUERRA
Keyword(s):  
Lactococcus Lactis ◽  
Viable Cell ◽  
Product Formation ◽  
Ph Gradient ◽  
Feeding Strategies ◽  
Fed Batch ◽  
Batch Cultures ◽  
Cell Counts ◽  
First Time ◽  
Kinetics Of

Two glucose-limited realkalized fed-batch cultures of Lactococcus lactis CECT 539 were carried out in a diluted whey medium (DW) using two different feeding media. The cultures were fed a mixture of a 400 g/l concentrated lactose and a concentrated mussel processing waste (CMPW, 101.72 g glucose/l) medium (fermentation I) or a CMPW medium supplemented with glucose and KH2PO4 up to concentrations of 400 g glucose/l and 3.21 g total phosphorus/l, respectively (fermentation II). For an accurate description and a better understanding of the kinetics of both cultures, the growth and product formation by L. lactis CECT 539 were both modelled, for the first time, as a function of the amounts of glucose (G) added and the pH gradient (VpH) generated in every realkalization and feeding cycle, by using an empirical polynomial model. With this modeling procedure, the kinetics of biomass, viable cell counts, nisin, lactic acid, acetic acid and butane-2,3-diol production in both cultures were successfully described (R2 values > 0.970) and interpreted for the first time. In addition, the optimum VpH and G values for each product were accurately calculated in the two realkalized fed-batch cultures. This approach appears to be useful for designing feeding strategies to enhance the productions of biomass, bacteriocin, and metabolites by the nisin-producing strain in wastes from the food industry.

Dynamic mathematical models to describe the growth and nisin production by Lactococcus lactis subsp. lactis CECT 539 in both batch and re-alkalized fed-batch cultures

2007 ◽  
Vol 82 (2) ◽  
pp. 103-113 ◽  
Author(s):  
Nelson P. Guerra ◽  
Ana Torrado Agrasar ◽  
Cristina López Macías ◽  
Paula Fajardo Bernárdez ◽  
Lorenzo Pastrana Castro
Keyword(s):  
Mathematical Models ◽  
Lactococcus Lactis ◽  
Fed Batch ◽  
Nisin Production ◽  
Batch Cultures ◽  
Lactococcus Lactis Subsp

scholarly journals Model System for Growing and Quantifying Streptococcus pneumoniae Biofilms In Situ and in Real Time

2004 ◽  
Vol 70 (8) ◽  
pp. 4980-4988 ◽  
Author(s):  
R. M. Donlan ◽  
J. A. Piede ◽  
C. D. Heyes ◽  
L. Sanii ◽  
R. Murga ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Extracellular Polymeric Substances ◽  
Viable Cell ◽  
Protein Band ◽  
Biofilm Reactor ◽  
Cell Counts ◽  
Biofilm Structure ◽  
Kinetics Of ◽  
Over Time

ABSTRACT Streptococcus pneumoniae forms biofilms, but little is known about its extracellular polymeric substances (EPS) or the kinetics of biofilm formation. A system was developed to enable the simultaneous measurement of cells and the EPS of biofilm-associated S. pneumoniae in situ over time. A biofilm reactor containing germanium coupons was interfaced to an attenuated total reflectance (ATR) germanium cell of a Fourier transform infrared (FTIR) laser spectrometer. Biofilm-associated cells were recovered from the coupons and quantified by total and viable cell count methods. ATR-FTIR spectroscopy of biofilms formed on the germanium internal reflection element (IRE) of the ATR cell provided a continuous spectrum of biofilm protein and polysaccharide (a measure of the EPS). Staining of the biofilms on the IRE surface with specific fluorescent probes provided confirmatory evidence for the biofilm structure and the presence of biofilm polysaccharides. Biofilm protein and polysaccharides were detected within hours after inoculation and continued to increase for the next 141 h. The polysaccharide band increased at a substantially higher rate than did the protein band, demonstrating increasing coverage of the IRE surface with biofilm polysaccharides. The biofilm total cell counts on germanium coupons stabilized after 21 h, at approximately 105 cells per cm2, while viable counts decreased as the biofilm aged. This system is unique in its ability to detect and quantify biofilm-associated cells and EPS of S. pneumoniae over time by using multiple, corroborative techniques. This approach could prove useful for the study of biofilm processes of this or other microorganisms of clinical or industrial relevance.

scholarly journals Modelling the Biphasic Growth and Product Formation byEnterococcus faeciumCECT 410 in Realkalized Fed-Batch Fermentations in Whey

2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Nelson Pérez Guerra ◽  
Paula Fajardo ◽  
Clara Fuciños ◽  
Isabel Rodríguez Amado ◽  
Elisa Alonso ◽  
...  
Keyword(s):  
Logistic Models ◽  
Product Formation ◽  
Monod Model ◽  
Fed Batch ◽  
Acid Fermentation ◽  
Total Sugars ◽  
Batch Cultures ◽  
Mixed Acid ◽  
Initial Ph ◽  
Product Accumulation

The influence of initial pH on growth and nutrient (total sugars, nitrogen, and phosphorous) consumption byEnterococcus faeciumCECT 410 was studied during batch cultures in whey. With these data, two realkalized fed-batch fermentations were developed using different feeding substrates. The shift from homolactic to mixed acid fermentation, the biphasic kinetics observed for cell growth and nitrogen consumption and the increase in the concentrations of biomass and products (lactic acid, acetic acid, ethanol, and butane-2,3-diol) were the most noteworthy observations of these cultures. Modelling the fed-batch growth ofEnt. faeciumwith the Logistic and bi-Logistic models was not satisfactory. However, biomass production was best mathematically described with the use of a double Monod model, which was expressed in terms of biomass, product accumulation, and nitrogen utilization. Product formation was successfully modelled with a modified form of the Luedeking and Piret model developed in this study.

scholarly journals Glucose Metabolism in Lactococcus lactis MG1363 under Different Aeration Conditions: Requirement of Acetate To Sustain Growth under Microaerobic Conditions

2003 ◽  
Vol 69 (6) ◽  
pp. 3462-3468 ◽  
Author(s):  
Mikkel Nordkvist ◽  
Niels Bang Siemsen Jensen ◽  
John Villadsen
Keyword(s):  
Lactococcus Lactis ◽  
Specific Growth ◽  
Acid Synthesis ◽  
Product Formation ◽  
Defined Medium ◽  
Acetyl Coa ◽  
Dissolved Oxygen Tension ◽  
Batch Cultures ◽  
Aeration Conditions ◽  
Microaerobic Conditions

ABSTRACT Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation with air was used as the reference). The maximum specific growth rate was high (0.78 to 0.91 h−1) under all aeration conditions but decreased with increasing aeration, and more than 90% of the glucose was converted to lactate. However, a shift in by-product formation was observed. Increasing aeration resulted in acetate, CO2, and acetoin replacing formate and ethanol as end products. Under microaerobic conditions, growth came to a gradual halt, although more than 60% of the glucose was still left. A decline in growth was not observed during microaerobic cultivation when acetate was added to the medium. We hypothesize that the decline in growth was due to a lack of acetyl coenzyme A (acetyl-CoA) needed for fatty acid synthesis since acetyl-CoA can be synthesized from acetate by means of acetate kinase and phosphotransacetylase activities.

scholarly journals Towards the development of automated fed-batch cell culture processes at microscale

BioTechniques ◽  
2019 ◽  
Vol 67 (5) ◽  
pp. 238-241
Author(s):  
Vincent Wiegmann ◽  
Maria Giaka ◽  
Cristina Bernal Martinez ◽  
Frank Baganz
Keyword(s):  
Feeding Strategy ◽  
Viable Cell ◽  
Feeding Strategies ◽  
Fed Batch ◽  
Cho Cell ◽  
Feed Medium ◽  
Cell Densities ◽  
The Impact ◽  
Batch Cell ◽  
Selection Of

Aim: To investigate the impact of various feeding strategies on the growth and productivity of a GS-CHO cell line. Methods: Feed additions were conducted at fixed volumes or linked to a marker such as cell growth or metabolism and added as bolus or near-continuously using the automated feeding module of the micro-Matrix (Applikon). Results: The selected feeding regimens supported maximum viable cell densities of up to 1.9 × 107 cells ml−1 and final titers of up to 1.13 g l−1. Differences in growth and titer between feeding strategies were insignificant, with the exception of one feeding strategy. Conclusion: As the more complex feeding strategies did not create an advantage, the selection of a simple feeding strategy such as bolus or continuous addition of feed medium is preferred.

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