scholarly journals Strategies for improved rhamnolipid production by Pseudomonas aeruginosa PA1

2015 ◽  
Author(s):  
Alexandre Soares dos Santos ◽  
Nei Pereira Jr ◽  
Denise M G Freire
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Culture Medium ◽  
Fold Increase ◽  
Batch Process ◽  
Measurable Effect ◽  
Fed Batch ◽  
Batch Operation ◽  
Ph Values ◽  
Influence Of Ph

Rhamnolipids are biosurfactants with potential for diversified industrial and environmental uses. The present study evaluated three strategies to increase the production of rhamnolipid-type biosurfactants produced by Pseudomonas aeruginosa strain PA1. The influence of pH, the addition of endogenous autoinducers and the use of a fed batch process were examined. The culture medium adjusted to pH 7.0 was the most productive. Furthermore, the pH of the culture medium had a measurable effect on the ratio of mono- and dirhamnolipids synthesized. At pH values below 7.3, the proportion of monorhamnolipids decreased from 45 to 24%. Additionally, recycling 20% of the spent culture medium where P. aeruginosa was grown up to the later stationary phase was responsible for a 100% increase in rhamnolipid volumetric productivity in the new culture medium. Finally, the use of fed batch operation under conditions of limited nitrogen resulted in a 3.8-fold increase in the amount of rhamnolipids produced (1.29 g L-1 to 4.90 g L-1, as rhamnose). These results offer promising paths to optimize processes for the production of rhamnolipids.

scholarly journals Strategies for improved rhamnolipid production by Pseudomonas aeruginosa PA1

2015 ◽  
Author(s):  
Alexandre Soares dos Santos ◽  
Nei Pereira Jr ◽  
Denise M G Freire
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Culture Medium ◽  
Fold Increase ◽  
Batch Process ◽  
Measurable Effect ◽  
Fed Batch ◽  
Batch Operation ◽  
Ph Values ◽  
Influence Of Ph

Rhamnolipids are biosurfactants with potential for diversified industrial and environmental uses. The present study evaluated three strategies to increase the production of rhamnolipid-type biosurfactants produced by Pseudomonas aeruginosa strain PA1. The influence of pH, the addition of endogenous autoinducers and the use of a fed batch process were examined. The culture medium adjusted to pH 7.0 was the most productive. Furthermore, the pH of the culture medium had a measurable effect on the ratio of mono- and dirhamnolipids synthesized. At pH values below 7.3, the proportion of monorhamnolipids decreased from 45 to 24%. Additionally, recycling 20% of the spent culture medium where P. aeruginosa was grown up to the later stationary phase was responsible for a 100% increase in rhamnolipid volumetric productivity in the new culture medium. Finally, the use of fed batch operation under conditions of limited nitrogen resulted in a 3.8-fold increase in the amount of rhamnolipids produced (1.29 g L-1 to 4.90 g L-1, as rhamnose). These results offer promising paths to optimize processes for the production of rhamnolipids.

scholarly journals Strategies for improved rhamnolipid production byPseudomonas aeruginosaPA1

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2078 ◽  
Author(s):  
Alexandre Soares dos Santos ◽  
Nei Pereira Jr ◽  
Denise M.G. Freire
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Culture Medium ◽  
Fold Increase ◽  
Batch Process ◽  
Measurable Effect ◽  
Fed Batch ◽  
Batch Operation ◽  
Ph Values ◽  
Influence Of Ph

Rhamnolipids are biosurfactants with potential for diversified industrial and environmental uses. The present study evaluated three strategies for increasing the production of rhamnolipid-type biosurfactants produced byPseudomonas aeruginosastrain PA1. The influence of pH, the addition ofP. aeruginosaspent culture medium and the use of a fed-batch process were examined. The culture medium adjusted to pH 7.0 was the most productive. Furthermore, the pH of the culture medium had a measurable effect on the ratio of synthesized mono- and dirhamnolipids. At pH values below 7.3, the proportion of monorhamnolipids decreased from 45 to 24%. The recycling of 20% of the spent culture medium in whereP. aeruginosawas grown up to the later stationary phase was responsible for a 100% increase in rhamnolipid volumetric productivity in the new culture medium. Finally, the use of fed-batch operation under conditions of limited nitrogen resulted in a 3.8-fold increase in the amount of rhamnolipids produced (2.9 g L−1–10.9 g L−1). These results offer promising pathways for the optimization of processes for the production of rhamnolipids.

Production of Rhamnolipid Biosurfactant from Fed Batch Culture by Pseudomonas aeruginosa using Multiple Substrates

2020 ◽  
Vol 16 (6) ◽  
pp. 928-933
Author(s):  
Jujjavarapu S. Eswari
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Batch Process ◽  
Time Interval ◽  
Fed Batch ◽  
Multiple Substrates ◽  
Surface Active Agents ◽  
Limiting Nutrients ◽  
Limiting Nutrient ◽  
Surface Active ◽  
Rhamnolipid Biosurfactant

Objective: Biosurfactants are the surface active agents which are used for the reduction of surface and interfacial tensions of liquids. Rhamnolipids are the surfactants produced by Pseudomonas aeruginosa. It requires minimum nutrition for its growth as it can also grow in distilled water. The rhamnolipids produced by Pseudomonas aeruginosa are extra-cellular glycolipids consisting of L-rhamnose and 3-hydroxyalkanoic acid. Methods: The fed-batch method for the rhamnolipid production is considered in this study to know the influence of the carbon, nitrogen, phosphorous substrates as growth-limiting nutrients. Pulse feeding is employed for limiting nutrient addition at particular time interval to obtain maximum rhamnolipid formation from Pseudomonas aeruginosa compared with the batch process. Results: Out of 3 fed batch strategies constant glucose fed batch strategy shows best and gave maximum rhamnolipid concentration of 0.134 g/l.

scholarly journals An Antipersister Strategy for Treatment of Chronic Pseudomonas aeruginosa Infections

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Martina Koeva ◽  
Alina D. Gutu ◽  
Wesley Hebert ◽  
Jeffrey D. Wager ◽  
Lael M. Yonker ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Lactate Dehydrogenase ◽  
Stationary Phase ◽  
Persister Cells ◽  
Content Type ◽  
Ph Values ◽  
Potentiation Effect ◽  
Metabolite Concentrations ◽  
Ldh Assay

ABSTRACTBacterial persisters are a quasidormant subpopulation of cells that are tolerant to antibiotic treatment. The combination of the aminoglycoside tobramycin with fumarate as an antibacterial potentiator utilizes an antipersister strategy that is aimed at reducing recurrentPseudomonas aeruginosainfections by enhancing the killing ofP. aeruginosapersisters. Stationary-phase cultures ofP. aeruginosawere used to generate persister cells. A range of tobramycin concentrations was tested with a range of metabolite concentrations to determine the potentiation effect of the metabolite under a variety of conditions, including a range of pH values and in the presence of azithromycin or cystic fibrosis (CF) patient sputum. In addition, 96-well dish biofilm and colony biofilm assays were performed, and the cytotoxicity of the tobramycin-fumarate combination was determined utilizing a lactate dehydrogenase (LDH) assay. Enhanced killing of up to 6 orders of magnitude ofP. aeruginosapersisters over a range of CF isolates, including mucoid and nonmucoid strains, was observed for the tobramycin-fumarate combination compared to killing with tobramycin alone. Furthermore, significant fumarate-mediated potentiation was seen in the presence of azithromycin or CF patient sputum. Fumarate also reduced the cytotoxicity of tobramycin-treatedP. aeruginosato human epithelial airway cells. Finally, in mucoid and nonmucoid CF isolates, complete eradication ofP. aeruginosabiofilm was observed in the colony biofilm assay due to fumarate potentiation. These data suggest that a combination of tobramycin with fumarate as an antibacterial potentiator may be an attractive therapeutic for eliminating recurrentP. aeruginosainfections in CF patients through the eradication of bacterial persisters.

Regulation of expression of the cyanide-insensitive terminal oxidase in Pseudomonas aeruginosa

Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1275-1284 ◽  
Author(s):  
Megan Cooper ◽  
Gholam Reza Tavankar ◽  
Huw D. Williams
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Culture Medium ◽  
Homoserine Lactone ◽  
Exponential Phase ◽  
Terminal Oxidase ◽  
Regulation Of Expression ◽  
Potent Inducer ◽  
Protein Levels ◽  
In The Wild

The regulation of the cyanide-insensitive oxidase (CIO) in Pseudomonas aeruginosa, a bacterium that can synthesize HCN, is reported. The expression of a cioA–lacZ transcriptional fusion, CioA protein levels and CIO activity were low in exponential phase but induced about fivefold upon entry into stationary phase. Varying the O2 transfer coefficient from 11·5 h−1 to 87·4 h−1 had no effect on CIO expression and no correlation was observed between CIO induction and the dissolved O2 levels in the growth medium. However, a mutant deleted for the O2-sensitive transcriptional regulator ANR derepressed CIO expression in an O2-sensitive manner, with the highest induction occurring under low-O2 conditions. Therefore, CIO expression can respond to a signal generated by low O2 levels, but this response is normally kept in check by ANR repression. ANR may play an important role in preventing overexpression of the CIO in relation to other terminal oxidases. A component present in spent culture medium was able to induce CIO expression. However, experiments with purified N-butanoyl-l-homoserine lactone or N-(3-oxododecanoyl)homoserine lactone ruled out a role for these quorum-sensing molecules in the control of CIO expression. Cyanide was a potent inducer of the CIO at physiologically relevant concentrations and experiments using spent culture medium from a ΔhcnB mutant, which is unable to synthesize cyanide, showed that cyanide was the inducing factor present in P. aeruginosa spent culture medium. However, the finding that in a ΔhcnB mutant cioA–lacZ expression was induced normally upon entry into stationary phase indicated that cyanide was not the endogenous inducer of the terminal oxidase. The authors suggest that the failure of O2 to have an effect on CIO expression in the wild-type can be explained either by the requirement for an additional, stationary-phase-specific inducing signal or by the loss of an exponential-phase-specific repressing signal.

The Influence of pH and Lichen Metabolites (Vulpinic Acid and (+) Usnic Acid) on the Growth of the Lichen Photobiont Trebouxia 1rregularis.

1998 ◽  
Vol 30 (06) ◽  
pp. 577-582 ◽  
Author(s):  
M. Bačkor ◽  
J. Hudá ◽  
M. Repčák ◽  
W. Ziegler§ ◽  
M. Bačkorová
Keyword(s):  
Biomass Production ◽  
Culture Medium ◽  
Usnic Acid ◽  
Concentration Effect ◽  
Medium Ph ◽  
Ph Values ◽  
Lichen Metabolites ◽  
Influence Of Ph ◽  
Quantitative Response

AbstractThe quantitative response to two lichen metabolites, vulpinic acid and (+) usnic acid, on biomass production by the photobiontTrebouxia irregularis, isolated from the lichenCladina mitis, was determined experimentally. The presence of usnic acid resulted in inhibition of photobiont growth, and the effect depended on the pH of the culture medium. The concentration effect of usnic acid was observed. The application of vulpinic acid almost completely inhibited the growth ofT.irregularisand no significant differences were found among samples at different medium pH values.

Model and Kinetic Parameters Identification for Therapeutical Product Obtained According to the GMP Guidelines

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Camelia Ungureanu ◽  
Mihai Caramihai ◽  
Ana Aurelia Chirvase ◽  
Ovidiu Muntean ◽  
Iosif Nagy ◽  
...  
Keyword(s):  
Operation Mode ◽  
Batch Process ◽  
Good Manufacturing Practice ◽  
Biomass Growth ◽  
Fed Batch ◽  
Production Flow ◽  
Batch Operation ◽  
Modelling Error ◽  
Selection Of ◽  
Batch Modelling

The technological solutions were elaborated to achieve the design of the production flow with respect of the Good Manufacturing Practice (GMP) guidelines. To be in line with the GMP rules a fed-batch operation mode is be designed based on the batch modelling results. As the production rate of the microbial immunomodulator is associated with the biomass growth rate, it was required to study the bacterium growth kinetics in batch process. After the selection of the kinetic model based on several batches experimental data by using the analysis criteria - modelling error and estimation rule convergence, the limiting substrate concentration to be maintained during fed-batch cells exponential growth was determined as 115 - 125 mg/L. The batch bioprocess was performed in a Bioengineering AG bioreactor with a software based control of the main variables.

The Influence of pH and Lichen Metabolites (Vulpinic Acid and (+) Usnic Acid) on the Growth of the Lichen Photobiont Trebouxia Irregularis

1992 ◽  
Vol 30 (6) ◽  
pp. 577-582 ◽  
Author(s):  
M. Bačkor ◽  
J. Hudá ◽  
M. Repčák ◽  
W. Ziegler§ ◽  
M. Bačkorová
Keyword(s):  
Biomass Production ◽  
Culture Medium ◽  
Usnic Acid ◽  
Concentration Effect ◽  
Medium Ph ◽  
Ph Values ◽  
Lichen Metabolites ◽  
Influence Of Ph ◽  
Quantitative Response

AbstractThe quantitative response to two lichen metabolites, vulpinic acid and (+) usnic acid, on biomass production by the photobiont Trebouxia irregularis, isolated from the lichen Cladina mitis, was determined experimentally. The presence of usnic acid resulted in inhibition of photobiont growth, and the effect depended on the pH of the culture medium. The concentration effect of usnic acid was observed. The application of vulpinic acid almost completely inhibited the growth of T.irregularis and no significant differences were found among samples at different medium pH values.

Development of the rat conceptus in vitro and associated changes in components of culture medium

Development ◽  
1980 ◽  
Vol 58 (1) ◽  
pp. 1-12
Author(s):  
Mrinal K. Sanyal
Keyword(s):  
Culture Medium ◽  
Fold Increase ◽  
Lactic Dehydrogenase ◽  
Simultaneous Increase ◽  
Ph Values ◽  
Embryonic Growth ◽  
Fresh Serum ◽  
Tenfold Increase ◽  
Roller Bottles

Rat conceptuses of pregnancy day 11 (embryonic age approximately 10·5 days) with embryos within the yolk and amniotic sacs and polar allantoic placental tissues were cultured by the ‘New system’ utilizing homologous serum in 60ml roller bottles with 20% O2, 5% CO2 and 75% N2 gas environment (five conceptuses/10 ml serum). Embryonic growth and development was assessed by external morphology and somite counts, and by measurement of DNA, RNA and protein contents. The embryonic growth was considerably retarded beyond 24 h when culture was extended to 48 h. During continuous culture of conceptuses for 48 h, the partial pressure of O2 in the medium decreased gradually with simultaneous increase of pCO2 and decline of pH values. Glucose level was depleted considerably and small quantities of urea, uric acid and creatinine accumulated in the medium. The concentrations of electrolytes (Na+, K+, Cl−) and total Ca and P, and lactic dehydrogenase activity in the medium increased during the latter part of the 48 h culture period. The growth and differentiation of embryos were significantly improved by transferring conceptuses to fresh serum medium with 40% O2, 5% CO2 and 55% N2 gas phase after 22—24 h culture and continuing the culture for an additional 24 h. Embryos grown in vitro for 48 h developed 39 somites and showed a tenfold increase in DNA content and a five- to seven-fold increase in RNA and protein contents, over initial values.

scholarly journals Establishing a Fed‐Batch Process for Protease Expression with Bacillus licheniformis in Polymer‐Based Controlled‐Release Microtiter Plates

2019 ◽  
Vol 15 (2) ◽  
pp. 1900088 ◽  
Author(s):  
Tobias Habicher ◽  
Edward K. A. Rauls ◽  
Franziska Egidi ◽  
Timm Keil ◽  
Tobias Klein ◽  
...  
Keyword(s):  
Controlled Release ◽  
Bacillus Licheniformis ◽  
Batch Process ◽  
Fed Batch ◽  
Microtiter Plates ◽  
Protease Expression
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