Exponentially fed-batch cultures as an alternative to chemostats: The case of penicillin acylase production by recombinant E. coli

Ramı́rez, Octavio T.; Zamora, Rosario; Quintero, Rodolfo; López-Munguı́a, Agustı́n

doi:10.1016/0141-0229(94)90065-5

Cited by 28 publications

(7 citation statements)

References 46 publications

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“…Utilization of fed-batch fermentation as compared to that of batch fermentation usually implies an increase in final product concentration and productivity, and a decrease in manufacturing cost ( 12) mainly because of the use of smaller fermenter size. In addition, in contrast to continuous operation, fed-batch cultures present less risk of contamination, and when used under quasi-steady state conditions, fed-batch cultures can closely approximate continuous culture mode without the risk of a washout (18).…”

Section: Introductionmentioning

confidence: 99%

Strategies in fed-batch cultivation on the production performance of Lactobacillus salivarius I 24 viable cells

Ming

Halim

Rahim

et al. 2016

Food Sci Biotechnol

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The potential use of fed-batch cultivation (FBC) for improvement of the production of I 24 biomass for subsequent use as probiotics was studied using a 2-L stirredtank bioreactor. Three different constant feeding rates (0.1, 0.05, and 0.033 L/h) were applied in FBCs and their effect on carbon metabolism was evaluated. The carbon flux for cell built-up with reduction in lactic acid synthesis was observed in the fed-batch as compared to the batch cultivation mode. The viable cell number obtained in the constant FBC (CFBC) operated at a feeding rate of 0.05 L/h was 8 times higher (10.7×10 CFU/mL) than that recorded in the batch cultivation. This gave the viable cell yield based on glucose consumed for CFBC of 26 times higher (11.3×10 CFU/g) than the batch cultivation. This study demonstrated CFBC, which is simple with minimal use of process control equipment, has an industrial potential for improvement of probiotic production.

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Section: Introductionmentioning

confidence: 99%

Strategies in fed-batch cultivation on the production performance of Lactobacillus salivarius I 24 viable cells

Ming

Halim

Rahim

et al. 2016

Food Sci Biotechnol

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“…Details of the construction have been published elsewhere (Ramirez et al, 1994a). Culture conditions.…”

Section: Microorganismmentioning

confidence: 99%

Recombinant whole cell penicillin acylase biocatalyst: Production, characterization and use in the synthesis and hydrolysis of antibiotics

et al. 1995

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“…Different high-expression recombinant systems have been developed (Panbangred et al, 1990;Ramírez et al, 1994a;Ramírez et al, 1994b) in which the cloned pga gene is under the control of a strong promoter and PGA is therefore overproduced. When the various strains were evaluated as hosts for the constructed recombinant plasmids, the highest enzyme production was usually achieved in self-cloning expression systems: the donor strain for pga serves simultaneously as a host strain for the recombinant plasmid (Robas et al, 1993;Zhang et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

A chemostat culture as a tool for the improvement of a recombinant E. coli strain over‐producing penicillin G acylase

Marešová¹,

Štěpánek²,

Kyslı́k³

2001

Biotech & Bioengineering

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The recombinant strain RE3(pKA18) of Escherichia coli constitutively overproduces penicillin G acylase (PGA) from plasmid-borne gene pga. The host strain RE3 bears the same pga gene on its chromosome, the expression of which is controlled by the natural mechanism of induction with phenylacetic acid (PA). To evaluate the maximum biosynthetic capacity for PGA, induction of the chromosomal pga by PA was studied in a culture of the recombinant strain. PGA production by batch cultures of RE3(pKA18) and RE3 showed a different response to the addition of PA to the medium: while an addition of PA induces PGA in a culture of strain RE3 as expected, in recombinant cells it lowers the specific activity of PGA and a large amount of PGA is released into the culture medium. To improve the PGA production, the strain RE3(pKA18) was cultured in a carbon-limited chemostat and subjected to selection pressure in a medium supplemented with phenylacetic acid amide (PAA). Phenylacetic acid amide served as a source of nitrogen, an inducer of PGA and a factor exerting positive selection pressure on the maintenance of the recombinant plasmid. After 130 generations of growth in the presence of the inducer, no recombinant strain with constitutive expression of the chromosomal gene pga was detected in the prevailing P(+) subpopulation in the chemostat. Shake-flask experiments with the parent recombinant strain RE3(pKA18), host strain RE3, chemostat evolvant ERE3(epKA18), the cured host ERE3 alone, and its derivative after retransformation with ancestral plasmid ERE3(pKA18) showed that inactivation of the plasmid-borne pga by a frame-shift mutation (plasmid epKA18) occurred in the plasmid-bearing subpopulation accumulated in the chemostat. Marked adaptive changes evolved in the host ERE3 during a 130 generation culture: (1) the specific growth rate of the host increased by 30% in a medium without PA, (2) the copy number of plasmids pKA18 and epKA18 in the host cultured in PA-free medium dropped by about 40%, and (3) the leakage of PGA from the cell in the presence of PA found in strain RE3(pKA18) was not observed in strain ERE3(pKA18). This new recombinant strain with modified traits was constructed by means of retransformation of the evolved host ERE3 with ancestral plasmid pKA18.

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Exponentially fed-batch cultures as an alternative to chemostats: The case of penicillin acylase production by recombinant E. coli

Cited by 28 publications

References 46 publications

Strategies in fed-batch cultivation on the production performance of Lactobacillus salivarius I 24 viable cells

Strategies in fed-batch cultivation on the production performance of Lactobacillus salivarius I 24 viable cells

Recombinant whole cell penicillin acylase biocatalyst: Production, characterization and use in the synthesis and hydrolysis of antibiotics

A chemostat culture as a tool for the improvement of a recombinant E. coli strain over‐producing penicillin G acylase

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