Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures

The exopolysaccharide (EPS)-producing cultures such as Lactobacillus rhamnosus RW-9595M present a challenge for the culture producers because the high viscosity of the fermented growth medium makes it difficult to recover the cells by centrifugation or filtration. This study examined four approaches...

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Autores principales:	Champagne,Claude P, Gardner,Nancy J, Lacroix,Christophe
Lenguaje:	English
Publicado:	Pontificia Universidad Católica de Valparaíso 2007
Materias:	alginate beads fed-batch culture temperature
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582007000200005
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spelling	oai:scielo:S0717-345820070002000052007-10-29Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated culturesChampagne,Claude PGardner,Nancy JLacroix,Christophe alginate beads fed-batch culture temperature The exopolysaccharide (EPS)-producing cultures such as Lactobacillus rhamnosus RW-9595M present a challenge for the culture producers because the high viscosity of the fermented growth medium makes it difficult to recover the cells by centrifugation or filtration. This study examined four approaches to reduce viscosity of the medium while producing high cell densities: incubation temperature, extended incubation in the stationary growth phase, production in alginate gel beads and fed-batch fermentation technology. Automated spectrophotometry (AS) was used to study the effects of temperature, pH and lactate level on growth of the strain. In AS assays, there was no significant difference in final maximal biomass production at temperatures ranging between 34ºC to 44ºC, but lower yields were noted at 46ºC. A pH below 6.0 and a lactate concentration higher than 4% almost completely prevented growth. Under batch fermentation conditions, the viscosity of the medium obtained at 37ºC was two fold higher than for 44ºC. For cultures produced at 37ºC, centrifugation at 10000 g during 5 min did not allow complete recovery of cells, in contrast to cultures grown at 44ºC. An extended period of incubation (5 hrs) in the stationary growth phase did not reduce the final viscosity of the growth medium. For similar biomass levels, the glucose-based fed-batch fermentation allowed a 40% reduction in viscosity of the fermented medium in comparison to traditional batch cultures. High-density cell populations (3 x 10(10) CFU/g) were obtained when L. rhamnosus RW-9595M was grown in alginate beads. However, overall biomass yields in the immobilized cell bioreactor were half of those obtained in free-cell fermentations. Therefore three methods of producing concentrated EPS-producing cultures are proposedinfo:eu-repo/semantics/openAccessPontificia Universidad Católica de ValparaísoElectronic Journal of Biotechnology v.10 n.2 20072007-04-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582007000200005en10.4067/S0717-34582007000200005
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	alginate beads fed-batch culture temperature
spellingShingle	alginate beads fed-batch culture temperature Champagne,Claude P Gardner,Nancy J Lacroix,Christophe Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures
description	The exopolysaccharide (EPS)-producing cultures such as Lactobacillus rhamnosus RW-9595M present a challenge for the culture producers because the high viscosity of the fermented growth medium makes it difficult to recover the cells by centrifugation or filtration. This study examined four approaches to reduce viscosity of the medium while producing high cell densities: incubation temperature, extended incubation in the stationary growth phase, production in alginate gel beads and fed-batch fermentation technology. Automated spectrophotometry (AS) was used to study the effects of temperature, pH and lactate level on growth of the strain. In AS assays, there was no significant difference in final maximal biomass production at temperatures ranging between 34ºC to 44ºC, but lower yields were noted at 46ºC. A pH below 6.0 and a lactate concentration higher than 4% almost completely prevented growth. Under batch fermentation conditions, the viscosity of the medium obtained at 37ºC was two fold higher than for 44ºC. For cultures produced at 37ºC, centrifugation at 10000 g during 5 min did not allow complete recovery of cells, in contrast to cultures grown at 44ºC. An extended period of incubation (5 hrs) in the stationary growth phase did not reduce the final viscosity of the growth medium. For similar biomass levels, the glucose-based fed-batch fermentation allowed a 40% reduction in viscosity of the fermented medium in comparison to traditional batch cultures. High-density cell populations (3 x 10(10) CFU/g) were obtained when L. rhamnosus RW-9595M was grown in alginate beads. However, overall biomass yields in the immobilized cell bioreactor were half of those obtained in free-cell fermentations. Therefore three methods of producing concentrated EPS-producing cultures are proposed
author	Champagne,Claude P Gardner,Nancy J Lacroix,Christophe
author_facet	Champagne,Claude P Gardner,Nancy J Lacroix,Christophe
author_sort	Champagne,Claude P
title	Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures
title_short	Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures
title_full	Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures
title_fullStr	Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures
title_full_unstemmed	Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures
title_sort	fermentation technologies for the production of exopolysaccharide-synthesizing lactobacillus rhamnosus concentrated cultures
publisher	Pontificia Universidad Católica de Valparaíso
publishDate	2007
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582007000200005
work_keys_str_mv	AT champagneclaudep fermentationtechnologiesfortheproductionofexopolysaccharidesynthesizinglactobacillusrhamnosusconcentratedcultures AT gardnernancyj fermentationtechnologiesfortheproductionofexopolysaccharidesynthesizinglactobacillusrhamnosusconcentratedcultures AT lacroixchristophe fermentationtechnologiesfortheproductionofexopolysaccharidesynthesizinglactobacillusrhamnosusconcentratedcultures
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Fermentation technologies for the production of exopolysaccharide-synthesizing Lactobacillus rhamnosus concentrated cultures

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