The influence of agitation rate on xanthan production by <i>Xanthomonas campestris</i>

Peters, Hans‐Udo; Herbst, Holger; Hesselink, Paul G.M.; Lünsdorf, Heinrich; Schumpe, Adrian; Deckwer, Wolf‐Dieter

doi:10.1002/bit.260341108

Cited by 76 publications

(53 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Obviously, at high levels of oxygen stress, cells tend to produce an alginate as the capsule on the cell surface that is more compact and has a greater guluronic acid content at the expense of release of alginate into culture broth. In this connection, it is worth mentioning that the formation of a compact slime layer or capsule on the cell surface is not common for other polysaccharide-producing bacterial strains under highly turbulent conditions in a bioreactor, as was discussed by Peters et al (31) for the formation of xanthan by Xanthomonas campestris and by Lobas et al (27) for the production of gellan by Sphingomonas paucimobilis. Both X. campestris and S. paucimobilis are non-O 2 -sensitive strains and form no slime layer at high shear rates.…”

Section: Discussionmentioning

confidence: 96%

Effect of Oxygen on Formation and Structure of Azotobacter vinelandii Alginate and Its Role in Protecting Nitrogenase

Sabra

Zeng

Lünsdorf

et al. 2000

Appl Environ Microbiol

185

139

View full text Add to dashboard Cite

The activity of nitrogenase in the nitrogen-fixing bacterium Azotobacter vinelandii grown diazotrophically under aerobic conditions is generally considered to be protected against O 2 by a high respiration rate. In this work, we have shown that a high rate of respiration is not the prevailing mechanism for nitrogenase protection in A. vinelandii grown in phosphate-limited nitrogen-free chemostat culture. Instead, the formation of alginate appeared to play a decisive role in protecting the nitrogenase that is required for cell growth in this culture. Depending on the O 2 tension and cell growth rate, the formation rate and composition of alginate released into the culture broth varied significantly. Furthermore, transmission electron microscopic analysis of cell morphology and the cell surface revealed the existence of an alginate capsule on the surface of A. vinelandii. The composition, thickness, and compactness of this alginate capsule also varied significantly. In general, increasing O 2 tension led to the formation of alginate with a higher molecular weight and a greater L-guluronic acid content. The alginate capsule was accordingly thicker and more compact. In addition, the formation of the alginate capsule was found to be strongly affected by the shear rate in a bioreactor. Based on these experimental results, it is suggested that the production of alginate, especially the formation of an alginate capsule on the cell surface, forms an effective barrier for O 2 transfer into the cell. It is obviously the quality, not the quantity, of alginate that is decisive for the protection of nitrogenase.

show abstract

Section: Discussionmentioning

confidence: 96%

Effect of Oxygen on Formation and Structure of Azotobacter vinelandii Alginate and Its Role in Protecting Nitrogenase

Sabra

Zeng

Lünsdorf

et al. 2000

Appl Environ Microbiol

185

139

View full text Add to dashboard Cite

show abstract

“…Ever since Xanthan gum was first reported by Rogovin et al (1961), considerable research has been devoted to address the problems of poor bulk mixing and low oxygen transfer rates in Xanthan gum fermentations (Flores et al, 1994;Funahashi et al, 1987bFunahashi et al, , 1988aFunahashi et al, , 1988bNienow, 1992, 1993;Herbst et al, 1992;Nienow, 1984;Nienow and Elson, 1988;Moraine and Rogovin, 1973;Peters et al, 1989aPeters et al, , 1989bPeters et al, , 1992Zhao et al, 1994). It is generally agreed upon in the literature that the process bottleneck in highly productive Xanthan fermentations is related to these two parameters.…”

Section: Introductionmentioning

confidence: 96%

Agitator speed and dissolved oxygen effects in Xanthan fermentations

Amanullah

Tuttiett²,

Nienow³

1998

Biotechnol. Bioeng.

View full text Add to dashboard Cite

“…O aumento da velocidade de agitação empregada durante a fermentação, segundo Peters et al (1989), influenciou a massa molar da xantana, alcançando 6,9 x 10 6 g mol -1 em 200 rpm e 8,6 x 10 6 g mol -1…”

Section: Massa Molarunclassified

“…Em sistemas não-newtonianos, como na fermentação para produção de xantana, a agitação é mais significativa para a transferência de oxigênio do que a aeração (CASAS; SANTOS; RICHARD;MARGARITIS, 2002). Grande parte da literatura estuda diferentes condições de aeração alterando a velocidade de agitação, entre outros autores, pode-se citar Peters et al (1989); Lorda, Pastor e Balatti (1995); Casas, Santos e García-Ochoa (2000); Papagianni et al (2001).…”

Section: Agitação E Aeraçãounclassified

“…A produção de xantana em diferentes velocidades de agitação (200, 400, 600 e 800 rpm) foi avaliada por Peters et al (1989), utilizando uma aeração de 0,33 vvm. Os resultados mostraram que a limitação de oxigênio foi possivelmente a causa da baixa produção (6,3 g L -1 ) em 200rpm, entretanto, com a aplicação de 800rpm a maior produção foi alcançada (16,4 g L -1 ).…”

Section: Agitação E Aeraçãounclassified

See 1 more Smart Citation

Goma Xantana: características e condições operacionais de produção

Borges¹,

Vendruscolo²

2008

Semin. Cienc. Biol. Saude

View full text Add to dashboard Cite

ResumoGoma xantana é um polissacarídeo extracelular produzido pelas bactérias do gênero Xanthomonas. Sua funcionalidade é uma conseqüência direta de sua estrutura química. Esta estrutura tem sido amplamente estudada por ser passível de mudanças, sendo dependente do microrganismo produtor e das condições operacionais aplicadas durante a fermentação. O trabalho tem como objetivo revisar a influência das condições operacionais de produção de xantana nas características físico-químicas da goma produzida. Palavras-chave: Xantana. Condições operacionais. Composição química. Reologia. AbstractXanthan gum is an extracelullar polysaccharide produced by bacteria of the genus Xanthomonas. Its functionality is a direct consequence of its chemical structure. This structure has been widely studied because it is subject to changes, dependant on the producer microrganism and on the operational conditions applied during the fermentation. The purpose of this paper is to review the influence of the operational conditions of xanthan production in the physiochemical characteristics of the gum produced.

show abstract

The influence of agitation rate on xanthan production by Xanthomonas campestris

Cited by 76 publications

References 7 publications

Effect of Oxygen on Formation and Structure of Azotobacter vinelandii Alginate and Its Role in Protecting Nitrogenase

Effect of Oxygen on Formation and Structure of Azotobacter vinelandii Alginate and Its Role in Protecting Nitrogenase

Agitator speed and dissolved oxygen effects in Xanthan fermentations

Goma Xantana: características e condições operacionais de produção

Contact Info

Product

Resources

About