Agitator speed and dissolved oxygen effects in Xanthan fermentations

Amanullah, Ashraf; Tuttiett, B.; Nienow, Alvin W.

doi:10.1002/(sici)1097-0290(19980120)57:2<198::aid-bit8>3.0.co;2-i

Cited by 59 publications

(13 citation statements)

References 26 publications

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“…It is important to point out that our results contrast with those reported for the synthesis of other biopolymers, such as the case of xanthan [22]. Amanullah et al [22] studied the influence of the agitation rate (500 and 1000 rpm) and therefore the oxygen transfer rate of the culture, maintaining constant the DOT at 20% of air saturation using gas blending.…”

Section: Discussioncontrasting

confidence: 61%

“…Amanullah et al [22] studied the influence of the agitation rate (500 and 1000 rpm) and therefore the oxygen transfer rate of the culture, maintaining constant the DOT at 20% of air saturation using gas blending. According to such authors, the biological performance of the culture was independent of the agitation rate as long as the broth homogeneity could be ensured.…”

Section: Discussionmentioning

confidence: 99%

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Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

2011

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BackgroundThe oxygen transfer rate (OTR) and dissolved oxygen tension (DOT) play an important role in determining alginate production and its composition; however, no systematic study has been reported about the independent influence of the OTR and DOT. In this paper, we report a study about alginate production and the evolution of the molecular mass of the polymer produced by a wild-type A. vinelandii strain ATCC 9046, in terms of the maximum oxygen transfer rate (OTRmax) in cultures where the dissolved oxygen tension (DOT) was kept constant.ResultsThe results revealed that in the two dissolved oxygen conditions evaluated, strictly controlled by gas blending at 0.5 and 5% DOT, an increase in the agitation rate (from 300 to 700 rpm) caused a significant increase in the OTRmax (from 17 to 100 mmol L-1 h-1 for DOT of 5% and from 6 to 70 mmol L-1 h-1 for DOT of 0.5%). This increase in the OTRmax improved alginate production, as well as the specific alginate production rate (SAPR), reaching a maximal alginate concentration of 3.1 g L-1 and a SAPR of 0.031 g alg g biom-1 h-1 in the cultures at OTRmax of 100 mmol L-1 h-1. In contrast, the mean molecular mass (MMM) of the alginate isolated from cultures developed under non-oxygen limited conditions increased by decreasing the OTRmax, reaching a maximal of 550 kDa at an OTRmax of 17 mmol L-1 h-1 . However, in the cultures developed under oxygen limitation (0.5% DOT), the MMM of the polymer was practically the same (around 200 kDa) at 300 and 700 rpm, and this remained constant throughout the cultivation.ConclusionsOverall, our results showed that under oxygen-limited and non oxygen-limited conditions, alginate production and its molecular mass are linked to the OTRmax, independently of the DOT of the culture.

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Section: Discussioncontrasting

confidence: 61%

Section: Discussionmentioning

confidence: 99%

Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

2011

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“…With further prolongation of the cultivation, oxygen concentration was slowly decreased in cultivation medium to final concentration of 60.30%. This value is well above 10% which represents a critical oxygen level for the successful xanthan biosynthesis (Amanullah et al, 1998).…”

Section: Analysis Of Produced Xanthanmentioning

confidence: 85%

Xanthan biosynthesis by Xanthomonas campestris ATCC 13951 on wastewaters from white grape processing

Rončević¹,

Zahović²,

Dodić³

et al. 2017

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Summary:Wastewaters from grape processing in wineries are characterized by large seasonal fluctuations in volume and composition, and are often discarded into environment with little or no treatment. The biotechnological production of valuable products is the most promising alternative for reducing the negative environmental impact and recycling these effluents. Results from previous study show that mixed winery wastewaters, after additional optimization of the medium preparation, may be a suitable raw material for industrial xanthan production. Therefore, the aim of this work was to examine the possibility of xanthan production by Xanthomonas campestris ATCC 13951 on mixed wastewaters from different stages of white grape processing in winery with initial sugars content of 20 g/L. In addition to the media characteristics and indicators of biopolymer quality, raw xanthan yield and degree of sugars conversion into product were determined in order to examine the success of performed bioprocess. The results for biopolymer yield (14.66 g/L) and sugars conversion into desired product (70.21%) obtained in applied experimental conditions confirm that wastewaters from white grape processing have a great potential to be used as a substrate for xanthan biosynthesis.

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“…From a technical point of view, the most convenient method of supplying sufficient oxygen to a large-scale suspension cell culture is by sparging air. However, in many cases significant cell damage associated with cell-bubble interactions has been observed [26][27][28].…”

Section: Effect Of a 5% Co 2 Atmosphere Upon 293 Cellsmentioning

confidence: 99%

Effect of Pluronic F-68, 5% CO, Atmosphere, HEPES, and Antibiotic-Antimycotic on Suspension Adapted 293 Cells

Negrete¹,

Ling²,

Lyddiatt³

2008

TOBIOTJ

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Abstract:The influence of different parameters upon cell culture of serum-free adapted 293 cells including the surfactant Pluronic F-68, carbon dioxide (5% CO 2 atmosphere), buffer HEPES and antibiotic-antimycotic has been explored. A defined serum-free medium (SFM) formulated without human or animal origin components from Invitrogen was used to grow the suspension adapted 293 cells. For all cell culture parameters cell density and viability of the suspension adapted 293 cells were monitored. The results indicated that the PF68 concentrations ranging from 0.05% to 0.2% can be used in the culture of the suspension adapted 293 cells since no negative effect upon either cell density or viability was detected. This will minimize the formation of aggregates during cell culture. It was demonstrated that neither the cell density nor the viability of the suspension adapted 293 cells were affected by the 5% CO 2 atmosphere at the inoculation cell densities evaluated. The use of the buffer HEPES in the cultivation of suspension adapted 293 cells did not cause negative effects upon cell density and viability. The addition of HEPES makes more robust the culture to pH fluctuations. The antibioticantimycotic can be used when needed at concentrations of up to 50 IU/ml for the culture of this particular cell line, with no apparent effect upon cell growth. The results obtained will contribute to a basic understanding of the 293 cell culture in the 293 SFM II and to the process development of their culture in bioreactors for the expression of different products of biotechnology interest.

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Agitator speed and dissolved oxygen effects in Xanthan fermentations

Cited by 59 publications

References 26 publications

Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

Xanthan biosynthesis by Xanthomonas campestris ATCC 13951 on wastewaters from white grape processing

Effect of Pluronic F-68, 5% CO, Atmosphere, HEPES, and Antibiotic-Antimycotic on Suspension Adapted 293 Cells

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