Enhancement and scale-up of β-(1, 3) glucan production by Agrobacterium sp.
17 Jan 2010-International Journal of Food Engineering (Berkeley Electronic Press)-Vol. 6, Iss: 1, pp 16
TL;DR: Investigation of the effects of pH, amounts of ammonium, sucrose and trace elements, and time the addition of sucrose, ammonium and uracil on the production of curdlan in a shake flask found it to be higher in the bioreactor than the shake flask under batch conditions.
Abstract: Curdlan is a water insoluble polysaccharide composed exclusively of ?-(1, 3) linked glucose residues. Agrobacterium sp. is known to produce extracellular curdlan under nitrogen-limited conditions. The purpose of this study was to investigate the effects of pH, amounts of ammonium, sucrose and trace elements, and time the addition of sucrose, ammonium and uracil on the production of curdlan in a shake flask and to further scale-up the process to a 5 L fermentor. A maximum of 48.7 g L-1 of curdlan was obtained in a shake flask when 150 and 1.4 g L-1 of sucrose and ammonium were used at the initial pH of 6.5. The production was enhanced to 57 g L-1 by adding one third of sucrose and 1 g L-1 of uracil at the 48th h in a fed batch mode. The process was scaled up to a 5 L bioreactor in a batch mode where the oxygen transfer rate was higher (0.192 mg L-1s-1) when compared to that in the shake flask (0.096 mg L-1s-1). Curdlan production was 58 g L-1 in the bioreactor, which was higher than the shake flask under batch conditions (48.7 g L-1). The viscosity average molecular weight of the curdlan produced was found to be 1.4 × 105.
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TL;DR: A simple and reproducible two-stage DO control process for curdlan production was developed and showed that curdLAN production had positive relationship with intracellular levels of UTP, ADP, AMP, NAD+, NADH and UDP-glucose.
Abstract: A significant problem in scale-down cultures, rarely studied for metabolic characterization and curdlan-producing Agrobacterium sp. ATCC 31749, is the presence of dissolved oxygen (DO) gradients combined with pH control. Constant DO, between 5% and 75%, was maintained during batch fermentations by manipulating the agitation with PID system. Fermentation, metabolic and kinetic characterization studies were conducted in a scale-down system. The curdlan yield, intracellular nucleotide levels and glucose conversion efficiency into curdlan were significantly affected by DO concentrations. The optimum DO concentrations for curdlan production were 45–60%. The average curdlan yield, curdlan productivity and glucose conversion efficiency into curdlan were enhanced by 80%, 66% and 32%, respectively, compared to that at 15% DO. No apparent difference in the gel strength of the resulting curdlan was detected. The comparison of curdlan biosynthesis and cellular nucleotide levels showed that curdlan production had positive relationship with intracellular levels of UTP, ADP, AMP, NAD+, NADH and UDP-glucose. The curdlan productivity under 45% DO and 60% DO was different during 20–50 h. However, after 60 h curdlan productivity of both conditions was similar. On that basis, a simple and reproducible two-stage DO control process for curdlan production was developed. Curdlan production yield reached 42.8 g/l, an increase of 30% compared to that of the single agitation speed control process.
43 citations
Cites background from "Enhancement and scale-up of β-(1, 3..."
...ATCC 31749 through enhancement of the glucose metabolic flux into curdlan biosynthesis (Kim et al. 1999; Jin et al. 2008; Puliga et al. 2010)....
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...…on intracellular nucleotide levels It was reported that curdlan production yield was affected by the intracellular nucleotide levels ofAgrobacterium sp. ATCC 31749 through enhancement of the glucose metabolic flux into curdlan biosynthesis (Kim et al. 1999; Jin et al. 2008; Puliga et al. 2010)....
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TL;DR: A coupled fermentation system of Agrobacterium sp.
21 citations
TL;DR: This is the first report that DO concentration apparently regulates curdlan biosynthesis in Agrobacterium sp.
Abstract: Expression at the mRNA level of ten selected genes in Agrobacterium sp. ATCC 31749 under various dissolved oxygen (DO) levels during curdlan fermentation related to electron transfer chain (ETC), tricarboxylic acid (TCA) cycle, peptidoglycan/lipopolysaccharide biosynthesis, and uridine diphosphate (UDP)-glucose biosynthesis were determined by qRT-PCR. Experiments were performed at DO levels of 30%, 50%, and 75%, as well as under low-oxygen conditions. The effect of high cell density on transcriptional response of the above genes under low oxygen was also studied. Besides cytochrome d (cyd A), the transcription levels of all the other genes were increased at higher DO and reached maximum at 50% DO. Under 75% DO, the transcriptional levels of all the genes were repressed. In addition, transcription levels of icd, sdh, cyo A, and fix N genes did not exhibit significant fluctuation with high cell density culture under low oxygen. These results suggested a mechanism for DO regulation of curdlan synthesis through regulation of transcriptional levels of ETCs, TCA, and UDP-glucose synthesis genes during curdlan fermentation. To our knowledge, this is the first report that DO concentration apparently regulates curdlan biosynthesis in Agrobacterium sp. ATCC 31749 providing essential lead for the optimization of the fermentation at the industrial scale.
21 citations
Cites background from "Enhancement and scale-up of β-(1, 3..."
...…of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China e-mail: xbzhan@yahoo.com saccharides, the industrial fermentation process using Agrobacterium sp. ATCC 31749 for curdlan production is an aerobic process (Puliga et al. 2010)....
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TL;DR: The results showed for the first time the evolution of the molecular weight of alginate and OTR profiles for two different scales of stirred fermentors, opening the possibility of using qO2 instead of OTRmax as a scaling criterion to produce polymers with similar molecular weights during fermentation.
Abstract: The oxygen transfer rate (OTR) was evaluated as a scale-up criterion for alginate production in 3- and 14-L stirred fermentors. Batch cultures were performed at different agitation rates (200, 300, and 600 rpm) and airflow rates (0.25, 0.5, and 1 vvm), resulting in different maximum OTR levels (OTRmax). Although the two reactors had a similar OTRmax (19 mmol L(-1) h(-1)) and produced the same alginate concentration (3.8 g L(-1)), during the cell growth period the maximum molecular weight of the alginate was 1,250 kDa in the 3-L stirred fermentor and 590 kDa in 14-L stirred fermentor. The results showed for the first time the evolution of the molecular weight of alginate and OTR profiles for two different scales of stirred fermentors. There was a different maximum specific oxygen uptake rate between the two fermenters, reaching 8.3 mmol g(-1) h(-1) in 3-L bioreactor and 10.6 mmol g(-1) h(-1) in 14-L bioreactor, which could explain the different molecular weights observed. These findings open the possibility of using [Formula: see text] instead of OTRmax as a scaling criterion to produce polymers with similar molecular weights during fermentation.
20 citations
Cites methods from "Enhancement and scale-up of β-(1, 3..."
...Given that the OTR influences alginate production and that this parameter has been used as a criterion for scalingup the production of other polysaccharides [9]....
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TL;DR: A large number of cells physically adhered to the surface of loofa sponge fibers, and its use as an immobilization matrix to produce curdlan was effective, and the used in a functional yogurt formulation resulted in a product with lower syneresis.
Abstract: BACKGROUND
Agrobacterium sp. IFO 13140 cells were immobilized on a loofa sponge and used to produce curdlan over five successive cycles. The interaction between microbial cells and the loofa sponge as well as the produced curdlan were characterized by Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectrometry. The purity of the curdlan was also evaluated. The storage stability of the immobilized cells was assessed and the produced curdlan was used in a functional yogurt formulation.
RESULTS
The average curdlan production by immobilized cells was 17.84 g L−1. The presence of the microorganism in the sponge was confirmed and did not cause alterations in the matrix, and the chemical structure of the curdlan was the same as that of commercial curdlan. The purity of both was similar. The immobilized cells remained active after 300 days of storage at −18 °C. The use of the produced curdlan in a functional yogurt resulted in a product with lower syneresis.
CONCLUSION
A large number of cells physically adhered to the surface of loofa sponge fibers, and its use as an immobilization matrix to produce curdlan was effective. The use of the produced curdlan in yogurt allowed the development of a more stable product. © 2015 Society of Chemical Industry
15 citations
References
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25,389 citations
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...Sucrose concentration was determined using DNS method [15]....
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Book•
15 Jan 1984
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Abstract: An introduction to fermentation processes Microbial growth kinetics The isolation, preservation and improvement of industrially important micro-organisms Media for industrial fermentations Sterilization The development of inocula for industrial fermentations Design of a fermenter Instrumentation and control Aeration and agitation The recovery and purification of fermentation products Effluent treatment Fermentation economics.
840 citations
"Enhancement and scale-up of β-(1, 3..." refers methods in this paper
...KLa was determined by the static gassing out method [30]....
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TL;DR: The gel-forming β-1, 3-glucan of A lcaligenes faecalis var. myxogenes 10C3, mutant K, has been shown by methylation and periodate oxidation studies to be a β- 1, 3 -d -glucans.
250 citations
"Enhancement and scale-up of β-(1, 3..." refers background in this paper
...Harada and coworkers discovered this biopolymer and named it curdlan because it curdled on heating [7]....
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TL;DR: Redox-sensitive transcription factors such as the E. coli OxyR and S. cerevisiae Yap1, are activated by conformational changes that stem from the post-translational modification of reactive protein thiols.
160 citations
TL;DR: All the experimental results suggest that the hydrogen bonds that bind curdlan with interstitial water to form the micelles have been destroyed completely and that the hydrophobic interactions related to the methylene groups at C-6 formed above 55 degrees C disappeared due to the introduction of the Hydrophilic carboxymethyl group.
140 citations
"Enhancement and scale-up of β-(1, 3..." refers methods in this paper
...FTIR (Fourier transform Infra Red) spectroscopic analysis of curdlan was performed by the KBr disc method [20]....
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