Continuous production of citric acid with recirculation of the fermentation broth after product recovery

Rehm²

2006

Abbreviations: R j : formation rate of the generic product, g citric acid/(l x hr) (volumetric productivity) m p :specific citric acid productivity, g citric acid/(g biomass x hr) RT: Residence time -hrs Rs: glucose consumption rate, g/(l x hr)The effect of air saturation on citric acid production in batch, repeated batch and chemostat cultures has been studied. It was shown that, under continuous fermentation (chemostat mode), the highest concentration of citric acid equal of 98 g/l was produced at 20% of air saturation. In contrary to continuous fermentation, displaying an optimum at 20%, 80% air saturation yielded higher values in repeated batch fermentation process. 167 g/l citric acid were produced continuously with the fill and drain technique at 4.85 days, at 80% air saturation, compared with 157.6 g/l achieved within 5.4 days at 20%. Under repeated batch fermentation, the formation rate of the generic product (Rj) as well as the specific citric acid productivity (m p ) reached a maximum of 1.283 g/(l x hr) at 4.01 days and of 0.0375 g/(g x hr) at 4.58 days, respectively. The glucose consumption rate (Rx) reached a maximum value of 3.33 g/(l x hr) entering stationary phase after 2.56 days at a glucose concentration of 131.2 g/l.

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Section: Discussionmentioning

confidence: 99%

Citric acid production from glucose by yeast Candida oleophila ATCC 20177 under batch, continuous and repeated batch cultivation

Rehm²

2006

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“…Tisnadjaja et al (1996) reported about a higher productivity of citric acid using C. guilliermondii in continuous culture compared with the batch process. About a four stage process for continuous production of citric acid using A. niger has been reported by Wieczorek and Brauer (1998).…”

Section: Discussionmentioning

confidence: 99%

Continuous citric acid secretion by a high specific pH dependent active transport system in yeast Candida oleophila ATCC 20177

Rehm²

2005

The pH influence on continuous citric acid secretion was investigated in Candida oleophila ATCC 20177 (var.) under NH 4 + limiting state steady conditions, using glucose. Highest citric acid concentration of 57.8 g/l, citrate/isocitrate ratio of 15.6, space-time yield of 0.96 g/(l x hr) and biomass specific productivity of 0.041 g/(g x hr) were obtained at pH 5 and 60 hrs residence time. Only 22.8 g/l (39.4%) and a ratio of 9.9 were achieved at pH 6 pH and 12.4 g/l (21.5%) and a ratio of 3.7 at pH 3. Under non producing conditions, in excess of nitrogen, biomass concentration increased at raising pH. An iron concentration of 200 ppm was determined in biomass of C. oleophila at pH 5, compared with only 26 ppm found at pH 3 (factor 7.7). Intra-and extracellular concentrations of citrates and glucose confirmed the existence of a high specific, pH dependent active transport system for citrate secretion, while isocitrate isn't a high-affine substrate, displaying a strong correlation with ATP/ADP ratio. Differences between extra-and intracellular concentration of citrate higher than 1 and up to about 60 were determined. The active transport systemfor citrate excretion appears to be the main speed-determining factor in citrate overproduction by yeasts.Although citric acid production using mutant strains of A. niger or yeast strains has almost been extensively optimised, there is still no comprehensive explanation for citrate overproduction, and many aspects related to citrate accumulation and secretion remain unclear. There are many *Corresponding author similarities between A. niger and yeast strains in mechanism of citric acid synthesis, however, differences still exist in terms of triggering out and regulation of citrate overproduction. Many models have been developed describing the biochemistry of citrate synthesis, using glucose and other carbon sources, however a complete picture of formation pathway, regulation and secretion has not been described.Overproduction of citric acid in moulds and yeast has been reported to be triggered out by limitations of certain elements, like N, P, Mn, Fe or Zn, essential for citrate accumulation in A. niger (Shu and Johnson, 1948a;Shu and Johnson, 1948b;Noguchi and Johnson, 1961; Kisser et al. 1980; Kapoor et al. 1982;Kristiansen et al. 1982;Crueger and Crueger, 1989;Dawson and Maddox, 1989;Grewal and Kalra, 1995), as well as N, P, S and Mg in yeasts Yarrowia lipolytica and Candida oleophila (Lozinov et al. 1974;Behrens et al. 1987; Stottmeister and Hoppe, 1991;Anastassiadis, 1994;Anastassiadis et al. 2001;Anastassiadis et al. 2002; Anastassiadis et al. 2004). The yeasts can use various carbon sources for the formation of citric acid (Ikeno et al. 1975; Stottmeister and Hoppe, 1991;Grewal and Kalra, 1995; Mansfeld et al. 1995;Crolla and Kennedy, 2001;Crolla and Kennedy, 2004;Venter et al. 2004) or lipid production (Papanikolaou and Aggelis, 2002). Intracellular nitrogen limitation and low intracellular nitrogen content (Briffaud and Engasser, 1979;Moresi, 1994;Anastassiadis et...

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“…A multi-tank system was suggested for the continuous operation using A. niger, which would separate growth phase and idiophase from each other. This would essentially require higher investments and efforts, making a commercial production uneconomical (Lockwood, 1979;Milson, 1987;Crueger and Crueger, 1989;Klasson et al 1989;Saha and Takahashi, 1997;Wieczorek and Brauer, 1997;Wieczorek and Brauer, 1998). Continuous single-stage operations using A. niger yielded low citric acid concentrations (Kristiansen and Sinclair, 1979;Saha and Takahashi, 1997;Wieczorek and Brauer, 1997;Wieczorek and Brauer, 1998).…”

mentioning

confidence: 99%

“…The main actual problems at citric acid industry today are the still low productivities of discontinuous A. niger processes, requiring long operational times, higher investments and production costs, compared with the novel yeast processes (Legisa and Gradisnik-Grapulin, 1995;Anastassiadis et al 2001;Kumar et al 2003;Ikram-ul et al 2004;Ali and Ikramul, 2005;Anastassiadis and Rehm, 2005). Wieczorek and Brauer (1997) reported about slowing down of continuous citric acid formation by A. niger in a reciprocating-jetbioreactor at increasing fermentation time (more than 20 days), still without achieving of steady state conditions. Continuous operations for the production of citric acid by yeasts have increasingly received research interest in last years.…”

mentioning

confidence: 99%

“…This would essentially require higher investments and efforts, making a commercial production uneconomical (Lockwood, 1979;Milson, 1987;Crueger and Crueger, 1989;Klasson et al 1989;Saha and Takahashi, 1997;Wieczorek and Brauer, 1997;Wieczorek and Brauer, 1998). Continuous single-stage operations using A. niger yielded low citric acid concentrations (Kristiansen and Sinclair, 1979;Saha and Takahashi, 1997;Wieczorek and Brauer, 1997;Wieczorek and Brauer, 1998). The main actual problems at citric acid industry today are the still low productivities of discontinuous A. niger processes, requiring long operational times, higher investments and production costs, compared with the novel yeast processes (Legisa and Gradisnik-Grapulin, 1995;Anastassiadis et al 2001;Kumar et al 2003;Ikram-ul et al 2004;Ali and Ikramul, 2005;Anastassiadis and Rehm, 2005).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Oxygen and temperature effect on continuous citric acid secretion in Candida oleophila

Rehm²

2006