Effect of temperature and pH on growth and product formation of Lactococcus lactis ssp. lactis ATCC 19435 growing on maltose

Hofvendahl, Karin; Niel, Ed W. J. van; Hahn‐Hägerdal, Bärbel

doi:10.1007/s002530051449

Cited by 28 publications

(18 citation statements)

References 23 publications

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“…In previous studies fixed acids have been shown to be formed when lactococci metabolize maltose (24,42,47). To investigate whether formation of mixed acid products from maltose is related to growth, formation of products by four strains of L. lactis was studied during growth in semidefined medium (55) and in resting cell experiments (Table 1).…”

Section: Resultsmentioning

confidence: 99%

“…The first enzyme in the pathway, PFL, converts pyruvate to formate and acetyl coenzyme A, which is further metabolized to either ethanol or acetate. PFL is inactive in the presence of oxygen and at a low pH (24,35). With an active PFL pathway, three molecules of ATP are conserved per hexose molecule catabolized, compared with the two ATP molecules conserved per hexose molecule when LDH is used.…”

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confidence: 99%

“…However, mixed acid product formation from maltose has been shown to decrease at the end of cultivation when the pH is low (42), which can be attributed to inhibition of PFL at low pH (24). Galactosefermenting L. lactis NCDO 2118 was recently shown to produce less mixed acids when the growth rate in batch mode was limited by means of a defined medium with a low concentration of amino acids (17).…”

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confidence: 99%

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The Pool of ADP and ATP Regulates Anaerobic Product Formation in Resting Cells of Lactococcus lactis

Palmfeldt

Paese

Hahn‐Hägerdal

et al. 2004

Appl Environ Microbiol

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Lactococcus lactis grows homofermentatively on glucose, while its growth on maltose under anaerobic conditions results in mixed acid product formation in which formate, acetate, and ethanol are formed in addition to lactate. Maltose was used as a carbon source to study mixed acid product formation as a function of the growth rate. In batch and nitrogen-limited chemostat cultures mixed acid product formation was shown to be linked to the growth rate, and homolactic fermentation occurred only in resting cells. Two of the four lactococcal strains investigated with maltose, L. lactis 65.1 and MG1363, showed more pronounced mixed acid product formation during growth than L. lactis ATCC 19435 or IL-1403. In resting cell experiments all four strains exhibited homolactic fermentation. In resting cells the intracellular concentrations of ADP, ATP, and fructose 1,6-bisphosphate were increased and the concentration of P i was decreased compared with the concentrations in growing cells. Addition of an ionophore (monensin or valinomycin) to resting cultures of L. lactis 65.1 induced mixed acid product formation concomitant with decreases in the ADP, ATP, and fructose 1,6-bisphosphate concentrations. ADP and ATP were shown to inhibit glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and alcohol dehydrogenase in vitro. Alcohol dehydrogenase was the most sensitive enzyme and was totally inhibited at an adenine nucleotide concentration of 16 mM, which is close to the sum of the intracellular concentrations of ADP and ATP of resting cells. This inhibition of alcohol dehydrogenase might be partially responsible for the homolactic behavior of resting cells. A hypothesis regarding the level of the ATP-ADP pool as a regulating mechanism for the glycolytic flux and product formation in L. lactis is discussed.Lactococcus lactis is a lactic acid bacterium that is used as a starter culture in the dairy industry. L. lactis has a rather simple and well-characterized metabolism and converts sugars mainly into lactic acid. In recent years L. lactis has also been evaluated as organism for production of industrial lactic acid (23, 38) and has been subjected to metabolic engineering to reroute its metabolism towards novel products (13,18,22,25,26). To take full advantage of bacterial processes, it is very important to understand which intracellular and extracellular factors influence the metabolic rate and product formation. L. lactis is an attractive model organism for studies of glycolysis and pyruvate metabolism, since oxidative phosphorylation normally does not occur and more than 90% of the carbon source is recovered as fermentation by-products, mainly lactate. In glycolysis glyceraldehyde-3-phosphate dehydrogenase (GAPDH) converts NAD ϩ to NADH, which must be regenerated for continued carbon catabolism. Lactate dehydrogenase (LDH) regenerates NAD ϩ by converting the end product of glycolysis, pyruvate, to lactate. An alternative way for lactococci to regenerate NAD ϩ is by production of ethanol by alcohol dehydrogenase (ADH...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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The Pool of ADP and ATP Regulates Anaerobic Product Formation in Resting Cells of Lactococcus lactis

Palmfeldt

Paese

Hahn‐Hägerdal

et al. 2004

Appl Environ Microbiol

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“…1.73 ± 0.14 270 ± 41 46.6 ± 2.1 210.3 ± 1.2 homolactic to heterolactic fermentation for certain lactobacilli (Borch et al, 1991;Torino et al, 2001) and lactococci (Hofvendahl et al, 1999) and from acidogenesis to solventogenesis in ABE fermentation by C. acetobutylicum (Girbal et al, 1995;Rogers and Gottschalk, 1993). Different patterns of organic acid production were also observed in C. sporogenes fermentation at different pHs, and butyric acid production was favored at pH 5.5 (Montville et al, 1985).…”

Section: Effect Of Ph On Metabolic Pathwaymentioning

confidence: 99%

Effect of pH on metabolic pathway shift in fermentation of xylose by Clostridium tyrobutyricum

Zhu

Yang

2004

Journal of Biotechnology

210

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The effect of pH (between 5.0 and 6.3) on butyric acid fermentation of xylose by Clostridium tyrobutyricum was studied. At pH 6.3, the fermentation gave a high butyrate production of 57.9 g l −1 with a yield of 0.38-0.59 g g −1 xylose and a reactor productivity up to 3.19 g l −1 h −1 . However, at low pHs (<5.7), the fermentation produced more acetate and lactate as the main products, with only a small amount of butyric acid. The metabolic shift from butyrate formation to lactate and acetate formation in the fermentation was found to be associated with changes in the activities of several key enzymes. The activities of phosphotransbutyrylase (PTB), which is the key enzyme controlling butyrate formation, and NAD-independent lactate dehydrogenase (iLDH), which catalyzes the conversion of lactate to pyruvate, were higher in cells producing mainly butyrate at pH 6.3. In contrast, cells at pH 5.0 had higher activities of phosphotransacetylase (PTA), which is the key enzyme controlling acetate formation, and lactate dehydrogenase (LDH), which catalyzes the conversion of pyruvate to lactate. Also, PTA was very sensitive to the inhibition by butyric acid. Difference in the specific metabolic rate of xylose at different pHs suggests that the balance in NADH is a key in controlling the metabolic pathway used by the cells in the fermentation.

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“…The references [19][20][21] have proved that two-stage pH control strategy was effective for the other products' accumulation such as pyruvate and transglutaminase, and Song and Chang investigated the effect of pH on ILE fermentation [11,12]. On the basis of two-stage agitation speed control strategy, fermentation was conducted at various pH values (5.7, 6.2, 6.7, 7.2, 7.7 and 8.2) in order to investigate the effects of pH on ILE fermentation.…”

Section: Development Of a Two-stage Agitation Speed Control Strategy mentioning

confidence: 99%

Combined dissolved oxygen and pH control strategy to improve the fermentative production of l-isoleucine by Brevibacterium lactofermentum

Peng

Fang

et al. 2009

Bioprocess Biosyst Eng

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The effect of both dissolved oxygen (DO) and pH on L: -isoleucine production by batch culture of Brevibacterium lactofermentum was investigated. A two-stage agitation speed control strategy was developed, and the isoleucine production reached 23.3 g L(-1) in a relative short time (52 h), increased by 11.6% compared to the results obtained in the single agitation speed control process. In order to make sure whether the combination of DO and pH control can boost the production by a mutual effect, different control modes were conducted, based on the data obtained from the two-stage agitation speed control strategy and the analysis of kinetics parameters at different pH values. The results showed that the mode of combining two-stage DO with two-stage pH control strategy was the optimal for isoleucine production. The isoleucine production can reach 26.6 g L(-1) at 56 h, increased by 14.3% comparing to that obtained by the single two-stage DO control strategy.

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Effect of temperature and pH on growth and product formation of Lactococcus lactis ssp. lactis ATCC 19435 growing on maltose

Cited by 28 publications

References 23 publications

The Pool of ADP and ATP Regulates Anaerobic Product Formation in Resting Cells of Lactococcus lactis

The Pool of ADP and ATP Regulates Anaerobic Product Formation in Resting Cells of Lactococcus lactis

Effect of pH on metabolic pathway shift in fermentation of xylose by Clostridium tyrobutyricum

Combined dissolved oxygen and pH control strategy to improve the fermentative production of l-isoleucine by Brevibacterium lactofermentum

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