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Enhanced production of Ca²⁺-polymalate (PMA) with high molecular mass by Aureobasidium pullulans var. pullulans MCW.

Wang YK, Chi Z, Zhou HX, Liu GL, Chi ZM - Microb. Cell Fact. (2015)

Bottom Line: The medium containing only 140.0 g/L glucose, 65.0 g/L CaCO3 and 7.5 g/L corn steep liquor was found to be the most suitable for Ca(2+)-PMA production.During 10-L batch fermentation, 152.52 g/L of Ca(2+)-PMA in the culture and 8.6 g/L of cell dry weight were obtained within 96 h, leaving 4.5 g/L of reducing sugar in the fermented medium.Mw (the apparent molecular weight) of the purified PMA was 2.054 × 10(5) (g/moL) and the purified PMA was estimated to be composed of 1784 L-malic acids.

View Article: PubMed Central - PubMed

Affiliation: College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China. w84234102@sina.com.

ABSTRACT

Background: Polymalic acid (PMA) has many applications in food and medical industries. However, so far it has not been commercially produced by fermentation. Therefore, it is very important how to develop an economical process for a large scale production of PMA by one step fermentation.

Results: After over 200 strains of Aureobasidium spp. isolated from the mangrove systems in the South of China were screened for their ability to produce Ca(2+)-polymalate (PMA), it was found that Aureobasidium pullulans var. pullulans MCW strain among them could produce high level of Ca(2+)-PMA. The medium containing only 140.0 g/L glucose, 65.0 g/L CaCO3 and 7.5 g/L corn steep liquor was found to be the most suitable for Ca(2+)-PMA production. Then, 121.3 g/L of Ca(2+)-PMA was produced by A. pullulans var. pullulans MCW strain within 120 h at flask level. During 10-L batch fermentation, 152.52 g/L of Ca(2+)-PMA in the culture and 8.6 g/L of cell dry weight were obtained within 96 h, leaving 4.5 g/L of reducing sugar in the fermented medium. After purification of the Ca(2+)-PMA from the culture and acid hydrolysis of the purified Ca(2+)-PMA, HPLC analysis showed that A. pullulans var. pullulans MCW strain produced only one main component of Ca(2+)-PMA and the hydrolysate of the purified Ca(2+)-PMA was mainly composed of L-malic acid. Mw (the apparent molecular weight) of the purified PMA was 2.054 × 10(5) (g/moL) and the purified PMA was estimated to be composed of 1784 L-malic acids.

Conclusions: It was found that A. pullulans var. pullulans MCW strain obtained in this study could yield 152.52 g/L of Ca(2+)-PMA within the short time, the produced PMA had the highest molecular weight and the medium for production of Ca(2+)- PMA by this yeast was very simple.

No MeSH data available.


Related in: MedlinePlus

The proposed pathway of the PMA metabolism in the yeast cells.
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Related In: Results  -  Collection

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Fig4: The proposed pathway of the PMA metabolism in the yeast cells.

Mentions: CSL has been reported to have a rich source of nitrogen, water soluble vitamins including biotin, amino acids, minerals and other stimulants [25]. Therefore, effects of different concentrations of CSL on Ca2+-PMA production and cell growth by the yeast strain MCW were tested. It can be observed from the data in Fig. 3 that when the initial CSL concentrations in the PMA production medium were increased from 2.5 to 7.5 g/L, the Ca2+-PMA titers were also significantly increased from 86.54 to 121.31 g/L. However, when the initial CSL concentrations in the PMA production medium were increased from 7.5 to 12.5 g/L, the Ca2+-PMA titers were rapidly decreased from 121.31 to 51.12 g/L (Fig. 3). Therefore, 7.5 g/L of CSL in the PMA production medium was the most suitable for Ca2+-PMA production by the yeast strain MCW. This meant that like the calcium malate production [15], CSL indeed greatly promoted the Ca2+-PMA production by the yeast strain MCW. Furthermore, addition of CSL could significantly simplify the Ca2+-PMA production medium because the medium only contained glucose, CaCO3 and CSL. However, as the initial CSL concentrations in the Ca2+-PMA production medium were increased from 2.5 to 12.5 g/L, its cell growth was also increased continuously (Fig. 3). The data of the Ca2+-PMA titers and cell mass obtained above were subjected to One-way Analysis of Variance (ANOVA) [20]. P values were calculated by Student’s t test (n = 3). P values less than 0.05 were considered statistically significant. The statistical analysis was performed using SPSS 11.5 for Windows (SPSS Inc., Chicago, IL, USA). The results demonstrated that there were big differences between the Ca2+-PMA titers and cell mass shown in Fig. 3. According to the pathway of PMA biosynthesis [2], pyruvate carboxylase (PYC) and malate dehydrogenase (MDH) are involved in PMA biosynthesis in the non-oxidative pathway (Fig. 4). It has been known that PYC is a biotin-dependent tetrameric enzyme that catalyzes the carboxylation of pyruvic acid to form oxaloacetic acid, suggesting that biotin is required during biosynthesis of PMA [26]. Therefore, in the presence of CSL, activities of PYC and MDH may be promoted so that l-malic acid biosynthesis was enhanced, causing high level production of PMA by the yeast strain MCW (Fig. 3). In addition, CSL was also found to stimulate malate production by P. viticola 152 isolated from marine algae [15]. However, the exact mechanisms of the promotion of the activities of PYC and MDH and the Ca2+-PMA production by CSL are still completely unknown. Maybe biotin present in CSL was required by PYC.Fig. 3


Enhanced production of Ca²⁺-polymalate (PMA) with high molecular mass by Aureobasidium pullulans var. pullulans MCW.

Wang YK, Chi Z, Zhou HX, Liu GL, Chi ZM - Microb. Cell Fact. (2015)

The proposed pathway of the PMA metabolism in the yeast cells.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4528779&req=5

Fig4: The proposed pathway of the PMA metabolism in the yeast cells.
Mentions: CSL has been reported to have a rich source of nitrogen, water soluble vitamins including biotin, amino acids, minerals and other stimulants [25]. Therefore, effects of different concentrations of CSL on Ca2+-PMA production and cell growth by the yeast strain MCW were tested. It can be observed from the data in Fig. 3 that when the initial CSL concentrations in the PMA production medium were increased from 2.5 to 7.5 g/L, the Ca2+-PMA titers were also significantly increased from 86.54 to 121.31 g/L. However, when the initial CSL concentrations in the PMA production medium were increased from 7.5 to 12.5 g/L, the Ca2+-PMA titers were rapidly decreased from 121.31 to 51.12 g/L (Fig. 3). Therefore, 7.5 g/L of CSL in the PMA production medium was the most suitable for Ca2+-PMA production by the yeast strain MCW. This meant that like the calcium malate production [15], CSL indeed greatly promoted the Ca2+-PMA production by the yeast strain MCW. Furthermore, addition of CSL could significantly simplify the Ca2+-PMA production medium because the medium only contained glucose, CaCO3 and CSL. However, as the initial CSL concentrations in the Ca2+-PMA production medium were increased from 2.5 to 12.5 g/L, its cell growth was also increased continuously (Fig. 3). The data of the Ca2+-PMA titers and cell mass obtained above were subjected to One-way Analysis of Variance (ANOVA) [20]. P values were calculated by Student’s t test (n = 3). P values less than 0.05 were considered statistically significant. The statistical analysis was performed using SPSS 11.5 for Windows (SPSS Inc., Chicago, IL, USA). The results demonstrated that there were big differences between the Ca2+-PMA titers and cell mass shown in Fig. 3. According to the pathway of PMA biosynthesis [2], pyruvate carboxylase (PYC) and malate dehydrogenase (MDH) are involved in PMA biosynthesis in the non-oxidative pathway (Fig. 4). It has been known that PYC is a biotin-dependent tetrameric enzyme that catalyzes the carboxylation of pyruvic acid to form oxaloacetic acid, suggesting that biotin is required during biosynthesis of PMA [26]. Therefore, in the presence of CSL, activities of PYC and MDH may be promoted so that l-malic acid biosynthesis was enhanced, causing high level production of PMA by the yeast strain MCW (Fig. 3). In addition, CSL was also found to stimulate malate production by P. viticola 152 isolated from marine algae [15]. However, the exact mechanisms of the promotion of the activities of PYC and MDH and the Ca2+-PMA production by CSL are still completely unknown. Maybe biotin present in CSL was required by PYC.Fig. 3

Bottom Line: The medium containing only 140.0 g/L glucose, 65.0 g/L CaCO3 and 7.5 g/L corn steep liquor was found to be the most suitable for Ca(2+)-PMA production.During 10-L batch fermentation, 152.52 g/L of Ca(2+)-PMA in the culture and 8.6 g/L of cell dry weight were obtained within 96 h, leaving 4.5 g/L of reducing sugar in the fermented medium.Mw (the apparent molecular weight) of the purified PMA was 2.054 × 10(5) (g/moL) and the purified PMA was estimated to be composed of 1784 L-malic acids.

View Article: PubMed Central - PubMed

Affiliation: College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China. w84234102@sina.com.

ABSTRACT

Background: Polymalic acid (PMA) has many applications in food and medical industries. However, so far it has not been commercially produced by fermentation. Therefore, it is very important how to develop an economical process for a large scale production of PMA by one step fermentation.

Results: After over 200 strains of Aureobasidium spp. isolated from the mangrove systems in the South of China were screened for their ability to produce Ca(2+)-polymalate (PMA), it was found that Aureobasidium pullulans var. pullulans MCW strain among them could produce high level of Ca(2+)-PMA. The medium containing only 140.0 g/L glucose, 65.0 g/L CaCO3 and 7.5 g/L corn steep liquor was found to be the most suitable for Ca(2+)-PMA production. Then, 121.3 g/L of Ca(2+)-PMA was produced by A. pullulans var. pullulans MCW strain within 120 h at flask level. During 10-L batch fermentation, 152.52 g/L of Ca(2+)-PMA in the culture and 8.6 g/L of cell dry weight were obtained within 96 h, leaving 4.5 g/L of reducing sugar in the fermented medium. After purification of the Ca(2+)-PMA from the culture and acid hydrolysis of the purified Ca(2+)-PMA, HPLC analysis showed that A. pullulans var. pullulans MCW strain produced only one main component of Ca(2+)-PMA and the hydrolysate of the purified Ca(2+)-PMA was mainly composed of L-malic acid. Mw (the apparent molecular weight) of the purified PMA was 2.054 × 10(5) (g/moL) and the purified PMA was estimated to be composed of 1784 L-malic acids.

Conclusions: It was found that A. pullulans var. pullulans MCW strain obtained in this study could yield 152.52 g/L of Ca(2+)-PMA within the short time, the produced PMA had the highest molecular weight and the medium for production of Ca(2+)- PMA by this yeast was very simple.

No MeSH data available.


Related in: MedlinePlus