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Extracellular Polyhydroxyalkanoate Depolymerase by Acidovorax sp. DP5.

Vigneswari S, Lee TS, Bhubalan K, Amirul AA - Enzyme Res (2015)

Bottom Line: The highest degradation activity of P(3HB) was also observed with depolymerase enzyme of DP5 in mineral salt medium containing P(3HB).Based on biochemical characterization and 16S rRNA cloning and sequencing, isolate DP5 was found to belong to the genus Acidovorax and subsequently named as Acidovorax sp.The highest extracellular depolymerase enzyme activity was achieved when 0.25% (w/v) of P(3HB) and 1 g/L of urea were used as carbon and nitrogen source, respectively, in the culture media.

View Article: PubMed Central - PubMed

Affiliation: Malaysian Institute of Pharmaceuticals and Nutraceuticals, NIBM, MOSTI, 11700 Penang, Malaysia ; Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Malaysia.

ABSTRACT
Bacteria capable of degrading polyhydroxyalkanoates (PHA) by secreting extracellular depolymerase enzymes were isolated from water and soil samples collected from various environments in Malaysia. A total of 8 potential degraders exhibited clear zones on poly(3-hydroxybutyrate) [P(3HB)] based agar, indicating the presence of extracellular PHA depolymerase. Among the isolates, DP5 exhibited the largest clearing zone with a degradation index of 6.0. The highest degradation activity of P(3HB) was also observed with depolymerase enzyme of DP5 in mineral salt medium containing P(3HB). Based on biochemical characterization and 16S rRNA cloning and sequencing, isolate DP5 was found to belong to the genus Acidovorax and subsequently named as Acidovorax sp. DP5. The highest extracellular depolymerase enzyme activity was achieved when 0.25% (w/v) of P(3HB) and 1 g/L of urea were used as carbon and nitrogen source, respectively, in the culture media. The most suitable assay condition of the depolymerase enzyme in response to pH and temperature was tested. The depolymerase produced by strain Acidovorax sp. DP5 showed high percentage of degradation with P(3HB) films in an alkaline condition with pH 9 and at a temperature of 40°C.

No MeSH data available.


Related in: MedlinePlus

Effect of percentage of weight loss (degradation) of P(3HB) films at various temperatures at pH 9. Values are mean of two replicates.
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fig6: Effect of percentage of weight loss (degradation) of P(3HB) films at various temperatures at pH 9. Values are mean of two replicates.

Mentions: On the other hand, temperature also has a significant influence on the solubility of organic compounds [20]. At a high temperature, P(3HB) was considered to be amorphous and more sensitive to the degrading enzyme, allowing its degradation. Based on result obtained in Figure 6, it was found that, by increasing the incubation temperature from 30°C to 40°C, the surface erosion of the film can be increased up to 50% at 60 h of cultivation. Degradation was the highest at 40°C, whereby up to 25% of film erosion was observed within 24 h. However, for the other temperatures, the percentage of degradation was below 20% at this point of time. Further increment in temperature only reduced the overall rate of degradation. From these experiments, it was concluded that pH 9 and temperature of 40°C were the optimal conditions for competent hydrolysis of P(3HB) film using the depolymerase enzyme secreted by Acidovorax sp. DP5. The molecular weights and mechanical properties of enzyme degraded P(3HB-co-4HB) copolymer scaffolds using the optimal conditions were also studied (Table 4). Interestingly, it was observed that the 4HB mol% increased by 2–8 mol% when the copolymer films were degraded with the depolymerase enzyme.


Extracellular Polyhydroxyalkanoate Depolymerase by Acidovorax sp. DP5.

Vigneswari S, Lee TS, Bhubalan K, Amirul AA - Enzyme Res (2015)

Effect of percentage of weight loss (degradation) of P(3HB) films at various temperatures at pH 9. Values are mean of two replicates.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4664802&req=5

fig6: Effect of percentage of weight loss (degradation) of P(3HB) films at various temperatures at pH 9. Values are mean of two replicates.
Mentions: On the other hand, temperature also has a significant influence on the solubility of organic compounds [20]. At a high temperature, P(3HB) was considered to be amorphous and more sensitive to the degrading enzyme, allowing its degradation. Based on result obtained in Figure 6, it was found that, by increasing the incubation temperature from 30°C to 40°C, the surface erosion of the film can be increased up to 50% at 60 h of cultivation. Degradation was the highest at 40°C, whereby up to 25% of film erosion was observed within 24 h. However, for the other temperatures, the percentage of degradation was below 20% at this point of time. Further increment in temperature only reduced the overall rate of degradation. From these experiments, it was concluded that pH 9 and temperature of 40°C were the optimal conditions for competent hydrolysis of P(3HB) film using the depolymerase enzyme secreted by Acidovorax sp. DP5. The molecular weights and mechanical properties of enzyme degraded P(3HB-co-4HB) copolymer scaffolds using the optimal conditions were also studied (Table 4). Interestingly, it was observed that the 4HB mol% increased by 2–8 mol% when the copolymer films were degraded with the depolymerase enzyme.

Bottom Line: The highest degradation activity of P(3HB) was also observed with depolymerase enzyme of DP5 in mineral salt medium containing P(3HB).Based on biochemical characterization and 16S rRNA cloning and sequencing, isolate DP5 was found to belong to the genus Acidovorax and subsequently named as Acidovorax sp.The highest extracellular depolymerase enzyme activity was achieved when 0.25% (w/v) of P(3HB) and 1 g/L of urea were used as carbon and nitrogen source, respectively, in the culture media.

View Article: PubMed Central - PubMed

Affiliation: Malaysian Institute of Pharmaceuticals and Nutraceuticals, NIBM, MOSTI, 11700 Penang, Malaysia ; Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Malaysia.

ABSTRACT
Bacteria capable of degrading polyhydroxyalkanoates (PHA) by secreting extracellular depolymerase enzymes were isolated from water and soil samples collected from various environments in Malaysia. A total of 8 potential degraders exhibited clear zones on poly(3-hydroxybutyrate) [P(3HB)] based agar, indicating the presence of extracellular PHA depolymerase. Among the isolates, DP5 exhibited the largest clearing zone with a degradation index of 6.0. The highest degradation activity of P(3HB) was also observed with depolymerase enzyme of DP5 in mineral salt medium containing P(3HB). Based on biochemical characterization and 16S rRNA cloning and sequencing, isolate DP5 was found to belong to the genus Acidovorax and subsequently named as Acidovorax sp. DP5. The highest extracellular depolymerase enzyme activity was achieved when 0.25% (w/v) of P(3HB) and 1 g/L of urea were used as carbon and nitrogen source, respectively, in the culture media. The most suitable assay condition of the depolymerase enzyme in response to pH and temperature was tested. The depolymerase produced by strain Acidovorax sp. DP5 showed high percentage of degradation with P(3HB) films in an alkaline condition with pH 9 and at a temperature of 40°C.

No MeSH data available.


Related in: MedlinePlus