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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 various nitrogen sources on the enzyme activity. N1: NH4Cl, N2: (NH4)2SO4, N3: NH4NO3, N4: (NH4)2HPO4, N5: (NH2)2CO, and N6: control (without nitrogen source). Values are mean of two replicates.
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fig4: Effect of various nitrogen sources on the enzyme activity. N1: NH4Cl, N2: (NH4)2SO4, N3: NH4NO3, N4: (NH4)2HPO4, N5: (NH2)2CO, and N6: control (without nitrogen source). Values are mean of two replicates.

Mentions: The highest enzyme activities of 0.056 mg/mL/min and 0.066 mg/mL/min were achieved at 72 h of incubation when P(3HB) concentration was 0.1% and 0.25% (w/v), respectively. On the other hand, no enzymatic activity was detected at 72 h with cultures fed with 0.5% (w/v) and 0.75% (w/v) of P(3HB). The depolymerase activity showed a sharp decrease for these concentrations of P(3HB) after 24 h of cultivation. This result might contradict the usual presumption that a higher P(3HB) concentration would possibly contribute to a higher depolymerase enzyme activity. The reduction in enzyme activity may have been caused by surplus product formation when higher concentrations of P(3HB) were supplied. This was evident in increased cell growth observed with higher P(3HB) concentrations (Figure 3(a)). Nitrogen plays a crucial role in supporting bacterial growth and the type of nitrogen source supplied in the medium is known to affect the secretion of enzymes and production of an intermediate and the final product. Various nitrogen sources such as NH4Cl, NH4SO4, NH4NO3, (NH4)2HPO4, and (NH2)2CO [1 g/L] were screened in relation to depolymerase enzyme activity. Among these nitrogen sources, urea resulted in the highest enzyme activity (Figure 4).


Extracellular Polyhydroxyalkanoate Depolymerase by Acidovorax sp. DP5.

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

Effect of various nitrogen sources on the enzyme activity. N1: NH4Cl, N2: (NH4)2SO4, N3: NH4NO3, N4: (NH4)2HPO4, N5: (NH2)2CO, and N6: control (without nitrogen source). Values are mean of two replicates.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Effect of various nitrogen sources on the enzyme activity. N1: NH4Cl, N2: (NH4)2SO4, N3: NH4NO3, N4: (NH4)2HPO4, N5: (NH2)2CO, and N6: control (without nitrogen source). Values are mean of two replicates.
Mentions: The highest enzyme activities of 0.056 mg/mL/min and 0.066 mg/mL/min were achieved at 72 h of incubation when P(3HB) concentration was 0.1% and 0.25% (w/v), respectively. On the other hand, no enzymatic activity was detected at 72 h with cultures fed with 0.5% (w/v) and 0.75% (w/v) of P(3HB). The depolymerase activity showed a sharp decrease for these concentrations of P(3HB) after 24 h of cultivation. This result might contradict the usual presumption that a higher P(3HB) concentration would possibly contribute to a higher depolymerase enzyme activity. The reduction in enzyme activity may have been caused by surplus product formation when higher concentrations of P(3HB) were supplied. This was evident in increased cell growth observed with higher P(3HB) concentrations (Figure 3(a)). Nitrogen plays a crucial role in supporting bacterial growth and the type of nitrogen source supplied in the medium is known to affect the secretion of enzymes and production of an intermediate and the final product. Various nitrogen sources such as NH4Cl, NH4SO4, NH4NO3, (NH4)2HPO4, and (NH2)2CO [1 g/L] were screened in relation to depolymerase enzyme activity. Among these nitrogen sources, urea resulted in the highest enzyme activity (Figure 4).

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