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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

Clear zone formation produced by Acidovorax sp. DP5 on P(3HB) agar plate. Cells were grown for 4-5 days at 30°C to form clear zone surrounding the bacterial colony.
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fig1: Clear zone formation produced by Acidovorax sp. DP5 on P(3HB) agar plate. Cells were grown for 4-5 days at 30°C to form clear zone surrounding the bacterial colony.

Mentions: It has been estimated that the percentage of PHA-degrading microorganisms in the environment falls in the range of 0.5–9.6% of the total colonies present [28]. In this study, a total of 18 strains were isolated by culturing environmental samples in MSM-P(3HB) broth. This method serves as an initial screening for bacteria capable of hydrolyzing P(3HB) using it as carbon source for growth. Next, the isolates were further screened on MSM-P(3HB) agar to avoid the presence of pseudo-positive degraders. This is because it is possible for other non-P(3HB) degrading bacteria to establish symbiotic reactions in the presence of positive P(3HB) degraders. Formation of “clear-zones” around bacterial colonies indicates positive results and confirms the P(3HB) degrading ability of strains [29]. From the 18 isolates initially obtained, only eight were identified as potential PHA-degrading microorganisms based on the formation of clear zone (Figure 1) and by observing the degradation index. The formation of the clear zones around the colonies is an indication that the polymer is hydrolyzed by the enzyme into water-soluble products [29]. In order to be classified as PHA-degraders, a degradation index of more than one should be obtained. It was visually observed and calculated that eight strains out of the 18 isolates produced a degradation index of more than 1.00.


Extracellular Polyhydroxyalkanoate Depolymerase by Acidovorax sp. DP5.

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

Clear zone formation produced by Acidovorax sp. DP5 on P(3HB) agar plate. Cells were grown for 4-5 days at 30°C to form clear zone surrounding the bacterial colony.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig1: Clear zone formation produced by Acidovorax sp. DP5 on P(3HB) agar plate. Cells were grown for 4-5 days at 30°C to form clear zone surrounding the bacterial colony.
Mentions: It has been estimated that the percentage of PHA-degrading microorganisms in the environment falls in the range of 0.5–9.6% of the total colonies present [28]. In this study, a total of 18 strains were isolated by culturing environmental samples in MSM-P(3HB) broth. This method serves as an initial screening for bacteria capable of hydrolyzing P(3HB) using it as carbon source for growth. Next, the isolates were further screened on MSM-P(3HB) agar to avoid the presence of pseudo-positive degraders. This is because it is possible for other non-P(3HB) degrading bacteria to establish symbiotic reactions in the presence of positive P(3HB) degraders. Formation of “clear-zones” around bacterial colonies indicates positive results and confirms the P(3HB) degrading ability of strains [29]. From the 18 isolates initially obtained, only eight were identified as potential PHA-degrading microorganisms based on the formation of clear zone (Figure 1) and by observing the degradation index. The formation of the clear zones around the colonies is an indication that the polymer is hydrolyzed by the enzyme into water-soluble products [29]. In order to be classified as PHA-degraders, a degradation index of more than one should be obtained. It was visually observed and calculated that eight strains out of the 18 isolates produced a degradation index of more than 1.00.

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