Isolation of a Gram-positive poly(3-hydroxybutyrate) (PHB)-degrading bacterium from compost, and cloning and characterization of a gene encoding PHB depolymerase of<i>Bacillus megaterium</i>N-18-25-9

Takaku, Hiroaki; Kimoto, Ayumi; Kodaira, Shoko; Nashimoto, Masayuki; Takagi, Masamichi

doi:10.1111/j.1574-6968.2006.00448.x

Cited by 40 publications

(26 citation statements)

References 19 publications

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“…Its enzyme activity was not increased by the addition of 1 mM CaCl 2 to the reaction mixture and was not inhibited by the presence of 10 mM EDTA, suggesting that the calcium ion is not required as a cofactor for the enzyme activity. This is in striking contrast to the B. megaterium N-18-25-9 PhaZ (37). To analyze the dPHB-binding ability of PhaZ, the mature form of PhaZ was pretreated with 1 mM PMSF to inhibit the dPHB-degrading activity.…”

Section: Resultsmentioning

confidence: 99%

“…NRRL B-14911 has been partially determined and is available from GenBank. It encodes a putative PHB depolymerase (GenBank accession number ZP_01169502) of 592 amino acids (see Discussion) that shows 53% identity and 68% similarity to the extracellular PHB depolymerase of B. megaterium N-18-25-9 (590 amino acids; BAF35850) (37). The analysis of the putative PhaZ of Bacillus sp.…”

Section: Resultsmentioning

confidence: 99%

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Identification and Characterization of a Novel Class of Extracellular Poly(3-Hydroxybutyrate) Depolymerase from Bacillus sp. Strain NRRL B-14911

Ma¹,

Lin²,

Chen³

et al. 2011

Appl Environ Microbiol

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The catalytic, linker, and denatured poly(3-hydroxybutyrate) (dPHB)-binding domains of bacterial extracellular PHB depolymerases (PhaZs) are classified into several different types. We now report a novel class of extracellular PHB depolymerase from Bacillus sp. strain NRRL B-14911. Its catalytic domain belongs to type 1, whereas its putative linker region neither possesses the sequence features of the three known types of linker domains nor exhibits significant amino acid sequence similarity to them. Instead, this putative linker region can be divided into two distinct linker domains of novel types: LD1 and LD2. LD1 shows significant amino acid sequence similarity to certain regions of a large group of PHB depolymerase-unrelated proteins. LD2 and its homologs are present in a small group of PhaZs. The remaining C-terminal portion of this PhaZ can be further divided into two distinct domains: SBD1 and SBD2. Each domain showed strong binding to dPHB, and there is no significant sequence similarity between them. Each domain neither possesses the sequence features of the two known types of dPHBbinding domains nor shows significant amino acid sequence similarity to them. These unique features indicate the presence of two novel and distinct types of dPHB-binding domains. Homologs of these novel domains also are present in the extracellular PhaZ of Bacillus megaterium and the putative extracellular PhaZs of Bacillus pseudofirmus and Bacillus sp. strain SG-1. The Bacillus sp. NRRL B-14911 PhaZ appears to be a representative of a novel class of extracellular PHB depolymerases.Poly(3-hydroxybutyrate) (PHB) is synthesized and accumulated intracellularly as a carbon and energy storage material by a wide variety of bacteria (14,28,29). When nutrient availability is restricted or unbalanced, the accumulated PHB is subject to degradation by the intracellular PHB depolymerase(s) (PhaZ) to produce 3-hydroxybutyrate (3HB) oligomers and/or monomers. These products subsequently are metabolized by the intracellular 3HB-oligomer hydrolase and/or the 3HB dehydrogenase as carbon and energy sources (21,22,30,36,38). The intracellular PHB exists in an amorphous state. When the amorphous PHB is subjected to solvent extraction or exposed to the extracellular environment due to cell death or lysis, the amorphous PHB is transformed into denatured semicrystalline PHB (dPHB) (13, 16).A wide variety of bacteria can produce and secrete extracellular PHB depolymerases for the specific degradation of dPHB (12,16,40), with some exceptions. One exception is the extracellular PHB depolymerase PhaZ7 of Paucimonas lemoignei, which can only degrade amorphous PHB (7). Another known exception is the periplasm-located PHB depolymerase of Rhodospirillum rubrum, which shows substrate specificity for amorphous PHB (8). Like intracellular PHB depolymerases, extracellular PHB depolymerases can degrade PHB into 3HB oligomers and/or monomers. The produced 3HB oligomers can be further degraded by extracellular 3HB-oligomer hydrolases into 3HB monomers or degraded ...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Identification and Characterization of a Novel Class of Extracellular Poly(3-Hydroxybutyrate) Depolymerase from Bacillus sp. Strain NRRL B-14911

Ma¹,

Lin²,

Chen³

et al. 2011

Appl Environ Microbiol

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“…Similarly, maximum production of PHB depolymerase by A, fumigates was observed at pH 7 after 24 h of incubation in liquid medium (Lodhi et al, 2011). The maximum activity of extracellular PHB depolymerase produced by Bacillus megaterium N-18-25-9, was observed at pH 9.0 at 65ºC (Takaku et al, 2006) and at pH 7.5-8.0 when sewage sludge was used as inoculum (Briese et al, 1994). In the present study, the maximum production of PHB depolymerase was found at 0.3% of substrate concentration as indicated by the maximum enzyme activity, while it decreased with further increase in polymer concentration which might be due to substrate level inhibition (Manna and Paul, 2000).…”

Section: Discussionmentioning

confidence: 96%

Poly-𝛽-hydroxy butyrate Depolymerase from Streptomyces lydicus MM10, Isolated from Wastewater Sample

Aly¹,

Tork²,

Qari³

et al. 2015

IJAB

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To cite this paper: Aly, M.M., S. AbstractPlastics are an integral part in our daily life activities and it is difficult to conceive how we could function without them. Burning or chemical treatments of these plastic materials destroys the environment and have many dangerous effects on, water air and human health. Thus, other sources of plastic (biodegradable plastic) must be introduced. Under unfavorable growth conditions Poly ß-hydroxybutyrate (PHB) is accumulated intracellular by many bacteria and the principal enzyme for the degradation of PHB is PHB depolymerase. A number of thermophilic actinomycetes have been screened for PHB degradation on agar plats. All these isolates were recovered from soil, sand and wastewater samples on starch nitrate agar at incubation temperature of 45. Five isolates (50%) out of 10 showed degradation activities, detected by the diameter of the clear zone. The Actinomycete isolate MM10 was the most PHB degrader and it was identified using morphological, physiological and biochemical characters. According to 16SrRNA analysis, it was identified as Streptomyces lydicusMM10. Growth at 45ᵒC, in minimal medium (pH7.0) containing glucose and0.3% PHB as enzyme inducer, enhanced enzyme production and maximum activity was obtained after 24 h of incubation. The PHB depolymerase was precipitated and purified using column chromatography. The optimum temperature and pH of the pure enzyme were 45°C and pH 8, respectively. However, production of bioplastics is cost effective as compared to synthetic plastics they were non-toxic and completely biodegradable by some actinomycete isolates

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“…Composting is a high-temperature process; hence, thermophilic microbes capable of degrading various kinds of polyesters are of interest (Takeda et al 1998;Romen et al 2004, Takaku et al 2006. Actinomycetes capable of PHA degradation at high temperature, especially poly[(R)-3-hydroxybutyrate] (PHB) Polyhydroxyalkanoate degradation by a Streptomyces sp.…”

Section: Introductionmentioning

confidence: 99%

Microbial degradation and physico-chemical alteration of polyhydroxyalkanoates by a thermophilic Streptomyces sp.

et al. 2009

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A thermophilic Streptomyces sp. capable of degrading various aliphatic polyesters was isolated from a landfill site. The isolate, Streptomyces sp. BCC23167, demonstrated rapid aerobic degradation of several polyesters, including polyhydroxyalkanoate copolymers, poly(ε-caprolactone) and polybutylene succinate at 50• C and neutral pH. The degrading activity was repressed by glucose and cellobiose, but tolerant to repression by other carbon substrates. Degradation of a commercial poly[(R)-3-hydroxybutyrate-co-3-hydroxyhexanoate] (PHBHx) by Streptomyces sp. BCC23167 progressed from surface to bulk as suggested by the slight decrease in polymer molecular weight. Differential scanning calorimetry analysis of PHBHx film degradation by Streptomyces sp. BCC23167 showed that relative crystallinity of the film increased slightly in the early stage of degradation, followed by a marked decrease later on. The surface morphology of degraded films was analyzed by scanning electron microscopy, which showed altered surface structure consistent with the changes in crystallinity. The isolate is thus of potential for application in composting technology for bio-plastic degradation.

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Isolation of a Gram-positive poly(3-hydroxybutyrate) (PHB)-degrading bacterium from compost, and cloning and characterization of a gene encoding PHB depolymerase ofBacillus megateriumN-18-25-9

Cited by 40 publications

References 19 publications

Identification and Characterization of a Novel Class of Extracellular Poly(3-Hydroxybutyrate) Depolymerase from Bacillus sp. Strain NRRL B-14911

Identification and Characterization of a Novel Class of Extracellular Poly(3-Hydroxybutyrate) Depolymerase from Bacillus sp. Strain NRRL B-14911

Poly-𝛽-hydroxy butyrate Depolymerase from Streptomyces lydicus MM10, Isolated from Wastewater Sample

Microbial degradation and physico-chemical alteration of polyhydroxyalkanoates by a thermophilic Streptomyces sp.

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