scholarly journals Production, purification, and kinetics of the poly-β-hydroxybutyrate depolymerase from Microbacterium paraoxydans RZS6: A novel biopolymer-degrading organism isolated from a dumping yard

2019 ◽  
Author(s):  
RZ Sayyed ◽  
SJ Wani ◽  
Abdullah A. Alyousef ◽  
Abdulaziz Alqasim ◽  
Asad Syed

AbstractPoly-β-hydroxybutyrate (PHB) depolymerase can decompose biodegradable polymers and therefore has great commercial significance in the bioplastic sector. However, few reports have described PHB depolymerases based on isolates obtained from plastic-contaminated sites that reflect the potential of the source organism. In this study, we evaluated Microbacterium paraoxydans RZS6 as a producer of extracellular PHB depolymerase isolated from a plastic-contaminated site in the municipal area of Shahada, Maharashtra, India, for the first time. The isolate was identified using the polyphasic approach, i.e., 16S rRNA gene sequencing, gas chromatographic analysis of fatty acid methyl esters, and BIOLOG identification, and was found to hydrolyze PHB on minimal salt medium containing PHB as the only source of carbon. Both isolates produced PHB depolymerase at 30°C within 2 days and at 45°C within 4 days. The enzyme was purified most efficiently using an octyl-sepharose CL-4B column, with the highest purification yield of 6.675 U/mg/mL. The enzyme required Ce2+ and Mg2+ ions but was inhibited by Fe2+ ions and mercaptoethanol. Moreover, enzyme kinetic analysis revealed that the enzyme was a metalloenzyme requiring Mg2+ ions, with optimum enzyme activity at 45°C (thermophilic) and under neutrophilic conditions (optimum pH = 7). The presence of Fe2+ ions (1 mM) and mercaptoethanol (1000 ppm) completely inhibited the enzyme activity. The molecular weight of the enzyme (40 kDa), as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, closely resembled that of PHB depolymerase from Aureobacterium saperdae. Scale-up from the shake-flask level to a laboratory-scale bioreactor further enhanced the enzyme yield. Our findings highlighted the applicability of M. paraoxydans as a producer of extracellular PHB depolymerase isolated from a plastic-contaminated site in the municipal area of Shahada, Maharashtra, India.

Biologia ◽  
2014 ◽  
Vol 69 (4) ◽  
Author(s):  
Fatma Matpan Bekler ◽  
Kemal Güven

AbstractA novel amylolytic enzyme producing thermophilic bacterial strain KP1 from the Diyadin hot spring water in Ağri, Turkey, was isolated in the present study. Phylogenetic analysis based on the partial 16S rRNA gene, biochemical and physiological tests revealed that the strain KP1 belongs to the genus Anoxybacillus. The pH and temperature optima for the α-amylase production by Anoxybacillus sp. KP1 were 8.0 and 50°C, respectively, where the maximum growth was obtained at the 28th hour of incubation and the highest α-amylase activity was obtained at the 40th hour of incubation (8979.6 U/mL). The optimum pH and temperature for the enzyme activity were 8.0 and 60°C, respectively. The maximum α-amylase production was secreted in the presence of 2% (w/v) soluble starch (10837.7 U/mL). Among the various organic and inorganic nitrogen sources tested, while keeping the beef extract concentration constant, casamino acid (14310.6 U/mL), urea (14126 U/mL), and tryptone (13217.2 U/mL) at a concentration of 2% gave the maximum α-amylase production. The enzyme activity was enhanced in the presence of 1.5 mM Mn2+ (123%), whereas it was strongly inhibited 1.5 mM by Hg2+. Inhibition by 89% was obtained also with sodium dodecyl sulphate (1%). The enzyme was found to be relatively stable at a range of pH and temperature.


1979 ◽  
Vol 177 (1) ◽  
pp. 49-62 ◽  
Author(s):  
C M Clarke ◽  
B S Hartley

The restriction endonuclease BstI was purified from 70kg of Bacillus stearothermophilus. The final product is at least 97% pure as judged by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis; this major protein species co-migrates with the enzyme activity on native polyacrylamide-gel electrophoresis and isoelectric focusing. Pure restriction endonuclease BstI has a subunit mol.wt. of 26,000 and is probably a loosely associated dimer. The enzyme shows maximum activity at pH values between 7 and 9.5, and in the presence of 0.5-2mM-Mg2+. NaCl inhibits the restriction enzyme activity. Restriction endonuclease BstI cleaves DNA in a position identical with that cleaved by endonuclease BamHI (for Bacillus amyloliquefaciens), i.e.: (formula: see text). In the presence of high concentrations of enzyme, DNA cleavage occurs at secondary sites. This side-specificity is enhanced by the addition of glycerol. Preliminary studies indicate that these sites are of the type: (formula: see text).


1985 ◽  
Vol 31 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Resham S. Bhella ◽  
Illimar Altosaar

Alpha-amylase was purified from the extracellular culture medium of Aspergillus awamori by means of ethanol precipitation. Sephacryl-200 gel filtration and anion-exchange chromatography on Dowex (AG1-X4) resin. The enzyme preparation was found to be homogeneous by means of sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The purified enzyme had a molecular weight of 54 000 ± 2 500 and its isoelectric point was pH 4.2. The enzyme was found to be most active between pH 4.8 and 5.0 and was stable between pH 3.5 and 6.5. The optimal temperature for the enzyme activity was around 50 °C and the enzyme was stable for at least 1 h up to 45 °C retaining more than 80% of its original activity. The Km (37 °C, pH 5.3) for starch hydrolysis was 1.0 g∙L−1 and maltose inhibited the enzyme activity uncompetitively with a K1 value of 20.05 g∙L−1


2009 ◽  
Vol 79 (3) ◽  
pp. 188-194 ◽  
Author(s):  
Melda Sisecioglu ◽  
Murat Cankaya ◽  
Hasan Ozdemir

Objective: The present paper investigates the in vitro effect of L-ascorbic acid (vitamin C), menadione sodium bisulfate (vitamin K3), and folic acid on purified lactoperoxidase (LPO). Methods: This enzyme was purified from bovine milk by Amberlite CG 50 resin, CM Sephadex C-50 ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography. Results: Rz (A412/A280) value for the purified LPO was found to be 0.8. Lactoperoxidase was purified 20.45-fold with a yield of 28.8 %. Purity of enzyme was checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method and a single band was observed. All tested vitamins caused inhibition of the enzyme activity and displayed a competitive type of inhibition mechanism. IC50 values of these three vitamins were 2.03 µM, 0.025 mM, and 0.0925 mM, and the Ki constants were 0.508±0.257 µM, 0.0107±0.0044 mM, and 0.0218±0.0019 mM respectively. Conclusion: The vitamins discussed here displayed inhibition-type competition with LPO enzyme at varying concentrations. Our study showed that L-ascorbic acid exhibited a much higher inhibitory effect at lower concentrations, so it was evidently a more potent inhibitor than other vitamins tested.


2003 ◽  
Vol 69 (2) ◽  
pp. 980-986 ◽  
Author(s):  
Dae Heoun Baek ◽  
Seok-Joon Kwon ◽  
Seung-Pyo Hong ◽  
Mi-Sun Kwak ◽  
Mi-Hwa Lee ◽  
...  

ABSTRACT A gene encoding a new thermostable d-stereospecific alanine amidase from the thermophile Brevibacillus borstelensis BCS-1 was cloned and sequenced. The molecular mass of the purified enzyme was estimated to be 199 kDa after gel filtration chromatography and about 30 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that the enzyme could be composed of a hexamer with identical subunits. The purified enzyme exhibited strong amidase activity towards d-amino acid-containing aromatic, aliphatic, and branched amino acid amides yet exhibited no enzyme activity towards l-amino acid amides, d-amino acid-containing peptides, and NH2-terminally protected amino acid amides. The optimum temperature and pH for the enzyme activity were 85°C and 9.0, respectively. The enzyme remained stable within a broad pH range from 7.0 to 10.0. The enzyme was inhibited by dithiothreitol, 2-mercaptoethanol, and EDTA yet was strongly activated by Co2+ and Mn2+. The k cat/Km for d-alaninamide was measured as 544.4 ± 5.5 mM−1 min−1 at 50°C with 1 mM Co2+.


Author(s):  
Abimbola Olajide ◽  
Felicia C. Adesina ◽  
Abiodun A. Onilude

Aim: The study aimed at producing and purifying thermostable and alkalitolerant microbial arabinofuranosidase using local Palm Kernel Cake (PKC) as substrate. Study Design: This is an experimental design in which samples were collected thrice and  subjected to laboratory analyses from which quantitative data were obtained and analysed. Place and Duration of Study: Ibadan, Nigeria, Five months. Methodology: Bacterial strains were isolated from degrading PKC by serial dilution and pour plate technique on formulated Modified Basal Salt Agar Medium and incubated at 50°C for enzyme activity screening. Plates were afterwards flooded with 1% congo red solution for visualization of hydrolysis zone. Its arabinofuranosidase activity was optimized in solid state fermentation in PKC. Production temperature, pH, moisture content, inoculum size and agitation were studied for optimization test. Optimal production temperature and pH for arabinofuranosidase by isolate was 45°C and pH 9. Produced arabinofuranosidase was purified to apparent homogeneity with ammonium sulphate precipitation, dialysis and column chromatography techniques. Stability of arabinofuranofuranosidase obtained to temperature, pH, substrate concentration and some ions was determined as well as its molecular weight using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Results: Isolate with highest arabinofuranosidase activity was selected and identified as Streptomyces lividus. Purity level attained was 16.36 fold. Enzyme had a specific activity of 25.4 U/mg, and total enzyme activity of 13.2 U.  Molecular weight of enzyme appeared as a band of 30 kDa. Purified arabinofuranosidase enzyme revealed optimum temperature and pH as 60oC and 9 respectively. Enzyme was stable over a broad pH range of 3-11, and temperature of 30-80oC. Residual activity after incubating for 1 hour at 70oC was 64%. Enzyme kinetics studies showed Km and Vmax values for P-nitrophenyl arabinofuranoside were 2.3mM and 0.7U/min respectively. Conclusion: Apart from Solid State Fermentation (SSF) of PKC being a potential fermentation technique for production of arabinofuranosidase by Streptomyces lividus, the enzyme was highly stable.


1982 ◽  
Vol 2 (11) ◽  
pp. 1346-1353
Author(s):  
M Debatisse ◽  
M Berry ◽  
G Buttin

Addition of coformycin (0.5 microgram/ml) to a culture medium containing adenine causes in Chinese hamster fibroblasts a lethal depletion of IMP. Resistant variants have been recovered, some of which exhibit increased adenylate deaminase activity. (Debatisse et al., J. Cell. Physiol., 106:1-11, 1981). The selective medium was made more specific for the isolation of this class of variants by supplementation with azaserine. The hyperactive variants remained sensitive to coformycin concentrations above that used for their selection and were unstable. Their frequency was not increased by ethyl methane sulfonate mutagenesis. The resistant phenotype and the increased activity of adenylate deaminase behaved as semidominant traits in hybrids. No change was detected in the Km for AMP, the cofactor requirement, or the chromatographic properties of adenylate deaminase in the variants. Through stepwise selection in media supplemented with increasing coformycin concentrations, unstable clones with adenylate deaminase activity up to 150-fold the wild-type level were isolated; from an unstable clone, a stable subclone with reduced resistance and enzyme activity was recovered. Evidence that increased adenylate deaminase activity is the manifestation of overaccumulation of the enzyme protein was supplied by the correlation of enzyme activity with the intensity of a protein band comigrating with purified adenylate deaminase during sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cell extracts. Several unidentified additional bands showed comparable quantitative changes. The striking similarity between the adenylate deaminase-overproducing lines and unstable dihydrofolate reductase-overproducing lines generated by gene amplification strongly suggests that the coformycin-resistant variants also resulted from amplification of an adenylate deaminase gene.


1999 ◽  
Vol 65 (5) ◽  
pp. 1991-1997 ◽  
Author(s):  
Yoshihisa Tachibana ◽  
Akiko Kuramura ◽  
Naoki Shirasaka ◽  
Yuji Suzuki ◽  
Tomoko Yamamoto ◽  
...  

ABSTRACT The extremely thermophilic anaerobic archaeon strain B1001 was isolated from a hot-spring environment in Japan. The cells were irregular cocci, 0.5 to 1.0 μm in diameter. The new isolate grew at temperatures between 60 and 95°C (optimum, 85°C), from pH 5.0 to 9.0 (optimum, pH 7.0), and from 1.0 to 6.0% NaCl (optimum, 2.0%). The G+C content of the genomic DNA was 43.0 mol%. The 16S rRNA gene sequencing of strain B1001 indicated that it belongs to the genusThermococcus. During growth on starch, the strain produced a thermostable cyclomaltodextrin glucanotransferase (CGTase). The enzyme was purified 1,750-fold, and the molecular mass was determined to be 83 kDa by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Incubation at 120°C with SDS and 2-mercaptoethanol was required for complete unfolding. The optimum temperatures for starch-degrading activity and cyclodextrin synthesis activity were 110 and 90 to 100°C, respectively. The optimum pH for enzyme activity was pH 5.0 to 5.5. At pH 5.0, the half-life of the enzyme was 40 min at 110°C. The enzyme formed mainly α-cyclodextrin with small amounts of β- and γ-cyclodextrins from starch. This is the first report on the presence of the extremely thermostable CGTase from hyperthermophilic archaea.


1977 ◽  
Vol 165 (3) ◽  
pp. 511-518 ◽  
Author(s):  
O G Issinger

A casein kinase was isolated and purifed from rabbit reticulocytes. About 90% of the enzyme activity co-sedimented with the ribosomal fraction, whereas about 10% of the enzyme activity was found in the ribosome-free supernatant. Both casein kinases (the ribosome-bound enzyme as well as the free enzyme) showed identical activity and the same molecular weight. On sodium dodecyl sulphate/polyacrylamide-gel electrophoresis a single band of about 70 000 mol.wt. was observed. Sucrose-gradient analysis, however, showed that the enzyme activity sedimented with a s20,w of approx. 7.5S. This observation suggested that the casein kinase is a dimer composed of subunits of identical molecular weight. The enzyme utilizes GTP as well as ATP as a phosphoryl donor. It preferentially phosphorylates acidic proteins, in particular the model substrates casein and phosvitin. Casein kinase is cyclic AMP-indepenoent. The Km values for ATP and GTP with phosvitin as a substrate were determined as 1.2 and 8.8 micrometer respectively.


1977 ◽  
Vol 161 (1) ◽  
pp. 167-174 ◽  
Author(s):  
R G Dennick ◽  
R J Mayer

1. Monoamine oxidase from rat and human liver was purified to homogeneity by the criterion of polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. 2. The enzyme activity was extracted from mitochondrial preparations by Triton X-100. The enzyme was purified by (NH4)2SO4 fractionation followed by chromatography on DEAE-cellulose, Sepharose 6B, spheroidal hydroxyapatite, and finally chromatography on diazo-coupled tyramine-Sepharose. 3. Distinct differences occur in the chromatographic behaviour of the two enzymes on both DEAE-cellulose and spheroidal hydroxyapatite. 4. It is unlikely that the purification of the enzymes on tyramine-Sepharose is due to affinity chromatography and reasons for this are discussed. 5. The purified enzymes did not oxidize-5-hydroxytryptamine and the relative activities of the enzymes with benzylamine were increased approx. 1.25-fold compared with the enzyme activities of mitochondrial preparations. 6. Immunotitration of enzyme activity in extracts of mitochondrial preparations from rat liver was carried out with 5-hydroxytryptamine, tyramine and benzylamine. The enzyme activities were completely immunoprecipitated by the same volume of antiserum. Similar results were obtained with the antiserum to the enzyme from human liver.


Sign in / Sign up

Export Citation Format

Share Document