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Krishanu Chakrabarti - One of the best experts on this subject based on the ideXlab platform.
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arg 235 is an essential catalytic residue of bacillus pumilus dks1 pectate lyase to degum Ramie Fibre
Biodegradation, 2011Co-Authors: Snehasish Basu, Dhrubajyoti Chattopadhyay, Abhrajyoti Ghosh, Amit Bera, Arunava Roy, Krishanu ChakrabartiAbstract:After 24 h of incubation with only purified pectate lyase isolated from Bacillus pumilus DKS1 (EF467045), the weight loss of the Ramie Fibre was found to be 25%. To know the catalytic residue of pectate lyase the pel gene encoding a pectate lyase from the strain Bacillus pumilus DKS1 was cloned in E. coli XL1Blue and expressed in E. coli BL21 (DE3) pLysS. The pel gene was sequenced and showed 1032 bp length. After purification using CM-Sepharose the enzyme showed molecular weight of 35 kDa and maximal enzymatic activity was observed at 60°C and a pH range of 8.5–9.0. Both Ca2+ and Mn2+ ions were required for activity on Na-pectate salt substrates, while the enzyme was strongly inhibited by Zn2+ and EDTA. The deduced nucleotide sequence of the DKS1 pectate lyase (EU652988) showed 90% homology to pectate lyases from Bacillus pumilus SAFR-032 (CP000813). The 3D structure as well as the catalytic residues was predicted using EasyPred software and Catalytic Site Atlas (CSA), respectively. Site directed mutagenesis confirmed that arginine is an essential catalytic residue of DKS1 pectate lyase.
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degumming and characterization of Ramie Fibre using pectate lyase from immobilized bacillus pumilus dks1
Letters in Applied Microbiology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:Aims: The present study was aimed at finding the optimal conditions for the production of pectate lyase using immobilized Bacillus pumilus DKS1 cells in calcium-alginate (Ca-alginate) beads and determining the efficient degumming of Ramie Fibre. Methods and Results: The active cells of B. pumilus DKS1 were immobilized in Ca-alginate and used for the production of pectate lyase. The production of enzyme increased significantly with increasing alginate concentration and reached a maximum enzyme yield of 38AE 5Um l )1 at 18 g l )1 . This was about 1AE5-fold higher than that obtained by free cells. Degummed Fibre using immobilized cells showed better tenacity than that prepared by using nonimmobilized cells. Conclusions: The Ca-alginate entrapment is a promising immobilization method of B. pumilus DKS1 for semicontinuous enzyme production. Enzyme production by immobilized cells is superior to that of free cells because it leads to higher volumetric activities within the same period of fermentation. Fibre degumming by using immobilized cells produced better quality Fibre. Significance and Impact of the Study: This is the first report of degumming of Fibre using enzyme from immobilized B. pumilus cells as per our knowledge. High-quality degummed Fibre could be prepared with relatively inexpensive inputs for use in the textile and paper industry.
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large scale degumming of Ramie Fibre using a newly isolated bacillus pumilus dks1 with high pectate lyase activity
Journal of Industrial Microbiology & Biotechnology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:A combined (enzymatic and chemical) process using a Bacillus pumilus strain (DKS1), isolated from the soil, was used to degum Ramie bast Fibres. After 24 h of incubation with the isolated pectinolytic strain using a low-cost medium, the weight loss of the Ramie Fibre was found to be 25% under small scale. High activity of pectate lyase was detected in the culture supernatants; 400 kg of Ramie Fibres was degummed with 24% weight loss in large-scale degumming under field conditions. No cellulase activity was found. Microbial intervention followed by mild (0.1%) alkali treatment showed high percentage of weight loss from the Ramie Fibre. Bacterial degumming followed by chemical treatment resulted in an increase of single Fibre tenacity (cN/tex) by more than 20.81% as compared to non-degummed (decorticated) Fibre samples. Scanning electron micrographs (SEM) and fluorescence microscope showed that after Bacillus pumilus DKS1 treatment the surface of the decorticated Ramie Fibre becomes very smooth. These results indicate the process provides an economical and eco-friendly method for the small scale as well as large-scale degumming of decorticated Ramie Fibre. This study has great relevance to the textile as well as paper industry.
Snehasish Basu - One of the best experts on this subject based on the ideXlab platform.
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arg 235 is an essential catalytic residue of bacillus pumilus dks1 pectate lyase to degum Ramie Fibre
Biodegradation, 2011Co-Authors: Snehasish Basu, Dhrubajyoti Chattopadhyay, Abhrajyoti Ghosh, Amit Bera, Arunava Roy, Krishanu ChakrabartiAbstract:After 24 h of incubation with only purified pectate lyase isolated from Bacillus pumilus DKS1 (EF467045), the weight loss of the Ramie Fibre was found to be 25%. To know the catalytic residue of pectate lyase the pel gene encoding a pectate lyase from the strain Bacillus pumilus DKS1 was cloned in E. coli XL1Blue and expressed in E. coli BL21 (DE3) pLysS. The pel gene was sequenced and showed 1032 bp length. After purification using CM-Sepharose the enzyme showed molecular weight of 35 kDa and maximal enzymatic activity was observed at 60°C and a pH range of 8.5–9.0. Both Ca2+ and Mn2+ ions were required for activity on Na-pectate salt substrates, while the enzyme was strongly inhibited by Zn2+ and EDTA. The deduced nucleotide sequence of the DKS1 pectate lyase (EU652988) showed 90% homology to pectate lyases from Bacillus pumilus SAFR-032 (CP000813). The 3D structure as well as the catalytic residues was predicted using EasyPred software and Catalytic Site Atlas (CSA), respectively. Site directed mutagenesis confirmed that arginine is an essential catalytic residue of DKS1 pectate lyase.
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degumming and characterization of Ramie Fibre using pectate lyase from immobilized bacillus pumilus dks1
Letters in Applied Microbiology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:Aims: The present study was aimed at finding the optimal conditions for the production of pectate lyase using immobilized Bacillus pumilus DKS1 cells in calcium-alginate (Ca-alginate) beads and determining the efficient degumming of Ramie Fibre. Methods and Results: The active cells of B. pumilus DKS1 were immobilized in Ca-alginate and used for the production of pectate lyase. The production of enzyme increased significantly with increasing alginate concentration and reached a maximum enzyme yield of 38AE 5Um l )1 at 18 g l )1 . This was about 1AE5-fold higher than that obtained by free cells. Degummed Fibre using immobilized cells showed better tenacity than that prepared by using nonimmobilized cells. Conclusions: The Ca-alginate entrapment is a promising immobilization method of B. pumilus DKS1 for semicontinuous enzyme production. Enzyme production by immobilized cells is superior to that of free cells because it leads to higher volumetric activities within the same period of fermentation. Fibre degumming by using immobilized cells produced better quality Fibre. Significance and Impact of the Study: This is the first report of degumming of Fibre using enzyme from immobilized B. pumilus cells as per our knowledge. High-quality degummed Fibre could be prepared with relatively inexpensive inputs for use in the textile and paper industry.
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large scale degumming of Ramie Fibre using a newly isolated bacillus pumilus dks1 with high pectate lyase activity
Journal of Industrial Microbiology & Biotechnology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:A combined (enzymatic and chemical) process using a Bacillus pumilus strain (DKS1), isolated from the soil, was used to degum Ramie bast Fibres. After 24 h of incubation with the isolated pectinolytic strain using a low-cost medium, the weight loss of the Ramie Fibre was found to be 25% under small scale. High activity of pectate lyase was detected in the culture supernatants; 400 kg of Ramie Fibres was degummed with 24% weight loss in large-scale degumming under field conditions. No cellulase activity was found. Microbial intervention followed by mild (0.1%) alkali treatment showed high percentage of weight loss from the Ramie Fibre. Bacterial degumming followed by chemical treatment resulted in an increase of single Fibre tenacity (cN/tex) by more than 20.81% as compared to non-degummed (decorticated) Fibre samples. Scanning electron micrographs (SEM) and fluorescence microscope showed that after Bacillus pumilus DKS1 treatment the surface of the decorticated Ramie Fibre becomes very smooth. These results indicate the process provides an economical and eco-friendly method for the small scale as well as large-scale degumming of decorticated Ramie Fibre. This study has great relevance to the textile as well as paper industry.
Dhrubajyoti Chattopadhyay - One of the best experts on this subject based on the ideXlab platform.
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arg 235 is an essential catalytic residue of bacillus pumilus dks1 pectate lyase to degum Ramie Fibre
Biodegradation, 2011Co-Authors: Snehasish Basu, Dhrubajyoti Chattopadhyay, Abhrajyoti Ghosh, Amit Bera, Arunava Roy, Krishanu ChakrabartiAbstract:After 24 h of incubation with only purified pectate lyase isolated from Bacillus pumilus DKS1 (EF467045), the weight loss of the Ramie Fibre was found to be 25%. To know the catalytic residue of pectate lyase the pel gene encoding a pectate lyase from the strain Bacillus pumilus DKS1 was cloned in E. coli XL1Blue and expressed in E. coli BL21 (DE3) pLysS. The pel gene was sequenced and showed 1032 bp length. After purification using CM-Sepharose the enzyme showed molecular weight of 35 kDa and maximal enzymatic activity was observed at 60°C and a pH range of 8.5–9.0. Both Ca2+ and Mn2+ ions were required for activity on Na-pectate salt substrates, while the enzyme was strongly inhibited by Zn2+ and EDTA. The deduced nucleotide sequence of the DKS1 pectate lyase (EU652988) showed 90% homology to pectate lyases from Bacillus pumilus SAFR-032 (CP000813). The 3D structure as well as the catalytic residues was predicted using EasyPred software and Catalytic Site Atlas (CSA), respectively. Site directed mutagenesis confirmed that arginine is an essential catalytic residue of DKS1 pectate lyase.
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degumming and characterization of Ramie Fibre using pectate lyase from immobilized bacillus pumilus dks1
Letters in Applied Microbiology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:Aims: The present study was aimed at finding the optimal conditions for the production of pectate lyase using immobilized Bacillus pumilus DKS1 cells in calcium-alginate (Ca-alginate) beads and determining the efficient degumming of Ramie Fibre. Methods and Results: The active cells of B. pumilus DKS1 were immobilized in Ca-alginate and used for the production of pectate lyase. The production of enzyme increased significantly with increasing alginate concentration and reached a maximum enzyme yield of 38AE 5Um l )1 at 18 g l )1 . This was about 1AE5-fold higher than that obtained by free cells. Degummed Fibre using immobilized cells showed better tenacity than that prepared by using nonimmobilized cells. Conclusions: The Ca-alginate entrapment is a promising immobilization method of B. pumilus DKS1 for semicontinuous enzyme production. Enzyme production by immobilized cells is superior to that of free cells because it leads to higher volumetric activities within the same period of fermentation. Fibre degumming by using immobilized cells produced better quality Fibre. Significance and Impact of the Study: This is the first report of degumming of Fibre using enzyme from immobilized B. pumilus cells as per our knowledge. High-quality degummed Fibre could be prepared with relatively inexpensive inputs for use in the textile and paper industry.
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large scale degumming of Ramie Fibre using a newly isolated bacillus pumilus dks1 with high pectate lyase activity
Journal of Industrial Microbiology & Biotechnology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:A combined (enzymatic and chemical) process using a Bacillus pumilus strain (DKS1), isolated from the soil, was used to degum Ramie bast Fibres. After 24 h of incubation with the isolated pectinolytic strain using a low-cost medium, the weight loss of the Ramie Fibre was found to be 25% under small scale. High activity of pectate lyase was detected in the culture supernatants; 400 kg of Ramie Fibres was degummed with 24% weight loss in large-scale degumming under field conditions. No cellulase activity was found. Microbial intervention followed by mild (0.1%) alkali treatment showed high percentage of weight loss from the Ramie Fibre. Bacterial degumming followed by chemical treatment resulted in an increase of single Fibre tenacity (cN/tex) by more than 20.81% as compared to non-degummed (decorticated) Fibre samples. Scanning electron micrographs (SEM) and fluorescence microscope showed that after Bacillus pumilus DKS1 treatment the surface of the decorticated Ramie Fibre becomes very smooth. These results indicate the process provides an economical and eco-friendly method for the small scale as well as large-scale degumming of decorticated Ramie Fibre. This study has great relevance to the textile as well as paper industry.
Manabendra N Saha - One of the best experts on this subject based on the ideXlab platform.
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degumming and characterization of Ramie Fibre using pectate lyase from immobilized bacillus pumilus dks1
Letters in Applied Microbiology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:Aims: The present study was aimed at finding the optimal conditions for the production of pectate lyase using immobilized Bacillus pumilus DKS1 cells in calcium-alginate (Ca-alginate) beads and determining the efficient degumming of Ramie Fibre. Methods and Results: The active cells of B. pumilus DKS1 were immobilized in Ca-alginate and used for the production of pectate lyase. The production of enzyme increased significantly with increasing alginate concentration and reached a maximum enzyme yield of 38AE 5Um l )1 at 18 g l )1 . This was about 1AE5-fold higher than that obtained by free cells. Degummed Fibre using immobilized cells showed better tenacity than that prepared by using nonimmobilized cells. Conclusions: The Ca-alginate entrapment is a promising immobilization method of B. pumilus DKS1 for semicontinuous enzyme production. Enzyme production by immobilized cells is superior to that of free cells because it leads to higher volumetric activities within the same period of fermentation. Fibre degumming by using immobilized cells produced better quality Fibre. Significance and Impact of the Study: This is the first report of degumming of Fibre using enzyme from immobilized B. pumilus cells as per our knowledge. High-quality degummed Fibre could be prepared with relatively inexpensive inputs for use in the textile and paper industry.
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large scale degumming of Ramie Fibre using a newly isolated bacillus pumilus dks1 with high pectate lyase activity
Journal of Industrial Microbiology & Biotechnology, 2009Co-Authors: Snehasish Basu, Manabendra N Saha, Dhrubajyoti Chattopadhyay, Krishanu ChakrabartiAbstract:A combined (enzymatic and chemical) process using a Bacillus pumilus strain (DKS1), isolated from the soil, was used to degum Ramie bast Fibres. After 24 h of incubation with the isolated pectinolytic strain using a low-cost medium, the weight loss of the Ramie Fibre was found to be 25% under small scale. High activity of pectate lyase was detected in the culture supernatants; 400 kg of Ramie Fibres was degummed with 24% weight loss in large-scale degumming under field conditions. No cellulase activity was found. Microbial intervention followed by mild (0.1%) alkali treatment showed high percentage of weight loss from the Ramie Fibre. Bacterial degumming followed by chemical treatment resulted in an increase of single Fibre tenacity (cN/tex) by more than 20.81% as compared to non-degummed (decorticated) Fibre samples. Scanning electron micrographs (SEM) and fluorescence microscope showed that after Bacillus pumilus DKS1 treatment the surface of the decorticated Ramie Fibre becomes very smooth. These results indicate the process provides an economical and eco-friendly method for the small scale as well as large-scale degumming of decorticated Ramie Fibre. This study has great relevance to the textile as well as paper industry.
C. Bozzi - One of the best experts on this subject based on the ideXlab platform.
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Ramie (Boehmeria nivea (L.) Gaud.) and Spanish Broom (Spartium junceum L.) Fibres for composite materials: agronomical aspects, morphology and mechanical properties
Industrial Crops and Products, 2000Co-Authors: Luciana Gabriella Angelini, Andrea Lazzeri, Giovanni Levita, D. Fontanelli, C. BozziAbstract:The agronomic characteristics of Ramie and Spanish Broom were investigated for seven years in the pedoclimatic conditions of Central Italy. The chemical, physical and mechanical properties of these Fibres were also examined in order to evaluate the feasibility to use them in composite materials. Results demonstrate that Ramie grown in the temperate environment can be harvested three times a year. The yield of green Ramie plants per annum was almost 10 000 g m−2. The fresh Ramie plant is composed, by weight, of 30% green leaves and 70% green stems. The yield dry Fibre is almost 3% of the green stems, giving a total yield of 200 g m−2. Spanish Broom can reach a fresh biomass yield of 4000 g m−2 per annum, represented by 53% of long slender terete green branches which constitutes the economic products. The dry yield per annum was about 1800 g m−2 with a dry branchlets yield of 900 g m−2. Ramie and Spanish Broom cortical Fibres are multiple elementary Fibres (ultimates) arranged in bundles. In Ramie, the elementary Fibres are bound by gums and pectins, while in Spanish Broom they are bound together by lignin. Both species showed a thick secondary cell wall indicating a high cellulose content. Ramie ultimate Fibres are flattened and irregular in shape, while those of Spanish Broom are more regular in shape. The diameter of the ultimates varies from 10 to 25 μm in Ramie, while the Spanish Broom ultimates ranges from 5 to 10 μm; the diameter of the whole bundle is about 50 μm for both species. Ramie Fibre showed a content of lignin, pentosans and extractives lower than Spanish Broom. Both Fibres had a high content of cellulose which, on the base of X-ray analysis, was evaluated to be in excess of 70%. Ramie and Spanish Broom Fibres had tensile strength of 950 MPa and 700 MPa, respectively. The elastic moduli were ≈65 and ≈20 GPa, respectively, which well compare with the modulus of E-glass Fibres (70–90 GPa). The strength of the Fibre-matrix interface was measured using the single filament fragmentation technique and an epoxy resin as the polymer matrix. Values for carbon and glass Fibres in the same resin were also measured for comparison. The interface strength for the vegetable Fibres was higher than that of carbon and glass, likely due to a mechanical lock mechanism. These values confirm both Fibres as potential replacement for man made Fibres in composite materials.