Proteins secreted by the white-rot, softwood-degrading fungus Phanerochaete carnosa during growth... more Proteins secreted by the white-rot, softwood-degrading fungus Phanerochaete carnosa during growth on cellulose and spruce were analyzed using tandem mass spectrometry and de novo sequencing. Homology-driven proteomics was applied to compare P. carnosa peptide sequences to proteins in Phanerochaete chrysosporium using MS BLAST and non-gapped alignment. In this way, 665 and 365 peptides from cellulose and spruce cultivations, respectively, were annotated. Predicted activities included endoglucanases from glycoside hydrolase (GH) families 5, 16, and 61, cellobiohydrolases from GH6 and GH7, GH3 β-glucosidases, xylanases from GH10 and GH11, GH2 β-mannosidases, and debranching hemicellulases from GH43 and CE15. Peptides corresponding to glyoxal oxidases, peroxidases, and glycopeptides that could participate in lignin degradation were also detected. Overall, predicted activities detected in extracellular filtrates of cellulose and spruce cultures were similar, suggesting that the adaptation of P. carnosa to growth on lignocellulose might result from fine tuning the expression of similar enzyme families.
Biochemical studies to elucidate the structural basis for xyloglucan specificity among GH12 xylog... more Biochemical studies to elucidate the structural basis for xyloglucan specificity among GH12 xyloglucanases are lacking. Accordingly, the substrate specificity of a GH12 xyloglucanase from Aspergillus niger (AnXEG12A) was investigated using pea xyloglucan and 12 xylogluco-oligosaccharides, and data were compared to a structural model of the enzyme. The specific activity of AnXEG12A with pea xyloglucan was 113 lmol min À1 mg À1 , and apparent k cat and K m values were 49 s À1 and 0.54 mg mL À1 , respectively.
Journal of The American Oil Chemists Society, 2006
Commerical biodiesel is composed of FAME. It may also contain small amounts of FA, which are quan... more Commerical biodiesel is composed of FAME. It may also contain small amounts of FA, which are quantified by an acid number, expressed as milligrams of potassium hydroxide required to neutralize 1 g of sample. In 2006, the ASTM D 6751 biodiesel acid-number limit was harmonized with the European biodiesel value of 0.50. ASTM D 664 is the standard reference method for measuring the acid number of both ASTM biodiesel and petroleum-derived diesel. This potentiometric method cites acceptable repeatability and mediocre reproducibility, but no information on accuracy. ASTM D 974 is a non-aqueous colorimetric titration that uses potassium hydroxide in isopropanol as the titrant and p-naphtholbenzein as indicator. It was designed for petroleum products and is suitable for colored samples. It has been tested on nine palmitic acid/soybean oil standards in the acid-number range of 0.198 to 1.17. All accuracies were within 3.3%. The repeatability was approximately 6% at an acid number of 0.5. The reproducibility appears to be only slightly greater than the repeatability at an acid number of 0.5. It is concluded that ASTM D 974 is a good method for evaluating the acid-number compliance of biodiesel samples.
Journal of The American Oil Chemists Society, 2007
Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic... more Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. The oils must be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and European biodiesel standards. It is also believed that sodium hydroxide can never be used as the catalyst because it causes soap formation, which either lowers the yield or raises the acid number and makes product isolation difficult. Methods for producing standard biodiesel from low-acid-number soybean oil, in one chemical reaction using sodium hydroxide and a cosolvent, were recently reported. This study reports the effects of variables on the acid numbers and chemically bound glycerol contents of the products which led to the methods. These variables were the molar ratio of alcohol to oil, catalyst concentration, cosolvent volume, and reaction time. The alcohol-to-oil molar ratio must be at least 14, and the sodium hydroxide concentration should be at least 1.2 wt% (based on oil), to meet the necessary acid number and glycerol contents of the biodiesel. The volume of tetrahydrofuran cosolvent used must be 90–130% of that required to just create complete miscibility at the beginning of the reactions.
Journal of The American Oil Chemists Society, 2006
Laboratory methods are described for producing standard biodiesel from low-acid-number vegetable ... more Laboratory methods are described for producing standard biodiesel from low-acid-number vegetable oils in single-step reactions without distillation of the products. Either sodium hydroxide or methoxide is used as the catalyst. Biodiesel fuel is currently made from vegetable oils using basic catalysts. With this methodology, the oils must be reacted two or three times with methanol, in the presence of sodium methoxide, to make a product that meets the standard for the total chemically bound and unbound glycerol content. Previously it was thought that sodium hydroxide could never be used as the catalyst because it forms soap with the ester, which lowers the yield and makes product isolation difficult. Two of the described methods use sodium hydroxide as the catalyst and the other uses sodium methoxide. These methods rely on the use of oxolane as co-solvent to manipulate phase behavior during the reaction. Reactant molar ratios and base concentrations are also optimized to drive the reactions to the necessary degree of completion.
Proteins secreted by the white-rot, softwood-degrading fungus Phanerochaete carnosa during growth... more Proteins secreted by the white-rot, softwood-degrading fungus Phanerochaete carnosa during growth on cellulose and spruce were analyzed using tandem mass spectrometry and de novo sequencing. Homology-driven proteomics was applied to compare P. carnosa peptide sequences to proteins in Phanerochaete chrysosporium using MS BLAST and non-gapped alignment. In this way, 665 and 365 peptides from cellulose and spruce cultivations, respectively, were annotated. Predicted activities included endoglucanases from glycoside hydrolase (GH) families 5, 16, and 61, cellobiohydrolases from GH6 and GH7, GH3 β-glucosidases, xylanases from GH10 and GH11, GH2 β-mannosidases, and debranching hemicellulases from GH43 and CE15. Peptides corresponding to glyoxal oxidases, peroxidases, and glycopeptides that could participate in lignin degradation were also detected. Overall, predicted activities detected in extracellular filtrates of cellulose and spruce cultures were similar, suggesting that the adaptation of P. carnosa to growth on lignocellulose might result from fine tuning the expression of similar enzyme families.
Biochemical studies to elucidate the structural basis for xyloglucan specificity among GH12 xylog... more Biochemical studies to elucidate the structural basis for xyloglucan specificity among GH12 xyloglucanases are lacking. Accordingly, the substrate specificity of a GH12 xyloglucanase from Aspergillus niger (AnXEG12A) was investigated using pea xyloglucan and 12 xylogluco-oligosaccharides, and data were compared to a structural model of the enzyme. The specific activity of AnXEG12A with pea xyloglucan was 113 lmol min À1 mg À1 , and apparent k cat and K m values were 49 s À1 and 0.54 mg mL À1 , respectively.
Journal of The American Oil Chemists Society, 2006
Commerical biodiesel is composed of FAME. It may also contain small amounts of FA, which are quan... more Commerical biodiesel is composed of FAME. It may also contain small amounts of FA, which are quantified by an acid number, expressed as milligrams of potassium hydroxide required to neutralize 1 g of sample. In 2006, the ASTM D 6751 biodiesel acid-number limit was harmonized with the European biodiesel value of 0.50. ASTM D 664 is the standard reference method for measuring the acid number of both ASTM biodiesel and petroleum-derived diesel. This potentiometric method cites acceptable repeatability and mediocre reproducibility, but no information on accuracy. ASTM D 974 is a non-aqueous colorimetric titration that uses potassium hydroxide in isopropanol as the titrant and p-naphtholbenzein as indicator. It was designed for petroleum products and is suitable for colored samples. It has been tested on nine palmitic acid/soybean oil standards in the acid-number range of 0.198 to 1.17. All accuracies were within 3.3%. The repeatability was approximately 6% at an acid number of 0.5. The reproducibility appears to be only slightly greater than the repeatability at an acid number of 0.5. It is concluded that ASTM D 974 is a good method for evaluating the acid-number compliance of biodiesel samples.
Journal of The American Oil Chemists Society, 2007
Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic... more Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. The oils must be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and European biodiesel standards. It is also believed that sodium hydroxide can never be used as the catalyst because it causes soap formation, which either lowers the yield or raises the acid number and makes product isolation difficult. Methods for producing standard biodiesel from low-acid-number soybean oil, in one chemical reaction using sodium hydroxide and a cosolvent, were recently reported. This study reports the effects of variables on the acid numbers and chemically bound glycerol contents of the products which led to the methods. These variables were the molar ratio of alcohol to oil, catalyst concentration, cosolvent volume, and reaction time. The alcohol-to-oil molar ratio must be at least 14, and the sodium hydroxide concentration should be at least 1.2 wt% (based on oil), to meet the necessary acid number and glycerol contents of the biodiesel. The volume of tetrahydrofuran cosolvent used must be 90–130% of that required to just create complete miscibility at the beginning of the reactions.
Journal of The American Oil Chemists Society, 2006
Laboratory methods are described for producing standard biodiesel from low-acid-number vegetable ... more Laboratory methods are described for producing standard biodiesel from low-acid-number vegetable oils in single-step reactions without distillation of the products. Either sodium hydroxide or methoxide is used as the catalyst. Biodiesel fuel is currently made from vegetable oils using basic catalysts. With this methodology, the oils must be reacted two or three times with methanol, in the presence of sodium methoxide, to make a product that meets the standard for the total chemically bound and unbound glycerol content. Previously it was thought that sodium hydroxide could never be used as the catalyst because it forms soap with the ester, which lowers the yield and makes product isolation difficult. Two of the described methods use sodium hydroxide as the catalyst and the other uses sodium methoxide. These methods rely on the use of oxolane as co-solvent to manipulate phase behavior during the reaction. Reactant molar ratios and base concentrations are also optimized to drive the reactions to the necessary degree of completion.
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