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Commercial Enzyme Preparations (commercial + enzyme_preparation)
Selected AbstractsEffect of Enzyme Treatments and Drying Temperatures on Methylpyrazine Content in Cocoa (Theobroma Cacao L.) Powder ExtractJOURNAL OF FOOD SCIENCE, Issue 9 2006Leila Moulay ABSTRACT:, The effects of combining enzyme treatments and heating protocols on pyrazine formation in cocoa powder extracts have been studied. Five commercial enzyme preparations containing protease and carbohydrase activities were initially assessed for their ability to release amino acids and reducing sugars, both of which are substrates for Maillard reactions. The enzyme preparation Flavourzyme was subsequently selected for further study given its ability to liberate both types of substrate. Cocoa powder solutions were treated with 2 doses of Flavourzyme and processed at 2 drying temperatures. The combination of the higher dose of the enzyme (12% w/w enzyme/substrate) and the higher drying temperature (150 °C) resulted in a synergistic increase in the concentration of methyl- and dimethylpyrazines. A statistically significant increase in the concentration of tetramethylpyrazine occurred in samples treated at 150 °C that was independent of the enzyme dose assayed. No significant changes in trimethylpyrazine content were detected in treated compared to untreated samples. [source] Effect of endo -xylanase-containing enzyme preparations and laccase on the solubility of rye bran arabinoxylanJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2003Roger Andersson Abstract Three commercial enzyme preparations with endo -xylanase activity, namely Bio-Feed Wheat, Bio-Feed Plus and Grindamyl H 640, and laccase have been tested for their effects on the solubilisation of arabinoxylan (AX) in rye bran or autoclaved rye bran. Autoclaving efficiently increased the availability of AX for enzymatic degradation. Both Bio-Feed Wheat (a monocomponent enzyme) and Bio-Feed Plus (a multicomponent preparation with different enzymatic activities) efficiently degraded the autoclaved rye bran AX into lower-molecular-weight fragments. As much as 70% of the xylose residues and 58% of the arabinose residues in the autoclaved bran were soluble after treatment with Bio-Feed Plus; the weight,average molecular weight of the detectable portion of these soluble polymers was 104,000,Da. Grindamyl H 640 solubilised only a small fraction of the AX in autoclaved rye bran; the molecular weight of these soluble fragments was higher than that of those released by the Bio-Feed xylanases. Addition of laccase during treatment with Bio-Feed Wheat or Grindamyl H 640 decreased the yield of water-soluble AX. © 2003 Society of Chemical Industry [source] Optimization of enzyme complexes for lignocellulose hydrolysisBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2007Alex Berlin Abstract The ability of a commercial Trichoderma reesei cellulase preparation (Celluclast 1.5L), to hydrolyze the cellulose and xylan components of pretreated corn stover (PCS) was significantly improved by supplementation with three types of crude commercial enzyme preparations nominally enriched in xylanase, pectinase, and ,-glucosidase activity. Although the well-documented relief of product inhibition by ,-glucosidase contributed to the observed improvement in cellulase performance, significant benefits could also be attributed to enzymes components that hydrolyze non-cellulosic polysaccharides. It is suggested that so-called "accessory" enzymes such as xylanase and pectinase stimulate cellulose hydrolysis by removing non-cellulosic polysaccharides that coat cellulose fibers. A high-throughput microassay, in combination with response surface methodology, enabled production of an optimally supplemented enzyme mixture. This mixture allowed for a ,twofold reduction in the total protein required to reach glucan to glucose and xylan to xylose hydrolysis targets (99% and 88% conversion, respectively), thereby validating this approach towards enzyme improvement and process cost reduction for lignocellulose hydrolysis. Biotechnol. Bioeng. 2007;97: 287,296. © 2006 Wiley Periodicals, Inc. [source] Methodological analysis for determination of enzymatic digestibility of cellulosic materialsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2007Y.-H. Percival Zhang Abstract Accurate measurement of enzymatic cellulose digestibility (X) is important in evaluating the efficiency of lignocellulose pretreatment technologies, assessing the performance of reconstituted cellulase mixtures, and conducting economic analysis for biorefinery processes. We analyzed the effect of sugars contained in enzymes solutions, usually added as a preservative, and random measurement errors on the accuracy of X calculated by various methods. The analysis suggests that exogenous sugars at levels measured in several commercial enzyme preparations significantly bias the results and that this error should be minimized by accounting for these sugars in the calculation of X. Additionally, a method of calculating X equating the ratio of the soluble glucose equivalent in the liquid phase after hydrolysis to the sum of the soluble glucose equivalent in the liquid phase and the insoluble glucose equivalent in the residual solid after hydrolysis was found to be the most accurate, particularly at high conversion levels (>ca. 50%). Biotechnol. Bioeng. 2007;96: 188,194. © 2006 Wiley Periodicals, Inc. [source] Standard assays do not predict the efficiency of commercial cellulase preparations towards plant materialsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Mirjam A. Kabel Abstract Commercial cellulase preparations are potentially effective for processing biomass feedstocks in order to obtain bioethanol. In plant cell walls, cellulose fibrils occur in close association with xylans (monocotyls) or xyloglucans (dicotyls). The enzymatic conversion of cellulose/xylans is a complex process involving the concerted action of exo/endocellulases and cellobiases yielding glucose and xylanases yielding xylooligomers and xylose. An overview of commonly measured cellulase-, cellobiase-, and xylanase-activity, using respectively filter paper, cellobiose, and AZCL-dyed xylan as a substrate of 14 commercially available enzyme preparations from several suppliers is presented. In addition to these standardized tests, the enzyme-efficiency of degrading native substrates was studied. Grass and wheat bran were fractionated into a water unsoluble fraction (WUS), which was free of oligosaccharides and starch. Additionally, cellulose- and xylan-rich fractions were prepared by alkaline extraction of the WUS and were enzymatically digested. Hereby, the capability of cellulose and xylan conversion of the commercial enzyme preparations tested was measured. The results obtained showed that there was a large difference in the performance of the fourteen enzyme samples. Comparing all results, it was concluded that the choice of an enzyme preparation is more dependent on the characteristics of the substrate rather than on standard enzyme-activities measured. © 2005 Wiley Periodicals, Inc. [source] | ||||||||||