“…The sample injection was of 10 μl. TAH activity was assayed using the HPLC method reported by Aguilar et al (1999). A TAH unit was defined as the amount of enzyme required to release one micromole of gallic acid under assay conditions.…”
The ability of Aspergillus niger GH1 in converting creosote bush ellagitannins into ellagic acid (EA) was evaluated in solid state culture. Creosote bush leaves were used to extract the ellagitannins fraction, which was impregnated in polyurethane foam used as support of solid state culture. Ellagitannins content, EA accumulation, and the related enzymatic activities were evaluated. A. niger GH1 was able to completely degrade creosote bush ellagitannins with an EA yield of 23.1% at 36 h of culture. The ability to degrade creosote bush ellagitannins exhibited by A. niger GH1 was clearly associated to an ellagitannin-hydrolysing enzyme with a maximum activity of 43 U/l, while that ability was not associated to tannase activity that was detected in the culture extract. This study demonstrated the great ability of A. niger GH1 to hydrolyze ellagitannins and the potential of solid state culture to produce the antioxidant EA by degradation of creosote bush ellagitannins.
“…The sample injection was of 10 μl. TAH activity was assayed using the HPLC method reported by Aguilar et al (1999). A TAH unit was defined as the amount of enzyme required to release one micromole of gallic acid under assay conditions.…”
The ability of Aspergillus niger GH1 in converting creosote bush ellagitannins into ellagic acid (EA) was evaluated in solid state culture. Creosote bush leaves were used to extract the ellagitannins fraction, which was impregnated in polyurethane foam used as support of solid state culture. Ellagitannins content, EA accumulation, and the related enzymatic activities were evaluated. A. niger GH1 was able to completely degrade creosote bush ellagitannins with an EA yield of 23.1% at 36 h of culture. The ability to degrade creosote bush ellagitannins exhibited by A. niger GH1 was clearly associated to an ellagitannin-hydrolysing enzyme with a maximum activity of 43 U/l, while that ability was not associated to tannase activity that was detected in the culture extract. This study demonstrated the great ability of A. niger GH1 to hydrolyze ellagitannins and the potential of solid state culture to produce the antioxidant EA by degradation of creosote bush ellagitannins.
“…Several studies have determined the presence of hydrolysable tannins in the plant, particularly in the seeds, increasing the chance of obtaining endophytic microorganisms that (3)(4)(5). Tannins can also be found in the sap, fruits, leaves, skin and root system (6). It is noteworthy that the level and type vary according to the climate and geography of the environment, not only from one plant to another but also from one part of the same plant to another (7).…”
Section: Introductionmentioning
confidence: 99%
“…Tannin acyl hydrolase (TAH, EC 3.1.1.20), known as tannase, is an intracellular or extracellular inducible enzyme produced in the presence of tannic acid by bacteria, moulds and yeasts (6). In addition to these sources, it can be produced by animals and tannin-rich plants (8,9).…”
SummaryTannase (EC 3.1.1.20) is an enzyme that hydrolyzes the ester and depside bonds of tannic acid to gallic acid and glucose. In the production of foods and beverages, it contributes to the removal of the undesirable eff ects of tannins. The aim of this study is to investigate the potential of endophytic fungi isolated from jamun (Syzygium cumini (L.) Skeels) leaves, and identifi ed as Pestalotiopsis guepinii, in the production of tannase. Tannase was produced extracellularly by P. guepinii under submerged, slurry-state and solid-state fermentations. The submerged fermentation was found to be the most promising (98.6 U/mL). Response surface methodology was employed to evaluate the eff ect of variables (pH and temperature), and the results showed that the best conditions for tannase activity were pH=6.9 and 30 °C. K m was found to be 7.18·10 -4 mol/L and v max =250.00 U/mL. The tannase activity was the highest in the presence of Ca 2+ at a concentration of 5·10 -3 mol/L. Moreover, the enzyme was not inhibited by the tested chelators and detergents. The stability of the enzyme was also studied, and crude enzyme was evaluated in simulation of gastrointestinal digestion of monogastric animals. The crude enzyme was highly stable under simulated conditions; it retained 87.3 % of its original activity a er 6 h. The study contributes to the identifi cation of microbial species that produce tannase, with potential application in biotechnology.
“…Contrary to the availability of lipase activity screening methods [13,14], there are few reports concerning rapid and continuous methods for the screening of feruloyl esterases, tannases, and chlorogenate esterases. Several methods for measuring their activities have been reported [15][16][17]. These methods are largely based on high-performance liquid chromatography (HPLC) techniques, using enzymatic hydrolysis of hydroxycinnamic esters.…”
Feruloyl, chlorogenate esterases, and tannases are enzymes useful in phenolic modifications of pharmaceutical relevance as protectors against several degenerative human diseases. Therefore, there is a growing interest in discovering new sources of these enzymes. However, traditional methods for their activity measurements are time-consuming and poorly adapted for high-throughput screening. In this study, a successful new microplate high-throughput screening method for the simultaneous quantification of all mentioned activities is demonstrated. This method allows the detection of activities as low as 1.7 mU ml(-1). Furthermore, reaction rates increased proportionally with the amount of enzyme added, and no interferences with the other commercial hydrolases tested were found. The utility of the method was demonstrated after simultaneously screening feruloyl, chlorogenate esterase, and tannase activities in solid state fermentation extracts obtained during the kinetics of production of 20 fungal strains. Among these, seven strains were positive for at least one of the esterase activities tested. This result shows the potential for the rapid routine screening assays for multiple samples of moderate low to high enzymatic levels.
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