PRODUCTION, PURIFICATION AND CHARACTERIZATION OF A TANNASE FROM ASPERGILLUS-NIGER LCF-8

Tannase (Tannin acyl hydrolase EC 3.1.1.20) is produced in high yield by Aspergillus niger LCF 8. Optimal conditions of production were dete rmined. Induction of the strain, pH and aeration are the main paramete rs influencing the production yield. A pure enzyme sample (1,980 nKat/ mg protein) was obtained by physical disruption of the mycelium, ultra filteration and high pressure size exclusion chromatography (HPSEC). T he biochemical properties of the enzyme were investigated. It is a gly coprotein of about 186,000 Dal, containing 43% sugars. The pI is 4.3. The optimal temperature for activity was 35 degrees C. Esterase activi ty peaked at pH 5.0 while tannase activity was optimal at pH 6.0. The tannase was stable between pH 3.5 and 8.0 at temperature below 50 degr ees C. An in situ immobilized enzyme was also obtained. This was highl y active towards gallotannins and ellagitannins. Since A. niger is off icially approved in numerous countries for enzyme production in the fo od industry, the in situ immobilised tannase can be used for removing tannins responsible for unwanted effects in food or cosmetology proces sing.