Purification and characterization of an amylase from Opuntiaficus-indica seeds.
BACKGROUND
In Tunisia, prickly pear fruit grow spontaneously; it is consumed as fresh fruit, juice or jam. When the fruit is used for juice production, the seeds are discarded and go to waste. Our study aimed to extract biomolecules from seeds by producing value-added products from the fruits.


RESULTS
An amylase from Opuntia ficus-indica seeds was extracted and purified to homogeneity. An increase in specific activity of 113-fold was observed. The apparent molecular mass of the enzyme is 64 kDa. The optimum pH and temperature for enzyme activity were pH 5 and 60 °C, respectively. Under these conditions, the specific activity is 245.5 U mg(-1) . The enzyme was activated by Co(2+) and Mg(2+) (relative activity 117% and 113% respectively) at lower ion concentrations. It was strongly inhibited by Mn(2+) and Fe(2+) . Cu(2+) inhibited totally the activity of this enzyme, but Ca(2+) has an inhibitory effect which increases with ion concentration.


CONCLUSIONS
The extracted enzyme belongs to the exo type of amylases and is classified as a β-cyclodextrin glycosyltransferase since it generates mainly β-cyclodextrin from starch. It exhibits high thermal stability and a broad range of pH stability, making it a promising prospect for industrial and food applications.
Higher Institute of Applied Sciences and Technology of Mahdia, Sidi Messaoud 5111Mahdia, Tunisia; Alimentary Analysis Unit, National Engineering School of Sfax, 3038 Sfax, Tunisia.
Monia
M
Ennouri
Bassem
B
Khemakhem
Hanen
H
Ben Hassen
Imen
I
Ammar
Karima
K
Belghith
Hamadi
H
Attia
D000681:Amylases / Q000737:chemistry / Q000302:isolation & purification*; D001628:Beverages; D004789:Enzyme Activation; D005638:Fruit; D005964:Glucosyltransferases / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008970:Molecular Weight; D029747:Opuntia / Q000737:chemistry / Q000201:enzymology*; D012639:Seeds / Q000737:chemistry*; D013696:Temperature; D014416:Tunisia; D014866:Waste Products
D007477:Ions; D014866:Waste Products; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; D000681:Amylases