title: Enzymatic activities in different strains isolated from healthy and brittle leaf disease affected date palm leaves: study of amylase production conditions.
abstract: The present study aimed to investigate and compare the enzymatic production of endophytic bacteria isolated from healthy and brittle leaf disease affected date palm leaves (pectinase, cellulase, lipase, and amylase). The findings revealed that the enzymatic products from the bacterial isolates of healthy date palm leaves were primarily 33% amylolytic enzyme, 33 % cellulase, 25 % pectinase, and 25 % lipase. The isolates from brittle leaf disease date palm leaves, on the other hand, were noted to produce 16 % amylolytic enzyme, 20 % cellulose, 50 % pectinase, and 50 % lipase. The effects of temperature and pH on amylase, pectinase, and cellulose activities were investigated. The Bacillus subtilis JN934392 strain isolated from healthy date palm leaves produced higher levels of amylase activity at pH 7. A Box Behnken Design (BBD) was employed to optimize amylase extraction. Maximal activity was observed at pH and temperature ranges of pH 6-6.5 and 37-39 °C, respectively. Under those conditions, amylase activity was noted to be attained 9.37 U/ml. The results showed that the enzyme was able to maintain more than 50 % of its activity over a temperature range of 50-80 °C, with an optimum at 70 °C. This bacterial amylase showed high activity compared to other bacteria, which provides support for its promising candidacy for future industrial application.
authors.affiliation: Laboratory of Plant Biotechnology Applied to Crop Improvement, Faculty of Science of Sfax, University of Sfax, 3038, Sfax, Tunisia, jradmouna@yahoo.com.
authors.forename: Jrad
authors.initials: J
authors.lastname: Mouna
authors.forename: Fendri
authors.initials: F
authors.lastname: Imen
authors.forename: Ben
authors.initials: B
authors.lastname: Choba Ines
authors.forename: Drira
authors.initials: D
authors.lastname: Nourredine
authors.forename: Kadri
authors.initials: K
authors.lastname: Adel
authors.forename: Gharsallah
authors.initials: G
authors.lastname: Néji
mesh_terms: D000681:Amylases / Q000302:isolation & purification / Q000378:metabolism*; D001412:Bacillus subtilis / Q000737:chemistry / Q000201:enzymology*; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002480:Cellulase / Q000302:isolation & purification / Q000378:metabolism*; D005163:Factor Analysis, Statistical; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism*; D065749:Phoeniceae / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology*; D011096:Polygalacturonase / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D008049:Lipase; D000681:Amylases; D011096:Polygalacturonase; D002480:Cellulase