title: Screening and characterization of thermo-active enzymes of biotechnological interest produced by thermophilic Bacillus isolated from hot springs in Tunisia.
abstract: As part of the contribution to the global efforts in research of thermostable enzymes being of industrial interest, we focus on the isolation of thermophilic bacteria from Tunisian hot springs. Among the collection of 161 strains of thermophilic Bacillus isolated from different samples of thermal water in Tunisia, 20% are capable of growing at 100°C and the rest grow at 70°C or above. Preliminary activity tests on media supplemented with enzyme-substrates confirmed that 35 strains produced amylases, 37 - proteases, 43 - cellulases, 31 - xylanases and 37 - mannanases. The study of the effect of temperature on enzyme activity led to determination of the optimal temperatures of activities that vary between 60 and 100°C. Several enzymes were active at high temperatures (80, 90 and 100°C) and kept their activity even at 110°C. Several isolated strains producing enzymes with high optimal temperatures of activity were described for the first time in this study. Both strains B62 and B120 are producers of amylase, protease, cellulase, xylanase, and mannanase. The sequencing of 16S DNA identified isolated strains as Geobacillus kaustophillus, Aeribacillus pallidus, Geobacillus galactosidasus and Geobacillus toebii.
authors.affiliation: Laboratory of Biochemistry & Technobiology, Faculty of Science of Tunis, University of Tunis El Manar, Campus University Farhat HACHED El Manar 2092, Tunis.
authors.forename: Wajdi
authors.initials: W
authors.lastname: Thebti
authors.affiliation: Laboratory of Biochemistry & Technobiology, Faculty of Science of Tunis, University of Tunis El Manar, Campus University Farhat HACHED El Manar 2092, Tunis.
authors.forename: Yosra
authors.initials: Y
authors.lastname: Riahi
authors.affiliation: Laboratory of Biochemistry & Technobiology, Faculty of Science of Tunis, University of Tunis El Manar, Campus University Farhat HACHED El Manar 2092, Tunis.
authors.forename: Rawand
authors.initials: R
authors.lastname: Gharsalli
authors.affiliation: Laboratory of Biochemistry & Technobiology, Faculty of Science of Tunis, University of Tunis El Manar, Campus University Farhat HACHED El Manar 2092, Tunis.
authors.forename: Omrane
authors.initials: O
authors.lastname: Belhadj
mesh_terms: D000681:Amylases / Q000096:biosynthesis / Q000737:chemistry; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000737:chemistry; D002480:Cellulase / Q000096:biosynthesis / Q000737:chemistry; D010450:Endopeptidases / Q000096:biosynthesis / Q000737:chemistry; D004795:Enzyme Stability; D056506:Geobacillus / Q000201:enzymology* / Q000235:genetics; D045482:Hot Springs / Q000382:microbiology; D006358:Hot Temperature; D058889:Molecular Typing; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D014416:Tunisia; D014871:Water Microbiology; D014995:Xylosidases / Q000096:biosynthesis / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D000681:Amylases; D014995:Xylosidases; D002480:Cellulase; D010450:Endopeptidases