title: Production and Properties of a Thermostable, pH-Stable Exo-Polygalacturonase Using Aureobasidium pullulans Isolated from Saharan Soil of Algeria Grown on Tomato Pomace.
abstract: Polygalacturonase is a valuable biocatalyst for several industrial applications. Production of polygalacturonase using theAureobasidium pullulansstain isolated from Saharan soil of Algeria was investigated. Its capacity to produce polygalacturonase was assessed under submerged culture using tomato pomace as an abundant agro-industrial substrate. Optimization of the medium components, which enhance polygalacturonase activity of the strainAureobasidium pullulans, was achieved with the aid of response surface methodology. The composition of the optimized medium was as follows: tomato pomace 40 g/L, lactose 1.84 g/L, CaCl₂0.09 g/L and pH 5.16. Practical validation of the optimum medium provided polygalacturonase activity of 22.05 U/mL, which was 5-fold higher than in unoptimized conditions. Batch cultivation in a 20 L bioreactor performed with the optimal nutrients and conditions resulted in a high polygalacturonase content (25.75 U/mL). The enzyme showed stability over a range of temperature (5-90 °C) with an optimum temperature of 60 °C with pH 5.0, exhibiting 100% residual activity after 1h at 60 °C. This enzyme was stable at a broad pH range (5.0-10). The enzyme proved to be an exo-polygalacturonase, releasing galacturonic acid by hydrolysis of polygalacturonic acid. Moreover, the exo-polygalacturonase was able to enhance the clarification of both apple and citrus juice. As a result, an economical polygalacturonase production process was defined and proposed using an industrial food by-product.
authors.affiliation: Laboratoire de Génie Microbiologiques et Applications, Faculté des Sciences de la Nature et de la Vie, Département de Biochimie et Biologie Cellulaire & Moléculaire, Université Frères Mentouri Constantine, Route Ain El Bey 25017, Algeria. leila_bennamoun@hotmail.com.
authors.forename: Leila
authors.initials: L
authors.lastname: Bennamoun
authors.affiliation: Walloon Center of Industrial Biology, University of Liège, Boulevard du Rectorat 29, B40 Building, 4000 Liège, Belgium. serge.hiligsmann@ulb.ac.be.
authors.forename: Serge
authors.initials: S
authors.lastname: Hiligsmann
authors.affiliation: Laboratoire de Génie Microbiologiques et Applications, Faculté des Sciences de la Nature et de la Vie, Département de Biochimie et Biologie Cellulaire & Moléculaire, Université Frères Mentouri Constantine, Route Ain El Bey 25017, Algeria. scheherazad2002@hotmail.com.
authors.forename: Scheherazad
authors.initials: S
authors.lastname: Dakhmouche
authors.affiliation: Laboratoire de Génie Microbiologiques et Applications, Faculté des Sciences de la Nature et de la Vie, Département de Biochimie et Biologie Cellulaire & Moléculaire, Université Frères Mentouri Constantine, Route Ain El Bey 25017, Algeria. ait-kaki.amel@umc.edu.dz.
authors.forename: Amel
authors.initials: A
authors.lastname: Ait-Kaki
authors.affiliation: Laboratoire de Génie Microbiologiques et Applications, Faculté des Sciences de la Nature et de la Vie, Département de Biochimie et Biologie Cellulaire & Moléculaire, Université Frères Mentouri Constantine, Route Ain El Bey 25017, Algeria. labkenza@yahoo.fr.
authors.forename: Fatima-Zohra Kenza
authors.initials: FK
authors.lastname: Labbani
authors.affiliation: Laboratoire de Génie Microbiologiques et Applications, Faculté des Sciences de la Nature et de la Vie, Département de Biochimie et Biologie Cellulaire & Moléculaire, Université Frères Mentouri Constantine, Route Ain El Bey 25017, Algeria. nouadri2000@yahoo.fr.
authors.forename: Tahar
authors.initials: T
authors.lastname: Nouadri
authors.affiliation: Laboratoire de Génie Microbiologiques et Applications, Faculté des Sciences de la Nature et de la Vie, Département de Biochimie et Biologie Cellulaire & Moléculaire, Université Frères Mentouri Constantine, Route Ain El Bey 25017, Algeria. meraihi27@yahoo.com.
authors.forename: Zahia
authors.initials: Z
authors.lastname: Meraihi
authors.affiliation: Department of Agricultural, Food and Environmental Science, Industrial Yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno 74, I-06121 Perugia, Italy. benedetta.turchetti@unipg.it.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Turchetti
authors.affiliation: Department of Agricultural, Food and Environmental Science, Industrial Yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno 74, I-06121 Perugia, Italy. pietro.buzzini@unipg.it.
authors.forename: Pietro
authors.initials: P
authors.lastname: Buzzini
authors.affiliation: Walloon Center of Industrial Biology, University of Liège, Boulevard du Rectorat 29, B40 Building, 4000 Liège, Belgium. p.thonart@ulg.ac.be.
authors.forename: Philippe
authors.initials: P
authors.lastname: Thonart
keywords: Aureobasidium pullulans; characterization; exo-polygalacturonase; response surface methodology; tomato pomace