Production and Properties of a Thermostable, pH—Stable Exo-Polygalacturonase Using Aureobasidium pullulans Isolated from Saharan Soil of Algeria Grown on Tomato Pomace
Leila Bennamoun,
Serge Hiligsmann,
Scheherazad Dakhmouche,
Amel Ait-Kaki,
Fatima-Zohra Kenza Labbani,
Tahar Nouadri,
Zahia Meraihi,
Benedetta Turchetti,
Pietro Buzzini,
Philippe Thonart
Affiliations
Leila Bennamoun
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
Serge Hiligsmann
Walloon Center of Industrial Biology, University of Liège, Boulevard du Rectorat 29, B40 Building, 4000 Liège, Belgium
Scheherazad Dakhmouche
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
Amel Ait-Kaki
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
Fatima-Zohra Kenza Labbani
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
Tahar Nouadri
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
Zahia Meraihi
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
Benedetta Turchetti
Department of Agricultural, Food and Environmental Science, Industrial Yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno 74, I-06121 Perugia, Italy
Pietro Buzzini
Department of Agricultural, Food and Environmental Science, Industrial Yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno 74, I-06121 Perugia, Italy
Philippe Thonart
Walloon Center of Industrial Biology, University of Liège, Boulevard du Rectorat 29, B40 Building, 4000 Liège, Belgium
Polygalacturonase is a valuable biocatalyst for several industrial applications. Production of polygalacturonase using the Aureobasidium pullulans stain 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 strain Aureobasidium 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.
