*Article* **An Alkalothermophilic Amylopullulanase from the Yeast** *Clavispora lusitaniae* **ABS7: Purification, Characterization and Potential Application in Laundry Detergent**

**Scheherazed Dakhmouche Djekrif 1,2,\* , Leila Bennamoun <sup>2</sup> , Fatima Zohra Kenza Labbani 1,2 , Amel Ait Kaki <sup>3</sup> , Tahar Nouadri <sup>2</sup> , André Pauss <sup>4</sup> , Zahia Meraihi <sup>2</sup> and Louisa Gillmann <sup>5</sup>**


**Abstract:** In the present study, α-amylase and pullulanase from *Clavispora lusitaniae* ABS7 isolated from wheat seeds were studied. The gel filtration and ion-exchange chromatography revealed the presence of α-amylase and pullulanase activities in the same fraction with yields of 23.88% and 21.11%, respectively. SDS-PAGE showed a single band (75 kDa), which had both α-amylase (independent of Ca2+) and pullulanase (a calcium metalloenzyme) activities. The products of the enzymatic reaction on pullulan were glucose, maltose, and maltotriose, whereas the conversion of starch produced glucose and maltose. The α-amylase and pullulanase had pH optima at 9 and temperature optima at 75 and 80 ◦C, respectively. After heat treatment at 100 ◦C for 180 min, the pullulanase retained 42% of its initial activity, while α-amylase maintained only 38.6%. The cations Zn2+, Cu2+, Na<sup>+</sup> , and Mn2+ increased the α-amylase activity. Other cations Hg2+, Mg2+, and Ca2+ were stimulators of pullulanase. Urea and Tween 80 inhibited both enzymes, whereas EDTA only inhibited pullulanase. In addition, the amylopullulanase retained its activity in the presence of various commercial laundry detergents. The performance of the alcalothermostable enzyme of *Clavispora lusitaniae* ABS7 qualified it for the industrial use, particularly in detergents, since it had demonstrated an excellent stability and compatibility with the commercial laundry detergents.

**Keywords:** α-amylase; pullulanase; *Clavispora lusitaniae*; purification; enzyme characterization
