Identification of α-amylase by random and specific mutagenesis of Texcoconibacillus texcoconensis 13CC T strain isolated from extreme alkaline–saline soil of the former Lake Texcoco (Mexico) Juan Manuel Bello-López & Yendi E. Navarro-Noya & Selene Gómez-Acata & Zahuiti Hernández-Montañez & Luc Dendooven Received: 12 June 2013 /Accepted: 17 October 2013 /Published online: 3 November 2013 # Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i. 2013 Abstract The alkaline α -amylase produced by Texcoconibacillus texcoconensis 13CC T strain was identified by random mutagenesis and confirmed by directed mutagenesis. A transposon mutagenesis approach was taken to identify the gene responsible for the degradation of starch in T. texcoconensis 13CC T strain. The deduced amino acids of the amy gene had a 99 % similarity with those of Bacillus selenitireducens MLS10 and 97 % with those of Paenibacillus curdlanolyticus YK9. The enzyme showed a maximum activity of 131.1 U/mL at 37 °C and pH 9.5 to 10.5. In situ activity of the enzyme determined by polyacrylamide gel electrophoresis showed only one band with amylolytic activity. This is the first report of a bacterium isolated from the extreme alkaline–saline soil of the former Lake Texcoco (Mexico) with amylolytic activity in alkaline conditions while its potential as a source of amylases for the industry is discussed. Introduction Starch degradation is a capacity widespread among bacteria, filamentous fungi, and yeasts (Bano et al. 2011; Hernández- Montañez et al. 2012; Murakoshi et al. 2012). Amylases are among the most important commercial enzymes with wide applications in starch processing, brewing, alcohol production, textile, paper, detergent, clinical, medicinal, and analytical chemistry (Sivaramakrishnan et al. 2006). Alkaline α-amylases have a high catalytic efficiency and stability in pH ranging from 9 to 11 (Annamalai et al. 2011; Hagihara et al. 2001). They have potential applications for hydrolyzing starch in high-pH environments, such as starch and textile industries and as ingredients in detergents for dishwashers and laundries (van den Burg 2003). Recently, different novel strains have been isolated from alkaline–saline soils and characterized (Alazard et al. 2007; Ruiz-Romero et al. 2013; Shi et al. 2012). However, only a few have been investigated as potential providers of biotechnological exoenzymes (Annamalai et al. 2011). A Gram-positive bacterium was isolated from an alkaline–saline soil, and analysis based on morphological, staining, and metabolic features and analysis of the structure of peptidoglycan, fatty acid ratio, % G+C, and J. M. Bello-López : Y. E. Navarro-Noya : S. Gómez-Acata : L. Dendooven (*) Laboratory of Soil Ecology, Department of Biotechnology and Bioengineering, ABACUS, CINVESTAV, Av. I.P.N. 2508, C.P. 07360 Mexico, D.F., Mexico e-mail: dendooven@me.com Z. Hernández-Montañez Laboratory of Industrial Microbiology, Department of Microbiology, Escuela Nacional de Ciencias Biológicas, IPN, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás, C. P. 11340 Mexico, D.F., Mexico Folia Microbiol (2014) 59:235–240 DOI 10.1007/s12223-013-0289-8