Three signal peptides of alpha amylase genes of three isolated strains: Bacillus licheniformis DA23, Bacillus subtilis D5-2, Bacillus cereus CN1-5 were successfully sequenced. Three predicted “Sec – type” signal peptides have a length varying from 27 (CN1-5) to 33 residues (D5-2). | Vietnam Journal of Science and Technology 56 (1) (2018) 7-16 DOI: CONSTITUTION OF DIFFERENT SIGNAL PEPTIDES FOR ENHANCED THERMOSTABLE ALPHA AMYLASE SECRETION IN Bacillus subtilis Nguyen Thi Da, Nguyen Kim Thoa, Tran Dinh Man* Institute of Biotechnology, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi * Email: ntda@ Received: 22 April 2017, Accepted for publication: 28 November 2017 Abstract. Three signal peptides of alpha amylase genes of three isolated strains: Bacillus licheniformis DA23, Bacillus subtilis D5-2, Bacillus cereus CN1-5 were successfully sequenced. Three predicted “Sec – type” signal peptides have a length varying from 27 (CN1-5) to 33 residues (D5-2). The secretion of alpha amylase of the recombination B. subtilis 168MPgrac strain (pHV33–PgracAmy3BT2) with ± U/ml and the ratio of α – amylase activities to total amount of protein secretion reached U/mg was larger than that of 168MPamy with U/ml. Base on analyzed results of PAGE and zymogram about molecular weight, alpha amylases in both strains were the same size, nearly 58 kDa. Three signal peptides were constructed in recombinant pHV33 – Pgrac vectors. To further evaluate the efficiency of these SPs in , α-amylase activity was measured. The extracellular amylase activity of signal peptide in 168M was the highest with ± U/ml in four signal peptide targets. These results indicated that the promoter Pgrac and signal peptide amylase gen tested in this study might be used for secretion α – amylase in B. subtilis 168M. Keywords: Bacillus, signal peptide, secretion, amylase, megaprimer. Classification number: ; ; . 1. INTRODUCTION Amylases are important hydrolase enzymes which have been widely used since many decades. Among the amylase family, α - amylase is an industrially important one because of the ubiquitous nature, easy of production and broad spectrum of applications. This enzyme .
