*Article* **Identification of New Amylolytic Enzymes from Marine Symbiotic Bacteria of** *Bacillus* **Species**

**Mohammad Reza Erfanimoghadam and Ahmad Homaei \***

Department of Marine Biology, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas P.O. Box 3995, Iran

**\*** Correspondence: a.homaei@hormozgan.ac.ir or a.homaei@gmail.com; Tel.: +98-76-33711000-11; Fax: +98-76-33670716

**Abstract:** α-amylases are one of the most common and important industrial enzymes widely used in various industries. The present study was conducted with the aim of isolating and identifying symbiotic α-amylase enzyme-producing bacteria in the intestine of *Silago Sihama* and *Rasterliger Canagorta* fish living in Qeshm Island, Hormozgan. The intestinal symbiotic bacteria of these species were isolated using nutrient agar culture medium; then, α-amylase producing bacteria were screened using a special culture medium containing starch and the Lugol's solution test. The α-amylase enzyme activity of enzyme-producing bacteria was measured using the starch substrate. Finally, bacteria with the highest enzyme activity were selected and identified by the 16S rRNA gene sequence analysis. The results showed that out of 22 isolated bacteria, 10 were able to grow in a special culture medium, and 5 strains of these 10 bacteria had the ability to produce relatively stronger halos. The four bacterial strains belonging to the genus *Bacillus* that had the highest α-amylase enzyme activity were identified and registered in the NCBI gene database as *B. subtilis* strains HR13, HR14, HR15, and HR16. Among these four strains, two strains of *B. subtilis,* HR13 and HR16, displayed high enzyme activity and maximum activity at 60 ◦C at pH values of 5 and 7, respectively. α-Amylase enzymes isolated from marine symbiotic bacteria of *Bacillus* species can be considered potential candidates for application in various industries.

**Keywords:** α-amylase; starch hydrolysis; marine enzymes; Persian Gulf
