Document Type : Research Paper

Authors

• Babak Hajizadeh ¹
• Nima Shaykh-Baygloo ¹
• Mehdi Imani ²
• Rashid Jamei ³

¹ Department of Biology, Faculty of Science, Urmia University, Urmia, Iran

² Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

³ Department of Biology, Faculty of Science, Urmia University, Urmia,Iran

Abstract

Laccases, copper-containing polyphenol oxidases, have numerous biotechnological and industrial applications, especially in industries that require high salt concentrations such as pulp and paper industries, tanneries, and textile industries. In the current study, solid and liquid bacterial culture media containing CuSO4 (3 mM) and guaiacol (0.01% w/v) were used to isolate laccase-producing bacteria from the shore sediments of hypersaline Lake Urmia. Bacteria producing reddish-brown colonies on the culture medium containing guaiacol were considered as laccase-producing strains. Intracellular and extracellular laccase activities were measured spectrophotometrically at 420 nm using ABTS (2,2-azino-di-[3-ethylbenzo-thiazolin-sulphonate]) as a substrate. In this study, four bacterial strains were isolated from the shore sediments of Lake Urmia using a culture medium containing guaiacol, of which only one strain was detected with significant extracellular laccase activity. Microscopic investigation and 16S rRNA gene sequence analysis showed that this strain is a rod-shaped Gram-positive bacterium belonging to the genus Brevibacterium and was named Brevibacterium sp. strain LUBr01. The 16S rRNA sequence of LUBr01 strain is available on the GenBank nucleotide database under the accession number MN588176.1. Due to the proper laccase activity, LUBr01 can be useful for industrial process related to laccase. Also, saline Lake Urmia can act as a source of microorganisms with the ability to produce special enzymes such as laccase that can be used in salinity conditions.

Keywords

• Laccase
• saline Lake Urmia
• Brevibacterium

Main Subjects

• Microbiology