Isolation, Identification and Evaluation of activity and stability of Laccase Production by Halotolerant Enterobacter sp. GR۱۸ Isolated from Grawan Mineral Spring

BACKGROUND AND OBJECTIVESIn recent years, enzymes have gained increased importance due to their applications in a variety of industries. Laccases are one of the most widely studied oxidoreductase enzymatic systems which are amply present in nature. They are widely explored as they can catalyze oxidization of a large range of phenolic and aromatic compounds. The objective of this study was to isolate, identify and investigate the activity and stability of laccase produced by a halotolerant bacteria isolated from Gravan mineral spring.MATERIALS AND METHODSThe isolation of bacteria producing Laccase from diverse samples such as water, sludge, and soil was conducted using MHM medium. The identification of bacterial isolates with positive Laccase activity was achieved through a combination of morphological, biochemical, and ۱۶S rRNA methods. Enzyme activity was measured using a colorimetric method. Finally, the effect of various physic-chemical factors such as carbon and nitrogen sources, metal ions, inducers, incubation time, temperature and pH on the enzyme stability and activity was evaluated.RESULTS AND DISCUSSIONOut of the ۵ enzyme-producing isolates screened on MHM medium, one was identified as excellent producer. Analysis of the ۱۶S rRNA sequences of these isolates revealed a remarkable ۹۹.۶% similarity with Enterobacter hormaechei. Results showed that glucose and yeast extract are the optimal sources of carbon and nitrogen, respectively. Cu۲+ and bis-phenol emerged as the best cation and inducer. Optimal laccase activity was achieved at a pH of ۶ and a temperature of ۳۰°C, following a ۹۶-hour incubation time.CONCLUSIONFindings of this study suggest that the Grawan mineral spring serves as a valuable resource for isolating robust microorganism capable of producing economically significant enzymes, thereby facilitating cost-effective industrial applications.

کلیدواژه ها:

Laccase ، Enterobacter hormaechei ، Stability ، Grawan mineral spring