ISOLATION AND CHARACTERISATION OF A NEW ALKALI-HALOTOLERANT BACILLUS AQUIMARIS STRAIN LGMT10, PRODUCING EXTRACELLULAR HYDROLASES, FROM THE EFFLUENTS OF A THERMAL POWER PLANT, IN ALGERIA

Abstract

Modern biotechnology takes into account cost, performance, and respect for the environment to set up an industrial process. In this sense, the study's goal is to highlight the presence of indigenous microbial microflora in the Terga thermal power plant effluents, which are capable of secreting extracellular hydrolases. Four different extracellular hydrolases classes, which are most of the time used in bioindustry, namely protease, amylase, lipase, and cellulase, were investigated in agar plate assay, to select microorganisms with an interesting enzymatic potential adapted to this type of environment. Consequently, the results have shown that among twelve isolated bacterial strains, three strains were screened based on their enzymatic potential, and were later identified by 16S rRNA gene sequencing, i.e. showing that the strains belong to the genus Pseudomonas aeruginosa, and Bacillus wiedmannii with a similarity percentage of 99.33% and 100%, respectively, with their corresponding type of strains. Among them, the strain LGMT10 that belongs to the Bacillus genus, and is closely related to Bacillus aquimaris, showed a 16S rRNA sequence similarity with the type of strain of 99.23%. This strain presents adequate characteristics to resist the harsh conditions of pH and NaCl. It could grow against wide ranges of NaCl concentrations between 0-12% (w/v), pH 5.5-12, and was able to produce extracellular hydrolases (i.e., protease, amylase, and cellulase) against pH ranges of 6.8-12 and NaCl concentrations between 0-12% (w/v) at 30 °C. This strain's intriguing enzymatic potential, as well as its pH and salinity tolerance, make it a promising candidate for various biotechnological applications in detergent, leather, textile, and food processing industries.