Isolation of thermophilic esterase or lipase producing bacteria from hot springs at the East coast of Peninsular Malaysia

Hot spring is a natural habitat for thermophilic bacteria and is the major source of thermostable enzymes useful in industrial application. In Malaysia, the search for thermophilic organisms have been focused on hot springs especially on the West coast of the peninsular. In this work, lipase or esterase producing thermophilic microorganisms were isolated from East coast hot springs in the states of Pahang and Terengganu. Morphological and biochemical analysis were carried out on Isolates LH1, LH2, LH3, LH4, LH5, B2B2 and S1B4, which showed that they are Gram positive, aerobic, spore forming and motile organisms. All of the 7 isolates showed the ability to grow at 45°C and formed hydrolysis zones on tributyrin agar plates. However, only isolate B2B2 and S1B4 were able thrive at higher temperatures of up to 65°C. Genotypic characterisation was carried out using 16S rRNA sequencing. Bacillus and Geobacillus species were found to be the dominant bacteria isolated from these hot springs. From La hot spring, isolate LH1 (MT 645486), Isolates LH2 (MT645483), LH3 (MT645484), LH4 (MT 645485) and LH5 (MT 645487) were all closely related to Bacillus sp. (at 97.3-97.9%). Meanwhile, from Bentong and Sungai Lembing hot springs, isolates B2B2 (MT668631) and S1B4 (MT668632) were closely related to either Geobacillus kaustophilus or Geobacillus thermoleovorans; each at 98.5% and 97.9% similarity, respectively. These strains from Geobacillus Sp. were able to thrive at higher temperature and their thermostable esterases or lipases have properties useful for biotechnological applications