Screening and characterization of thermophiles from Malacca hot spring

Abstract

Seven strains of thermophilic bacteria (GD-1, GD-2, GD-3, GD-4, GD-5, GD-6 and GD-7) and three strains of thermophilic bacteria (JS-1, JS-2 and JS-3) were isolated and cultivated from samples collected from Kg Ganun Gadek, Alor Gajah and Kg Air Panas, Bemban hot springs respectively which both located at Malacca. The temperature and pH of the Kg Ganun Gadek sampling sites were 55°C and 7.59 respectively while 52 °C and 7.7 for Kg Air Panas Sampling sites. Thermus medium was found to be the most suitable medium for the growth for the eight strains. Strains GD-1, GD-2, GD-3 and GD 5 formed yellow colonies while strains GD-4, GD-6, JS-1, JS-2 and JS-3 formed white colonies. Further studies were done for strains GD-1, GD-2, GD-3, GD-4, GD-5, JS-1, JS-2 and JS-3. Cells of these strains were rod-shaped and occurred in single and chain like arrangement. Only two strains were Gram-negative (JS-2 and JS-3). Strains GD-1, GD-2 and GD-6 were able to hydrolyse starch. Catalase test revealed that strains GD-1, GD-2, GD-3, GD-6, JS-1 and JS-2 able to degraded hydrogen peroxide (H2O2) to water and oxygen. Blast search results of partial 16S rRNA sequences revealed strains GD-1, GD-2 and GD-6 to be Anoxybacillus gonesis while strains GD-3 and GD-5 are Anoxybacillus sp. Strain GD-4 showed closest to Bacillus licheniformis. Strain JS-1 showed closest relationship to Bacillus sp. and Geobacillus kautophilus while the result showed strain JS-3 is the most similar to Bacillus licheniformis and Bacillus sp.. All result has 99% identity. The tentative identities of the strain were supported by the phenotypic and phylogenetic evidence.