Diversity of Thermophilic Bacteria Isolated from Extreme Environments in Indonesia: A Perspective in Biotechnology Applications

Indonesia, located along the Pacific Ring of Fire, hosts abundant geothermal sites and hot springs, creating ideal environments for thermophilic bacteria, which are microorganisms capable of thriving at elevated temperatures. These bacteria are recognized for producing thermostable enzymes, including amylases, proteases, cellulases, xylanases, and lipases, which are highly valuable for various industrial applications. This review compiles and analyses the diversity of thermophilic bacteria isolated from 13 geothermal locations across Indonesia, highlighting their enzymatic capabilities and potential applications in biotechnology. Notable genera include Bacillus, Geobacillus, Pseudomonas, Anoxybacillus, and Thermoanaerobacterium. These isolates demonstrate promising roles in bioenergy production, waste treatment, environmental bioremediation, food processing, agriculture, and pharmaceuticals. Additionally, several strains exhibit the capacity to produce bioactive compounds such as antimicrobial agents and natural pigments. The review also details standardized screening methods using selective solid media and outlines molecular identification techniques, including 16S rRNA gene sequencing and whole genome sequencing. Furthermore, it explores recombinant enzyme technologies applied to thermophiles, enabling enhanced expression, activity, and thermal stability of enzymes for industrial processes. Despite Indonesia's extensive geothermal resources, its microbial biodiversity remains largely untapped. This review not only serves as a scientific inventory of thermophilic strains but also emphasizes their relevance for biotechnological innovations. It aims to support future research, bioprospecting strategies, and industrial applications based on Indonesia’s unique thermophilic microbial diversity, ultimately contributing to sustainable technological advancement and resource utilisation.