## 4 Discussion  
The genomic characterization and functional analysis of _Geobacillus_ sp. G4, isolated from the geothermal field of Calientes in Tacna, Peru, provided valuable insights into its biotechnological potential. _Geobacillus_ sp. G4 exhibited morphological and physiological characteristics typical of the _Geobacillus_ genus. Initially, a direct comparison with _Geobacillus kaustophilus_ and _Geobacillus thermoleovorans_ was established, given that preliminary phylogenetic analyses and previous studies identified these species as the closest phylogenetic relatives to strain G4, sharing similar physiological profiles and temperature ranges [1, 46]. Morphologically, strain G4 is characterized as a Gram-positive, endospore-forming rod, producing yellowish-white colonies approximately 1.4 mm in diameter, features that are commonly observed among thermophilic _Geobacillus_ strains [3, 5]. Its growth within a temperature range of 50-70 \({}^{\circ}\)C and an optimal pH of 6.0-7.5 further confirms its adaptation to thermophilic environments. Table 1 specifically compares the properties of G4 with _G. kaustophilus_ and _G. thermoleovorans_, highlighting relevant similarities and differences. All three strains are aerobic, Gram-positive, non-motile, and endospore-forming; however, notable differences were observed regarding acid production from various substrates. For instance, _G. kaustophilus_ does not produce acid from lactose, whereas G4 does, along with cellobiose, glycerol, sucrose, and xylose, indicating broader or more efficient metabolic pathways for sugar degradation. The shared ability of G4 and _G. thermoleovorans_ to metabolize lactose and glycerol supports their close relationship [1]. Regarding the optimal pH range, _Geobacillus_ sp. G4 exhibits growth between pH 6.0 and 7.5, slightly narrower compared to some _G. thermoleovorans_ strains that can tolerate conditions up to approximately pH 9.0. Additionally, the tolerance of strain G4 to NaCl concentrations up to 2.5% (\(w/v\)) indicates adaptations to moderately saline environments, a trait shared by many thermophilic _Geobacillus_ species inhabiting geothermal springs [19, 54, 55]. _Geobacillus_ sp. G4 exhibited extracellular enzymatic activities for cellulase, pectinase, xylanase, amylase, protease, and lipase on agar plates, with notably prominent hydrolysis halos observed particularly on starch-containing media. Similar enzyme profiles were previously reported for other thermophilic strains, such as _G. stearothermophilus_, _Geobacillus_ sp. GS33, _Geobacillus_ sp. WSUCF1, and _Geobacillus_ sp. DUSELR13, particularly regarding the stability of amylase and xylanase at elevated temperatures [56, 57, 58, 59]. Although protease and lipase activities were detectable in solid media assays, they were not quantifiable in liquid cultures, potentially due to differences in gene regulation or specific culture conditions [60, 61]. Moreover, the diverse enzymatic profile identified in _Geobacillus_ sp. G4 highlights a promising opportunity for developing enzyme cocktails tailored for efficient lignocellulosic biomass conversion into bioethanol and other valuable bioproducts. Despite their recognized biotechnological potential, relatively few studies have focused on formulating enzyme cocktails based on multiple thermostable enzymes derived from _Geobacillus_ species [2, 18]. Genome sequencing revealed a 3.4 Mb genome with a G+C content of 52.59%, consistent with genomic attributes previously reported for the _Geobacillus_ genus, including strains such as _Geobacillus stearothermophilus_ EF60045 and SJEF4-2 and _Geobacillus_ sp. E55-1, and _Geobacillus_ sp. 56T2 and 56T3 [62, 22, 63]. Studies demonstrate that the pan-genome of these bacteria reveals great genetic diversity, facilitated by horizontal gene transfer (HGT), which enables adaptation to various ecological niches [64]. However, classification based solely on 165 rRNA sequences has proven to be limited due to the high similarity betweenspecies [9].