Diverse thermophilic Bacillus species with multiple biotechnological activities are associated within the Egyptian soil and compost samples

Thermophilic strains of Bacillus can express enzymes of higher thermal stability, which allows carrying out industrial fermentations under higher temperatures. This lowers the contamination potential, accelerates mixing rates and facilitates the recovery of fermentation end products. The present study was thus designed to isolate and characterize thermophilic Bacillus cultures from soil and compost samples. Forty-two thermophilic Bacillus isolates could be identified employing morphological, physiological and the 16S rRNA gene sequencing analyses. The isolates showed a high degree of biological diversity involving 13 Bacillus species and 1 subspecies but were dominated by Bacillus licheniformis. Phylogenetic analysis of B. licheniformis isolates based on the DNA sequencing of gyrA and rpoB genes presented them in two main genetic groups. Isolates of five thermophilic species including B. licheniformis, Bacillus altitudinis, Bacillus paralicheniformis, Bacillus subtilis and Bacillus thermoamylovorans showed multiple activities to degrade all of cellulose, hemicellulose and lignin. Those multifunctional thermophilic Bacillus isolates can be harnessed in the degradation of plant wastes for the production of biofuels and compost.

Bacteriophages of Thermophilic ‘Bacillus Group’ Bacteria—A Review

Bacteriophages of thermophiles are of increasing interest owing to their important roles in many biogeochemical, ecological processes and in biotechnology applications, including emerging bionanotechnology. However, due to lack of in-depth investigation, they are underrepresented in the known prokaryotic virosphere. Therefore, there is a considerable potential for the discovery of novel bacteriophage-host systems in various environments: marine and terrestrial hot springs, compost piles, soil, industrial hot waters, among others. This review aims at providing a reference compendium of thermophages characterized thus far, which infect the species of thermophilic ‘Bacillus group’ bacteria, mostly from Geobacillus sp. We have listed 56 thermophages, out of which the majority belong to the Siphoviridae family, others belong to the Myoviridae and Podoviridae families and, apparently, a few belong to the Sphaerolipoviridae, Tectiviridae or Corticoviridae families. All of their genomes are composed of dsDNA, either linear, circular or circularly permuted. Fourteen genomes have been sequenced; their sizes vary greatly from 35,055 bp to an exceptionally large genome of 160,590 bp. We have also included our unpublished data on TP-84, which infects Geobacillus stearothermophilus (G. stearothermophilus). Since the TP-84 genome sequence shows essentially no similarity to any previously characterized bacteriophage, we have defined TP-84 as a new species in the newly proposed genus Tp84virus within the Siphoviridae family. The information summary presented here may be helpful in comparative deciphering of the molecular basis of the thermophages’ biology, biotechnology and in analyzing the environmental aspects of the thermophages’ effect on the thermophile community.

Evaluation of Heterologous Biosynthetic Pathways for Methanol-Based 5-Aminovalerate Production by Thermophilic Bacillus methanolicus

The use of methanol as carbon source for biotechnological processes has recently attracted great interest due to its relatively low price, high abundance, high purity, and the fact that it is a non-food raw material. In this study, methanol-based production of 5-aminovalerate (5AVA) was established using recombinant Bacillus methanolicus strains. 5AVA is a building block of polyamides and a candidate to become the C5 platform chemical for the production of, among others, δ-valerolactam, 5-hydroxy-valerate, glutarate, and 1,5-pentanediol. In this study, we test five different 5AVA biosynthesis pathways, whereof two directly convert L-lysine to 5AVA and three use cadaverine as an intermediate. The conversion of L-lysine to 5AVA employs lysine 2-monooxygenase (DavB) and 5-aminovaleramidase (DavA), encoded by the well-known Pseudomonas putida cluster davBA, among others, or lysine α-oxidase (RaiP) in the presence of hydrogen peroxide. Cadaverine is converted either to γ-glutamine-cadaverine by glutamine synthetase (SpuI) or to 5-aminopentanal through activity of putrescine oxidase (Puo) or putrescine transaminase (PatA). Our efforts resulted in proof-of-concept 5AVA production from methanol at 50°C, enabled by two pathways out of the five tested with the highest titer of 0.02 g l–1. To our knowledge, this is the first report of 5AVA production from methanol in methylotrophic bacteria, and the recombinant strains and knowledge generated should represent a valuable basis for further improved 5AVA production from methanol.

Hot Resistance of Spores from the Thermophilic Bacillus horneckiae SBP3 of Shallow Hydrothermal Vent Origin Elucidated by Spectroscopic Analyses

Spores from Bacillus horneckiae SBP3 (SBP3) of shallow hydrothermal vent origin have recently been reported to survive extreme conditions more often than their close phylogenetic relatives B. horneckiae DSM 23495T (BHO) and B. subtilis 168 (BSU) used in biodosimetry and the space microbiology model. To investigate the structures of unheated spores, Fourier-transform infrared spectroscopy (FTIR) analysis was used. The FTIR spectra of the spores from the strains SBP3, BHO and BSU mainly differed in the region that referred to lipids and amino acids or polypeptides, indicating that the SBP3 spores were richer in saturated fatty acids, and the protein structures of SBP3 and BHO spores were more aggregated and complex than those of BSU. SBP3 spores were more resistant (LD90 = 4.2 ± 0.3 min) to wet heat treatment (98 °C) than BHO (LD90 = 1.8 ± 0.2 min) and BSU (LD90 = 2.9 ± 0.5 min) spores were. In comparison to the untreated spores, the Raman spectra of the wet-heat-treated SBP3 spores showed minor variations in the bands that referred to proteins, whereas major changes were observed in the bands that referred to lipids and amide I in the heated BSU spores and to both lipids and proteins bands in the treated BHO spores. These results suggest that the major stability of SBP3 spore proteins could explain their greater resistance to wet heat compared to BHO and BSU. Our findings provide basic information for further comparative studies into spore responses to natural and laboratory stresses, which are useful in several different fields, such as astrobiology.

Antibiotic resistance profile of local thermophilic Bacillus licheniformis isolated from Maysan province soil

The key concern for public health is that bacterial strains isolated from various ecosystems are immune to antibiotics used in human medicine, thus dramatically limiting therapeutic options and threatening the lives of infected people. The present study aims to reveal the antibiotics profile of fiftysix isolates of local thermophilic Bacillus licheniformis isolated from different environmental soil sites in Maysan city, Iraq. The antimicrobial agent resistance profile of B. licheniformis isolates was performed using the disc diffusion assay according to Kirby-Bauer susceptibility test protocol. The results showed that isolates were resistance against cefepime (n=56; 100%), amoxicillin (n=13; 23.3%) and ampicillin (n=52; 92.9%); and intermediate (n=56; 100%) against cephalothin and naldixic acid. The percentage resistance was low for aztreonam (n=4; 7%), chloramphenicol (n=3; 5%), clotrimazole (n=6; 10%), novobiocin (n=2; 3.5%) and ticarcillin (n=3; 5%). On the other hand, all isolates were sensitive (n=56; 100%) towards the following antibiotics: amikacin, ceftazidime, ciprofloxacin, clindamycin, imipenem, netilmycin, gentamicin, nitrofurantion, rifampin, trimethoprim and vancomycin. The results of this study suggest that the Iraqi thermophilic B. licheniformis isolates are variable in their susceptibility towards the standards antimicrobial agents. Furthermore, the presence of cefepime, amoxicillin, ampicillin, cephalothin and naldixic resistant isolates of B. licheniformis in Iraqi soils is of concern about how resistance could spread to other bacteria, and ultimately to humans.

Characterization and identification of three thermophilic Bacillus strain isolated from Domas Crater, Mt. Tangkuban Perahu, Indonesia

Safitri R, Kusumawardhani PD, Annisa, Partasasmita R, Asharina S, Maskoen AM. 2020. Characterization and identification of three thermophilic Bacillus strains isolated from Domas Crater, Mt. Tangkuban Perahu, Indonesia. Biodiversitas 21: 3444-3453. A community of thermophiles within the hot spring of Domas Crater, Mount Tangkuban West Java, has been cultivated and identified based on the 16S ribosomal RNA gene sequence. The hot spring has a temperature of 45°C-76 °C, pH 1-2, the isolate has been cultivated in Thermus medium at a temperature of 70 and pH 6. The three isolated strains were L61A, TS61A, and D41A identified based on the 16S ribosomal RNA gene sequence refer to the GenBank database and all of them belong to the Phylum Firmicutes, which are clustered within the taxonomic groups of Bacillus, the Bacillus, and Geobacillus genera. Nucleotide sequences were compared for homology with BLASTN search at the NCBI Web-site revealed that strains (L61A) had 99.93% similarity with Geobacillus uzenensis. TS61A strain has a 99.24% similarity with Bacillus wiedmannii. Whereas D41A has 99.79% similarity with Bacillus paramycoides. The characterization also includes the phenotypic and biochemical of strains. The bacillus genera were known as a source of thermostable enzymes, plant growth-promoting, probiotics, decomposers of various polysaccharide materials, and bioremediation.