The increasing worldwide demand for antimicrobial agents has significantly contributed to the alarming rise of antimicrobial resistance, posing a grave threat to human life. Consequently, there is a pressing need to explore uncharted environments, seeking out novel antimicrobial compounds that display exceptionally efficient capabilities. Hot springs harbor microorganisms possessing remarkable properties, rendering them an invaluable resource for uncovering groundbreaking antimicrobial compounds. In this study, thermophilic bacteria were isolated from Mahallat Hot Spring, Iran. Out of the 30 isolates examined, 3 strains exhibited the most significant antibacterial activities against Escherichia coli and Staphylococcus aureus. Furthermore, the supernatants of the isolated strains exhibited remarkable antibacterial activity, displaying notable resistance to temperatures as high as 75 °C for 30 min. It was determined that the two strains showed high similarity to the Bacillus genus, while strain Kh3 was classified as Saccharomonospora azurea. All three strains exhibited tolerance to NaCl. Bacillus strains demonstrated optimal growth at pH 5 and 40 °C, whereas S. azurea exhibited optimal growth at pH 9 and 45 °C. Accordingly, hot springs present promising natural reservoirs for the isolation of resilient strains possessing antibacterial properties, which can be utilized in disease treatment or within the food industry.

Biodegradable Polyhydroxyalkanoates (PHAs), produced by bacteria, are a solid alternative to native plastic. However, in the archaea domain, some members of the haloarchaea genera have been identified as PHAs producers. In the present study, we selected Halarchaeum acidiphilum strain and optimized it for PHB production. We isolated the Halarchaeum acidiphilum strain from the Lut desert of Iran and performed Sudan black stain and UV absorption of crotonic acid. The results showed that the strain produced PHA in the medium containing 12.5% sodium chloride and pH equal to 7.6 at 37°C at the stationary phase. The PHA was extracted in sterile water, and the Physico-chemical analysis of PHA was detected by FTIR and 1HNMR test, which approved the ester structure and the efficiency was almost 71%. The use of haloarchaea in the production of PHA has advantages such as no need for sterile conditions, simple raw materials, and fast lysis of bacteria in the absence of salt, which help the processes of the economic cycle of PHAs extraction.

Background and Objective: Chitin and its hydrolyzing enzyme, chitinase, are produced by a variety of organisms and microorganisms. Production chitinase with Archaea are more concern today, for easy to extraction and contamination control. Therefor in this research the production of this enzyme is reported by Archaea. Materials and Methods: 60 samples were collected from different saline areas of Iran and then enrichment and qualitative screening were performed to isolate chitinase-producing archaea. The selected strain was identified biochemically and molecularly and its optimal growth conditions were determined. Results: Halophilic Archaea strains were isolated on chitin as the only sources of carbon for chitinase-producing archaeal strains. The result showed, a pink colony strain from Lake Urmia with chitinase activities of 5.1875 IU/ml was selected for maximum enzyme production and identified as Haloferax mediterranei by PCR reaction test. The enzyme was concentrated and partial extracted. Conclusion: Enzyme production from archaea can be useful for industries. The hydrolysis of chitin, the second biopolymer after cellulose, which also leaves a lot of waste every year, is of great importance, therefore, with high chitinase activity from haloarchaea, it can be used in industry without bacterial contamination science this microorganism is stable only in high salt solution.