Microalgae are photoautotrophic microorganisms known as producers of a large variety of metabolites. The taxonomic diversity of these microorganisms has been poorly explored. In this study, a newly isolated strain was identified based on the 18S rRNA encoding gene. The phylogenetic analysis showed that the isolated strain was affiliated with the Rhodomonas genus. This genus has greatly attracted scientific attention according to its capacity to produce a large variety of metabolites, including phycoerythrin. Growth and phycoerythrin production conditions were optimized using a Plackett–Burman design and response surface methodology. An expression profile analysis of the cpeB gene, encoding the beta subunit of phycoerythrin, was performed by qRT-PCR under standard and optimized culture conditions. The optimization process showed that maximum cell abundance was achieved under the following conditions: CaCl₂ = 2.1328 g/L, metal solution = 1 mL/L, pH = 7 and light intensity = 145 μmol photons/m²/s, whereas maximum phycoerythrin production level occurred when CaCl₂ = 1.8467 g/L, metal solution = 1 mL/L, pH = 7 and light intensity = 157 μmol/m²/s. In agreement, positive transcriptional regulation of the cpeB gene was demonstrated using qRT-PCR. This study showed the successful optimization of abiotic conditions for highest growth and phycoerythrin production, making Rhodomonas sp. suitable for several biotechnological applications.

The exploitation of thermophilic hydrocarbon-utilizing bacilli could provide novel environmentally friendly surfactants. In this work, 80 thermophilic bacilli isolated from shallow hydrothermal vents of the Eolian Islands (Italy) were screened for their ability to utilize hydrocarbons and produce biosurfactants (BSs). Among them, 15 strains grew with kerosene or gasoline (2% v/v) as the only carbon and energy source, and most of them were positive to the methylene blue agar as prescreening assay for BSs production and displayed emulsifying activity. The cell-free supernatants (CFSs) from two selected strains, Bacillus licheniformis B3-15 and Bacillus horneckiae SBP3, were both surface active and able to emulsify different hydrocarbons and vegetable oils. BSs from B3-15 (910 mg L⁻¹) and SBP3 (950 mg L⁻¹) were chemically different surfactin-like lipopeptides, with specific mineral-, castor- and crude oil removal ability from the cotton matrix. CFSs from the 15 thermophilic strains, which harbor both lipolytic and surfactant abilities, could be suitable for industrial-based applications and environmental issues, such as oil recovery and removal from polluted areas or surfaces, (e.g., oil pipelines, bilge tankers, or industrial silos), whereas the crude BSs, as high-value compounds, may be used in different fields of application, as detergent, cosmeceutical, and pharmaceutical industries.

Indoor air sanitizers contrast airborne diseases and particularly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/Coronavirus disease 2019 (COVID-19). The commercial air sanitizer Zefero (Cf7 S.r.l., San Giovanni La Punta, Italy) works alternatively using a set of integrated disinfecting technologies (namely Photocatalysis/UV mode) or by generating ozone (Ozone mode). Here we evaluated the virucidal efficacy of Zefero setup modes against human Betacoronavirus OC43 and SARS-CoV-2. For this purpose, we designed a laboratory test system in which each virus, as aerosol, was treated with Photocatalysis/UV or Ozone mode and returned into a recirculation plexiglass chamber. Aerosol samples were collected after different times of exposure, corresponding to different volumes of air treated. The viral RNA concentration was determined by qRT-PCR. In Photocatalysis/UV mode, viral RNA of OC43 or SARS-CoV-2 was not detected after 120 or 90 min treatment, respectively, whereas in Ozone mode, viruses were eliminated after 30 or 45 min, respectively. Our results indicated that the integrated technologies used in the air sanitizer Zefero are effective in eliminating both viruses. As a reliable experimental system, the recirculation chamber developed in this study represents a suitable apparatus for effectively comparing the disinfection capacity of different air sanitizers.