First characterization of cultivable extremophile Chroococcidiopsis isolates from a solar panel

Abstract

IntroductionMicroorganisms colonize a wide range of natural and artificial environments. Even though most of them are unculturable in laboratory conditions, some ecosystems are ideal niches for bioprospecting extremophiles with unique properties. Up today, there are few reports concerning microbial communities found on solar panels, a widespread, artificial, extreme habitat. Microorganisms found in this habitat belong to drought-, heat- and radiation-adapted genera, including fungi, bacteria, and cyanobacteria.MethodsHere we isolated and identified several cyanobacteria from a solar panel. Then, some strains isolated were characterizated for their resistance to desiccation, UV-C exposition, and their growth on a range of temperature, pH, NaCl concentration or diverse carbon and nitrogen sources. Finally, gene transfer to these isolates was evaluated using several SEVA plasmids with different replicons to assess their potential in biotechnological applications.Results and discussionThis study presents the first identification and characterization of cultivable extremophile cyanobacteria from a solar panel in Valencia, Spain. The isolates are members of the genera Chroococcidiopsis, Leptolyngbya, Myxacorys, and Oculatella all genera with species commonly isolated from deserts and arid regions. Four of the isolates were selected, all of them Chroococcidiopsis, and characterized. Our results showed that all Chroococcidiopsis isolates chosen were resistant up to a year of desiccation, viable after exposition to high doses of UV-C, and capable of being transformed. Our findings revealed that a solar panel is a useful ecological niche in searching for extremophilic cyanobacteria to further study the desiccation and UV-tolerance mechanisms. We conclude that these cyanobacteria can be modified and exploited as candidates for biotechnological purposes, including astrobiology applications.

Growth characterization and biostimulant potential ofCoelastrellasp. D14 a green microalga isolated from a solar panel

“…Solar panel samples were collected during the summertime of 2013 and 2014 for screening cyanobacteria and microalgae. The first isolation was made in Castenholz-D medium (Baldanta et al, 2023) and afterwards, microalgae and cyanobacteria were maintained growing on BG11. At this time, a consortium among microorganisms, bacteria and cyanobacteria/microalgae, was evident on BG11 plates.…”

“…At this time, a consortium among microorganisms, bacteria and cyanobacteria/microalgae, was evident on BG11 plates. After several streaks, different strains were isolated (Baldanta et al, 2023). One of these strains, a unicellular green microalga, named D14, was identified by PCR 18S rRNA amplification reaching a homology of 99% with other Coelastrella strains.…”

“…The microalga used in this study, Coelastrella sp. D14, was isolated from a solar panel in Valencia (Spain) (Baldanta et al, 2023). Coelastrella sp.…”

“…Coelastrella sp. D14 was previously identified using primers for 18rRNA amplification (18S-Fw 5'-GTCAGAGGTGAAATTCTTGGATTTA-3', 18S-Rv 5'-AGGGCAGGGACGTAATCAACG-3') (Baldanta et al, 2023). The 18S rRNA gene sequence of Coelastrella sp.…”

Oxygen evolution from extremophilic cyanobacteria confined in hard biocoatings

“…It can be genetically engineered to withstand biofuels and ethanol ( 23 , 24 ) and was also able to produce hydrogen when immobilized in alginate beads ( 25 ). The third choice is Chroococcidiopsis cubana PCC 7433 (SAG39.79), which was first isolated from a dried pool in Cuba and is part of a genus that has extremophilic features, e.g., desiccation- and radiation-resistance ( 26 – 29 ). As an example, Fagliarone et al demonstrated that members of this genus were able to survive air-dried storage for 4 years ( 26 ).…”