The west coast of the Arabian Peninsula borders the Red Sea, a water body which maintains high average temperatures and increased salinity compared to other seas or oceans. This geography has many resources which could be used to support algal biotechnology efforts in bio-resource circularity. However, summer conditions in this region may exceed the temperature tolerance of most currently cultivated microalgae. The Cyanidiophyceae are a class of polyextremophilic red algae that natively inhabit acidic hot springs. C. merolae 10D has recently emerged as an interesting model organism capable of high-cell density cultivation on pure CO2 with optimal growth at elevated temperatures and acidic pH. C. merolae biomass has an interesting macromolecular composition, is protein rich, and contains valuable bio-products like heat-stable phycocyanin, carotenoids, β-glucan, and starch. Here, photobioreactors were used to model C. merolae 10D growth performance in simulated environmental conditions of the mid-Red Sea coast across four seasons, it was then grown at various scales outdoors in Thuwal, Saudi Arabia during the Summer of 2022. We show that C. merolae 10D is amenable to cultivation with industrial-grade nutrient and CO2 inputs outdoors in this location and that its biomass is relatively constant in biochemical composition across culture conditions. We also show the adaptation of C. merolae 10D to high salinity levels of those found in Red Sea waters and conducted further modeled cultivations in nutrient enriched local sea water. It was determined that salt-water adapted C. merolae 10D could be cultivated with reduced nutrient inputs in local conditions. The results presented here indicate this may be a promising alternative species for algal bioprocesses in outdoor conditions in extreme coastal desert summer environments.

The polyextremophilic Cyanidiales are eukaryotic red microalgae with promising biotechnological properties arising from their low pH and elevated temperature requirements which can minimize culture contamination at scale. Cyanidioschyzon merolae 10D is a cell wall deficient species with a fully sequenced genome that is amenable to nuclear transgene integration by targeted homologous recombination. C. merolae maintains a minimal carotenoid profile and here, we sought to determine its capacity for ketocarotenoid accumulation mediated by heterologous expression of a green algal beta-carotene ketolase (BKT) and hydroxylase (CHYB). To achieve this, a synthetic transgene expression cassette system was built to integrate and express Chlamydomonas reinhardtii (Cr) sourced enzymes by fusing native C. merolae transcription, translation and chloroplast targeting signals to codon-optimized coding sequences. Chloramphenicol resistance was used to select for the integration of synthetic linear DNAs into a neutral site within the host genome. CrBKT expression caused accumulation of canthaxanthin and adonirubin as major carotenoids while co-expression of CrBKT with CrCHYB generated astaxanthin as the major carotenoid in C. merolae. Unlike green algae and plants, ketocarotenoid accumulation in C. merolae did not reduce total carotenoid contents, but chlorophyll a reduction was observed. Light intensity affected global ratios of all pigments but not individual pigment compositions and phycocyanin contents were not markedly different between parental strain and transformants. Continuous illumination was found to encourage biomass accumulation and all strains could be cultivated in simulated summer conditions from two different extreme desert environments. Our findings present the first example of carotenoid metabolic engineering in a red eukaryotic microalga and open the possibility for use of C. merolae 10D for simultaneous production of phycocyanin and ketocarotenoid pigments.

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The west coast of Saudi Arabia borders the Red Sea, which maintains high average temperatures and increased salinity compared to other seas or oceans. Summer conditions in the Arabian Peninsula may exceed the temperature tolerance of most currently cultivated microalgae. The Cyanidiales are polyextremophilic red algae whose native habitats are at the edges of acidic hot springs. Cyanidioschyzon merolae 10D has recently emerged as an interesting model organism capable of high-cell density cultivation on pure CO2 with optimal growth at 42 degrees C and low pH between 0.5-2. C. merolae biomass has an interesting macromolecular composition, is protein rich, and contains valuable bio-products like heat-stable phycocyanin, carotenoids, beta-glucan, and starch. Here, photobioreactors were used to model C. merolae 10D growth performance in simulated environmental conditions of the mid-Red Sea coast across four seasons, it was then grown at various scales outdoors in Thuwal, Saudi Arabia during the Summer of 2022. We show that C. merolae 10D is amenable to cultivation with industrial-grade nutrient and CO2 inputs outdoors in this location and that its biomass is relatively constant in biochemical composition across culture conditions. We also show the adaptation of C. merolae 10D to high salinity levels of those found in Red Sea waters and conducted further modeled cultivations in nutrient enriched local sea water. It was determined that salt-water adapted C. merolae 10D could be cultivated with reduced nutrient inputs in local conditions. The results presented here indicate this may be a promising alternative species for algal bioprocesses in outdoor conditions in extreme desert summer environments.

BACKGROUND: Colombia has a high diversity of medicinal plants, including Tachuelo (Zanthoxylum rhoifolium), a tree belonging to the family Rutaceae, which has been attributed an analgesic use by communities of the Colombian southwest. Nevertheless, this species has been scarce studied in Colombia. The studies have been limited to the isolation of compounds with antifungal and insecticide activity, using the leaves, branches, and bark of the plant in aqueous, and organic extracts. Neither pharmacological tests have been carried out, nor the analgesic and neuromotor activity have been tested from preparations with this plant’s fruits. OBJECTIVES: To evaluate the analgesic and neuromotor effect of the aqueous and hexane extract of the fruits of Z. rhoifolium. METHODS: As there were no preliminary reports of this study, the first observation was made through Irwin’s test. The formalin and the rotarod test were performed to determine the analgesic and motor coordination effects, respectively. RESULTS: All the evaluated treatments demonstrated to generate analgesia, anesthesia, passivity, reduction in the alarm reaction, and have antinociceptive activity in the formalin test; while only the high dose of the nonpolar extract generated a deficit in the motor performance of the rodents in the rotarod test. CONCLUSIONS: the antinociceptive effect of the aqueous and hexane extracts of this species’ fruits was demonstrated. The hexane extract generated a neuromotor effect, which validates the ethnobotanical reports on Z. rhoifolium fruits.