A study on <i>Ochromonas</i> sp. as an alternate microalgal biomass for the synthesis of proteins and carotenoids

Microalgae are a good source of antioxidants and natural bioactive compounds utilized in the pharmaceutical and food industries.The present study aimed to explore Ochromonas gloeopara as an alternate microalgal biomass for synthesising proteins and carotenoids.The freshwater samples of microalgae collected from a lake had microalgae and macroalgae that feed on microalgae. This sample was further subcultured in BG-11 media with 20nM phosphate to inhibit the growth of predator species. The isolated microalgae were identified as Ochromonas cf. gloeopara by 18S rRNA sequencing. A comparison of growth characteristics and protein production by the isolate with Chlorella vulgaris indicated that O. gloeopara had a uniform growth rate and a better protein production of 33.83mg/g. Carotenoid production was found to be 424.64 µg/g and 263.87 µg/g dry biomass by O. gloeopara and C. vulgaris, respectively. Thin Layer Chromatography analysis revealed three types of carotenoids: β-carotene, astaxanthin mono and diesters produced by C. vulgaris, whereas Ochromonas produced only β-carotene. Physical parameter studies revealed that the optimum growth condition for C. vulgaris was at 1% salinity and pH 7, but it had a better carotenoid production at 0.5% salinity. O. gloeopara had better growth and production of carotenoids at 0% salinity and pH 7. These carotenoids and proteins can be used in various food and pharma industries.