Sustainable cultivation of Cylindrotheca sp. using organic carbon and nitrogen sources for enhanced biomass and metabolite production

The study explores the impact of different organic carbon sources and agricultural fertilizers on the growth and metabolite production of marine benthic diatom Cylindrotheca sp. The results revealed that the highest cell density was recorded in the cultures supplied with urea (1 g L −1 ), which was 1.9% more than the control. The protein content was increased (1.75%) in the cultures treated with different C and N sources compared to the control. The total chlorophyll and carotenoid content was highest in the cultures with 1.5 g L −1 sucrose (25 ± 0.33 mg g −1 ) and 0.5 g L −1 glucose (10.25 ± 0.13 mg g −1 ), respectively. Further, the fatty acid profile reveals that total MUFA (monounsaturated fatty acids) was maximum in sucrose at 1.5 g L −1 (45.63%) followed by control (31.25%). C22:5 (Docosapentaenoic acid) was found to be maximum in sucrose 1.5 g L −1 (6.98%) and eicosapentaenoic acid (EPA) was maximum in glycerol 1.5 g L −1 (14.37%). Thus, based on the results, it can be inferred that since different nutrients have varying effects on diatom growth and biomolecule production, this study can aid in selecting a suitable upstream approach based on the desired downstream application. The study provides pioneering evidence on how specific nutrient combinations (e.g., urea, sucrose, glucose) optimize the production of biomolecules such as MUFA and PUFA (polyunsaturated fatty acids), which have high value in nutraceutical and pharmaceutical industries.