Native Cyanobacteria from Sri Lankan Salt Marsh Ecosystem: A Promising Sustainable Solution to the Prevailing Food Crisis

Abstract

Hyperinflation, poverty, and environmental degradation lead to a sudden deterioration of the nutritional status in Sri Lanka. Crop-based food supply is more challenging due to rapid depletion of arable lands and limited availability of seasonal crops. Native cyanobacteria from extreme environments, specifically adapted with unique, richer nutrient profiles, could be promising alternatives for cropbased food production. Minimal growth requirements ensure their optimal growth in local environments and facilitate convenient utilization with minimal disturbance to the local biodiversity. In line with the above, 08 native cyanobacteria namely; Leptolyngbya, Phormidium, Nostoc, Pseudanabaena, Nodosilinea-I, Limnothrix, Nodosilinea-II, and Oscillatoria were isolated and morphologically characterized from salt marsh ecosystem in Mannar (8.9810° N, 79.9044° E), Sri Lanka, and nutrient analysis was carried out to identify their potential as promising natural alternatives to overcome food insecurity. Dry biomass of the strains was analyzed for total carbohydrate and protein contents using Dubois’ method and Lowry method, respectively. Two strains showed more than 50% of total protein contents with the highest (58.0%) in Pseudanabaena sp. Three strains showed more than 40% of total carbohydrate contents with the highest (44.6%) in Nodosilinea sp.-II. Two more strains showed more than 25% of total carbohydrate contents. Results were promising and comparable with/higher than the contents found in general protein and carbohydrate food sources, highlighting their significant potential to be developed as macronutrient supplements. Rapid regeneration, easy access and availability throughout the year, make their utilization more promising over plant materials, as a sustainable approach to overcome food insecurity.