Screening and optimization of starch from marine microalgae isolated from Penang sea water Malaysia

Starch is a major carbohydrate source in human staple foods and a component of raw materials for non-food applications. Microalgae are the subject of extensive investigation due to their high carbohydrate content, ease of growth, and capacity to absorb more carbon dioxide while still producing greenhouse gases during photosynthesis. Two marine microalgae strains from Malaysia's Penang Sea Water have been successfully isolated and are designated as Klebsormidium flaccidum GN-2, and Nannochloropsis oculata YG-2. K. flaccidum GN-2 produced 16.84% of starch, biomass 0.81 g/L whereas N. oculata YG-2 contained 3.06% and 0.40 g/L of starch and biomass, respectively. K. flaccidum GN-2 was selected to proceed for optimization using Response Surface Methodology (RSM). The starch produced was 19.06% and 0.98 g/L of biomass under the optimized conditions of 35.53 ppt salinity, 23 h of light exposure, and a flow rate of 1 v/v of carbon dioxide. Subsequent nutrient deprivation experiments showed a decrease in biomass and starch. In conclusion, marine microalgae isolated from the Penang Sea successfully produced starch. Further study should be carried out to improve the condition and factors to produce higher starch content in K. flaccidum GN-2 and make it a new promising starch source.