Chemical composition of selected marine microalgae, with emphasis on lipid and carbohydrate production for potential use as feed resources

Abstract

Marine microalgae are a promising sustainable source of lipids, omega-3 fatty acids, and carbohydrates. Selected microalgae species belonging to the Bacillariophyceae, Haptophyceae, Eustigmatophyceae, and Prasinophyceae were characterised for cellular content of carbon and nitrogen, and for production yields of lipids, fatty acids, total carbohydrates, and β-glucans. Carbon and nitrogen content showed a hyperbolic decrease with increasing cell numbers for Chaetoceros calcitrans, C. muelleri, Skeletonema costatum, Tetraselmis sp., and Nannochloropsis oculata. Cultures of Pavlova lutheri and Tisochrysis lutea showed an increase in carbon content per cell, but a decrease in nitrogen content. The total lipid content of C. muelleri, C. calcitrans, N. oculata, and T. lutea increased with decreasing relative growth rate; however, the highest productivity of lipids was found in T. lutea grown at 40% of the maximum specific growth rate. The highest content of eicosapentaenoic acid was found in C. muelleri, C. calcitrans, and N. oculata, and the highest content of docosahexaenoic acid was found in T. lutea. The β-glucan fraction of the carbohydrates was highest in C. muelleri and C. calcitrans and was very low in N. oculata. Out of the species investigated, C. muelleri had the highest production yield of β-glucans, obtained when cultivated at a 40% relative growth rate.

Resource allocation accounts for the large variability of rate-yield phenotypes across bacterial strains

“…Glycogen concentrations in wild-type E. coli cells are low, but there exist mutants which accumulate high amounts of glycogen, on the order of 25-30% of biomass (Morin et al, 2016). The biomass percentage of carbohydrates and lipids in other microorganisms, such as microalgae, reaches even higher levels (Finkel et al, 2016;Reitan et al, 2021). Some caution should be exercised in the biological interpretation of the points µ max and Y max though, as they are located on the upper boundary of the cloud of predicted rate-yield phenotypes.…”

Nutrient Deprivation Coupled with High Light Exposure for Bioactive Chrysolaminarin Production in the Marine Microalga Isochrysis zhangjiangensis

“…Microalgae are fast-growing single-celled photosynthetic microorganisms. They are considered an ideal source of β-glucan because of their ability to fix carbon dioxide and efficiently accumulate β-glucan under controllable cultivation conditions [ 11 , 12 ]. Microalgal β-glucan is produced mainly in the form chrysolaminarin in Haptophyta and Heterokontophyta, and paramylon in Euglenophyta [ 11 , 13 ].…”

Characterization of two 1,3-β-glucan-modifying enzymes from Penicillium sumatraense reveals new insights into 1,3-β-glucan metabolism of fungal saprotrophs

“…Our attention was drawn to the 1,3-β-glucan degrading machinery of P. sumatraense, since 1,3-β-glucan, differently from plant-specific cell wall polysaccharides, such as cellulose, hemicellulose and pectin, is widely distributed in several phylogenetically distant organisms. Indeed, the cell wall of many microalgae [11][12][13], bacteria [14], yeasts, and fungi, including Penicillium species [15], contains 1,3-β-glucans to a different extent. This polysaccharide is also present as a storage sugar in brown macroalgae from Laminaria genus (i.e., a 1,3/1,6-β-mixed glucan referred to as laminarin, [16]) and as defense-induced cell wall polysaccharide in land-plants (i.e., a 1,3/1,6-β-mixed glucan referred to as callose, [17]).…”