Solar cultivation of microalgae in a desert environment for the development of techno-functional feed ingredients for aquaculture in Qatar.

The demand for aquaculture feed will increase in the coming years in order to ensure food security for a growing global population. Microalgae represent a potential fish-feed ingredient; however, the feasibility of their sustainable production has great influence on its successful application. Geographical locations offering high light and temperature, such as Qatar, are ideal to cultivate microalgae with high productivities. For that, the environmental and biological interactions, including field and laboratory optimization, for solar production and application of two native microalgae, Picochlorum maculatum and Nannochloris atomus, were investigated as potential aquaculture feed ingredients. After validating pilot-scale outdoor cultivation, both strains were further investigated under simulated seasonal conditions using a thermal model to predict light and culture temperature cycles for the major climatic seasons in Qatar. Applied thermal and light variations ranged from 36 °C and 2049 µmol/m2/s in extreme summer, to as low as 15 °C and 1107 µmol/m2/s in winter, respectively. Biomass productivities of both strains varied significantly with maximum productivities of 32.9 ± 2.5 g/m2/d and 17.1 ± 0.8 g/m2/d found under moderate summer conditions for P. maculatum and N. atomus, respectively. These productivities were significantly reduced under both extreme summer, as well as winter conditions. To improve annual biomass productivities, the effect of implementation of a simple ground heat exchanger for thermal regulation of raceway ponds was also studied. Biomass productivities increased significantly, during extreme seasons due to respective cooling and heating of the culture. Both strains produced high amounts of proteins during winter, 54.5 ± 0.55% and 44 ± 2.25%, while lipid contents were high during summer reaching up to 29.6 ± 0.75 and 28.65 ± 0.65%, for P. maculatum and N. atomus respectively. Finally, using acute toxicity assay with zebra fish embryos, both strains showed no toxicity even at the highest concentrations tested, and is considered safe for use as feed ingredient and to the environment.

Microalgal-based feed: promising alternative feedstocks for livestock and poultry production.

There is an immediate need to identify alternative sources of high-nutrient feedstocks for domestic livestock production and poultry, not only to support growing food demands but also to produce microalgae-source functional foods with multiple health benefits. Various species of microalgae and cyanobacteria are used to supplement existing feedstocks. In this review, microalgae have been defined as a potential feedstock for domestic animals due to their abundance of proteins, carbohydrates, lipids, minerals, vitamins, and other high-value products. Additionally, the positive physiological effects on products of animals fed with microalgal biomass have been compiled and recommendations are listed to enhance the assimilation of biomolecules in ruminant and nonruminant animals, which possess differing digestive systems. Furthermore, the role of microalgae as prebiotics is also discussed. With regards to large scale cultivation of microalgae for use as feed, many economic trade-offs must be considered such as the selection of strains with desired nutritional properties, cultivation systems, and steps for downstream processing. These factors are highlighted with further investigations needed to reduce the overall costs of cultivation. Finally, this review outlines the pros and cons of utilizing microalgae as a supplementary feedstock for poultry and cattle, existing cultivation strategies, and the economics of large-scale microalgal production.

Sustainable Food Production and Nutraceutical Applications from Qatar Desert Chlorella sp. (Chlorophyceae).

Microalgae isolated from the Qatari desert was identified as thermotolerant, with a rich metabolite profile that is appropriate for use as food and health supplements. In this research, a species of Chlorella, QUCCCM3, from the Qatar University Culture Collection of Cyanobacteria and Microalgae, was investigated for its growth characteristics and metabolite compositions for use as potential feedstock for food production. The strain was cultivated at 30, 35, and 40 °C, covering the annual average low and high temperatures in Qatar. The highest growth rates were recorded for cultures at 30 °C with 0.64 ± 0.04 day-1, followed by a growth rate of 0.54 ± 0.06 day-1 at 40 °C, indicating its thermotolerance ability. The biomass exhibited a high protein content (43 ± 2.3%), with existence of lysine (4.13%) as an essential amino acid, and docosahexaenoic acid, linoleic acid, and alpha-linolenic acid as important omega fatty acids present. On the other hand, Chlorella sp. QUCCCM3 also exhibited a high capacity for scavenging free radicals with an antiproliferative effect against chronic myeloid leukemia K562 cancer cells. The results indicate that Chlorella sp. QUCCCM3 is a promising candidate that can be produced year-round, in the Qatar environment, for commercial applications such as feed and nutraceutical supplements.

Algae-Derived Bioactive Compounds with Anti-Lung Cancer Potential.

Lung cancer is one of the major causes of death worldwide. Natural molecules with anti-lung cancer potential are of a great interest and considered as very promising alternative to substitute or enhance the efficiency of the conventional drugs. Recently, algae as source of high value-added compounds are considered as very promising source of these bioactive molecules. These are secondary metabolites that consist mainly of derivatives of peptides, carbohydrates, and lipids with various structures. Accordingly, various mechanisms by which different algae molecules demonstrate attenuation of tumor angiogenesis were stated and discussed. The mode of action of the algae bioactives is closely related to their nature and chemical structure. Furthermore, this literature review considers the synergistic effect between microalgae bioactives and conventional drugs and discuss the economic feasibility of producing microalgae bioactives at large scale to conclude with some future perspectives related to algae-based drug discovery.