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Microalgae are one of the most promising sources of raw material for biofuel production and derivatives since its high yield of biomass and metabolites possess a low environmental impact. However, its implementation on large scale facilites still faces challenges such as the optimisation of lipid production (due to strain capacity and environmental factors) and downstream processes (extraction and separation of the lipidic fraction). The objective of the present investigation was to determine the potential of the carbon/nitrogen ratio as a technical tool for the improvement of total lipids on Scenedesmus obliquus. The carbon/nitrogen ratio was evaluated using a non-factorial design coupled with surface response methodology with sodium bicarbonate and sodium nitrate as carbon and nitrogen source. Results showed that the optimal conditions that enhanced the lipid deposition (up to 66% w/w) were 1.5 g L−1 sodium bicarbonate and 0,125 g L−1 of sodium nitrate. Finally, the results of the fatty acid profile shown the presence of stearic acid (C18: 0) with 22.63% and elaidic acid (C18:1) with 77.38%, with the absence of fatty acids of two or more double bonds. In conclusion, the adjustment in the carbon/nitrogen ratio favours the final deposition of lipids in Scenedesmus obliquus which is emerging as a possible candidate for the production of lipids of interest for the generation of biodiesel.

The use of pesticides in agriculture has ensured the production of different crops. However, pesticides have become an emerging public health problem for Latin American countries due to their excessive use, inadequate application, toxic characteristics, and minimal residue control. The current project evaluates the ability of two strains of algae (Chlorella and Scenedesmus sp.) and one cyanobacteria (Hapalosyphon sp.) to remove excess pesticides and other nutrients present in runoff water from rice production. Different concentrations of wastewater and carbon sources (Na2CO3 and NaHCO3) were evaluated. According to the results, all three strains can be grown in wastewater without dilution (100%), with a biomass concentration comparable to a synthetic medium. All three strains significantly reduced the concentration of NO3 and PO4 (95 and 85%, respectively), with no difference between Na2CO3 or NaHCO3. Finally, Chlorella sp. obtained the highest removal efficiency of the pesticide (Chlorpyrifos), followed by Scenedesmus and Hapalosyphon sp. (100, 75, and 50%, respectively). This work shows that it is possible to use this type of waste as an alternative source of nutrients to obtain biomass and metabolites of interest, such as lipids and carbohydrates, to produce biofuels.

Haematococcus pluvialis has attracted much global attention due to its ability to produce huge amounts of astaxanthin, a carotenoid pigment widely applied in pharmaceutical, cosmetic and food industries. In this work, production of astaxanthin from Haematococcus pluvialis was performed under three different salt concentrations (0, 0.45 and 0.9% v/v) and wavelengths (blue, white and red) in order to evaluate the effects of salinity and light wavelengths on microalgae growth. A multifactorial 3 2 experimental design was used and its results were studied by Manova analyzer with 95% of reliability. According to the results, the highest amount of astaxanthin (9.72 μg/mL) was obtained at 0.45 %v/v of salt concentration and blue wavelength.

The tannery industry is one of the economic sectors that contributes to the development of different countries. Globally, Europe and Asia are the main producers of this industry, although Latin America and Africa have been growing considerably in recent years. With this growth, the negative environmental impacts towards different ecosystem resources as a result of the discharges of recalcitrated pollutants, have led to different investigations to generate alternative solutions. Worldwide, different technologies have been studied to address this problem, biological and physicochemical processes have been widely studied, presenting drawbacks with some recalcitrant compounds. This review provides a context on the different existing technologies for the treatment of tannery wastewater, analyzing the physicochemical composition of this liquid waste, the impact it generates on human health and ecosystems and the advances in the different existing technologies, focusing on advanced oxidation processes and the use of microalgae. The coupling of advanced oxidation processes with biological processes, mainly microalgae, is seen as a viable biotechnological strategy, not only for the removal of pollutants, but also to obtain value-added products with potential use in the biorefining of the biomass.