Mohammed Amouri

Microalgae have been widely recognized as a promising feedstock for sustainable biofuels production to tackle global warming and pollution issues related to fossil fuels uses. This study identified and analyzed indigenous microalgae strains for biodiesel production, specifically Chlorella vulgaris and Coelastrella thermophila var. globulina, from two distinct locations in Algeria. Molecular identification confirmed their identity, and the microalgae exhibited notable growth characteristics. Local Chlorella vulgaris and Coelastrella thermophila var. globulina showed good growth and high biomass yield, compared to Chlorella vulgaris CCAP211/11B reaching a weight of 1.48 g L^‐1, 1.95 g L^‐1, and 2.10 g L^‐1, respectively. Lipids content of local Chlorella vulgaris, Coelastrella thermophila var. globulina, and Chlorella vulgaris CCAP211/11B, were found to be 31.39 ± 3.3%, 17 ± 2.26%, and 19 ± 0.64%, respectively. Chlorella vulgaris stood out as a candidate for biodiesel production due to its equilibrium between SFA and PUFA (43.24% and 45.27%). FAs are predominated by SFA and MUFA for Coelastrella thermophila var. globulina with value of 81.49% (SFA+MUFA). Predicted biodiesel qualities comply with ASTM6751 and EN14214 standards.Studied microalgae have therefore a promising potential for biodiesel production. However, optimising cultivation conditions is necessary to enhance biomass and lipids yield at a large scale.

This study investigates the use of cheese whey to enhance the microalgae cultivation for bioenergy and coproducts in the framework of circular economy and pollution attenuation. A local isolated indigenous Chlorella vulgaris strain using a growth medium containing BG11 and cheese whey (BG11/CW) was used. Algae density, dry weight, organic carbon consumption, biochemical composition, fatty acid profile, Total pigments were investigated. The best growth is obtained in the BG11/CW culture media, with a dry biomass and cell density of 2.5 g/L, 6.5×107 Cells/ml, respectively. This represents 5 times the dry biomass obtained in the BG11medium (0.45 g/L, 1.68×107 cells/ml). Indigenous Chlorella vulgaris growth is favored by glycose availability after lactose degradation with a consumption of 62% on the 7th day. Pigments content was improved with an average value of 34.5 mg/gDW and 9 mg/mgDW for total chlorophylls and carotenoids, respectively. Chlorella vulgaris cultivation on BG11/CW has showed a high protein content with a value of 46%. Indigenous Chlorella vulgaris was able to accumulate a suitable lipid content that could reach 23%, which are rich in C16:00, C18:00, C18:1. This strain is a potential candidate for a sustainable bioenergy and coproducts that could contribute efficiently to promote the circular economy.

This paper performs a thorough cradle to tank life cycle assessment to examine environmental impacts of Moringa oleifera derived biodiesel. Attributional LCA according to ISO 14040‐44, using CML‐IA baseline method, was conducted. Furthermore, Biodiesel versus petrodiesel comparison was undertaken.Moringa oleifera derived biodiesel shows a GWP of 39.94 gCO₂eq/MJ of biodiesel, which presents a reduction of 52.34%, compared to petrodiesel. It revealed an EROEI value of 1.48, which can reach 3.20 with allocation applying, presenting an energy saving over petrodiesel of 53%. In addition, Ozone layer depletion impact of Moringa based biodiesel is lower than that of petrodiesel. This good performance notwithstanding, Moringa oleifera derived biodiesel exhibits high environmental impacts in terms of Abiotic Depletion of elements, Human Toxicity, Fresh water aquatic ecotoxicity, Marine aquatic ecotoxicity, Terrestrial ecotoxicity, Acidification, Eutrophication, respectively, 96.60%, 60.22%, 82.13%, 64.77%, 98.71%, 35.68% and 76.70% higher than those of petrodiesel. Nevertheless, coproducts valorization and ecofriendly inputs use could contribute efficiently to improve its environmental performances compared to petrodiesel.According to our results and comparison with other feedstocks based biodiesel, Moringa biodiesel could be used as a sustainable biofuel with a high contribution to climate change mitigation and fossil energy savings in addition to reduced environmental impacts.

Microalgae have been recently recognized as a promising alternative for the effective treatment of anaerobic digestion effluents. However, to date, a widely applied microalgae-based process is still absent, due to several constraints mainly attributed to high ammonia concentrations and turbidity, both hindering microalgal growth. Within this scope, the purpose of the present study was to investigate the performance of two Chlorella strains, SAG 211-11b and a local Algerian isolate, under different nitrogen levels, upon ammonia stripping. The experiments were performed on cylindrical photobioreactors under controlled pH (7.8 ± 0.2) and temperature (25 ± 2 °C). Cultures were monitored for biomass production and substrate consumption. After sampling at the beginning of the stationary phase of growth (12th day) and after the maturation of the cells (24th day), an analysis of the produced biomass was conducted, in terms of its biochemical components. The local isolate grew better than C. vulgaris 211-11b, resulting in 1.43 mg L⁻¹ biomass compared to 1.02 mg L⁻¹ under 25 mg NH₄-N L⁻¹, while organic carbon and nutrient consumption varied between the two strains and different conditions. Concerning biomass quality, a high initial NH₄-N concentration led to high protein content, while low nitrogen levels favored fatty acid (FA) accumulation, though the production of pigments was inhibited. In particular, the protein content of the final biomass was determined close to 45% of the dry weight in all experimental scenarios with adequate nitrogen, while proteins decreased, and the fatty acids approached 20% in the case of the local isolate grown on the substrate with the lowest initial ammonium nitrogen (25 mg NH₄-N L⁻¹). The novelty of the present work lies in the comparison of a microalga with industrial applications against a local isolate of the same species, which may prove to be even more robust and profitable.

This paper aims to study a new growth media using cheese whey and drainage water from agriculture for indigenous microalgae cultivation for value-added product generation. In this context, four combinations are studied beside the BG11 as reference, where BG11/Cheese whey (60/40, %v/v), drainage water 100%, drainage water/Cheese whey (60/40, % v/v), and Cheese whey 100 % have been used. Moreover, investigated parameters are biomass dry weight, pH variation, total chlorophyll and carotenoid content. Results showed that used growth media have a significant impact on microaglae culture, particularly in terms of cells growth, pigment content and pH variation. Moreover, the mixture BG11/Cheese whey (60/40, %v/v) shows the best impact for total chlorophylls and carotenoids content. Likewise, the mixture cheese whey/drainage water (60/40, %v/v) presents a positive effect on pigments content. The use of cheese whey and drainage water lead to enhance the biomass and pigment production. This study showed that using agro-industrial C-rich wastes and drainage water enhanced microalgae biomass and pigment content, thus contributing to pollution abatement. This will contribute to both reducing the cost of production and resources recycling.