Lipid Production Research Articles

Evaluation of environmental parameters for optimal cell density, biomass, lipid, and biodiesel production in scenedesmus: Focus on suspension and biofilm methods

The study focused on investigating the impact of various environmental parameters on the production of Scenedesmus, a unicellular alga known for its industrial and food value. The parameters studied included production method, temperature, lighting period, light intensity, and pH, with a particular emphasis on suspension and biofilm production methods. The results highlighted optimal conditions for different aspects of production, such as cell density, biomass production, lipid production, and biodiesel production. Specifically, the findings indicated that the highest cell density was achieved at a temperature of 25 °C, light intensity of 3000 lux, lighting period of 16 h, and pH of 8. For biomass production, the optimal conditions were a temperature of 25 °C, light intensity of 3000 lux, lighting period of 18 h, and pH of 9. The greatest lipid production was observed at a temperature of 20 °C, light intensity of 4000 lux, lighting period of 18 h, and pH of 8. Moreover, the highest biodiesel production was recorded at a temperature of 25 °C, light intensity of 3000 lux, lighting period of 18 h, and pH of 8. Notably, the study found that the biofilm production method outperformed the suspension method across various parameters, including cell density, biomass production, lipid production, and biodiesel production. These results contribute to the existing knowledge of optimal conditions for microalgae production and underscore the potential of Scenedesmus in industrial and food applications.

Effects of supplementation of different selenium sources on lipid profile, selenium, and vitamin E concentration of yolk.

Egg preference as a source of protein also provides beneficial fatty acids, vital for human consumption. However, rich in lipid products are prone to oxidative damage. The study aims to determine the effect of supplementing biogenic selenium (Se) from Stenotrophomonas maltophilia, ADS18 (ADS18) in laying hens' diet on yolk lipid oxidation status (MDA), beta-carotene (β-carotene) content, cholesterol, fatty acids, Se, and vitamin E (VE) level. A total of one hundred and twenty (120) laying hens of Lohmann Brown strains aged 50 weeks, weighing 1500 to 2000g were reared individually in A-shape two-tier stainless-steel cages sized 30cm x 50cm x 40cm (width, depth height). The hens were randomly allotted into four treatments with six replications in a complete randomised design for the period of 12 weeks. The basal diet contains 100mg/kg VE. Treatment diets consist of basal diet as control, SS containing 0.3mg/kg sodium selenite, Se-yeast containing 0.3mg/kg selenised yeast, and VADS18 containing 0.3mg/kg of ADS18. Forty-eight eggs were collected and freeze-dried biweekly for analysis. The results of the present study showed that hens supplemented ADS18 had significantly (P < 0.05) lower MDA and cholesterol levels while their egg yolks had higher levels of Se and mono-unsaturated fatty acids (MUFA). The control group had significantly (P < 0.05) higher saturated fatty acid (SFA) contents than the VE and dietary Se-supplemented groups, while the ADS18 group had the lowest SFA contents. Conversely, in comparison to the inorganic and control groups, the VE content of the egg yolk was significantly (P < 0.05) higher in organic Se-supplemented (Se-yeast and VADS18) groups. Hens with SS supplementation had significantly (P < 0.05) higher egg yolk β-carotene content. When compared to other treatment groups, the control group had higher (P < 0.05) polyunsaturated fatty acids (PUFA) content. The ADS18 is therefore deemed comparable to other Se sources. To prevent Se toxicity, however, a better understanding of the levels of ADS18 incorporation in poultry diets is required.

Dual stress factors adaptive evolution for high EPA production in Schizochytrium sp. and metabolomics mechanism analysis.

Eicosapentaenoic acid (EPA) is a vital ɷ-3 polyunsaturated fatty acid (PUFA) for human body with various physiological functions. In this study, we proposed an adaptive evolutionary strategy based on high-temperature and high-oxygen two-factor stress to increase the EPA production capacity of Schizochytrium. High-temperature stress was used to increase EPA yield, and high oxygen was implemented to continuously stimulate cell growth and lipid accumulation. The biomass and EPA production of ALE-D50 reached 35.33g/L and 1.54g/L, which were 43.85% and 71.11% higher than that of the original strain, respectively. Lower in vivo reactive oxygen species levels indicated that the evolved strain possessed stronger antioxidant activity. Liquid chromatography-mass spectrometry metabolomics showed that enhanced glucose consumption and glycolysis metabolism, as well as a weakened tricarboxylic acid cycle and reduced amino acid metabolic tributaries in the evolved strain, might be associated with increased growth and EPA synthesis. Finally, the lipid production and EPA production in a fed-batch fermentation were further increased to 48.93g/L and 3.55g/L, improving by 54.30% and 90.86%, respectively. This study provides a novel pathway for promoting EPA biosynthesis in Schizochytrium.

Physiological responses and lipid accumulation of freshwater microalgae Chlorella sorokiniana under short-term zinc stress in water solution

As a potential toxic element, zinc exhibits strong environmental mobility and bioavailability, rendering it a subject of profound concern as a highly toxic pollutant. In this study, the toxic effects of divalent zinc ion (Zn2+) with high concentrations at 5, 10, 15, 20, and 25 mg/L on the physiological states of Chlorella sorokiniana were investigated, including growth inhibition, photosynthesis, oxidative damage, and lipid accumulation. The results unequivocally revealed a substantial inhibition of C. sorokiniana growth in response to above 5 mg/L Zn2+ exposure. The photosynthetic activity and photosynthetic pigment content of C. sorokiniana declined with the increase of Zn2+. However, the photosynthetic activity slowly recovered after 72 h of exposure. Zn2+ induced a rapid increase in reactive oxygen species (ROS) within the microalgae, subsequently stimulating superoxide dismutase activity. Nevertheless, the uneliminated excess ROS disrupted the cell membrane, leading to the production of malondialdehyde. Furthermore, Zn2+ at concentrations of 5 and 20 mg/L positively affected the lipid accumulation, resulting in the highest 4.10 mg/L/d lipid production.

Food waste recycling to Yarrowia biomass due to combined hydrothermal carbonization and biological treatment

Food waste (FW) to value-added application represents a demanding opportunity in the circular economy. As one of the approaches, FW hydrothermal carbonization (HTC) delivers an aqueous phase (HTC-AP), which would be suitable when applied to microbial growth and lipid production. In this context, this current work explored HTC-AP from FW obtained through HTC (temperatures 200 to 260 °C) for microbial growth of 14 different Yarrowia species. Among these strains, Y. lipolytica, Y. keelungensis, Y. porcina, and Y. galii showed the ability to utilize HTC-AP. In HTC from 200 °C high optical density (OD600) reaching above 1.2 for the 4 species was observed. An increase in the temperature by 20 °C declined the growth of Y. lipolytica, Y. porcina, and Y. galii by 17%. However, Y. keelungensis showed good growth regardless of the HTC temperature. Further, the lipid produced better at higher biomass 240 °C compared to 260 °C during the HTC. Further, Y. yakushimensis showed the highest growth rate among all the analyzed media (0.12 – for medium 2 (0.45 NH4+ and 200 °C). Although the composition of HTC-AP is very diverse and often toxic, some analyzed yeast species can use the contained compounds as a carbon source for biomass and lipid biosynthesis. The presented possibilities are a very good starting point for developing processes on a larger scale.

Alteration of epidermal lipid composition as a result of deficiency in the magnesium transporter Nipal4

Lipids in the stratum corneum play an important role in the formation of the skin permeability barrier. The causative gene for congenital ichthyosis, NIPAL4, encodes a Mg2+ transporter and is involved in increases in intracellular Mg2+ concentrations that depend on keratinocyte differentiation. However, the role of this increased Mg2+ concentration in skin barrier formation and its effect on the lipid composition of the stratum corneum has remained largely unknown. Therefore, in the present study, we performed a detailed analysis of epidermal lipids in Nipal4 KO mice via TLC and MS. Compared with WT mice, the Nipal4 KO mice showed compositional changes in many ceramide classes (including decreases in ω-O-acylceramides and increases in ω-hydroxy ceramides), together with increases in ω-hydroxy glucosylceramides, triglycerides, and free fatty acids and decreases in ω-O-acyl hydroxy fatty acids containing a linoleic acid. We also found increases in unusual ω-O-acylceramides containing oleic acid or palmitic acid in the KO mice. However, there was little change in levels of cholesterol or protein-bound ceramides. The TLC analysis showed that some unidentified lipids were increased, and the MS analysis showed that these were special ceramides called 1-O-acylceramides. These results suggest that elevated Mg2+ concentrations in differentiated keratinocytes affect the production of various lipids, resulting in the lipid composition necessary for skin barrier formation.

The phycosphere and its role in algal biofuel production

Oleaginous microalgae have become a focus for large-scale biofuel production due to their ability to accumulate large quantities of lipids. However, production is currently limited by cost and predation. At present, algal biofuel cultivation is optimized through starvation, supplementing media with nutrients, or genetic engineering; these methods can often be costly with little to no increase in lipid production or the culture’s defense. Investigating the phycosphere of algal-bacterial interactions may overcome these current barriers to large-scale production. The phycosphere of algal-bacterial interactions have formed over millions of years through mutualistic and symbiotic relationships and can provide a more direct source of nutrients compared to adding the nutrients in bulk. The most promising of these interactions include the production of phytohormones and quorum signaling compounds that alter the behaviors of the consortia. Phytohormones can improve algal growth rates, lipid production, and stress resistance. Quorum signaling could create consortia capable of warding off invaders—such as rotifers—while self-regulating and altering behavior based on population density. Mechanisms within the algal phycosphere present many opportunities for the development of novel engineering strategies to further improve algal lipid production and operational costs. This review outlines previous preliminary phycosphere research as well as posing possible opportunities to be pursued in future biofuel production.

Effect of carbon dots supplementation in Chlorella vulgaris biomass production and its composition

Microalgae cultures have an excellent ability to capture CO2 and produce high, medium, and low valuable biocompounds such as proteins, carbohydrates, lipids, pigments, and polyhydroxyalkanoates; those compounds have shown excellent properties in the pharmaceutical, cosmetic, food, and medical industries. Recently, the supplementation of carbon dots (CDs) in autotrophic microalgae cultures has been explored as a new strategy to increase light capture and improve photoluminescence, which in turn enhances biomass growth and biocompounds production. In this work, we synthesized CDs through a simple carbonization method using orange juice as a natural precursor. The green synthesized CDs were analyzed in detail through characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), UV–visible, fluorescence spectroscopy, and ζ potential analysis. Moreover, CDs were added to Chlorella vulgaris to analyze the response under different photoperiod cycles and CDs dosages. The optimal results were obtained with the addition of 0.5 mg l−1 of CDs under a photoperiod cycle of 16 h:8 h (light:dark). In these conditions, a maximum biomass production of 2.12 g l−1 was observed, which represents an enhancement of 112% and 17% in comparison to the control samples under the photoperiod of 12 h:12 h and 16 h:8 h (light/dark), respectively. Furthermore, the production of lipids, proteins, and carbohydrates was significantly increased to 249 mg g−1, 285 mg g−1, and 217 mg g−1 dry weight, respectively. These results suggest that the addition of CDs enhances cell growth and increases the production of lipids and proteins, being a strategy with great potential for the food and pharmaceutical industries.

Real time changes in the expression of eicosanoid synthesizing enzymes during inflammation

Immune responses during inflammation involve complex, well-coordinated lipid signaling pathways. Eicosanoids are a class of lipid signaling molecules derived from polyunsaturated fatty acids such as arachidonic acid and constitute a major network that controls inflammation and its subsequent resolution. Arachidonic acid is metabolized by enzymes in three different pathways to form a variety of lipid metabolites that can be either pro- or anti-inflammatory. Therefore, an understanding of the time-dependent gene expression, lipid metabolite profiles and cytokine profiles during the initial inflammatory response is necessary, as it will allow for the design of time-dependent therapeutics. Herein, we investigate the multi-level regulation of this process. After stimulating RAW 264.7 cells, a mouse-derived macrophage cell line commonly used to examine inflammatory responses, we examine the gene expression of 44 relevant lipid metabolizing enzymes from the different eicosanoid synthesizing classes. We also measure the formation of lipid metabolites and production of cytokines at selected time points. Results reveal a dynamic relationship between the time-course of inflammation dependent gene expression of the three eicosanoid synthesizing enzymes.

Enhancing Chlamydomonas reinhardtii growth and metabolite biosynthesis using organic dyes as spectral converters

The availability of light and its efficient utilisation is a major limiting factor in large scale algal cultures. While algae predominantly use the blue and red spectral regions, a significant amount of incoming light energy remains untapped outside these ranges. Converting this unused light into usable wavelengths could enhance photosynthesis. This study aimed to identify the optimal spectral converter among Lumogen Red (LR), Rhodamine 8G (R8G), and Lumogen Yellow (LY), providing efficient light utilisation for algal cultivation. Chlamydomonas reinhardtii was cultivated in double-jacketed cylindrical photo-bioreactors (PBRs) using 30% UV-a and 5% UV-b fluorescent tubes. The R8G dye displayed a slight wavelength shift with a sharp peak at about 498 nm. The LY dye demonstrated several sharp peaks at the green and blue light spectra evident of photo-degradation. The LR dye maintained better photo-stability compared to R8G and LY. Carbohydrate, lipid and protein were produced early, whereas biomass increased after day 4, as a result of photo-acclimation. The LR dye converted and emitted 3.17 × 10-19 J photon-1, enhancing biomass production and increasing photochemical energy utilisation [Y(II)] while decreasing regulated energy dissipation [Y(NPQ)]. Pigment biosynthesis was initially increased and then reduced to counteract heightened irradiation as a means of photo-protection. LR had a 1.6- and 2.9-fold up-regulation of the RuBisCo gene expression. The dye-based system correlated with improved growth, lipid, protein, carbohydrate, and pigment production. The dye-based wavelength conversion system was interlinked to the sustainable development goals addressing environmental, economic, and social aspects.

A decade development of lipase catalysed synthesis of acylglycerols using reactors: a systematic review

Abstract Glycerol esterification produces a variety of valuable chemicals and has been a subject of great interest in recent years. Lipase-catalysed synthesis of acylglycerols reactions have many potential applications, including in the production of structured lipids, biofuels and pharmaceuticals. It offers several benefits over traditional chemical methods, including higher selectivity, milder reaction conditions and increased sustainability. In this systematic review, we summarize 52 primary research of lipase catalysed synthesis of acylglycerol published from 2012 to 2022. Different types of reactions employed in the synthesis of acylglycerols using various lipases are thoroughly discussed. The use of lipase in as biocatalyst in the synthesis of acylglycerols is safe for consumption and sustainable as it can reduce the utilization of toxic and hazardous organic solvents and chemicals that cause harm to human health and the environment. This review serves as a reference for the research and development of acylglycerols using biocatalysts and reactors. It could be an interest to the food and pharmaceutical industries or individuals who are interested to explore this field. Several limitations associated with the overall research on production of acylglycerols are presented in the conclusion section.

Dissecting Holistic Metabolic Acclimatization of Mucor circinelloides WJ11 Defective in Carotenoid Biosynthesis.

Mucor circinelloides WJ11 is a lipid-producing strain with industrial potential. A holistic approach using gene manipulation and bioprocessing development has improved lipid production and the strain's economic viability. However, the systematic regulation of lipid accumulation and carotenoid biosynthesis in M. circinelloides remains unknown. To dissect the metabolic mechanism underlying lipid and carotenoid biosynthesis, transcriptome analysis and reporter metabolites identification were implemented between the wild-type (WJ11) and ΔcarRP WJ11 strains of M. circinelloides. As a result, transcriptome analysis revealed 10,287 expressed genes, with 657 differentially expressed genes (DEGs) primarily involved in amino acid, carbohydrate, and energy metabolism. Integration with a genome-scale metabolic model (GSMM) identified reporter metabolites in the ΔcarRP WJ11 strain, highlighting metabolic pathways crucial for amino acid, energy, and nitrogen metabolism. Notably, the downregulation of genes associated with carotenoid biosynthesis and acetyl-CoA generation suggests a coordinated relationship between the carotenoid and fatty acid biosynthesis pathways. Despite disruptions in the carotenoid pathway, lipid production remains stagnant due to reduced acetyl-CoA availability, emphasizing the intricate metabolic interplay. These findings provide insights into the coordinated relationship between carotenoid and fatty acid biosynthesis in M. circinelloides that are valuable in applied research to design optimized strains for producing desired bioproducts through emerging technology.

AtMYB41 acts as a dual-function transcription factor that regulates the formation of lipids in an organ- and development-dependent manner.

The plant cuticle controls non-stomatal water loss and can serve as a barrier against biotic agents, whereas the heteropolymer suberin and its associated waxes are deposited constitutively at specific cell wall locations. While several transcription factors controlling cuticle formation have been identified, those involved in the transcriptional regulation of suberin biosynthesis remain poorly characterized. The major goal of this study was to further analyse the function of the R2R3-Myeloblastosis (MYB) transcription factor AtMYB41 in formation of the cuticle, suberin, and suberin-associated waxes throughout plant development. For functional analysis, the organ-specific expression pattern of AtMYB41 was analysed and Atmyb41ge alleles were generated using the CRISPR/Cas9 system. These were investigated for root growth and water permeability upon stress. In addition, the fatty acid, wax, cutin, and suberin monomer composition of different organs was evaluated by gas chromatography. The characterization of Atmyb41ge mutants revealed that AtMYB41 negatively regulates the production of cuticular lipids and fatty acid biosynthesis in leaves and seeds, respectively. Remarkably, biochemical analyses indicate that AtMYB41 also positively regulates the formation of cuticular waxes in stems of Arabidopsis thaliana. Overall, these results suggest that the AtMYB41 acts as a negative regulator of cuticle and fatty acid biosynthesis in leaves and seeds, respectively, but also as a positive regulator of wax production in A. thaliana stems.

Enhancing the biosynthesis of polyunsaturated fatty acids by Rhodotorula mucilaginosa and Lodderomyces elongisporus

Single-cell oils (SCO) produced by oleaginous yeast hold promise as a sustainable alternative for producing nutritionally and pharmaceutically valuable lipids. However, the accumulation of oils varies substantially between yeast spp. Consequently, identifying well-suited producers with a high innate capacity for lipids biosynthesis is paramount. Equally important is optimizing culturing and processing conditions to realize the total lipids production potential of selected strains. The marine Rhodotorula mucilaginosa and Lodderomyces elongisporus yeast were investigated to explore their potential for polyunsaturated fatty acids (PUFAs) production on high glucose media (HGM) using two-stage culture mode. Both strains accumulated > 20% (w/w) of their dry cell weight as lipids when grown on HGM using a two-stage culture system. Both yeast isolates exhibited a maximal lipid/biomass coefficient (YL/X) of 0.58–0.66 mg/mg at 7 °C and 0.49–0.53 mg/mg at 26 °C when grown on 8% glucose and produced monounsaturated and PUFAs similar to that of Menhaden and Salmon marine oils. For the first time, significant amounts of Eicosapentaenoic acid (19%) and Eicosadienoic acid (19.6%) were produced by L. elongisporus and R. mucilaginosa, respectively. Thus, the SCO derived from these wild strains possesses significant potential as a substitute source for the industrial-scale production of long-chain PUFAs, making them a promising contender in the market.Graphical

Futuristic opportunities for pretreatment processes in biofuel production from microalgae

AbstractMicroalgal biofuel is a promising solution to replace fossil fuel as a renewable and environmental‐friendly energy source, thereby contributing to the United Nations (UN) Sustainable Development Goals (SDGs), in particular SDG‐7, or Affordable and Clean Energy. Unlike energy crops (like oil palm and sugar cane), microalgae benefit from faster growth rate, higher lipid content, smaller land area required, ability to flourish using waste or brackish water, and posing zero competition with food crops. Microalgae‐derived biofuels (like biodiesel, bioethanol, biomethane, and biohydrogen) are sustainable energy sources that can be produced using well‐developed techniques (e.g., transesterification, fermentation, anaerobic digestion, and Fisher–Tropsch process). To prevent dire climate conditions resulting from the global temperature rise of 1.5°C and resolve worldwide energy security issue, our generation will need to establish and implement renewables on a global scale. To improve the industrial production of microalgal biofuel, the efficiencies of biomass and metabolite production to post‐cultivation biofuel synthesis processes must be enhanced. For the cultivation step, there exist three key techniques that can directly change the traits, structure, and behavior of microalgal cells, and induce them to accumulate targeted metabolites rapidly and in large amounts. These techniques are genetic engineering, chemical modulation, and nanomaterial approach. Genetic engineering commonly alters the chloroplast DNA of microalgae to overexpress or down‐regulate key genes in various metabolic pathways so that the cells accumulate more lipids. Chemicals can also be used to modulate microalgal growth and lipid accumulation by inducing oxidative stress or prevent conversion of lipid molecules. Nanomaterials and nanoparticles can also enhance microalgal lipid production by microenvironmental stress induction, vitamin supplementation, and light backscattering. Therefore, in this review, the recent progress as well as the pros and cons of genetic engineering, chemical modulation, and nanomaterial approach in achieving greater biofuel production from microalgae are comprehensively examined.

Enhancing biomass and lipid accumulation by a novel microalga for unsterilized piggery biogas slurry remediation.

The cost and efficiency of an algal-BS treatment system are determined by the specific microalgal species and BS pretreatment method. This study examines the growth of a novel algae Chlorella sp. YSD-2 and the removal of nutrients from the BS using different pretreatment methods, including dilution ratio and sterilization. The highest biomass production (1.84 g L-1) was achieved in the 1:2 unsterilized biogas slurry, which was 2.03 times higher than that in the sterilized group, as well as higher lipid productivity (17.29 mg L-1 d-1). Nevertheless, the sterilized biogas slurry at a 1:1 dilution ratio exhibited the most notable nutrient-removal efficiency, with COD at 71.97%, TP at 91.32%, and TN at 88.80%. Additionally, the analysis of 16S rRNA sequencing revealed a significant alteration in the indigenous bacterial composition of the biogas slurry by microalgal treatment, with Proteobacteria and Cyanobacteria emerging as the predominant phyla, and unidentified_Cyanobacteria as the primary genus. These findings suggest that Chlorella sp. YSD-2 exhibits favorable tolerance and nutrient-removal capabilities in unsterilized, high-strength biogas slurry, along with high productivity of biomass and lipids. Consequently, these results offer a theoretical foundation for the development of an efficient and economically viable treatment method for algal-BS.

Growth, nutrient removal, and lipid productivity promotion of Chlorella sorokiniana by phosphate solubilizing bacteria Bacillus megatherium in swine wastewater: Performances and mechanisms

Effects of a phosphorus-solubilizing bacteria (PSB) Bacillus megatherium on growth and lipid production of Chlorella sorokiniana were investigated in synthesized swine wastewater with dissolved inorganic phosphorus (DIP), insoluble inorganic phosphorus (IIP), and organic phosphorus (OP). The results showed that the PSB significantly promoted the algal growth in OP and IIP, by 1.10 and 1.78-fold, respectively. The algal lipid accumulation was also greatly triggered, respectively by 4.39, 1.68, and 1.38-fold in DIP, IIP, and OP. Moreover, compared with DIP, OP improved the oxidation stability of algal lipid by increasing the proportion of saturated fatty acids (43.8 % vs 27.9 %), while the PSB tended to adjust it to moderate ranges (30.2–41.6 %). Further, the transcriptome analysis verified the OP and/or PSB-induced up-regulated genes involving photosynthesis, lipid metabolism, signal transduction, etc. This study provided novel insights to enhance microalgae-based nutrient removal combined with biofuel production in practical wastewater, especially with complex forms of phosphorus.

Improving lipid production by Rhodotorula glutinis for renewable fuel production based on machine learning

Improving lipid production by Rhodotorula glutinis for renewable fuel production based on machine learning

Enhanced Scenedesmus obliquus Cultivation in Plastic-Type Flat Panel Photobioreactor for Biodiesel Production

A plastic-type flat panel photobioreactor (PTFPP) prototype was designed for microalgae cultivation as biodiesel feedstock. The growth, biomass, and lipid production of the oleaginous microalga Scenedesmus obliquus were optimized through the enhanced design and cultivation conditions in the PTFPP. The optimization conditions include cultivation of the microalga in a flat panel photobioreactor manufactured from a 10 µm-thick plastic sheet with dimensions of 40 cm in width and 60 cm in height. The width of the designed plastic bags was adjusted by “4 ports” of circular adhesion points which make the volumetric cultural capacity 5 L. Cultivation of the microalga was optimized through the replacement of the sodium nitrate of the BBM medium with urea as a nitrogen source. Cultivation bags were subjected to continuous illumination with 3000 lux white, fluorescent lamps and aerated with 1.5 L air/min (equal to 0.3 VVM). Biomass production from the designed PTFPP reached 3 g/L with around 40% lipid content (on a dry weight basis). Based on a GC-MS analysis of the produced fatty acid methyl ester (biodiesel) from S. obliquus, the percentage of C16 and C18 fatty acids reached more than 90% of the defined fatty acids. Out of this percentage, 66.6% were unsaturated fatty acids. The produced fatty acid profile of the S. obliquus biomass cultivated in the designed PTFPP prototype could be considered a suitable feedstock for biodiesel production.

Influence of salinity, nitrogen and phosphorus concentrations on the physiological and biochemical characteristics of two Chlorophyceae isolated from Fez freshwater, Morocco

Microalgae are widely exploited for numerous biotechnology applications, including biofuels. In this context, Chlamydomonas debaryana and Chlorococcum sp. were isolated from Fez freshwater (Morocco), and their growth and lipid and carbohydrate production were assessed at different concentrations of NaCl, NaNO3, and K2HPO4. The results indicate a small positive variation in growth parameters linked to nutrient enrichment, with no considerable variation in carbohydrate and lipid levels in both algae. Moreover, a negative variation was recorded at increased salinity and nutrient limitation, accompanied by lipid and carbohydrate accumulation. Chlorococcum sp. showed better adaptation to salt stress below 200 mM NaCl. Furthermore, its growth and biomass productivity were strongly reduced by nitrogen depletion, and its lipid production reached 47.64% DW at 3.52 mM NaNO3. As for Chlamydomonas debaryana, a substantial reduction in growth was induced by nutrient depletion, a maximal carbohydrate level was produced at less than 8.82 mM NaNO3 (40.59% DW). The effect of phosphorus was less significant. However, a concentration of 0.115 mM K2HPO4 increased lipid and carbohydrate content without compromising biomass productivity. The results suggest that growing the two Chlorophyceae under these conditions seems interesting for biofuel production, but the loss of biomass requires a more efficient strategy to maximize lipid and carbohydrate accumulation without loss of productivity.