Search Results (205)

Phaeodactylum tricornutum is one of the most well-characterized microalgae and serves as a pivotal model diatom in global carbon fixation and the mediation of biogeochemical cycling of essential nutrients. Over the past few decades, the availability of a complete genome assembly, coupled with the development of robust DNA manipulation tools and efficient DNA delivery methodologies, has established P. tricornutum as a promising photosynthetic chassis for the sustainable bioproduction of high-value compounds, including fucoxanthin and eicosapentaenoic acid (EPA). This review systematically summarizes the research progress in the strain improvement toolkit of P. tricornutum, encompassing both genetic and non-genetic engineering strategies. It elaborates on the types and applications of its representative bioactive products, as well as the molecular mechanisms underlying key synthetic pathways. Additionally, this work synthesizes the research findings on the optimization of critical cultivation conditions (e.g., light, temperature, and nutrient composition) that modulate the growth and product synthesis of P. tricornutum. On this basis, the challenges encountered by P. tricornutum in industrial applications are proposed for further discussion, aiming to provide a reference for in-depth exploration of related research directions and facilitate the expansion of its application scope in the field of biomanufacturing. Full article

The marine unicellular red alga Rhodosorus marinus is a promising source of the valuable phycobiliprotein phycoerythrin and essential omega-3 polyunsaturated fatty acids (PUFAs), yet the environmental triggers for their optimal co-production remain to be fully elucidated. This study was conducted to investigate the effects of thermal and photic stress in terms of maximizing the yield of these high-value bioactive compounds. R. marinus was cultivated under a range of temperatures (18–24 °C) and light intensities (100–335 µmol photons m⁻² s⁻¹) to assess its physiological and biochemical responses, particularly focusing on lipid accumulation. This study investigates the effects of thermal (18–24 °C) and photic (100–335 µmol photons m⁻² s⁻¹) stress on the concurrent production of the valuable phycobiliprotein, phycoerythrin (PE), and essential omega-3 polyunsaturated fatty acids (PUFAs) in the marine red microalga Rhodosorus marinus. Fatty acid profiles were quantified using gas chromatography (GC), while pigment content was assessed via spectrophotometry. Statistical analyses, including one-way ANOVA and Tukey’s post hoc test, were employed to determine the significance of environmental effects. Our results demonstrate that a mild hypothermic condition of 18 °C significantly enhanced the production of eicosapentaenoic acid (EPA) compared to higher temperatures. Conversely, cell density was maximized at 22 °C. Under the 18 °C thermal regime, lower light intensities (100–185 µmol photons m⁻² s⁻¹) promoted a superior synthesis of both bioactive lipids and pigments. In conclusion, the strategic application of mild hypothermia combined with moderate light intensity is an effective approach to substantially boost the metabolic yield of high-value compounds in R. marinus, highlighting its potential as a sustainable source for nutraceutical and pharmaceutical applications. Full article

Landfill leachate is a complex pollutant that contains high levels of nitrogenous compounds, heavy metals, and organic contaminants, posing serious environmental risks. This study presents an innovative and sustainable strategy for leachate biotransformation using the microalgae Chlorella sp. (UFPS_016, 017) and the cyanobacteria Oscillatoria sp. (UFPS_004) and Potamosiphon sp. (UFPS_008), integrating circular economy and Blue Economy principles. Strains were cultivated in 5% and 10% leachate under optimized photoperiods, LED illumination, and controlled CO₂ supplementation. The best performance was achieved by Oscillatoria sp. (UFPS_004) with biomass productivity of 0.3923 g L⁻¹ and carbohydrate accumulation up to 64.97% w/w, while Potamosiphon sp. (UFPS_008) achieved the highest PHB content (19.7% w/w). Chlorella sp. strains exhibited greater lipid accumulation, reaching 14.96% w/w, and produced phytohormones (Indole-3-acetic acid) with potential for agricultural applications. 20 L reactors validated scalability, maintaining productivity like that of small-scale systems. This dual-purpose bioprocess simultaneously detoxifies leachate and produces valuable bioproducts, including bioplastics, biofertilizers, and biofuels. The results demonstrate a feasible, low-cost, and eco-efficient biotechnology for landfill leachate management, contributing to waste valorization and environmental sustainability. Full article

Photobioreactor-based microalgae cultivation offers an integrated approach for nutrient-rich wastewater treatment while producing valuable biomass. One of the main microalgae components is proteins, making them a biotechnological target. In this work, to develop efficient and greener extraction methodologies, aqueous two-phase systems (ATPSs) based on natural deep eutectic solvents (NADESs) were evaluated for one-step protein extraction from microalgae cultivated in swine wastewater. Six ATPSs combining two NADES—betaine:levulinic acid (Bet:2LA) and choline chloride:urea (ChCl:2Urea)—and their individual components (Bet or ChCl) with phosphate salts were compared. Systems {NADES + K₃PO₄ + water} were characterized and reported for the first time. Protein recovery yield (PRY) and selectivity (protein-to-carbohydrate mass ratio, R) were assessed for three extraction times and at room temperature. The ATPS {Bet:2LA + K₃PO₄ + H₂O} achieved a PRY of 16.4% and remarkable selectivity after 30 min (R = 2.17 g·g⁻¹), with proteins concentrated in the NADES-rich phase, and negligible recovery in the salt-rich phase. Although the maximum PRY (18.2% at 120 min) was achieved with the precursor betaine, the ATPS with Bet:2LA at 30 min offered an optimal balance between efficiency and process time. With a water content of up to 50%, these systems underscore the potential of NADES-based ATPSs as sustainable platforms for protein recovery. Full article

This study adopts a biochemical approach to sequester CO₂ while producing biomass rich in protein and lipids, using an adapted strain of Chlorella vulgaris (ALE-Cv), which had previously evolved to tolerate a gas mixture containing 10% CO₂ and 90% air. The research studied the operating parameters of the batch photobioreactor for ALE-Cv to evaluate the effects of inoculum size, photoperiod, light intensity, pH of culture, and CO₂ supply rate on biomass productivity and CO₂ bio-fixation rate. The optimal conditions were identified as 16:8 h light–dark cycles, 5000 lux, pH 7, 20 mL of 10 g/L inoculum, and 0.6 VVM; the system achieved a maximum total biomass production of 7.03 ± 0.21 g/L with a specific growth rate of 0.712 day⁻¹, corresponding to a CO₂ bio-fixation of 13.4 ± 0.45 g/L in batch cultivation. While the pre-adapted strain of Chlorella vulgaris under the same operating conditions, except for the gas supply, which was air, achieved a maximum total biomass production of 0.52 ± 0.008 g/L, and the total CO₂ bio-fixation was 1.036 ± 0.021 g/L during 7-day cultivation. A novel semi-continuous harvesting process, with and without nutrient addition, was also investigated to maximise biomass yield and enable water recycling for culture media. The maximum biomass production in semi-continuous harvesting process with and without nutrition added was 5.29 ± 0.09 and 9.91 ± 0.11 g/L, while the total corresponding CO₂ bio-fixation was 9.70 ± 0.13 and 18.16 ± 0.11 g/L, respectively, during 15-day cultivation. The findings provide critical insights into enhancing CO₂ bio-fixation through adaptive evolution of ALE-Cv and offer optimal operational parameters for future large-scale microalgae cultivation. This research also links microalgae-based CO₂ sequestration to green technologies and the bioeconomy, highlighting its potential contribution to climate change mitigation while supporting environmental sustainability, food security, and ecosystem resilience. Full article

The rapid rise in atmospheric CO₂ necessitates strategies for mitigation and valorization. Microalgae offer potential through simultaneous CO₂ capture and production of high-value biomolecules. Five Chlorophyta strains (A–E: Micractinium sp., Chlamydomonas sp., Micractinium sp., Chlorococcum sp., and Chlorella vulgaris) were isolated from temperate waters and soils and tested for growth and biochemical responses under controlled nitrogen availability (low: 0.346 g L⁻¹ nitrate; high: 0.6 g L⁻¹ nitrate + ammonia), carbon supply (low: 0.04% CO₂; high: 4% CO₂), and cultivation systems (batch reactors, fermenters, and varied illumination). Over 14 days, maximum dry biomass was achieved in batch cultivation with CO₂ sparging, low nitrogen, and continuous light, ranging from 1.47 g L⁻¹ (strain A) to 2.67 g L⁻¹ (strain D). Biomass composition varied: proteins, 25–45%; carbohydrates, 20–35%; and lipids, 18–28%. Nitrogen limitation promoted lipid accumulation (e.g., strain D: +40%) with concurrent protein decline (−25%). Chlorophyll a/b displayed strain-specific plasticity; high CO₂ generally increased chlorophyll, while nitrogen stress reduced it up to 50%. Overall, this study demonstrates that locally adapted Chlorophyta strains can achieve high biomass productivity under CO₂ enrichment while allowing for flexible redirection of carbon flux toward lipids, carbohydrates, or pigments through nutrient management. Among the tested isolates, strains D and E emerged as the most promising candidates for integrated CO₂ sequestration and biomass production, while strains B, C, and D showed strong potential for biodiesel feedstock; strain A for carbohydrate valorization; and strain E for chlorophyll extraction. Future research should focus on scale-up validation in pilot photobioreactors under continuous operation, optimization of two-stage cultivation strategies for lipid production, integration with industrial CO₂ point sources, and strain improvement using modern genomics-assisted breeding and genome-editing technologies. These efforts will support the translation of regional microalgal resources into scalable carbon-capture and bioproduct platforms. Full article

Background/Objectives: Microalgae are recognized as prolific producers of bioactive metabolites with pharmaceutical potential. This study aimed to isolate and characterize cytotoxic constituents from selected cytotoxic microalgae, collected in Hue city, Vietnam. Methods: Microalgal samples were collected from freshwater bodies, morphologically identified, and maintained in laboratory culture. Thirteen strains were successfully isolated and cultivated in BG11, Z8, and BBM media to determine optimal growth conditions. Cytotoxic effects of extracts/compounds were determined using the sulforhodamine B assay on human lung cancer (SK-LU-1) and human liver cancer (HepG2) cell lines. The methanol extract was partitioned with n-hexane and CH₂Cl₂, followed by extensive chromatographic separation and HPLC purification to afford twelve compounds, including two new and ten known compounds. The structures were elucidated by HR-ESI-MS and NMR spectra, chemical methods, and comparing compounds in the literature. Results: From the phytoplankton samples collected across six freshwater bodies in Hue city, Vietnam, thirteen microalgal strains were successfully isolated and purified under laboratory conditions. These strains were morphologically and taxonomically identified to be Microcystis aeruginosa HU05, Microcystis viridis HU13, Anabaena circinalis HU08, Aphanizomenon flos-aquae HU02, Dolichospermum smithii HU04, Calothrix braunii HU14, Nostoc muscorum HU12, Nostoc punctiforme HU11, Raphidiopsis raciborskii HU03, Lyngbya spiralis HU15, Planktothrix stagnina HU16, Phormidium subtilis HU06, and Scenedesmus quadricauda HU07. All methanol extracts of those microalgae were evaluated for cytotoxic activity. The MeOH extracts of M. viridis (HU13) and D. smithii (HU04) exhibited significant cytotoxic effects, with IC₅₀ values of 6.19 ± 0.80 and 4.89 ± 0.76 µg/mL for M. viridis, and 9.51 ± 0.84 and 8.32 ± 0.94 µg/mL for D. smithii against SK-LU-1 and HepG2 cell lines, respectively. Furthermore, chemical studies of D. smithii HU04 led to the isolation of two new compounds, smithioside A (1) and smithioside B (2) and ten known ones, 3,4,5-trimethoxyphenyl-1-O-β-D-glucopyranoside (3), 4′-hydroxy-3′-methoxyphenol-β-D-[6-O-(4″-hydroxy-3″,5″-dimethoxylbenzoate)]-glucopyranoside (4), 4′-hydroxy-2′,6′-dimethoxyphenol 1-O-β-D-(6-O-syringoyl)glucopyranoside (5), mallophenol B (6), pisoninol II (7), guaiacylglycerol (8), (E)-asarone (9), deacetylsarmentamide B (10), (E)-2-hexenyl-β-D-glucopyranoside (11), and 5,6-dihydropyridin-2(1H)-one (12). The cytotoxic activity of all isolated compounds was also evaluated against SK-LU-1 and HepG2 cancer cell lines. Compound 12 showed the strongest activity, with IC₅₀ values of 9.13 ± 0.89 µM (SK-LU-1) and 7.64 ± 0.46 µM (HepG2). Compounds 5 and 6 exhibited moderate cytotoxic activity on both human cancer cell lines with IC₅₀ values ranging from 25.99 to 51.47 µM. Conclusions: These results highlight the potential of Dolichospermum smithii HU04 as a source of bioactive compounds, particularly in anticancer applications. These findings suggest that D. smithii HU04 extracts could be developed for therapeutic purposes targeting cancer. Full article

The industrial cultivation of microalgae for high-value products faces significant challenges, particularly in maintaining long-term, cost-effective operations. Semi-continuous cultivation presents a promising solution to this problem. In this study, the green alga Chlorella sorokiniana IPPAS C-1 was cultivated in a flat-panel 5 L photobioreactor under optimized conditions, with three biological replicates. We evaluated batch mode against three semi-continuous dilution fractions (50%, 75%, and 87.5%). The 75% dilution fraction demonstrated superior performance, achieving the highest biomass productivity with an average specific productivity of 1.36 g DW L⁻¹ day⁻¹ over seven harvest cycles. Furthermore, this regime ensured stable biochemical composition—including proteins, lipids, carbohydrates, and pigments—as well as a consistent lipid profile and sustained photosynthetic activity throughout the cultivation. These findings are useful for the development of scalable and efficient technological protocols for the industrial production of Chlorella in flat-panel photobioreactors. Full article

The transition to a circular economy and the pursuit of environmental sustainability are driving humanity to develop alternative technologies for producing a range of bioproducts. In this context, microbial-mediated fermentation processes have gained prominence. Although yeasts are well known for their ability to produce alcohols, they can also generate a wide range of value-added bioproducts. At the same time, microalgae emerge as an advantageous unconventional raw material, as their cultivation does not require arable land, thus avoiding competition with food production. To meet this demand, this study aimed to produce biocomposites through submerged fermentation using biomass from the microalgae Chlorella sp. Enzymatic hydrolysis was optimized using a 2² Central Composite Rotational Design (CCRD), with algal biomass and enzyme mass as independent variables. This step was followed by fermentation with the yeast Wickerhamomyces sp. UFFS-CE-3.1.2. The enzyme alpha amylase employed is of commercial origin, commonly used in the brewing industry, characterized by its easy accessibility and lower environmental impact compared to chemical hydrolysis methods. The results demonstrated that the combination of microalgae biomass with the enzyme preparation led to the production of several compounds of interest, such as highly active enzymes, mainly protease (560 U/mL), catalase (3381 U/mL), and peroxidase (277 U/mL), as well as other compounds, such as glycerol (32.5 g/L) and acetic acid (22.8 g/L). These products have wide industrial applications and a strong market demand, reinforcing the potential of the yeast–microalgae synergy for the sustainable production of high-value biocompounds, which represents a matrix of environmentally friendly products. Full article

Microalgae represent some of the most promising eukaryotic platforms in biotechnology due to their rapid growth, simple cultivation requirements, reliance on sunlight as a primary energy source, and ability to synthesize high-value bioactive compounds. These characteristics have made microalgae attractive candidates in various fields, including biofuel production, carbon capture, and pharmaceutical development. However, several technical limitations have limited their large-scale use as sustainable biofactories. A paradigm shift is currently occurring thanks to the genetic manipulation of microalgae, driven by CRISPR-Cas technology. Significant progress has been made in the model species Chlamydomonas reinhardtii, particularly in the targeted and efficient insertion of foreign DNA. Despite this progress, key challenges remain, and further optimization of CRISPR-Cas methodologies is needed to fully unleash the genetic potential of this organism. This review provides an overview of the convergence of CRISPR-Cas technologies in microalgae research, highlighting their impact on genetic studies, metabolic engineering, and industrial applications. It summarizes recent advances in microalgal genome editing through CRISPR systems, outlines current technical challenges, and highlights future directions for improving the implementation of this innovative technology in microalgal biotechnology. Full article

Microalgal production has garnered increasing interest from both researchers and industry due to the wide range of biomass applications in food, feed, cosmetics, and pharmaceuticals. The successful cultivation of microalgae requires not only adequate supply of nutrients but also large volumes of water. The development of green technologies aimed at sustainable microalgae biomass production is expanding, though it presents several technological challenges. Recycling spent culture media and nutrients has emerged as a promising strategy to reduce water consumption and cultivation costs while supporting environmentally friendly practices. In this review, we first highlight the role of macro- and micronutrients in microalgal growth, then examine physicochemical and physical treatments for optimizing medium reuse, discuss the economic aspects of microalgae production, and outline key technologies for sustainable cultivation. The review underscores the potential of medium recycling to significantly lower costs and environmental impact, paving the way for a more sustainable and economically viable microalgae industry. Full article

In this study, two native microalgae, Chlorella sp. MC18 (CH) and Scenedesmus sp. MJ23-R (SC) were cultivated in bubble column photobioreactors for wastewater treatment. Domestic wastewater (DWW) was used as the main culture medium, alone (100%) and blended (10%) with vinasse, whey, or agro-food waste (AFW), respectively. Both species thrived in 100% DWW, achieving significantly high removal efficiencies for chemical oxygen demand, total nitrogen, and total phosphorus. Mineral removal exceeded 90% in all blended systems, highlighting the strong nutrient uptake capacity of both strains. The maximum specific growth rate (µ_max) in 100% DWW was higher for SC than in standard BG11 medium, and supplementation with vinasse, whey, or AFW further increased µ_max for both species. Blending DWW significantly enhanced microalgal biomass and lipid production compared to 100% DWW. Lipid production (max., 374 mg L⁻¹), proximate lipid composition (max., 30.4%), and lipid productivity (max., 52.9 mg L⁻¹ d⁻¹) significantly increased in all supplemented cultures relative to DWW alone, demonstrating the potential of co-substrate supplementation to optimize microalgal cultivation. This study contributes to reducing the water footprint and fills a gap in the bioprocessing potential of algae-based systems, highlighting wastewater blending as a circular economy-aligned approach that supports sustainable bioprocesses and resource recovery. Full article

Microalgae cultivation presents a promising pathway for sustainable agricultural development in arid environments by minimizing freshwater consumption. In Saudi Arabia, where agricultural expansion coincides with extensive coastal resources, algal biotechnology has emerged as a strategic approach to optimize resource use. This study applies a Geographic Information System (GIS)-based framework integrating the Analytic Hierarchy Process (AHP) within a Multi-Criteria Decision-Making (MCDM) approach to evaluate the suitability of coastal zones for seawater-based microalgae cultivation. Suitability assessment incorporated topography, land use, seawater accessibility, proximity to CO₂ emission sources, nutrient availability, and key environmental parameters. The analysis focused on a 24,771 km² area of interest (AOI) extending from the coastline to the nearest highway. The results indicate that 56% of the AOI is suitable for cultivation, including 4728 km² classified as highly suitable and 1606 km² as very highly suitable, predominantly located near industrial CO₂ sources and wastewater treatment facilities. Areas with lower suitability remain feasible for cultivation through targeted resource management. These findings highlight the significant potential for large-scale microalgae production in Saudi Arabia, contributing to sustainable biotechnology development and agricultural diversification under the country’s Vision 2030 strategy. Full article

Microalgae grow rapidly, require minimal space, can proliferate in non-agricultural land, do not compete with human food sources, and can be cultivated in a variety of environments, including wastewater. They are considered an ecological source of bioactive compounds, offering an environmentally friendly alternative to conventional industrial production methods, which are often resource-intensive. It is important to emphasize that both the species of microalgae and the specific culture conditions play a decisive role in the generation and storage of valuable bioactive compounds, which can act as biostimulants. Biostimulants are organic compounds or microorganisms capable of enhancing crop quality parameters by optimizing nutrient and water use efficiency, while also strengthening tolerance to abiotic stress. The aim of this article is to provide an updated understanding of biostimulants, their modes of action, and their role in regulating plant responses to abiotic stress. It further incorporates examples of successful trials that demonstrate the advantageous applications of microalgae-based biostimulants, while also addressing the barriers and limitations to their commercialization and integration into sustainable agricultural practices. Full article

This research work presents a techno-economic assessment of biodiesel production with non-standard waste cooking oil (WCO) (brown grease of small restaurants, yellow grease of households) and semi-open Chlorella sp. microalgal cultivation, which covers the problematic areas of scale and cost-efficiency in sustainable biodiesel production. Cost-effective biodiesel feedstock research has been motivated by the urgency of finding sustainable sources of energy. With base-catalyzed transesterification optimized by ANOVA and response surface methodology (RSM), the present study recorded biodiesel yields of up to 99.08% in household WCO (at optimum conditions; 55 °C, 3.3 mg/g NaOH, ethanol) and 96.61% in restaurant WCO (at optimum conditions; 54 °C, 1.5 mg/g NaOH, methanol) compared to 28.6% in Chlorella sp. (semi-open photobioreactors). Concerning the two types of WCO feedstocks, the obtained equations are able to compute the biodiesel viscosity and yield, in good correlation with the experimental values, in relation to the temperature and ratio of catalyst to oil/alcohol solution. The assessed household WCO has better yield and quality as it contains fewer impurities, whereas the restaurant WCO needed to be further purified, driving up the prices. Although Chlorella biodiesel is carbon neutral, its production and extraction costs are higher, making it less economically feasible for biodiesel production. Economic analysis showed that the capital costs of household WCO, restaurant WCO, and Chlorella sp. are USD 190,000, USD 220,000, and USD 720,000, respectively, based on 1,000,000 L/year as biodiesel production rate. Low capital costs as well as byproduct glycerol income of the two investigated types of WCO play a role in their low payback periods (0.23–0.91 years) and high ROI (110–444.4%). The analysis highlights the economic and environmental benefits of WCO, especially household WCO, as a scalable biodiesel feedstock, which provides new insights into process optimization and sustainable biodiesel strategies. To enhance its sustainability and cost-effectiveness and contribute to the transition to renewable biofuels globally, future studies need to emphasize energy reduction in microalgae production and purification of restaurant WCO. Full article