Automated accelerated solvent extraction method for total lipid analysis of microalgae

Sustainable microalgal biomass as a potential functional food and its applications in food industry: a comprehensive review

Microalgae (MA) are the most abundant seaweeds with high nutritional properties. They are accepted as potential biocatalysts for the bioremediation of wastewater. They are widely used in food, feed, and biofuel industries and can potentially be food for future generations. MA-based purification of wastewater technology could be a universal alternative solution for the recovery of resources from wastewater for low-cost biomass feedstock for industry. They provide a wide range of functional components, viz. omega-3 fatty acids, along with a plenteous number of pigments such as ß-carotene, astaxanthin, lutein, phycocyanin, and chlorophyll, which are used extensively as food additives and nutraceuticals. Further, proteins, lipids, vitamins, and carbohydrates are described as nutritional characteristics in MA. They are investigated as single-cell protein, thickening/stabilizing agents, and pigment sources in the food industry. The review emphasizes the production and extraction of nutritional and functional components of algal biomass and the role of microalgal polysaccharides in digestion and nutritional absorption in the gastrointestinal tract. Further, the use of MA in the food industry was also investigated along with their potential therapeutic applications.

Extraction methods of algae oils for the production of third generation biofuels - A review

Microalgae are the main source of third-generation biofuels because they have a lipid content of 20-70%, can be abundantly produced and do not compete in the food market besides other benefits. Biofuel production from microalgae is a promising option to contribute for the resolution of the eminent crisis of fossil energy and environmental pollution specially in the transporting sector. The choice of lipid extraction method is of relevance and associated to the algae morphology (i.e., rigid cells). Therefore, it is essential to develop suitable extraction technologies for economically viable and environment-friendly lipid recovery processes with the aim of achieving a commercial production of biofuels from this biomass. This review presents an exhaustive analysis and discussion of different methods and processes of lipid extraction from microalgae for the subsequent conversion to biodiesel. Physical methods based on the use of supercritical fluids, ultrasound and microwaves were reviewed. Chemical methods using solvents with different polarities, aside from mechanical techniques such as mechanical pressure and enzymatic methods, were also analyzed. The advantages, drawbacks, challenges and future prospects of lipid extraction methods from microalgae have been summarized to provide a wide panorama of this relevant topic for the production of economic and sustainable energy worldwide.

Microwave-assisted extraction in closed vessel in food analysis

Microwave-assisted extraction (MAE) is an important technique in analytical chemistry. It offers several advantages over traditional extraction methods, such as improved extraction efficiency, shorter extraction times, reduced solvent consumption, and enhanced analyte recovery. Using microwaves, heat is directly applied to the sample, leading to rapid and efficient extraction of target compounds by enhancing the solubility and diffusion of the target compounds, thus requiring lower solvent volume. Therefore, MAE can be considered a more environmentally friendly and cost-effective option facilitating the transition toward greener and more sustainable analytical chemistry workflows. This contribution systematically reviews the application of MAE to a selection of target compounds/compounds classes of relevance for food quality and safety assessment. As inclusion criteria, MAE active temperature control and molecularly-resolved characterization of the extracts were considered. Contents include a brief introduction of the principles of operation, available systems characteristics, and key parameters influencing extraction efficiency and selectivity. The application section covers functional food components (e.g., phenols, diterpenes, and carotenoids), lipids, contaminants (e.g., polycyclic aromatic hydrocarbons and mineral oil hydrocarbons), pesticides, veterinary drug residues, and a selection of process contaminants and xenobiotics of relevance for food safety.

Microalgal polyunsaturated fatty acids: Hotspots and production techniques

Algae play a crucial role in the earth’s primary productivity by producing not only oxygen but also a variety of high-value nutrients. One such nutrient is polyunsaturated fatty acids (PUFAs), which are accumulated in many algae and can be consumed by animals through the food chain and eventually by humans. Omega-3 and omega-6 PUFAs are essential nutrients for human and animal health. However, compared with plants and aquatic sourced PUFA, the production of PUFA-rich oil from microalgae is still in the early stages of exploration. This study has collected recent reports on algae-based PUFA production and analyzed related research hotspots and directions, including algae cultivation, lipids extraction, lipids purification, and PUFA enrichment processes. The entire technological process for the extraction, purification and enrichment of PUFA oils from algae is systemically summarized in this review, providing important guidance and technical reference for scientific research and industrialization of algae-based PUFA production.

Determination of active sites on the synthesis of novel Lewis acidic deep eutectic solvent catalysts and kinetic studies in microalgal biodiesel production

Experimental and theoretical considerations for kinetic modeling of the transesterification reaction of microalgae lipids into biodiesel were investigated using Lewis acid deep eutectic solvents (DESs) as a catalyst. The acid sites involved in the reaction were characterized using acetonitrile as a probe to understand the mechanism. DES ChCl-SnCl2 (choline chloride-tin ii chloride) showed higher catalytic activity in transesterification due to its higher acidity compared to DES ChCl-ZnCl2 (choline chloride-zinc chloride). This was illustrated by geometric optimization of the DES structures through density functional theory (DFT) which showed that the metal centers furthest from the choline moiety are the most acidic and the bond lengths of Sn-Cl were between 2.56 and 2.77 Å, and were greater than the Zn-Cl bond lengths from 2.30 to 2.48 Å, making the ChCl-SnCl2 DES more acidic and more suitable for the biodiesel production. The fatty acid methyl ester (FAME) conversion from microalgae lipid was 36.75 mg g-1 under ideal conditions (6 molar ratio methanol-lipid with 8 vol% DES dosage in methanol at 140 °C for 420 min). The activation energy is found to be 36.3 kJ mol-1 based on the pseudo-first-order reaction, in addition, the DES catalyst (ChCl-SnCl2) drove the reaction chemically and did not show mass transfer limitation. Information from this study can help to advance the development of an efficient and environmentally friendly industrial biodiesel production technology.

Quality of Tenebrio molitor Powders: Effects of Four Processes on Microbiological Quality and Physicochemical Factors

Tenebrio molitor, the first edible insect approved as a novel food in the EU, is a promising candidate for alternative protein sources, implementing circular and sustainable production systems. This study aims to determine the microbiological quality and physicochemical properties of mealworm powders obtained by four different processing pathways. Contents of dry matter, protein, fat, ash, water activity (aw) and a range of microbial counts were measured and analyzed by one-way ANOVA with Tukey's test. Results showed small differences in the proximate composition of the powder samples (protein 55.62-57.90% and fat 23.63-28.21% of dry matter, DM), except for the one that underwent a defatting step (protein 70.04% and fat 16.84%), p < 0.05. A level of water activity of less than 0.2 was reached for all pathways. Fresh mealworm samples had high total aerobic counts (8.4 log CFU/g) but were free of foodborne pathogens. Heat treatments applied during transformation were sufficient to kill vegetative cells (reduction of 2.8-5.1 log CFU/g) rather than bacterial endospores (reduction of 0.3-1.8 log CFU/g). Results were confirmed by predictive microbiology. This study validated the efficacy of a boiling step as critical control points (CCPs) of insect powder processing, providing primary data for the implementation of HACCP plans.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

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Alkyl carbamate ionic liquids for permeabilization of microalgae biomass to enhance lipid recovery for biodiesel production

Microalgae are potential biomass source for biodiesel production. However, their strong cell walls make efficient lipid extraction problematic. Disrupting the cell wall is a key point in enhancing lipid yield from microalgae biomass. A new type of ionic liquid (IL) has been suggested in this work as a potentially viable solvent to permeabilize the strong microalgae cell structure for the efficient extraction of lipids. Morphological changes in microalgae cells were studied before and after ionic liquid permeabilization to understand the mechanism of ionic liquid treatment. Among the three selected CO₂-based alkyl carbamate ionic liquids, DIMCARP performed with the best extraction efficiency. The effects of extraction variables (temperature, time, ratio ionic liquid/Methanol, and solvent to biomass) on lipid extraction were examined via single-factor experiments coupled with response surface methodology (RSM) using a Box-Behnken design (BBD). The highest lipid yield (16.40%) was obtained after 45 min of extraction at 45 °C using a 9:1 ionic liquid to methanol and 7 mL of solvent to biomass ratio. Transesterification of lipids to make fatty acid methyl esters found that the most common fatty acids were C16:0, C18:2, and C18:3 (19.50%). The quality of the biodiesel made meets European and US standards.

Limited Phosphorous Supply Improved Lipid Content of Chlorella vulgaris That Increased Phenol and 2-Chlorophenol Adsorption from Contaminated Water with Acid Treatment

Phenolic compounds are toxic and ominously present in industrial effluents, which can end up in water bodies, causing potential damage to living organisms. This study employed the dried biomass of freshwater green microalgae Chlorella vulgaris to remove phenol and 2-chlorophenol from an aqueous environment. C. vulgaris was grown under different phosphorus- (P) starved conditions, and biomass was treated with sulfuric acid. It was observed that reducing the P level enhanced the lipid content by 7.8 times while decreasing protein by 7.2 times. P-starved C. vulgaris dried biomass removed phenol and 2-chlorophenol by 69 and 57%, respectively, after 180 min from the contaminated water. Acid-treated P-starved C. vulgaris dried biomass removed phenol and 2-chlorophenol by 77 and 75%, respectively, after 180 min. Thus, an economical and eco-friendly P-starved and acid treated C. vulgaris biomass has better potential to remove phenol and 2-chlorophenol from contaminated ground water and industrial wastewater.

Extraction of lipids from microalgae using classical and innovative approaches

Microalgae, as a photosynthetic autotrophic organism, contain a variety of bioactive compounds, including lipids, proteins, polysaccharides, which have been applied in food, medicine, and fuel industries, among others. Microalgae are considered a good source of marine lipids due to their high content in unsaturated fatty acid (UFA) and can be used as a supplement/replacement for fish-based oil. The high concentration of docosahexaenoic (DHA) and eicosapentaenoic acids (EPA) in microalgae lipids, results in important physiological functions, such as antibacterial, anti-inflammatory, and immune regulation, being also a prerequisite for its development and application. In this paper, a variety of approaches for the extraction of lipids from microalgae were reviewed, including classical and innovative approaches, being the advantages and disadvantages of these methods emphasized. Further, the effects of microalgae lipids as high value bioactive compounds in human health and their use for several applications are dealt with, aiming using green(er) and effective methods to extract lipids from microalgae, as well as develop and extend their application potential.

Advances in Lipid Extraction Methods-A Review

Extraction of lipids from biological tissues is a crucial step in lipid analysis. The selection of appropriate solvent is the most critical factor in the efficient extraction of lipids. A mixture of polar (to disrupt the protein-lipid complexes) and nonpolar (to dissolve the neutral lipids) solvents are precisely selected to extract lipids efficiently. In addition, the disintegration of complex and rigid cell-wall of plants, fungi, and microalgal cells by various mechanical, chemical, and enzymatic treatments facilitate the solvent penetration and extraction of lipids. This review discusses the chloroform/methanol-based classical lipid extraction methods and modern modifications of these methods in terms of using healthy and environmentally safe solvents and rapid single-step extraction. At the same time, some adaptations were made to recover the specific lipids. In addition, the high throughput lipid extraction methodologies used for liquid chromatography-mass spectrometry (LC-MS)-based plant and animal lipidomics were discussed. The advantages and disadvantages of various pretreatments and extraction methods were also illustrated. Moreover, the emerging green solvents-based lipid extraction method, including supercritical CO2 extraction (SCE), is also discussed.

Currently Applied Extraction Processes for Secondary Metabolites from Lippia turbinata and Turnera diffusa and Future Perspectives

The poleo (Lippia turbinata Griseb.) and damiana (Turnera diffusa Wild) are two of the most valued species in the Mexican semidesert due to their medicinal uses. The conventional essential oil extraction process is hydrodistillation, and for the extraction of antioxidants, the use of organic solvents. However, these techniques are time-consuming and degrade thermolabile molecules, and the efficiency of the process is dependent on the affinity of the solvent for bioactive compounds. Likewise, they generate solvent residues such as methanol, hexane, petroleum ether, toluene, chloroform, etc. Therefore, in recent years, ecofriendly alternatives such as ohmic heating, microwaves, ultrasound, and supercritical fluids have been studied. These methodologies allow reducing the environmental impact and processing times, in addition to increasing yields at a lower cost. Currently, there is no up-to-date information that provides a description of the ecofriendly trends for the recovery process of essential oils and antioxidants from Lippia turbinata and Turnera diffusa. This review includes relevant information on the most recent advancements in these processes, including conditions and methodological foundation.

Accelerating strain engineering in biofuel research via build and test automation of synthetic biology

Biofuels are a type of sustainable and renewable energy. However, for the economical production of bulk-volume biofuels, biosystems design is particularly challenging to achieve sufficient yield, titer, and productivity. Because of the lack of predictive modeling, high-throughput screening remains essential. Recently established biofoundries provide an emerging infrastructure to accelerate biological design-build-test-learn (DBTL) cycles through the integration of robotics, synthetic biology, and informatics. In this review, we first introduce the technical advances of build and test automation in synthetic biology, focusing on the use of industry-standard microplates for DNA assembly, chassis engineering, and enzyme and strain screening. Proof-of-concept studies on prototypes of automated foundries are then discussed, for improving biomass deconstruction, metabolic conversion, and host robustness. We conclude with future challenges and opportunities in creating a flexible, versatile, and data-driven framework to support biofuel research and development in biofoundries.