Highest Lipid Yield Research Articles

Turning residues into valuable compounds: organic waste conversion into odd-chain fatty acids via the carboxylate platform by recombinant oleaginous yeast

Environmental concerns are rising the need to find cost-effective alternatives to fossil oils. In this sense, short-chain fatty acids (SCFAs) are proposed as carbon source for microbial oils production that can be converted into oleochemicals. This investigation took advantage of the outstanding traits of recombinant Yarrowia lipolytica strains to assess the conversion of SCFAs derived from real digestates into odd-chain fatty acids (OCFA). High yeast OCFAs content was aimed by using two engineered strains (Y. lipolytica JMY7780 and JMY7782). Batch and two-step batch fermentations were performed, reaching high lipid content (40.8% w/w) and lipid yield (0.07 g/g) with JMY7782, which overexpresses propionyl-CoA synthase. Fed-batch fermentation with an acetic acid pulse after 24 h was also carried out to promote SCFAs consumption and OCFAs production. In this case, SCFAs consumption rate increased and JMY7782 was able to accumulate up to 60.4% OCFAs of the total lipids produced from food waste-derived carbon sources.

Extraction of high-quality Antarctic krill (Euphausia Superba) oil using low-temperature continuous phase-transition extraction equipment.

The aim of this study was to explore a processing method for efficient extraction of high-quality krill oil (KO) using a low-temperature continuous phase-transition extraction equipment (LCPE). The efficiency of lipid extraction and quality of KO and defatted krill meal (DKM) by LCPE were compared with those of supercritical CO2 and n-hexane extraction. Results showed that compared to other methods, extraction using LCPE had the highest lipid yield (21.72±0.34%), bioactive substances, and dimethyl sulfide (3.12±0.09mg/kg), the lowest oxidative deterioration. Moreover, compared to other methods, DKM extracted by LCPE had the lowest fat (<2%), the highest protein (>60%), and the best oxidative stability. These benefits would ensure easier transportation and better long-term storage, allowing for its application on distant-ocean fishing vessels. Therefore, LCPE is a method that allows for efficient extraction of high-quality KO.

Experimental evaluation of Scenedesmus javanensis, Halochlorella rubescens, and Chlorolobion braunii for lipid-rich biomass production and phycoremediation of dairy wastewater

Phycoremediation uses algae as an ecotechnological tool to recycle eutrophic and polluted wastewater from industries. It is vital for fostering a sustainable circular bioeconomy, as the resulting algal biomass can be utilized as a versatile industrial bioresource. This approach is especially pertinent for the dairy industry, which produces substantial amounts of nutrient-rich dairy wastewater (DWW). The effectiveness of phycoremediation of DWW depends on the knowledge of indigenous algae that can thrive in such conditions and rapidly produce lipid-rich or nutraceutically or otherwise valuable biomass. This study assessed the lab-scale phycoremediation of DWW, emphasizing the biomass production potential and quality of three fast-growing green microalgae: Chlorolobion braunii, Scenedesmus javanensis, and Halochlorella rubescens, which are recognized for their high lipid yield potential in growth media. We assessed nutrient and mineral removal efficiency, biomass yield, productivity, biomass quality, and the biodiesel properties of lipids from these algae after ten days of growth in various dilutions and 100 % DWW. C. braunii demonstrated the highest biomass productivity of 149.32 mg L−1 d−1 in 100 % DWW. All species significantly reduced biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total dissolved solids (TDS) of DWW, achieving complete removal of nutrients, along with 80–100 % removal of heavy metals after growth in DWW. C. braunii had a lipid productivity of 49.79 mg L−1 d−1 in 100 % DWW, and lipids from C. braunii and S. javanensis were suitable for biodiesel production, highlighting their potential for large-scale industrial phycoremediation of DWW while generating biodiesel-grade lipids and other valuable bioproducts.

Two-Step Macromolecule Separation Process with Acid Pretreatment and High-Shear-Assisted Extraction for Microalgae-Based Biorefinery

A simple two-stage extraction and recovery method for macromolecules from microalgae biomass, termed CASS (concentrating the microalgae solution, acid pretreatment, high-shear-assisted lipid extraction, and separation), was developed. This method effectively processed the wet biomass of Chlorella sp. ABC-001 at a moderately low biomass concentration (50 g/L). The optimal conditions were acid pretreatment with 5 wt.% H2SO4 at 100 °C for 1 h, followed by high-shear extraction using hexane at 3000 rpm for 30 min. The acid pretreatment hydrolyzed carbohydrates and phospholipids, disrupting the cell wall and membrane, while high-shear mixing enhanced mass transfer rates between solvents and lipids, overcoming the hydraulic barrier at the cell surface. Within 10 min after completing the process, the extraction mixture achieved natural phase separation into water, solvent, and biomass residue layers, each enriched with carbohydrates, lipids, and proteins, respectively. The CASS process demonstrated high esterifiable lipid yields (91%), along with substantial recovery of glucose (90%) and proteins (100%). The stable phase separation prevented emulsion formation, simplifying downstream processing. This study presents the results on cell disruption, optimal acid treatment concentration, and high-shear mixing to achieve macromolecule separation, expanding the lipid-centric microalgal process to a comprehensive biorefinery concept.

PRODUCTION OF BIODIESEL FROM MICROALGAE CULTIVATED WITH VINASSE

Purpose: The objective of this work was to carry out the cultivation of the microalgae Chlorella sorokiniana with diluted vinasse, verifying its potential for remediation of nutrients and increase of its lipid fraction, to produce biodiesel according to the current regulation. Theoretical Framework: The quest to reduce fossil fuels, which are responsible for negative environmental impacts, has boosted the demand for biofuels in recent years. Biodiesel has been gaining prominence as a promising alternative to replace petroleum derivatives since it can be produced from various raw materials, such as microalgae. Design/Methodology/Approach: Different vinasse dilutions were studied for the cultivation of Chlorella sorokiniana CTT 7727, being 5, 10 and 15% (v v-1) and N:P:K (20:5:20) 1% (v v-1) medium as a comparative standard. Biodiesel was produced by direct transesterification and analyzed by gas chromatography coupled to a flame ionization detector, enabling the identification and quantification of the fatty acid profile. Findings: The results obtained indicated that vinasse 10% (v v-1) proved to be promising for application as a culture medium for this microalgae species, as it guaranteed a good cell growth rate, high biomass productivity and lipid yield. Considering the biodiesel produced, it fits the regulatory standards analyzed by the National Agency of Petroleum, Natural Gas and Biofuels (ANP). Research, Practical &amp; Social Implications: The research demonstrates the feasibility of cultivating the microalga Chlorella sorokiniana with diluted vinasse, highlighting the 10% concentration as promising for optimizing cell growth and lipid yield. The results ensure compliance with ANP regulations for biodiesel production, indicating immediate and sustainable applicability on an industrial scale. Socially, it contributes to the pursuit of biofuels, reducing dependence on fossil sources and promoting more sustainable practices in the bioenergy industry. Originality/Value: The study's originality lies in the unique combination of Chlorella sorokiniana CTT 7727, diluted vinasse, and biodiesel production in accordance with ANP regulations. It stands out for identifying the optimal vinasse concentration (10%) for cultivation, presenting an economical and effective approach. The strategic value is in the use of an alternative raw material cultivated with an industrial residue, promoting the diversification of the energy matrix and mitigating environmental impacts associated with conventional fuels.

A review on the optimization of light conditions in Chlorella culture

Chlorella has been widely used in bioenergy, environmental protection, carbon reduction, food, pharmaceutical and other fields. In this paper, a comprehensive analysis is made on the optimization of light conditions in chlorella in recent years by way of literature review. The results showed that the biomass accumulation rate of chlorella was faster in the light intensity range of 5500-7000lux, but the growth rate of chlorella reached a limit in the extremely high light intensity range of 10000-14000lux；blue and green light had the greatest effect on the biomass and photosynthetic pigment accumulation of chlorella; blue and green light monochromic light culture mode had the highest lipid yield; adding green light to blue-white light, red-white light and white-green light was beneficial to the lipid accumulation of chlorella; In the 24h culture mode, the low frequency light period of 14L:10D is the best scheme in general. According to the above conclusions, the light conditions, the effects of composite light on Chlorella and the optimal low-frequency light cycle will be the main research directions of large-scale cultivation of Chlorella in the future.

Unlocking the potential of microalgae cultivated on wastewater combined with salinity stress to improve biodiesel production

Microalgae have the potential as a source of biofuels due to their high biomass productivity and ability to grow in a wide range of conditions, including wastewater. This study investigated cultivating two microalgae species, Oocystis pusilla and Chlorococcus infusionum, in wastewater for biodiesel production. Compared to Kühl medium, KC medium resulted in a significant fold increase in cellular dry weight production for both O. pusilla and C. infusionum, with an increase of 1.66 and 1.39, respectively. A concentration of 100% wastewater resulted in the highest growth for O. pusilla, with an increase in biomass and lipid content compared to the KC medium. C. infusionum could not survive in these conditions. For further increase in biomass and lipid yield of O. pusilla, different total dissolved solids (TDS) levels were used. Maximum biomass and lipid productivities were achieved at 3000 ppm TDS, resulting in a 28% increase in biomass (2.50 g/L) and a 158% increase in lipid yield (536.88 mg/g) compared to KC medium. The fatty acid profile of O. pusilla cultivated on aerated wastewater at 3000 ppm TDS showed a high proportion of desirable saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) for biodiesel production. Cultivating microalgae in wastewater for biodiesel production can be cost-effective, especially for microalgae adapted to harsh conditions. It could be concluded that O. pusilla is a promising candidate for biodiesel production using wastewater as a growth medium, as it has high biomass productivity and lipid yield, and its fatty acid profile meets the standard values of American and European biodiesel standards. This approach offers a sustainable and environmentally friendly solution for producing biofuels while reducing the environmental impact of wastewater disposal.

The in vitro effects of black soldier fly larvae (Hermitia illucens) oil as a high-functional active ingredient for inhibiting hyaluronidase, anti-oxidation benefits, whitening, and UVB protection.

Objective: Larvae of Hermitia illucens, or black soldier fly larvae (BSFL), have been recognized for their high lipid yield with a remarkable fatty acid profile. BSFL oil (SFO) offers the added value of a low environmental footprint and a sustainable product. In this study, the characteristics and cosmetic-related activities of SFO were investigated and compared with rice bran oil, olive oil and krill oil which are commonly used in cosmetics and supplements. Methods: The physicochemical characteristics were determined including acid value, saponification value, unsaponifiable matter and water content of SFO. The fatty acid composition was determined using GC-MS equipped with TR-FAME. The in vitro antioxidant properties were determined using DPPH, FRAP and lipid peroxidation inhibition assays. Antihyaluronidase (anti-HAase) activity was measured by detecting enzyme activity and molecular docking of candidate compounds toward the HAase enzyme. The safety assessment towards normal human cells was determined using the MTT assay and the UVB protection upon UVB-irradiated fibroblasts was determined using the DCF-DA assay. The whitening effect of SFO was determined using melanin content inhibition. Results: SFO contains more than 60% polyunsaturated fatty acids followed by saturated fatty acids (up to 37%). The most abundant component found in SFO was linoleic acid (C18:2 n-6 cis). Multiple anti-oxidant mechanisms of SFO were discovered. In addition, SFO and krill oil prevented hyaluronic acid (HA) degradation via strong HAase inhibition comparable with the positive control, oleanolic acid. The molecular docking confirmed the binding interactions and molecular recognition of major free fatty acids toward HAase. Furthermore, SFO exhibited no cytotoxicity on primary human skin fibroblasts, HaCaT keratinocytes and PBMCs (IC50 values > 200μg/mL). SFO possessed significant in-situ anti-oxidant activity in UVB-irradiated fibroblasts and the melanin inhibition activity as effective as well-known anti-pigmenting compounds (kojic acid and arbutin, p < 0.05). Conclusion: This study provides scientific support for various aspects of SFO. SFO can be considered an alternative oil ingredient in cosmetic products with potential implications for anti-skin aging, whitening and UVB protection properties, making it a potential candidate oil in the cosmetic industry.

Optimization of Rhodococcus erythropolis JCM3201T Nutrient Media to Improve Biomass, Lipid, and Carotenoid Yield Using Response Surface Methodology.

The oleaginous bacterium Rhodococcus erythropolis JCM3201T offers various unique enzyme capabilities, and it is a potential producer of industrially relevant compounds, such as triacylglycerol and carotenoids. To develop this strain into an efficient production platform, the characterization of the strain's nutritional requirement is necessary. In this work, we investigate its substrate adaptability. Therefore, the strain was cultivated using nine nitrogen and eight carbon sources at a carbon (16 g L-1) and nitrogen (0.16 g L-1) weight ratio of 100:1. The highest biomass accumulation (3.1 ± 0.14 g L-1) was achieved using glucose and ammonium acetate. The highest lipid yield (156.7 ± 23.0 mg g-1DCW) was achieved using glucose and yeast extract after 192 h. In order to enhance the dependent variables: biomass, lipid and carotenoid accumulation after 192 h, for the first time, a central composite design was employed to determine optimal nitrogen and carbon concentrations. Nine different concentrations were tested. The center point was tested in five biological replicates, while all other concentrations were tested in duplicates. While the highest biomass (8.00 ± 0.27 g L-1) was reached at C:N of 18.87 (11 g L-1 carbon, 0.583 g L-1 nitrogen), the highest lipid yield (100.5 ± 4.3 mg g-1DCW) was determined using a medium with 11 g L-1 of carbon and only 0.017 g L-1 of nitrogen. The highest carotenoid yield (0.021 ± 0.001 Abs454nm mg-1DCW) was achieved at a C:N of 12 (6 g L-1 carbon, 0.5 g L-1 nitrogen). The presented results provide new insights into the physiology of R. erythropolis under variable nutritional states, enabling the selection of an optimized media composition for the production of valuable oleochemicals or pigments, such as rare odd-chain fatty acids and monocyclic carotenoids.

Supercritical CO2 extraction of neutral lipids from dry and wet Chlorella vulgaris NIES 227 microalgae for biodiesel production

This study investigates supercritical CO2 extraction of neutral lipids from Chlorella vulgaris NIES 227 microalgae, for biodiesel applications. While microalgae feedstocks are typically desiccated before extraction, drying is energy intensive and supercritical extraction from wet microalgae would be beneficial in reducing overall energy costs. The effects on the supercritical extraction kinetics, yields and extract composition of the water content of the initial biomass (either 0 or 27 wt%), and of the operating pressure (200 and 250 bar) and temperature (40 and 60 °C) were investigated. The highest total extraction yield (16.16 wt% extract/dry biomass) was obtained with freeze-dried microalgae at 40 °C and 200 bar. However, the extracts obtained at 40 °C and 250 bar were the richest in fatty acids (0.96 g FA/extract), and the extracts obtained at 60 °C and 250 bar had the highest cetane number (69) and oxidative stability (18 h). Water in the initial biomass had a negative impact on total extraction yields (3.89 wt% extract/dry biomass at 200 bar and 40 °C) and led to increased pigment extraction, but results suggest the presence of water may promote the extraction of fatty acids, in particular monounsaturated ones, highly desirable for biodiesel. In comparison, Soxhlet extraction with hexane was found to have higher lipid yields (31.20 wt% extract/dry biomass) than any of the tested supercritical conditions, but more pigments were also extracted alongside, having a negative impact on oxidative stability. All the extracts obtained with supercritical CO2 and Soxhlet hexane met biofuel European standards for density, cetane numbers and iodine values.

Detailed mechanistic investigation of stress-induced lipogenesis in oleaginous yeast for value-added metabolites

In the present study, a marine red yeast Rhodotorula glutinis ISO A1 cultivated under combinations of artificial seawater (ASW) and sewage wastewater (SWW) has been subjected to detailed mechanistic investigations via physiological and biochemical analysis to dissect the pathway of halotolerance behavior and carbon flux channelization towards enhanced lipid synthesis. Amid all tested groups (25–100% ASW), cells grown in 25% ASW yielded ∼ 1.4-fold higher lipid yield than glucose synthetic medium (GSM) and revealed metabolic rewiring of cells to channelize carbon pools for producing neutral lipids of vehicular quality. Detailed carbohydrate profiling showed enhanced glycerol, trehalose, mannose, and xylitol/arabitol under saline stress, suggesting the interplay of these metabolites to impart tolerance against osmotic imbalance. Further, the strengthened enzymatic activity (glutathione reductase, superoxide dismutase, ascorbate peroxidase) and non-enzymatic metabolites (betaine, proline) highlighted the active yeast defence network to counter altered redox state arise due to high salinity. The stress-induced responses also constituted substantial variations in membrane fluidity and production of biodiesel-quality lipids. Further findings like low thermal degradation temperature (at ∼ 265°C) and high chitin (can be converted into chitosan) entity in yeast de-oiled biomass primarily derived from yeast cells grown under contaminated environment; sea and sewage wastewater, signified its potential utilization for chitosan recovery, a commercially important product. Conclusively, this study elucidated a competent model of yeast-based biorefinery approach integrating seawater-wastewater utilization and simultaneous production of biodiesel and value-added products vital for a sustainable and circular bioeconomy.

Lipid extraction from Chlorella vulgaris &Haematococcus pluvialis using the switchable solvent DMCHA for biofuel production

Switchable solvents (SS), also termed smart solvents, have the unique ability to change their polarity/hydrophilicity through a protonation reaction using CO2. Recently, a novel method employing the use of SS for lipid extraction in microalgae has shown promising results. In this study the efficiency of the tertiary amine N, N-dimethyl cyclohexylamine (DMCHA) to extract lipids from the eukaryotic microalgae Chlorella vulgaris and Haematococcus pluvialis, was investigated using traditional hexane as a control under wet conditions. The results revealed that high lipid yields using DMCHA can be achieved in both species, however the extraction procedure is significantly more complex compared with hexane. This study found that lipid extraction of H. pluvialis, using DMCHA to be an efficient solvent, achieving a maximum lipid yield of 64.84%. Furthermore, DMCHA achieved a maximum lipid yield of 63.85% with C. vulgaris. The practicalities of DMCHA for lipid recovery are considerably more complex at larger volumes compared with hexane.

Production of biolipids from volatile fatty acids of sewage sludge by Yarrowia lipolytica

Sewage sludge (SS) can be used as a fantastic source of organic compounds instead of being considered as a waste. Thus, these compounds could be converted into microbial lipids (ML) by oleaginous microorganisms, these biolipids being used as raw material for the sustainable production of biodiesel. Nevertheless, the organic compounds are trapped in the complex structures of the sludge flocs. Therefore, in this study an integrated process of sludge management was developed to produce ML as a valuable alternative to oils from agricultural sources. In this sense, wet oxidation (WO) was used as a pre-treatment process of SS in order to maximise the generation of volatile fatty acids (VFAs) mainly acetic and propionic acids. Thus, the liquid fraction was employed as a substrate to produce biolipids by Yarrowia lipolytica, without adding any kind of (micro)nutrients. The optimum conditions for the VFA generation were found to be 205 °C and 120 min, obtaining a concentration of acetic and propionic acids of 4323 ± 112 mg/L and 565 ± 25 mg/L, respectively. Besides, during the WO, ammonium nitrogen was also released, which is a vital nutrient in the metabolism of the oleaginous yeast for cell proliferation. Regarding the fermentation with Y. lipolytica, the best pH value was established at 6.5. Under these conditions, 95% of acetic acid and 100% of propionic acid were metabolised by the yeast. This implied that approximately 30% of the organic carbon present in the oxidised SS was transformed into biolipids in 48 h of cultivation. High lipid content and lipid yield coefficient (YL/S) were achieved using VFAs derived from SS, the values being 35 ± 1% and 0.23 ± 0.02 g/g, respectively. The lipid profile mainly contained monounsaturated fatty acids, such as oleic acid (46.4 ± 0.4%), making it an interesting raw material for biodiesel production. Therefore, the proposed strategy can be a promising approach to produce clean biofuels from SS.

Determining mating type and ploidy in Rhodotorula toruloides and its effect on growth on sugars from lignocellulosic biomass.

The yeast Rhodotorula toruloides was used to produce oil using sugars extracted from a bioenergy grass.

Cultivation of Chlorella vulgaris in mediums with varying nitrogen sources and concentrations to induce the lipid yield

ABSTRACT The development of biofuel production is of high concern since energy and fuels have so far been fulfilled by fossil resources. Microalgae, as green biomass, has the potential to produce biofuel. Nevertheless, many studies still face low lipid yield due to insufficient nutrients in the medium, improper culture techniques, or inaccurate solvent composition used in the lipid extraction process. Therefore, this study aimed to enhance lipid production from the cultivation of Chlorella vulgaris. The cultivation was performed in mediums supplemented with low concentrations of low-cost exogenous N-sources, which are still rare to examine. The concentrations were varied at 10, 20 and 30 mg L−1 of urea and 35, 70 and 105 mg L−1 of KNO3. For both urea and KNO3, a faster growth rate (0.215 vs. 0.211 d−1) was found under the highest N-concentration in the medium. In contrast, lipid yield increased in the medium with the lowest N-concentration, with values of up to 50.27–51.63%. The produced lipids also contain palmitic, oleic and linoleic acids, and their spectra comply with the fatty acids composition in the biodiesel standard. Moreover, this study achieves a high lipid yield and offers an inexpensive lipid induction technique for C. vulgaris.

Comparative study on quality characteristics of Bischofia polycarpa seed oil by different solvents: Lipid composition, phytochemicals, and antioxidant activity

Bischofia polycarpa seed oil is rich in nutrition and positively affects on human health. We analyzed and compared the chemical compositions, antioxidant activities, and quality characteristics of Bischofia polycarpa seed oils using different solvents and cold-pressing. Hx: Iso (n-hexane/isopropanol, 3:2 v/v) had the highest lipid yield (35.13 %), while Folch (chloroform/methanol, 2:1 v/v) had the highest linolenic acid (50.79 %), LnLnLn (43.42 %), and LnLnL (23.43 %). Tocopherols (2108.99 mg/kg) were extracted most efficiently with Folch, whereas phytosterols (3852.97 mg/kg) and squalene (55.21 mg/kg) were extracted most efficiently with petroleum ether. Although the lower phytosterol was obtained using isopropanol, the polyphenol content (271.34 mg GAE/kg) was significantly higher than other solvents, showing the best antioxidant ability. Additionally, polyphenols were observed to be the most significant factor predicting antioxidant activity from the correlation analysis. The above information can provide a useful reference for manufacturers to obtain satisfactory Bischofia polycarpa seed oil.

SCREENING OF LIPID CONTENTS OF MICROALGAE BY OPTIMIZATION OF OIL EXTRACTION PROCESSES

Currently microalgae are considered as an efficient biological producer of oil.Present study was conducted to explore the lipid yield percentage of three microalgal strains Chlorellasp., Oedogonium sp. and Spirogyra sp. Bligh and Dyer, Soxhlet, Folch and Microwave assistedextraction methods were employed for oil extraction. It was observed that Bligh and Dyer method withChloroform-methanol (1:2, v/v) gave maximum extraction yield (15.46 ± 0.240 %) for Chlorella sp.whereas Folch method with chloroform-methanol (2:1, v/v) gave more lipid yield as compared toBligh and Dyer method i.e 5.53 ± 0.240 % for Spirogyra sp., 13.67 ± 0.240 % and 19.69 ± 0.667 % forOedogonium sp. and Chlorella sp. respectively. Soxhlet extraction resulted in less (14.5± 0.45)percentage yield as compared to Bligh and Dyer and Folch method (16.7± 0.24). Microwave assistedextraction with chloroform- methanol resulted in highest lipid yield (30%) with Chlorella sp.indicating that it contained the maximum lipid content among all the three species.

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.

Physicochemical study of Camellia oleifera Abel. seed oils produced using different pretreatment and processing methods

In this study, the effects of different pretreatment (microwave or roasting) and processing (cold pressing, hexane extraction, or aqueous enzymatic extraction) methods on the physicochemical properties, minor components, and antioxidant capacity of Camellia oleifera Abel. seed oil (COSO) were investigated. The results revealed that the fatty acid profiles of COSO were not affected by the different processing methods, while hexane extraction resulted in the highest lipid yield (41.30–44.42 g/100g), saponification value (195.23–197.33 mg/g), and polyphenol content (7.25–8.23 mg/kg). Hierarchical cluster analysis proved that the processing method had a more significant effect than the pretreatment method on the chemical composition of COSO. Principal component analysis of the antioxidant capacity revealed that the microwave–hexane extraction method resulted in the highest content of α-tocopherol (144.7 mg/kg) and polyphenols (8.17 mg/kg) in COSO, indicating a high antioxidant activity (OSI: 6.23 h; DPPH-oil: 237, DPPH-nonpolar: 150, DPPH-polar: 670, FRAP: 77.4, ABTS: 45.9 μmol TE/kg). Consequently, hexane extraction is a promising method for future COSO processing.

Phosphate limitation as crucial factor to enhance yeast lipid production from short-chain fatty acids.

Microbial lipids for chemical synthesis are commonly obtained from sugar-based substrates which in most cases is not economically viable. As a low-cost carbon source, short-chain fatty acids (SCFAs) that can be obtained from food wastes offer an interesting alternative for achieving an affordable lipid production process. In this study, SCFAs were employed to accumulate lipids using Yarrowia lipolytica ACA DC 50109. For this purpose, different amounts of SCFAs, sulfate, phosphate and carbon: phosphate ratios were used in both synthetic and real SCFAs-rich media. Although sulfate limitation did not increase lipid accumulation, phosphate limitation was proved to be an optimal strategy for increasing lipid content and lipid yields in both synthetic and real media, reaching a lipid productivity up to 8.95 g/L h. Remarkably, the highest lipid yield (0.30 g/g) was achieved under phosphate absence condition (0g/L). This fact demonstrated the suitability of using low-phosphate concentrations to boost lipid production from SCFAs.