Fatty Acid Methyl Ester Profiles Research Articles

The analysis of lamb and beef fatty acids with a 30 m BPX70 column is comparable with a 120 m column

Gas chromatography (GC) analysis of fatty acid methyl esters (FAME) typically uses long capillary columns (≥ 100 m) which can be expensive and time consuming. The current study determined whether the major FAME of interest for human health in lamb and beef can be quantified using a 30 m compared with 120 m moderately polar capillary (BPX70) column. Lamb and beef samples with a range of intramuscular fat content from either grass- or grain-fed animals were analysed. All major FAME of human health importance, including omega-3 and omega-6 polyunsaturated fatty acids and conjugated linoleic acid (CLA) isomers, could be identified on the 30 m BPX70 column. The correlation (r2) for fatty acid percentage between columns was > 0.98 for all major n–3PUFA and > 0.86 for all major CLAs. When animals were fed a grain-based diet, C18:1n–7t (vaccenic acid) could not be resolved from C18:1n-8t when analysed on the 30 m column. The FAME profile of lamb and beef, particularly those important for nutritional composition tables, can be determined using a 30 m BPX70 column, thereby saving time and expense compared with longer columns. Particular care should be employed when analysing samples from grain-fed animals due to co-eluting of C18:1n–8t.

Fatty Acid Methyl Ester Profiling of Californian Xylella fastidiosa Strains

Xylella fastidiosa ssp. fastidiosa ( Xff) is the causal agent of Pierce's disease of grapevine, a management-intensive and potentially deadly disease. However, different stains and other subspecies, such as Xylella fastidiosa ssp. multiplex ( Xfm), exist in the same regions and vary in capacity to cause disease. All strains differ in the fatty acids that comprise cell membranes, as these allow adaptations to specific host microenvironments. Therefore, studies were initiated to observe the fatty acid profiles of different Californian Xf isolates via fatty acid methyl ester (FAME) analysis. Observations revealed that the four Xff strains had similar FAME profiles that were distinct from those of the three Xfm strains, even in isolates that originated from the same host plant species. These data show consistent differences between Xff and Xfm strains and demonstrate the potential that FAME profiling has for Xylella subspecies identification of novel isolates. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Bioprospection of the Antarctic Diatoms Craspedostauros ineffabilis IMA082A and Craspedostauros zucchelli IMA088A.

In extreme environments such as Antarctica, a diverse range of organisms, including diatoms, serve as essential reservoirs of distinctive bioactive compounds with significant implications in pharmaceutical, cosmeceutical, nutraceutical, and biotechnological fields. This is the case of the new species Craspedostauros ineffabilis IMA082A and Craspedostauros zucchellii IMA088A Trentin, Moschin, Lopes, Custódio and Moro (Bacillariophyta) that are here explored for the first time for possible biotechnological applications. For this purpose, a bioprospection approach was applied by preparing organic extracts (acetone and methanol) from freeze-dried biomass followed by the evaluation of their in vitro antioxidant properties and inhibitory activities on enzymes related with Alzheimer's disease (acetylcholinesterase: AChE, butyrylcholinesterase: BChE), Type 2 diabetes mellitus (T2DM, α-glucosidase, α-amylase), obesity (lipase) and hyperpigmentation (tyrosinase). Extracts were then profiled by ultra-high-performance liquid chromatography-mass spectrometry (UPLC-HR-MS/MS), while the fatty acid methyl ester (FAME) profiles were established by gas chromatography-mass spectrometry (GC-MS). Our results highlighted strong copper chelating activity of the acetone extract from C. ineffabilis and moderate to high inhibitory activities on AChE, BChE, α-amylase and lipase for extracts from both species. The results of the chemical analysis indicated polyunsaturated fatty acids (PUFA) and their derivatives as the possible compounds responsible for the observed activities. The FAME profile showed saturated fatty acids (SFA) as the main group and methyl palmitoleate (C16:1) as the predominant FAME in both species. Overall, our results suggest both Antarctic strains as potential sources of interesting molecules with industrial applications. Further studies aiming to investigate unidentified metabolites and to maximize growth yield and natural compound production are required.

Potential of algal oil production from secondary treated sewage: a study using Chlorella vulgaris and synthetic wastewater

ABSTRACTTo assess the potential of using the secondary treated wastewater for the production of algal biofuel, batch experiments were carried out in photobioreactors using indigenous Chlorella vulgaris isolated from the natural freshwater body. Secondary treated wastewater with partial nitrification was simulated using various proportions of NO3-N and NH4-N while keeping the total nitrogen the same. Experiments with similar concentrations of nitrate without the NH4-N were used for comparison. In the presence of only NO3-N in the concentration range of 9–37 mg/L, the growth and fatty acid methyl ester (FAME) production was similar to the literature reports. When NH4-N was present along with NO3-N, the biomass growth was adversely affected, indicating an impact on the metabolic activity. For the same initial concentrations of nitrate in the culture, the maximum biomass concentration was reduced by 50–60% in the presence of NH4-N. The FAME profile changed significantly and a new FAME was identified, suggesting an impact on the lipid synthesis pathway. Comparison and analysis with the help of existing literature indicated that the adverse effect due to NH4-N was a function of pH. The growth, biomass yield, and FAME production were unaffected by a wide range of phosphorus concentrations. Maximum fatty acid methyl ester (FAME) suitable for biodiesel production (fatty acid carbon chain length C16 to C18) was 381.01 mg/L (224.58 mg/g of dry biomass), produced at NO3-N concentration of 18.5 mg/L and initial nitrogen loading per unit biomass of 0.37 g NO3-N/g of dry biomass.

Unveiling the anticancer potentiality of single cell oils produced by marine oleaginous Paradendryphiella sp. under optimized economic growth conditions

Bioprospecting about new marine oleaginous fungi that produce advantageous bioproducts in a green sustainable process is the key of blue bioeconomy. Herein, the marine Paradendryphiella sp. was utilized for single cell oils (SCOs) production economically, via central composite design, the lipid content enhanced 2.2-fold by 5.5 g/L lipid yeild on seawater-based media supplemented with molasses concentration 50 g/L, yeast extract, 2.25 g/L at initial pH value (5.3) and 8 days of static incubation. Subsequently, the fatty acid methyl esters profiles of SCOs produced on optimized media under different abiotic conditions were determined; signifying qualitative and quantitative variations. Interestingly, the psychrophilic-prolonged incubation increased the unsaturation level of fatty acids to 59.34%, while ω-6 and ω-3 contents representing 23.53% and 0.67% respectively. Remarkably, it exhibited the highest EC100 dose by 677.03 µg/mL on normal human lung fibroblast Wi-38 cells. Meanwhile, it showed the highest inhibiting proliferation potential on cancer cell lines of A549, MDA-MB 231 and HepG-2 cells by 372.37, 417.48 and 365.00 µg/mL, respectively. Besides, it elevated the oxidative stress, the expression of key apoptotic genes and suppressed the expression of key oncogenes (NF-κB, BCL2 and cyclin D); implying its promising efficacy in cancer treatment as adjuvant drug. This study denoted the lipogenesis capacity of Paradendryphiella sp. under acidic/alkaline and psychrophilic/mesophilic conditions. Hereby attaining efficient and economic process under seasonal variation with different Egyptian marine sources to fill the gap of freshwater crisis and simultaneously preserve energy.

Biological treatment of agro-processing industrial effluents from tannery, coffee and dairy plants using green algae (<i>Chlorella Ssp</i>.) cultured in a photo bioreactor

Due to increased environmental pollution as a result of high emission rates from agro-processing industries, the effluents must be cleaned up before being released into the environment. This study outlines the use of green algae for nutrient removal from agro-processing effluents discharged from three agro-industries (namely coffee, dairy, and tannery) in Kenya and how they can be used for the propagation of microalgae for biofuel production. Green algae were grown inside a photobioreactor containing the three agro-industrial effluents as nutrient media for 21 days. Thereafter, the algae were harvested and evaluated for biofuel production. The effectiveness of green algae (chlorella ssp) to extract the cations from the various agro-processing effluents was used to gauge how well they performed. Additionally, the algae growth rate, quantity of lipids, and biomass generated were used to evaluate the strains' effectiveness in producing biofuel. The results indicate that the highest maximum algae growth rate of 14.528 mg/mL occurred in the dairy effluent. The corresponding values for the coffee and tannery effluents were 13.016 mg/mL and 10.866 mg/mL, respectively. Biochemical analysis was done to establish the amount of biomass in the algae. The results showed that there was higher biomass productivity per day of 293.944, 124.849, and 91.997 μg/mL for the dairy, coffee, and tannery effluents, respectively. The contents of linolenic acid in the chlorella strain in the dairy, coffee, and tannery effluents were 13.21, 12.86, and 15.98%, respectively. The values obtained were slightly above the recommended lower limit value of 12% (EN 14214, 2004) for the production of quality biofuels. The results further show that high chemical oxygen demand removal (maximum of 47.7–67.8%) and total phosphorus removal (maximum of 95%) were achieved in all three effluents. Finally, the fatty acid methyl ester profiles produced indicated that the lipid content of the cultivated green algae was appropriate for the production of biofuel.

No‐till marginally mitigates the impact of harvesting corn stover on soil microbial parameters

AbstractHarvesting corn stover can negatively impact soil chemical and physical properties, but less is known regarding its effects on soil microbiology. We evaluated the impact of corn (Zea mays L.) stover removal level (SRL) on soil microbial biomass (MB) and extracellular enzyme activities (EEAs) in irrigated, continuous corn located in eastern Nebraska. Soil fatty acid‐methyl esters (FAMEs) and EEA of eight soil enzymes were measured over 2 years, 0‐ to 20‐cm soil depth, under conventional disk tillage (CT) and no‐till (NT) under three SRLs. Soil chemical properties were measured as explanatory variables for changes in soil microbial communities and their enzymatic potential. Potential EEA of all enzymes decreased with stover removal and tillage. Soil bacterial biomass (BB) and fungal biomass (FB) decreased with SRL, while mycorrhizal biomass was unresponsive. Impacts of tillage on MB groups varied by year; however, FB was consistently higher under CT. At all growth stages, NT with all stover retained, a “soil conservation target” had distinct soil enzyme and bacterial FAME profiles compared to CT across all SRLs and to NT under high and sometimes moderate SRLs. Principal component analysis of soil properties was dominated by SRL with EEAs, BB, soil organic matter (SOM), water‐extractable carbon, and H3A‐extractable potassium being positively correlated to stover retention. Reduced input of microbial substrates also led to a loss of fine particulate organic matter, an indicator correlated to stable macroaggregation. Because NT partially ameliorated the negative impact of stover removal on BB, SOM fractions, and soil enzymes critical to nutrient cycling, pairing NT with stover removal may be more sustainable in the long term.

Investigation on the Microbiological Quality and Fatty Acid Methyl Esters Composition of Commercially Available Cold-pressed Nigella sativa L. Oil

Background:: Nigella sativa is a traditional plant with several ethno-medicinal activities. There have been several health advantages associated with Nigella sativa (Ns) L. oil, which has a high concentration of bioactive compounds. Method:: This research aimed to examine the fatty acid methyl ester profiles, microbiological profiles, and aflatoxin profiles of cold-pressed Ns oils acquired from Turkish herbalists. For this, the fatty acids methyl esters (FAMEs) content and microbiological purity of 10 different Ns oils were examined. Results:: The principal FAME components in Ns seed oils were linoleic (C18:2), oleic (C18:1), and palmitic acid (C16:0), with relative percentages of 34.17-57.54%, 19.41-30.52%, and 7.05-12.54%, respectively. The quantity of total saturated fatty acids (SFA) in all investigated oils ranged from 11.47 to 18.69%, while the amount of total unsaturated fatty acids ranged from 80.94 to 88.53%. Six of ten products (0.35-1.49%) were found to contain cis-11 eicosenoic acid, a chemical unique to Ns oil. Conclusion:: Although no Aflatoxin was found in any of the samples, Enterobacteriaceae levels were exceptionally low, and yeast mold concentrations surpassed the Turkish Food Codex's permissible limit values.

Nutritional Value of Meals Designed for a School-Based Food Aid Program and Comparison with Similar Commercial Products: An Example of Good Practice from the DIATROFI Program.

Providing meals of high nutritional value should be the principal objective of large-scale school-based food aid programs. This study aimed at highlighting the nutritional value of meals distributed in the school-based food assistance DIATROFI Program by comparing them to their commercially available counterparts. For the purpose of this study, n = 13 DIATROFI meals and n = 50 commercial products from the 2016-2017 school year, and n = 12 DIATROFI meals and n = 40 commercial products from the 2022-2023 school year were selected. The protein, carbohydrate, total sugar, dietary fiber, total fat, sodium/salt content, and fatty acid methyl ester profile of DIATROFI meals were estimated through recipe simulation and national/international food databases, and verified through laboratory analyses while the relevant information was extracted from the label for commercial products. As verified by laboratory analyses and in comparison with food labels, most DIATROFI meals had lower total fat, saturated fatty acid, and sugar content, and most had higher dietary fiber content during both years. Many recipes' nutrient profiles also improved over time. DIATROFI meals present significant advantages over available commercial products. Such tailored-made school meals can prove to be advantageous in terms of nutrition profile compared to commercially available, which have yet to be impacted by food reformulation.

Establishment of Stable Genetic Transformation Conditions for Novel Thermotolerant Scenedesmus sp. (Chlorophyta)

Microalgae became an attractive source of high value compounds such as fatty acids, carotenoids and other nutrients in recent years. In a previous study, the characterization of a novel thermo-tolerant freshwater microalga, Scenedesmus sp. ME02 with high phenolic content, particularly rich in flavonoids was done. Here, two different approaches are reported to increase the efficiency of the growth parameters of this strain. Firstly, the effects of phosphorus (P) depletion on biomass and lipid characteristics of Scenedesmus sp. ME02 were investigated. Although, P depletion resulted in a slight reduction in biomass productivity of microalgae and had a minimal effect on the lipid content and productivity; fatty acid methyl ester profile changed substantially. Particularly, percent oleic acid (18:1) increased by more than two-fold, whereas percent linolelaidic acid (C18:2n6t) and linolenic acid (C18:3n6) decreased significantly when cells were switched from P-replete (control) to P-deplete conditions. Overall, the polyunsaturated fatty acid content was significantly reduced. Secondly, stable genetic transformation conditions for Scenedesmus sp. ME02 via electroporation were optimized using two different transformation vectors. GFP gene expression was detected in colonies transformed with both vectors by RT-PCR. GFP protein expression was detected in the transgenic lines one year after initial transformation by confocal microscopy.

Kinetic and thermodynamic evaluations of oil extraction from immobilized Chlorella vulgaris using different solvents

Investigating the effect of different solvents used for microalgae oil extraction on the determinations of kinetic values and thermodynamic parameters is a compelling novel approach for the current study. The primary concern of microalgae oil extraction is selecting a solvent system because it has a massive influence on the extraction yield, composition, and oil quality. Three different solvent systems were inspected to determine the suitable solvent for the oil extraction from immobilized Chlorella vulgaris: heptane, heptane:methanol, and heptane:ethanol. The research methodology begins with the immobilization of microalgae cells. The matured immobilized beads were then harvested, and dried biomass was recovered. The oil was extracted by solvent extraction method using the solvents mentioned. Finally, the extracted oil was trans-esterified and analyzed for fatty acid methyl ester profile. Based on the results calculated, heptane is determined to extract the most oil with 27.42 %, followed by H:M and H:E at the highest temperature and longest running time. When the polar solvent is mixed with a non-polar solvent, the mixture has the least kinetic value and immense activation energy. However, the activation energy for heptane is only 89.06 kJ/mol. Another essential objective of this research is to determine the effects of solvents on the thermodynamics parameters. The extraction process of microalgae oil using heptane alone is determined to have a ΔH value of 0.111 kJ/mol, followed by 0.201 and 0.102 kJ/mol for solvent system H:M and H:E respectively. All the values obtained are positive, thus making the extraction processes using various solvents to be endothermic. The positive values of ΔS and the negative values of ΔG indicated that the oil extraction using heptane is thermodynamically spontaneous and irreversible, thus making it economically feasible. The fatty acids methyl esters such as palmitic, stearic, oleic, linoleic, and linolenic were the prime constituents quantified in the oil extracted using heptane compared to other solvent systems. Therefore, with the larger and increasing kinetic values and lowest activation energy, it can be concluded that heptane is the most suitable solvent for the oil extraction of immobilized Chlorella vulgaris compared to other solvent systems employed in the current research work.

Persica Akhani Salicornia as novel biodiesel feedstock production for economic prosperity in salty and water scarcity areas: Optimized oil extraction process and transesterification reaction using new magnetic heterogenous nanocatalysts

As a new biodiesel feedstock, the oil extraction procedure from the seeds of the plant Salicornia (Persica Akhani subspecies) has been developed. Oil extraction from the seeds of the Salicornia Persica Akhani has been researched utilizing two different organic solvents and four different procedures, including the Soxhlet method, the traditional approach, the shaker method, and the ultrasonic probe method. The results indicated that oil yield by ultrasonic probe technique was higher than the other methods in a short time. Based on the outcomes, extracting the oil from Salicornia seeds using hexane resulted in a greater yield of oil than petroleum ether. This was true across all methods of extraction. The Physico-chemical properties and antioxidant activity of extracted oil suggested its suitability for biodiesel production. To transesterification reaction of Salicornia seeds oil with methanol into biodiesel, the heterogeneous magnetic Zn0.4Ni0.6Fe2O4 and Zn0.4Ni0.6Fe2O4@SO3H nanocomposites have been synthesized by sol-gel auto combustion procedure. FT-IR, FE-SEM, EDS, and VSM were used to determine the characteristics of the heterogeneous nanocomposites. These nanoparticles have a strong attraction to an outside magnet, which makes it much easier to collect them from the reaction environment for subsequent reuse. In the process of transesterification of Salicornia oil with methanol, novel sulfonated heterogeneous magnetic catalysts with a high density of superacid sites on the surface (2.50 mmol SO3H g−1) and significant magnetization (60 emu/g) afforded high activity and produced a biodiesel yield of 96%. In addition, the magnetic Zn0.4Ni0.6Fe2O4@SO3H nanoparticles could be reused up to five times in the process of turning oil into biodiesel, which resulted in reduced expenses associated with the manufacture of biodiesel. FT-IR and SEM analyses were performed both before and after the transesterification process, and the results showed that the absorption bands and particle distribution were practically the same in both new and used catalysts. The analysis of the FT-IR spectra reveals indications of the transformation of Salicornia oil into fatty acid methyl esters (FAMEs). Gas chromatography (GC) study of the FAME profiles of the as-prepared biodiesel also indicated that palmitic acid (C16:0) was the most saturated fatty acid (8.44%–8.50%), while linoleic acid (18:2) was the predominant unsaturated fatty acid (60.94%–60.97%).

Lipid content and fatty acid methyl ester profile by Chromochloris zofingiensis under chemical and metabolic stress

Lipid content and fatty acid methyl ester profile by Chromochloris zofingiensis under chemical and metabolic stress

Sustainable Biodiesel Production from a New Oleaginous Fungus, Aspergillus carneus Strain OQ275240: Biomass and Lipid Production Optimization Using Box–Behnken Design

Due to their low cost and ability to synthesize lipids for sustainable biodiesel production, oleaginous fungus has recently gained more prominence than other microorganisms. The new oleaginous fungus Aspergillus carneus OQ275240’s dry biomass, lipid content, and lipid yield were all optimized in this work, using the response surface methodology-based Box–Behnken design. Analysis of variance (ANOVA) was also used to examine the experimental data, and multiple regression analysis was used to fit the data to a second-order polynomial equation. Three independent variables, such as the concentration of yeast, glucose, and phosphorus, were examined for their mutual impacts. Maximum dry biomass (0.024 g/50 mL), lipid content (36.20%), and lipid yield (8.70 mg/50 mL) were achieved at optimal concentrations of 2.68 g/L of yeast, 20.82 g/L of glucose, and 0.10 g/L of phosphorus, respectively, showing that the actual data and predictions of the models were in good agreement. A. carneus OQ275240 has a favorable fatty acid profile that can be used to successfully create biodiesel, as shown by the presence of palmitic acid (C16:0), stearic acid (C18:0), and oleic acid (C18:1) in its fatty acid methyl esters (FAMEs) profile. Furthermore, the qualities of the biodiesel were investigated, and it was found that they fell within the parameters established by the international specifications EN 14214 (Europe) and ASTM D6751-08 (United States). These findings point to the newly evaluated filamentous fungal strain as a potential feedstock for the production of high-quality biodiesel.

Biodegradation of quinoline by Nitrosomonas mobilis Ms1 through nitrification: A mechanistic study

Effluents from pharmaceutical and coal gasification industries contain recalcitrant aromatic pollutants such as quinoline. Ammonia oxidizing bacteria (AOB) has been known to simultaneously oxidize ammonia and aromatic compounds. This study investigated the impact of quinoline, a nitrogen-containing heterocyclic aromatic compound, on nitrification by pure culture of AOB- Nitrosomonas mobilis Ms1. Quinoline has been found to inhibit nitrification to suspension culture by IC 50 value 40.01 μM. However, biofilm culture could withstand its inhibitory effect upto 50 μM. Morphological analysis of biofilm culture showed destruction in extracellularpolymeric substances (EPS) in the presence of quinoline at concentration of 1.5 mM and above. X-ray photoelectron spectroscopy (XPS) analysis of the biofilm surface showed loss of NH4+ peak in quinoline treated biofilm which indicated lower protein in EPS. Biodegradation analysis showed pyridine derivatives – 2,3-Pyridinedicarbonitrile, 2,4-Dicyanopyridine, and Pyridine, 2-[(3-methoxyphenyl) methyl] and hydroxylated aromatic such as 3-Hydroxy-4-methylbenzaldehyde and phenol, 4-[2-(methylamino) ethyl] as metabolic intermediates of quinoline degradation. These metabolic intermediates have been found to inhibit nitrification by blocking enzyme active site. Quinoline caused change in fatty acid methyl ester (FAME) profile which resulted in higher fraction of unsaturated FAME. This is one of the pioneer studies on quinoline biodegradation by a pure culture of AOB species, which could in turn aid to improve the efficacy of biological treatment of nitrogen-containing (heterocyclic compounds such as quinoline) wastewater.

Low-temperature thermal pre-treated sewage sludge for feeding of black soldier fly (Hermetia illucens) larvae: Protein, lipid and biodiesel profile and characterization

Previous work showed that low-temperature thermal pre-treatment of waste activated sludge (WAS) under different temperatures (30, 60, 75, 90 °C) and durations (2, 4, 8, 16 h) prior to black soldier fly larvae (BSFL) rearing could improve the larval growth. In this work, the biochemical profiles of WAS-fed BSFL and the characteristics of biodiesel produced were reported. The BSFL fed with pre-treated WAS had high protein contents (44%–54%) and moderate lipid contents (21%–25%). The WAS pre-treated at 90 °C for 16 h produced BSFL with the highest protein and lipid yields, achieving 69% and 71% of increments, respectively, as compared with the controlled WAS. Subsequently, high conversion of lipid into biodiesel (>90%) could be achieved through the acid-catalyzed transesterification process. The BSFL biodiesel was dominated by saturated fatty acid methyl esters (FAME), with C12:0 being the abundance. This unique FAME profile enabled BSFL biodiesel to have low iodine value, high cetane number and more oxidatively stable as compared with other reported biodiesels like palm oil and rapeseed oil biodiesels. The BSFL biodiesel also satiated the biodiesel standards of EN 14214 and ASTM D6751, except for the flash point, which was still higher and safer than petroleum diesel. In short, the thermal pre-treatment of WAS was effective in promoting BSFL growth and its lipid yield, ultimately leading to higher biodiesel production.

Prospecting the biofuel potential of new microalgae isolates

The continued search and urgent need for renewable fuel sources have necessitated the exploration of microalgae to identify relevant species for making biofuels. The aim of the study was bioprospecting and screening native microalgae strains from freshwater habitats of the Almaty region, Kazakhstan, to assess the potential for producing biofuel. The studied strains demonstrated simultaneous biomass productivity, lipid productivity, suitable fatty acid composition, and biodiesel properties. The sequence analysis of the ribosomal DNA internal transcribed spacer partial region and ribulose-bisphosphate carboxylase gene (rbcL) led to the identification of five microalgae: Monoraphidium griffithii ZBD-01, Nephrochlamys subsolitaria ZBD-02, Ankistrodesmus falcatus ZBD-03, Parachlorella kessleri ZBD-04, and Desmodesmus pannonicus ZBD-05. P. kessleri had the highest biomass production (1.42 ± 0.08 g L−1 day−1), lipid productivity (29 ± 1.2 g L−1day−1), and C16–C18 fatty acid contents (90%), followed by A. falcatus and M. griffithi. Gas chromatography/mass spectrometry analysis indicated that the dominant fatty acids in these strains were palmitic, stearic, and oleic acids. The calculated biodiesel properties of P. kessleri and A. falcatus based on fatty acid methyl esters (FAME) profiles showed relatively good fuel properties (cetane numbers - 48 and 50; iodine and saponification values - 83.4 and 103.6 g I₂/100 g oil, 260.8 and 199.5 mg KOH g−1), which correlate well with. Our results suggest that P. kessleri and A. falcatus are promising strains for biodiesel production due to their high lipid productivity, fatty acid profile with relatively high content of oleic acid, and suitable biodiesel properties. The isolated native species of microalgae from natural freshwater bodies of the Almaty region present opportunities for further exploitation for the sustainable production of biomass and biodiesel.

Effect of salt stress on the biomass productivity and potential bioenergy feedstock of Graesiella emersonii KNUA204 isolated from Ulleungdo Island, South Korea

Microalgae are versatile, profitable, and promising sources of bioenergy and high-value products, having various applications in the biotechnology industry. Herein, G. emersonii KNUA204 was isolated from Ulleungdo Island, South Korea, and exposed to stressors, i.e., MgCl2 (75 and 150 mM) and NaCl (200 and 400 mM), to investigate improvement in its biomass productivity and feasibility of the application of biomass. Treatment with mild MgCl2 (75 mM) afforded the highest specific growth rate (μ = 0.13 d−1), dry cell weight (3 g L−1), and total carbohydrate content (29.87%). Although all salt treatments decreased chlorophyll and carotenoid contents, treatment with high NaCl concentration (400 mM) afforded the highest zeaxanthin content (0.3 mg g−1). The proximate and ultimate analyses of biomass following treatment with 150 mM MgCl2 revealed 93.85% volatile matter and 22.55 MJ kg−1 calorific value, respectively, indicating that Graesiella emersonii KNUA204 can be potentially used as bioenergy feedstock. The biodiesel quality was established based on the fatty acid methyl ester profiles, and MgCl2 treatment increased the cetane number more than the control. Therefore, the treatment of G. emersonii KNUA204 with MgCl2 during cultivation could provide a microalgae-based bioenergy feedstock with high productivity.

Identifications of Surfactin-Type Biosurfactants Produced by Bacillus Species Isolated from Rhizosphere of Vegetables.

Surfactins are cyclic lipopeptides consisting of a β-hydroxy fatty acid of variable chain length and a peptide ring of seven amino acids linked together by a lactone bridge, forming the cyclic structure of the peptide chain. These compounds are produced mainly by Bacillus species and are well regarded for their antibacterial, antifungal, and antiviral activities. For their surfactin production profiling, several Bacillus strains isolated from vegetable rhizospheres were identified by their fatty acid methyl ester profiles and were tested against phytopathogen bacteria and fungi. The isolates showed significant inhibition against of E. amylovora, X. campestris, B. cinerea, and F. culmorum and caused moderate effects on P. syringae, E. carotovora, A. tumefaciens, F. graminearum, F. solani, and C. gloeosporioides. Then, an HPLC-HESI-MS/MS method was applied to simultaneously carry out the quantitative and in-depth qualitative characterisations on the extracted ferment broths. More than half of the examined Bacillus strains produced surfactin, and the MS/MS spectra analyses of their sodiated precursor ions revealed a total of 29 surfactin variants and homologues, some of them with an extremely large number of peaks with different retention times, suggesting a large number of variations in the branching of their fatty acid chains.

Phycoremediation of cashew nut processing wastewater and production of biodiesel using Planktochlorella nurekis and Chlamydomonas reinhardtii

The present study examined the biomass enrichment of two microalgal strains, Planktochlorella nurekis and Chlamydomonas reinhardtii in cashew nut processing wastewater (CNPW) along with the simultaneous production of biofuel as well as wastewater treatment. The strains were initially grown in Bold's Basal Medium (BBM) before being introduced into CNPW under experimental conditions. The physico-chemical parameters, heavy metal concentration and biomass content were analyzed periodically. The produced biomass was used for the production of biodiesel and the Fatty acid methyl esters (FAME) of the biodiesel were estimated along with its quality. The results of the study revealed a significant improvement in the quality of CNPW within 13 days. P. nurekis (1.914 ± 0.02 g/L) showed higher biomass production than C. reinhardtii (1.503 ± 0.069 g/L). The physico-chemical analysis showed that P. nurekis and C. reinhardtii could significantly reduce nitrate, phosphate and COD from CNPW. The percentage reduction of heavy metals such as Cd, Cr, Ni, Cu and As were 93.2 %, 99.7 %, 98.7 %, 99 % and 90.6 %, respectively when treated with P. nurekis. Similarly, the percentage reduction of the aforesaid heavy metals by C. reinhardtii were 75.7 %, 65.9 %, 72.5 %, 78.5 % and 87.4 % respectively. The FTIR analysis revealed the presence of the functional groups such as amines, alkenes, carboxylic acid, phenol, nitro compound, amide and alcohols in both strains. The FAME profile of both strains showed a moderate concentration of C16–C18 fatty acids content. The quality analysis of biodiesel produced by both species revealed that all the physical properties were within the permissible limits as per ASTM D6751–02 and EN 14214. Comparatively, P.nurekis exhibited notable phycoremediation capacity as well as lipid production potential than C. reinhardtii. The present study has shown that both species are the promising candidates for wastewater treatment.