Ultrasonic-Assisted Preparation of Biodiesel Products from Vegetable Oils.

Utilizing vegetable oil as a sustainable feedstock, this study presents an innovative approach to ultrasonic-assisted transesterification for biodiesel synthesis. This alkaline-catalyzed procedure harnesses ultrasound as a potent energy input, facilitating the rapid conversion of extra virgin olive oil into biodiesel. In this demonstration, the reaction is run in an ultrasonic bath under ambient conditions for 15 min, requiring a 1:6 molar ratio of extra virgin olive oil to methanol and a minimum amount of KOH as the catalyst. The physiochemical properties of biodiesel are also reported. Emphasizing the remarkable advantages of ultrasonic-assisted transesterification, this method demonstrates notable reductions in reaction and separation times, achieving near-perfect purity (~100%), high yields, and negligible waste generation. Importantly, these benefits are achieved within a framework that prioritizes safety and environmental sustainability. These compelling findings underscore the effectiveness of this approach in converting vegetable oil into biodiesel, positioning it as a viable option for both research and practical applications.

Identification of sorbitol esterification of glutamic acid by LC-MS/MS in a monoclonal antibody stability assessment.

The stability of monoclonal antibodies (mAbs) is vital for their therapeutic success. Sorbitol, a common mAb stabilizer used to prevent aggregation, was evaluated for any potential adverse effects on the chemical stability of mAb X. An LC-MS/MS based analysis focusing on the post-translational modifications (PTMs) of mAb X was conducted on samples that had undergone accelerated aging at 40°C. Along with PTMs that are known to affect mAbs' structure function and stability (such as deamidation and oxidation), a novel mAb PTM was discovered, the esterification of glutamic acid by sorbitol. Incubation of mAb X with a 1:1 ratio of unlabeled sorbitol and isotopically labeled sorbitol (13C6) further corroborated that the modification was the consequence of the esterification of glutamic acid by sorbitol. Levels of esterification varied across glutamic acid residues and correlated with incubation time and sorbitol concentration. After 4 weeks of accelerated stability with isotopically labeled sorbitol, it was found that 16% of the total mAb possesses an esterified glutamic acid. No esterification was observed at aspartic acid sites despite the free carboxylic acid side chain. This study unveils a unique modification of mAbs, emphasizing its potential significance for formulation and drug development.

Gas-Phase Functionalization of Phytoglycogen Nanoparticles and the Role of Reagent Structure in the Formation of Self-Limiting Hydrophobic Shells.

A suite of acyl chloride structural isomers (C6H11OCl) was used to effect gas-phase esterification of starch-based phytoglycogen nanoparticles (PhG NPs). The surface degree of substitution (DS) was quantified using X-ray photoelectron spectroscopy, while the overall DS was quantified using 1H NMR spectroscopy. Gas-phase modification initiates at the NP surface, with the extent of surface and overall esterification determined by both the reaction time and the steric footprint of the acyl chloride reagent. The less sterically hindered acyl chlorides diffuse fully into the NP interior, while the branched isomers are restricted to the near-surface region and form self-limiting hydrophobic shells, with shell thicknesses decreasing with increasing steric footprint. These differences in substitution were also reflected in the solubility of the NPs, with water solubility systematically decreasing with increasing DS. The ability to separately control both the surface and overall degree of functionalization and thereby form thin hydrophobic shells has significant implications for the development of polysaccharide-based biopolymers as nanocarrier delivery systems.

Physicochemical and functional properties of short-chain fatty acid starch modified with different acyl groups and levels of modification.

Rice and quinoa starches are modified with short-chain fatty acids (SCFA) with different SCFA acyl chain lengths and levels of modification. This work is aimed to investigate the impact of modifying rice and quinoa starches with short-chain fatty acids (SCFAs) on various physicochemical properties, including particle size, protein and amylose content, thermal behavior, pasting characteristics, and in vitro digestibility. Both native and SCFA-starches showed comparable particle sizes, with rice starches ranging from 1.58 to 2.22 µm and quinoa starches from 5.18 to 5.72 µm. SCFA modification led to lower protein content in both rice (0.218-0.255 %) and quinoa starches (0.537-0.619 %) compared to their native counterparts. Esterification led to the reduction of gelatinization and pasting temperatures as well as the hardness of the paste of SCFA-starches were reduced while paste clarity increased. The highest level of modification in SCFA-starch was associated with the highest amount of resistant starch fraction. Principal component analysis revealed that modification levels exerted a greater influence on starch properties than the types of SCFA used (acetyl, propionyl, and butyryl). These findings is importance in considering the degree of substitution or level of modification when tailoring starch properties through SCFA modification, with implications for various applications in food applications.

Differences in physicochemical properties of pectin extracted from pomelo peel with different extraction techniques.

In order to obtain high yield pomelo peel pectin with better physicochemical properties, four pectin extraction methods, including hot acid extraction (HAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction, and enzymatic assisted extraction (EAE) were compared. MAE led to the highest pectin yield (20.43%), and the lowest pectin recovery was found for EAE (11.94%). The physicochemical properties of pomelo peel pectin obtained by different methods were also significantly different. Pectin samples obtained by MAE had the highest methoxyl content (8.35%), galacturonic acid content (71.36%), and showed a higher apparent viscosity, thermal and emulsion stability. The pectin extracted by EAE showed the highest total phenolic content (12.86%) and lowest particle size (843.69 nm), showing higher DPPH and ABTS scavenging activities than other extract methods. The pectin extracted by HAE had the highest particle size (966.12 nm) and degree of esterification (55.67%). However, Fourier-transform infrared spectroscopy showed that no significant difference occurred among the different methods in the chemical structure of the extracted pectin. This study provides a theoretical basis for the industrial production of pomelo peel pectin.

Lipolytic production from solid-state fermentation of the filamentous fungus Penicillium polonicum and its applicability as biocatalyst in the synthesis of ethyl oleate.

Lipases represent versatile biocatalysts extensively employed in transesterification reactions for ester production. Ethyl oleate holds significance in biodiesel production, serving as a sustainable alternative to petroleum-derived diesel. In this study, our goal was to prospect lipase and assess its efficacy as a biocatalyst for ethyl oleate synthesis. For quantitative analysis, a base medium supplemented with Rhodamine B, olive oil, and Tween 80 was used. Solid-state fermentation utilized crambe seeds of varying particle sizes and humidity levels as substrates. In the synthesis of ethyl oleate, molar ratios of 1:3, 1:6, and 1:9, along with a total enzymatic activity of 60 U in n-heptane, were utilized at temperatures of 30 °C, 37 °C, and 44 °C. Reactions were conducted in a shaker at 200 rpm for 60 min. As a result, we first identified Penicillium polonicum and employed the method of solid-state fermentation using crambe seeds as a substrate to produce lipase. Our findings revealed heightened lipolytic activity (22.5 Ug-1) after 96 h of fermentation using crambe cake as the substrate. Optimal results were achieved with crambe seeds at a granulometry of 0.6 mm and a fermentation medium humidity of 60%. Additionally, electron microscopy suggested the immobilization of lipase in the substrate, enabling enzyme reuse for up to 4 cycles with 100% enzymatic activity. Subsequently, we conducted applicability tests of biocatalysts for ethyl oleate synthesis, optimizing parameters such as the acid/alcohol molar ratio, temperature, and reaction time. We attained 100% conversion within 30 min at 37 °C, and our results indicated that the molar ratio proportion did not significantly influence the outcome. These findings provide a methodological alternative for the utilization of biocatalysts in ethyl oleate synthesis.

Switchable CO2-Responsive Janus Nanoparticle for Lipase Catalysis in Pickering Emulsion.

The use of convertible immobilized enzyme carriers is crucial for biphasic catalytic reactions conducted in Pickering emulsions. However, the intense mechanical forces during the conversion process lead to enzyme leakage, affecting the stability of the immobilized enzymes. In this study, a CO2-responsive switchable Janus (CrSJ) nanoparticle (NP) was developed using silica NP, with one side featuring aldehyde groups and the other side adsorbing N,N-dimethyldodecylamine. A switchable Pickering emulsion catalytic system for biphasic interface reactions was prepared by covalently immobilizing lipase onto the CrSJ NPs. The CO2-responsive nature of the CrSJ NPs allowed for rapid conversion of the Pickering emulsion, and covalent immobilization substantially reduced lipase leakage while enhancing the stability of the immobilization during the conversion process. Impressively, after repeated transformations, the Pickering emulsion still maintains its original structure. Following 10 consecutive cycles of esterification and hydrolysis reactions, the immobilized enzyme's activity remains at 77.7 and 79.5% of its initial activity, respectively. The Km of the CrSJ catalytic system showed no significant change compared to the free enzyme, while its Vmax values were 1.2 and 1.6 times that of the free enzyme in esterification and hydrolysis reactions, respectively.

Synthesis of guar gum maleate under dry conditions: Reaction kinetics and characterization.

In the present study, a novel environment friendly dry method for preparation of guar gum maleate (GGM) with varying degrees of substitution (DS; 0.02-1.04) was optimized. GGM with a maximum DS of 1.04 was successfully synthesized using guar gum (GG) and maleic anhydride (MA) in proportion of 1: 1 at 80 °C with 4 h of reaction time. The activation energy for the reaction was determined to be 36.91 ± 3.61 kJ mol-1 with pre-exponential factor of 1392 min-1. Esterification of GG was confirmed by FT-IR and 13C NMR. Analysis using size exclusion chromatography (SEC) indicated a decrease in weight average molecular weight (Mw) of the polymer with an increase in polydispersity index (PDI) due to esterification. In comparison with GG, GGM displayed increased hydrophobicity and reduced thermal stability, as analysed by differential scanning calorimetry (DSC). Rheological studies of GGM revealed that initial apparent viscosity decreased with increasing DS. For the first time, the study offered valuable insights on GGM synthesis under dry solvent-less reaction conditions enabling simpler and scalable synthesis process.

Effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice.

Pectins are dietary fibers that are attributed with several beneficial immunomodulatory effects. Depending on the degree of esterification (DE), pectins can be classified as high methoxyl pectin (HMP) or low methoxyl pectin (LMP). The aim of this study was to investigate the effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice. Supplementation of the diet with LMP or HMP induced changes in the composition of the intestinal microbiota in mice toward Bacteroides, which was mainly promoted by HMP. Metabolome analysis of stool samples from pectin-fed mice showed a different effect of the two types of pectin on the levels of short-chain fatty acids and bile acids, which was consistent with highly efficient in vivo fermentation of LMP. Analysis of serum antibody levels showed a significant increase in IgG and IgA levels by both pectins, while FACS analysis revealed a decrease of infiltrating inflammatory cells in the intestinal lamina propria by HMP. Our study revealed that the structural properties of the investigated pectins determine fermentability, effects on microbial composition, metabolite production, and modulation of immune responses. Consumption of HMP preferentially altered the gut microbiota and suppressed pro-inflammatory immune responses, suggesting a beneficial role in inflammatory diseases.

Esterification of black bean anthocyanins with unsaturated oleic acid, and application characteristics of the product.

Esterification of anthocyanins with saturated fatty acids have been widely investigated, while that with unsaturated fatty acids is little understood. In this study, crude extract (purity âˆ¼ 35 %) of cyanidin-3-O-glucoside (C3G) from black bean seed coat was utilized as reaction substrate, and enzymatically acylated with unsaturated fatty acid (oleic acid). Optimization of various reaction parameters finally resulted in the highest acylation rate of 54.3 %. HPLC-MS/MS and NMR analyses elucidated the structure of cyanidin-3-O-glucoside-oleic acid ester (C3G-OA) to be cyanidin-3-O-(6″-octadecene)-glucoside. Introduction of oleic acid into C3G improved the lipophilicity, antioxidant ability, and antibacterial activity. Further, the color and substance stability analyses showed that the susceptibility of C3G and C3G-OA to different thermal, peroxidative, and illuminant treatments were highly pH dependent, which suggested individual application guidelines. Moreover, C3G-OA showed lower toxicity to normal cell (QSG-7701) and better inhibitory effect on the proliferation of HepG2 cells than C3G, which indicated its potential anti-tumor bioactivity.

Production of biodiesel from waste fish fat through ultrasound-assisted transesterification using petro-diesel as cosolvent and optimization of process parameters using response surface methodology.

Biodiesel is a highly promising and viable alternative to fossil-based diesel that also addresses the urgent need for effective waste management. It can be synthesized by the chemical modification of triglycerides sourced from vegetable origin, animal fat, or algal oil. The transesterification reaction is the preferred method of producing biodiesel. However, the non-miscibility of alcohol and oil layer causes excessive utilization of alcohol, catalyst, and a substantial reacting time and temperature. In the current investigation, transesterification of waste fish oil was performed with petro-diesel as cosolvent, under the influence of ultrasound energy. The combination of both techniques is a unique and efficient way to minimize the mass transfer limitations considerably and hence reduces the parameters of the reaction. It is also a sincere effort to comply with the principles of green chemistry. The optimum reaction conditions were obtained using response surface methodology (RSM) that were as follows: molar ratio of methanol to oil 9.09:1, catalyst concentration of 0.97 wt%, cosolvent concentration of 29.1 wt%, temperature 60.1℃, and a reacting time 30 min. Under these listed conditions, 98.1% biodiesel was achievable, which was in close agreement with the expected result. In addition, the cosolvent removal step from the crude biodiesel was also eliminated as it could be employed as a blended fuel in CI engines.

Effect of enzymatic de-esterification and RG-I degradation of high methoxyl pectin (HMP) on sugar-acid gel properties.

The influence of RG-I domains on high methoxyl pectin (HMP) sugar-acid gel properties has rarely been reported. In our work, HMP was modified by enzymatic de-esterification and degradation of RG-I domains to compare and analyze the relationship between the structure and final sugar-acid gel properties. The results showed that the degree of esterification (DE) of REP (pectin degraded by rhamnosidase) and GEP (pectin debranched by galactosidase) was the same as that of untreated HMP, whereas the DE of PMEP (pectin de-esterified by pectin methyl esterase) decreased from 59.63 % to 54.69 %. The monosaccharide composition suggested no significant changes in the HG and RG-I structural domains of PMEP. In contrast, the percentage of RG-I structural domains of REP and GEP dropped from 37 % to about 28 %, accompanied by a reduction in the proportion of the RG-I backbones and side chains. The rheological characterization of sugar-acid gels demonstrated an enhanced gel grade for PMEP and a weakened one for REP and GEP. Moreover, we constructed a correlation relationship between the fine structure of pectin and the properties of the sugar-acid gels, confirming the critical contribution of the RG-I region (especially the neutral sugar side chains) to the HMP sugar-acid gels.

Characterization of Palm Fatty Acid Distillate, Diacylglycerol Regioisomers, and Esterification Products Using High-Performance Size Exclusion Chromatography.

High-performance size exclusion chromatography (HPSEC) equipped with an evaporative light scattering detector (ELSD) was utilized for characterization of palm fatty acid distillate (PFAD) and its esterified products, with a particular focus on lipid profiles and diacylglycerol (DAG) regioisomers. The separation of triacylglycerol (TAG), DAG, monoacylglycerol (MAG), and free fatty acid (FFA) was achieved through a single 100-Å Phenogel column, coupled with a 2-cm C18 guard, utilizing toluene/acetic acid (100:0.25, v/v) as the mobile phase. This separation was based on size sieving principles and the interactions between the hydroxyl group(s) and the Phenogel matrix. The limit of detection (LOD) and limit of quantification (LOQ) for the esterified PFAD products analyzed by this method fell within the range of 4.8-5.5 µg/mL and 14.7-16.7 µg/mL, respectively. Additionally, the same column, paired with a 2-cm silica guard and a mobile phase comprised of toluene/isooctane/acetic acid (35:65:0.15, v/v/v), was used for the characterization of DAG regioisomers within the esterified PFAD. LODs and LOQs for sn-1,3-DAG and sn- 1,2-DAG were determined to be 39.2 and 118.7 µg/mL, and 32.8 and 99.5 µg/mL, respectively. Investigation of esterified PFAD products prepared using 4% H2SO4 at 120°C. After 2 h, the analysis revealed the highest MAG content at 31.85%, accompanied by 51.54% DAG, 2.35% TAG, and a residual 14.27% FFA. Notably, as the reaction time extended, the MAG content decreased, while both DAG and TAG levels exhibited an increasing trend. Further examination of DAG regioisomers during PFAD esterification, under varying catalyst concentrations (2-10%) and reaction temperatures (80-140°C), demonstrated a significant increase in the percentage of sn-1,3-DAG, inversely correlated with the reduction in FFA from 2% H 2 SO 4 and 80°C onwards. Remarkably, the percentage of sn-1,2-DAG remained relatively stable regardless of changes in catalyst concentrations or temperatures, confirming its susceptibility to isomerization into the thermodynamically more stable sn-1,3-DAG form. This study provides valuable insights into the composition and behavior of esterified PFAD products.

Measuring risk of renewable diesel production processes using a multi-criteria decision strategy.

This study proposes measuring the risk of five alternative renewable diesel production technologies using a multi-criteria decision matrix strategy. Evaluated criteria include environmental, economic, technological, social, and process safety risks. The subjective Analytical Hierarchy Process (AHP) with stakeholder input provides criteria and sub-criteria weightings and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) ranks alternatives. Alternative renewable diesel options are Green Diesel from first, second, and third-generation feedstocks, Fischer-Tropsch Diesel from second-generation biomass, and the transesterification of vegetable oils (VO) to make biodiesel. This study is a response to an earlier work measuring the sustainability of the same renewable technologies. While the previous work indicated Fischer-Tropsch Diesel as the most sustainable, this current work indicated the process as the "most risky," suggesting that risk is a significant driver of decision making over sustainability, and newly developed decision tools should address both perspectives.

Octadecyl and sulfonyl modification of diatomite synergistically improved the immobilization efficiency of lipase and its application in the synthesis of pine sterol esters.

Phytosterols usually have to be esterified to various phytosterol esters to avoid their disadvantages of unsatisfactory solubility and low bioavailability. The enzymatic synthesis of phytosterol esters in a solvent-free system has advantages in terms of environmental friendliness, sustainability, and selectivity. However, the limitation of the low stability and recyclability of the lipase in the solvent-free system, which often requires a relatively high temperature to induce the viscosity, also increased the industrial production cost. In this context, a low-cost material, namely diatomite, was employed as the support in the immobilization of Candida rugosa lipase (CRL) due to its multiple modification sites. The Fe3 O4 was also then introduced to this system for quick and simple separation via the magnetic field. Moreover, to further enhance the immobilization efficiency of diatomite, a modification strategy which involved the octadecyl and sulfonyl group for regulating the hydrophobicity and interaction between the support and lipase was successfully developed. The optimization of the ratio of the modifiers suggested that the -SO3 H/C18 (1:1.5) performed best with an enzyme loading and enzyme activity of 84.8 mg·g-1 and 54 U·g-1 , respectively. Compared with free CRL, the thermal and storage stability of CRL@OSMD was significantly improved, which lays the foundation for the catalytic synthesis of phytosterol esters in solvent-free systems. Fortunately, a yield of 95.0% was achieved after optimizing the reaction conditions, and a yield of 70.0% can still be maintained after six cycles.

Comparison of soluble dietary fibers from various quinoa microgreens: Structural characteristics and bioactive properties.

Quinoa (Chenopodium quinoa Willd.) microgreens are widely consumed as healthy vegetables around the world. Although soluble dietary fibers exist as the major bioactive macromolecules in quinoa microgreens, their structural characteristics and bioactive properties are still unclear. Therefore, the structural characteristics and bioactive properties of soluble dietary fibers from various quinoa microgreens (QMSDFs) were investigated in this study. The yields of QMSDFs ranged from 38.82 to 52.31 mg/g. Indeed, all QMSDFs were predominantly consisted of complex pectic-polysaccharides, e.g., homogalacturonan (HG) and rhamnogalacturonan I (RG I) pectic domains, with the molecular weights ranged from 2.405 × 104 to 5.538 × 104 Da. In addition, the proportions between RG I and HG pectic domains in all QMSDFs were estimated in the range of 1: 2.34-1: 4.73 (ratio of galacturonic acid/rhamnose). Furthermore, all QMSDFs exhibited marked in vitro antioxidant, antiglycation, prebiotic, and immunoregulatory effects, which may be partially correlated to their low molecular weights and low esterification degrees. These findings are helpful for revealing the structural and biological properties of QMSDFs, which can offer some new insights into further development of quinoa microgreens and related QMSDFs as value-added healthy products.

Extending the computational and experimental analysis of lipase active site selectivity.

Molecular docking is an important computational analysis widely used to predict the interaction of enzymes with several starting materials for developing new valuable products from several starting materials, including oils and fats. In the present study, molecular docking was used as an efficient in silico screening tool to select biocatalysts with the highest catalytic performance in butyl esters production in a solvent-free system, an eco-friendly approach, via direct esterification of free fatty acids from Licuri oil with butanol. For such purpose, three commercial lipase preparations were used to perform molecular docking studies such as Burkholderia cepacia (BCL), Porcine pancreatic (PPL), and Candida rugosa (CRL). Concurrently, the results obtained in BCL and CRL are the most efficient in the esterification process due to their higher preference for catalyzing the esterification of lauric acid, the main fatty acid found in the licuri oil composition. Meanwhile, PPL was the least efficient because it preferentially interacts with minor fatty acids. Molecular docking with the experimental results indicated the better performance in the synthesis of esters was BCL. In conclusion, experimental results analysis shows higher enzymatic productivity in esterification reactions of 1294.83 µmol/h.mg, while the CRL and PPL demonstrated the lowest performance (189.87 µmol / h.mg and 23.96 µmol / h.mg, respectively). Thus, molecular docking and experimental results indicate that BCL is a more efficient lipase to produce fatty acids and esters from licuri oil with a high content of lauric acid. In addition, this study also demonstrates the application of molecular docking as an important tool for lipase screening to achieve more sustainable production of butyl esters with a view synthesis of biolubricants.

Enhancing biocatalyst performance through immobilization of lipase (Eversa® Transform 2.0) on hybrid amine-epoxy core-shell magnetic nanoparticles.

Magnetic nanoparticles were functionalized with polyethylenimine (PEI) and activated with epoxy. This support was used to immobilize Lipase (Eversa® Transform 2.0) (EVS), optimization using the Taguchi method. XRF, SEM, TEM, XRD, FTIR, TGA, and VSM performed the characterizations. The optimal conditions were immobilization yield (I.Y.) of 95.04 ± 0.79 %, time of 15 h, ionic load of 95 mM, protein load of 5 mg/g, and temperature of 25 °C. The maximum loading capacity was 25 mg/g, and its stability in 60 days of storage showed a negligible loss of only 9.53 % of its activity. The biocatalyst demonstrated better stability at varying temperatures than free EVS, maintaining 28 % of its activity at 70 °C. It was feasible to esterify free fatty acids (FFA) from babassu oil with the best reaction of 97.91 % and ten cycles having an efficiency above 50 %. The esterification of produced biolubricant was confirmed by NMR, and it displayed kinematic viscosity and density of 6.052 mm2/s and 0.832 g/cm3, respectively, at 40 °C. The in-silico study showed a binding affinity of -5.8 kcal/mol between EVS and oleic acid, suggesting a stable substrate-lipase combination suitable for esterification.

Biodiesel production and exploring properties of Datura stramonium L. oil with its optimization using combined approaches-Taguchi, grey relational analysis, and response surface methodology.

Biodiesel production through the synthesis of Datura stramonium L. oil is studied to explore the most efficient approaches to suggest an alternate feedstock for biodiesel production. The main objective of this work is to optimize the process variables of biodiesel synthesis by using some statistical approach (Taguchi method, grey relational analysis (GRA), and response surface methodology (RSM) analyzing three parameters, i.e., alcohol-to-oil molar ratio, catalyst (NaOH) concentration, and process temperature for achieving maximum biodiesel derived from Datura stramonium L. oil. The transesterification process is applied by using an ultrasonic-assisted technique. Grey relational analysis (GRA) was successfully applied with the Taguchi method resulting in the optimum combination of A2B1C1. Based on the findings, the best operating conditions for transesterifying are attained with the RSM approach consisting of a 5.697:1 molar ratio (level 2), 0.3 (wt.%) NaOH concentration (level 1), and 70 °C process temperature (level 1). With a value of 87.02%, these ideal operating conditions produce the maximum yield as compared to grey relational analysis (GRA) yields 83.99%. The obtained results have been verified through the characterization of oil and biodiesel as well. Also, the fuel qualities of DSL biodiesel were identified and assessed. DSL oil was found 137.6 degrees of unsaturation during fatty acid profile analysis. DSL biodiesel was found the best kinematic viscosity (4.2 mm2/s) and acid value (0.49) when compared to Karanja and palm biodiesel. D. stramonium L. was recognized as a suitable species for biodiesel feedstock according to the findings.

Cassava starch esterification with formic acid for fabrication of electrospun fibers.

Formic acid is utilized to induce esterification and chemical gelatinization in starch, particularly in the fabrication of electrospun fibers for nanomaterial production. This study investigated the impact of different concentrations (15, 20, 25, and 30 %) of cassava starch and formic acid as a solvent on the characteristics of the resultant polymeric solutions and electrospun fibers. Morphology, size distribution, thermogravimetric properties, diffraction patterns, and relative crystallinity were evaluated for the electrospun fibers. The amylose content of starch varied from 16.5 to 23.7 %, decreasing with esterification, achieving a degree of substitution of approximately 0.93. The solution-rheology exhibited elastic behavior, with viscosity increasing as starch concentration increased, hindering the fabrication of fibers at 25 and 30 % starch. Successful electrospun fibers were formed using 15 % and 20 % starch, displaying homogeneous morphologies with mean diameters of 165 nm and 301 nm, respectively. Esterification influenced thermogravimetric properties, leading to fibers with reduced degradation temperatures and mass loss compared to native starches. The electrospun fibers presented an amorphous structure, indicating a drastic reduction in relative crystallinity from 35.2 % in native starch to 8.5 % for esterified starches. This study highlights the intricate relationship between starch concentration, esterification, and solution viscosity, affecting the electrospinnability and properties of starch-polymeric solutions.