Highest Fatty Acid Methyl Ester Research Articles

Algal-biochar and Chlorella vulgaris microalgae: a sustainable approach for textile wastewater treatment and biodiesel production

Microalgae technology is a viable solution for environmental conservation (carbon capture and wastewater treatment) and energy production. However, the nutrient cost, slow-kinetics, and low biosorption capacity of microalgae hindered its application. To overcome them, algal-biochar (BC) can be integrated with microalgae to treat textile wastewater (TWW) due to its low cost, its ability to rapidly adsorb pollutants, and its ability to serve as a nutrient source for microalgal-growth to capture CO2 and biodiesel production. Chlorella vulgaris (CV) and algal-BC were combined in this work to assess microalgal growth, carbon capture, TWW bioremediation, and biodiesel production. Results showed the highest optical density (3.70 ± 0.07 OD680), biomass productivity (42.31 ± 0.50 mg L−1 d−1), and dry weight biomass production (255.11 ± 6.01 mg L−1) in an integrated system of CV-BC-TWW by capturing atmospheric CO2 (77.57 ± 2.52 mg L−1 d−1). More than 99% bioremediation (removal of MB-pollutant, COD, nitrates, and phosphates) of TWW was achieved in CV-BC-TWW system due to biosorption and biodegradation processes. The addition of algal-BC and CV microalgae to TWW not only enhanced the algal growth but also increased the bioremediation of TWW and biodiesel content. The highest fatty acid methylesters (biodiesel) were also produced, up to 76.79 ± 2.01 mg g−1 from CV-BC-TWW cultivated-biomass. Biodiesel’s oxidative stability and low-temperature characteristics are enhanced by the presence of palmitoleic (C16:1) and linolenic (C18:3) acids. Hence, this study revealed that the integration of algal-biochar, as a biosorbent and source of nutrients, with living-microalgae offers an efficient, economical, and sustainable approach for microalgae growth, CO2 fixation, TWW treatment, and biodiesel production.Graphical

Enhancing efficiency of ultrasound-assisted biodiesel production catalyzed by Eversa® Transform 2.0 at low lipase concentration: Enzyme characterization and process optimization

This study focused on the ultrasound-assisted transesterification of simulated low-quality feedstocks using a low-cost liquid lipase Eversa® Transform 2.0 (ET2). Enzyme characterization was also performed to investigate the effect of ultrasound parameters on enzyme structure. The optimal ultrasound parameters, 40 % amplitude, and 5 % duty cycle effectively enhanced the reaction rate compared to the conventional stirring method while retaining 95 % of the enzyme activity. Analysis of circular dichroism (CD) spectra revealed the preservation of the secondary structure of ET2 under the optimal ultrasound intensities, while fluorescence spectra indicated a slight change in its tertiary structure. The implementation of a two-stage methanol dosing strategy in the ultrasound-assisted reaction effectively mitigated lipase inhibition, yielding a remarkable fatty acid methyl ester (FAME) content of 92.2 % achieved within a 12-h reaction time. Notable, this high FAME content was achieved with only a 4:1 methanol-to-oil molar ratio and a 0.5 wt% enzyme concentration. Under these optimized conditions, the ultrasound-assisted reaction also demonstrated a 15 % improvement in the final FAME content compared to the conventional stirring method. These promising results hold significant potential for advancing the field of biodiesel production via ultrasound technology, contributing substantively to sustainable energy sources.

Optimization of Enzymatic Transesterification of Acid Oil for Biodiesel Production Using a Low-Cost Lipase: The Effect of Transesterification Conditions and the Synergy of Lipases with Different Regioselectivity.

This study describes the enzymatic production of second-generation biodiesel using low-quality acid oil as a substrate. Biolipasa-R, a commercially available and low-cost lipase, was employed for enzymatic transesterification. Response surface methodology was applied to optimize the enzymatic transesterification process. The optimal conditions for biodiesel production, which comprised 42% lipase concentration (per weight of oil), 32% water content (per weight of oil), a methanol to oil molar ratio of 3:1, pH 7.0 and reaction temperature 30°C, resulted in the highest fatty acid methyl ester (FAME) content (71.3%). Subsequently, the synergistic effect of two lipases with different regioselectivities under the optimum transesterification conditions was studied, aiming at the enhancement of process efficiency. The transesterification efficiency of immobilized Biolipasa-R was determined and compared to that of Biolipasa-R in its free form. The results revealed a good performance on FAME content (66.5%), while the recycling of immobilized lipase resulted in a decrease in transesterification efficiency after three consecutive uses.

Evaluating nutrient limitation in co-culture of Chlorella pyrenoidosa and Rhodobacter sphaeroides

The influence of nitrogen deficiency on microalgae-bacteria co-culture has been studied mostly with nitrogen-fixing bacteria. Photosynthetic bacteria (PSB), which are non-nitrogen-fixing bacteria, the impact of N deficiency on its co-culture with microalgae is unknown. In this study, Chlorella pyrenoidosa and Rhodobacter sphaeroides co-culture was cultivated photoheterotrophically with acetate. The impact of N starvation and different P supply levels on oil production were examined. When phosphorus was sufficient, N starvation increased the fatty acid methyl ester (FAME) content from 21.7 % to 28.2 %, and also increased the FAME yield (g CODFAME/g CODAcetate) from 0.17 to 0.22. However, the biomass and FAME productivities decreased. Sufficient phosphorus was also essential for a high growth rate and FAME productivity. Deficiencies in either N or P led to a decrease in the proportion of unsaturated FAMEs. iTRAQ analysis indicated N starvation promoted oil accumulation by driving the carbon flow to fatty acid synthesis in microalgae from co-culture. This study improves the understanding of biomass and lipid production via microalgae-PSB co-culture in photoheterotrophic cultivation. The mechanism of interaction between microalgae and bacteria needs further study.

Long-term consumption of fermented pork fat-based diets differing in calorie, fat content, and fatty acid levels mediates oxidative stress, inflammation, redox imbalance, germ cell apoptosis, disruption of steroidogenesis, and testicular dysfunction in Wistar rats.

There is a dearth of experimental evidence available as to whether the consumption of fermented pork fat (FPF) food has any harmful effects on metabolism and reproduction due to its excessive calories, high fat content, and fatty acid methyl ester (FAME) levels. We hypothesized that exposure to a FPF-diet with excessive calories, a high fat content, and high FAME levels alters testicular physiology and metabolism, leading to permanent damage to the testicular system and its function. Thirteen-week-old male rats (n = 20) were assigned to a high-calorie, high-fat diet (FPF-H, fat-60%, 23kJ/g), a moderate-calorie, moderate-fat diet (FPF-M, fat-30%, 17.5kJ/g), a low-calorie and low-fat diet (FPF-L, fat-15%, 14.21kJ/g) compared to the standard diet (Control, fat-11%, 12.56kJ/g) orally for 90days. GC-MS analysis of the three FPF-diets showed high quantities of saturated fatty acids (SFAs) and polyunsaturated fatty acids-ω6 (PUFA-ω6) and low levels of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids-ω3 (PUFA-ω3) compared to the control diet. Consequently, the levels of serum FAMEs of the FPF-diet fed rats were significantly increased. In addition, a high level of n-6:n-3 PUFA towards PUFA-ω6 was observed in the serum of FPF-diet fed rats due to the high content of linoleic, γ-linolenic, and arachidonic acid. Long-term consumption of FPF-diets disturbed the anthropometrical, nutritional, physiological, and metabolic profiles. Furthermore, administration of FPF-diets generated metabolic syndrome (dyslipidemia, leptinemia, insulin resistance, obesity, hepato-renal disorder and function), increased the cardiovascular risk factors, and triggered serum and testis inflammatory markers (interleukin-1↑, interleukin-6↑, interleukin-10↓, leukotriene B4↑, prostaglandin↑, nitric oxide↑, myeloperoxidase↑, lactate dehydrogenase↑, and tumor necrosis factor-α↑). Activated testis oxidative stress (conjugated dienes↑, lipid hydroperoxides↑, malondialdehyde↑, protein carbonyl↑, and fragmented DNA↑) and depleted antioxidant reserve (catalase↓, superoxide dismutase↓, glutathione S-transferase↓, reduced glutathione↓, glutathione disulfide↑, and GSH:GSSG ratio↓) were observed in FPF-diet fed rats. Disrupted testis histoarchitecture, progressive deterioration of spermatogenesis, poor sperm quality and functional indices, significant alterations in the reproductive hormones (serum and testis testosterone↓, serum estradiol↑, serum luteinizing hormone↓, and follicle-stimulating hormone↑), were noted in rats fed with FPF diets than in the control diet. Severe steroidogenic impairment (steroidogenic acute regulatory protein, StAR↓; 3β-hydroxysteroid dehydrogenase, 3β-HSD↓; and luteinizing hormone receptor, LHR↓), deficiency in germ cells proliferation (proliferating cell nuclear antigen, PCNA↓), and abnormally enhanced testicular germ cell apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling, TUNEL assay↑; B-cell lymphoma-2, BCL-2↓; Bcl-2-associated X protein, BAX↑; and BAX/BCL-2 ratio↑) were remarked in the FPF-diet administered rats in comparison with the control diet. In conclusion, the long-term feeding of an FPF-diet with excessive calories, a high fat content, and high FAME levels induced oxidative stress, inflammation, and apoptosis, resulting in metabolic syndrome and hampering male reproductive system and functions. Therefore, the adoption of FPF diets correlates with irreversible changes in testis metabolism, steroidogenesis, germ cell proliferation, and apoptosis, which are related to permanent damage to the testicular system and function later in life.

Highly efficient scallop seashell-derived catalyst for biodiesel production from sunflower and waste cooking oils: Reaction kinetics and effect of calcination temperature studies

The sustainable production of biodiesel from waste materials has become of utmost importance in recent years. In this study, cheap CaO catalysts were prepared by calcination of waste scallop seashells (Noble Pectin). The seashells were thermally treated at different temperatures (600–1000 °C) and then used in the transesterification of sunflower oil for biodiesel production. The catalysts were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and simultaneous Thermal Gravimetric-Differential Scanning Calorimetry (TG-DSC) techniques. The highest Fatty Acid Methyl Esters (FAME) yield (97%) was obtained in the presence of the catalyst calcined at 700 °C under the following conditions: a methanol-to-oil molar ratio (MOMR) of 12:1, a catalyst-to-oil ratio (CTOR) of 10 wt%, a stirring rate of 700 rpm, a reaction temperature of 65 °C and a reaction time of 4 h. The seashell-derived catalyst was practically stable for at least 4 consecutive runs in the reusability study, maintaining a high FAME yield (>92%). The reaction followed pseudo-first order kinetics, with an activation energy (Ea) of 133.57 kJ/mol and a pre-exponential factor (A) of 4.025 × 1018 min−1. This catalyst additionally exhibited a very high activity in the transesterification of waste cooking oil, with a similar FAME yield of 97%. This shows that this catalyst is promising for potential biodiesel production scale-up schemes and industrial applications.

Direct and rapid production of biodiesel from algae foamate using a homogeneous base catalyst as part of an intensified process

• Continuous air flotation was used to harvest microalgae for transesterification. • KOH-catalysed in situ transesterification used to convert biomass into biodiesel. • Transesterification was not adversely affected by moisture of up to 80% in algae. • A 97% yield of biodiesel (FAME) was obtained in 10 minutes. • Energy savings were achieved by in situ transesterification of algae feedstock. Microalgae are important biodiesel feedstocks because of their high lipid content and low land requirement for cultivation. One method of harvesting and concentrating algal biomass is by means of a foam column using surfactant CTAB as a collector and foaming agent, however, the downstream treatments for the “foamate” produced have not yet been investigated. Here, the freshwater microalgae strain, Chlorella vulgaris , was harvested by a continuous dispersed air flotation column and the foamate obtained was used as the feedstock for conversion to biodiesel via in situ reactive extraction using KOH as the catalyst. The process variables were methanol: oil molar ratio (100:1 to 1000:1), reaction temperature (40–60°C) and reaction time (5–10 min). The maximum biodiesel yield from the foamate produced of 97% from C. vulgaris microalgae was accomplished at a molar ratio (methanol to oil) of 1000:1, a 60°C temperature of reaction and a 10 min time of reaction. Longer reaction times resulted in reduced fatty acid methyl ester (FAME) yield due to saponification, converting the FAME to soap. High FAME yields were obtained despite the presence of significant quantities of free fatty acids (6% lipid) in the C. vulgaris biomass. The method also exhibited greater tolerance to water than that observed in conventional transesterification conditions. At a methanol: oil molar ratio of 1000:1, the method was not adversely affected by the presence of up to 80% level of moisture in the microalgae. Hence, a viable, FFA-tolerant, water-tolerant process has been demonstrated for direct conversion of microalgae foamate to biodiesel, at mild conditions (60°C and below) in a short residence time (10 min).

Bifunctional 1,2,4-Triazole/12-Tungstophosphoric Acid Composite Nanoparticles for Biodiesel Production.

Here, a composite nanoparticle with an acid-base bifunctional structure has been reported for the transesterification of rapeseed oil to produce biodiesel. Triazole-PWA (PWA = 12-tungstophosphoric acid) composite materials with a hexahedral structure are produced using the precipitation method, showing the average particle diameters of 200-800 nm. XPS and FT-IR analyses indicate well-defined chemical bonding of triazole moieties to the PWA. The functionalization and immobilization of PWAs are investigated due to strong interactions with triazole, which significantly improves the thermal stability and even surface area of the heteropoly acid. Furthermore, various ratios of triazole and PWAs are examined using NH3-TPD and CO2-TPD to optimize the bi-functionality of acidity and basicity. The prepared nanomaterials are evaluated during the transesterification of rapeseed oil with methanol to analyze the effect of triazole addition to PWAs according to the different ratios. Overall, the bifunctional triazole-PWA composite nanoparticles exhibit higher fatty acid methyl ester (FAME) conversions than pure PWA nanoparticles. The optimized catalyst with a triazole:PWA ratio of 6:1 exhibits the best FAME-conversion performance due to its relatively large surface area, balance of acidity, and strong basicity from the well-designed chemical nano-structure.

A novel higher fatty acid-based polymeric cold flow improver with remarkable effects for biodiesel - diesel blends

In order to develop renewable resources of environment-friendly for the preparation of cold flow improvers for diesel-biodiesel blends, a novel comb-like copolymers were synthesized from higher fatty acids, para (p)-anisic acid, and glycidyl methacrylate. The effects of copolymers on cold flow properties and crystallization behaviors of biodiesel-diesel blends were evaluated and analyzed. This research pointed out that the higher fatty acids as the copolymer branch chain increased the matching ability with paraffin and higher fatty acid methyl esters (FAMEs), and the anisic acid side chain increased the rigidity of the copolymers. Therefore, the prepared copolymers can preferentially precipitate in the blends and act as the nucleation site so that lead to heterogeneous nucleation of paraffin and higher fatty acid methyl esters (FAMEs), thus improving the low-temperature fluidity. In addition, the copolymers exhibited satisfactory performance on reducing cloud point (CP), cold filter plugging point (CFPP), and pour point (PP), which were reduced respectively by 2, 8, and 10 °C for B10 (10 vol%. biodiesel +90 vol%. diesel); 2, 13, and 8 °C for B20 (20 vol%. biodiesel +80 vol%. diesel) and 2, 11, and 7 °C for B30 (30 vol%. biodiesel +70 vol%. diesel) at the addition of 1000 mg / kg.

Assessing the potential of green CdO2 nano-catalyst for the synthesis of biodiesel using non-edible seed oil of Malabar Ebony

Sustainable biodiesel synthesisfrom waste, toxic and non-edible oil seeds give a sustainable opportunity to combat energy crises and environmental depreciation.A new non-edible oil ofDiospyros malabarica(Malabar Ebony) was analyzed for the synthesis ofeco-friendly biodiesel using newly synthesized green nanoparticles (NPs) of Cadmium oxide (CdO2) prepared from leaf extract of Buxus papillosavia biological method followed by in situ wet impregnation approach. The highest fatty acid methyl ester (FAME) yield of 94 wt% was attained through the process of transesterification at ideal experimental conditions i.e., 1:9 M ratio of oil to methanol, catalyst loading 0.5 wt%, experiment duration 180 min and reaction temperature of 90 °C. Optimize biodiesel yield from Diospyros malabarica using response surface methodology was also applied. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetric analysis and X-ray diffraction (XRD) were utilized for the characterization of newly synthesized CdO2 NPs. The findings obtained from SEM revealed that CdO2 NPs were cubic in shape. The size of CdO2 NPs was 45 nm, which obtained from XRD analysis. EDX analysis showed 83.72 % cadmium composition. In thermogravimetric analysis, 5.2 % thermal degradation was observed which revealed that CdO2 NPs have strong thermal stability. The production of FAME was confirmed by using gas chromatography-mass spectroscopy (GC–MS), nuclear magnetic resonanceand Fourier transform infrared spectroscopy techniques. 9-Octadecenoic acid is the key fatty acid with the highest abundance in the GC–MS spectrum. This study revealed that inedible oil seed of Diospyros malabaricaand newly synthesized green NPs of CdO2 has the highest potential to be used as highly reliable cost-effective and sustainableentrants for synthesizing eco-friendly diesel which is ultimately open up the avenue for further research in the exploration and application of economical feedstock for biodiesel industry at a larger scale.

Attached microalgae converting spent coffee ground into lipid for biodiesel production and sequestering atmospheric CO2 simultaneously

The impacts of simultaneous exposures of arbitrary light intensities and photoperiods on attached Chlorella vulgaris microalgal growth onto spent coffee ground (SCG) were studied, and subsequently optimized using Response Surface Methodology (RSM) tool. The statistical analysis revealed the optimum light intensity and photoperiod were achieved at 100 μmol/m2s and 20:4 dark:light hours/cycle, respectively, producing microalgal density of 0.358 g/g and lipid productivity of 16.8 mg/Lday. The biodiesel yielded from the optimum condition possessed high cetane number and oxidative stability due to the high saturated fatty acid methyl esters (FAME) content of 63.7 %. In fact, the major FAME compositions ranged within C16 to C18 which were favourable for quality biodiesel production. Furthermore, the viability of SCG to serve as a carbon source was also evidenced by the high productivities of microalgal protein and carbohydrate at 94 and 168 mg/L day, respectively. The capability of attached microalgal cultivation in sequestering atmospheric CO2 was finally unveiled, with high CO2 capture rate being recorded at 9.38 mg/L h. Accordingly, growing attached microalgae onto SCG was recognized as an alternative approach for sustainable CO2 reduction, while producing green diesel to assuage the global warming phenomenon.

Fractionation of fatty acid methyl esters via urea inclusion and its application to improve the low-temperature performance of biodiesel

Biodiesel is viewed as the alternative to petroleum diesel, but its poor low-temperature performance constrains its utilization. Cloud point (CP), the onset temperature of thermal crystallization, appropriately shows the low-temperature performance. The effective way to reduce CP is to remove saturated fatty acid methyl esters (FAMEs). Compared to current methods, this work describes an extraordinary approach to fractionating FAMEs by forming solid urea inclusion compounds (UICs). Urea inclusion fractionation reduces the CPs by removing high melting-point linear saturated FAME components. Urea inclusion fractionation in this study was performed under various processing conditions: mass ratios of urea to FAMEs and solvents to FAMEs, various solvents, FAMEs from various feedstocks, and processing temperatures. Supersaturation of urea in the solution is the driving force, and it significantly affects yield, composition, CP, separation efficiency, and selectivity. Through a single urea inclusion fractionation process, FAMEs, except palm oil FAMEs, resulted in CP reduction ranging from 20 to 42 oC with a yield of 77–80% depending on the compositions. CP of palm oil FAMEs could reach as low as -17 oC with a yield of 46% after twice urea inclusion fractionation. According to the model prediction, the cetane number after urea inclusion fractionation decreased about 0.7–2 but was still higher than the minimum biodiesel requirement. Oxidation stability after urea inclusion decreased according to the proposed model, but this can be mitigated by adding antioxidants. Emission evaluation after urea inclusion fractionation indicated decreased hydrocarbons, carbon monoxide, and particulate matter. However, it resulted in the increasing emission of nitrogen oxides.

Biodiesel Production from Brassica juncea Using Oleaginous Yeast.

The present study explores the potential of Brassica juncea as a low-cost substrate for biodiesel production through the growth of oleaginous yeast. Firstly, the selected lignocellulosic biomass, i.e.,Brassica juncea, was thermochemically pretreated using dilute sodium hydroxide. Optimization of thermochemical pretreatment resulted in significant removal of lignin and hemicellulose with 8.4% increase in cellulose content. Further, the sugar hydrolysate of pretreated biomass was used as a substrate for the growth of selected oleaginous yeast (Cryptococcussp. MTCC 5455). Lipid and biomass production was optimized using central composite design (CCD) based on response surface methodology (RSM). Maximum biomass and lipid content of 32.50g/L and 11.05g/L, respectively, was obtained at 30°C temperature, pH 6.0, and after 5days of incubation. The oleaginous yeast lipid was further transesterified using immobilized lipase. The highest fatty acid methyl ester 15% FAME yield was obtained after 10h of enzymatic reaction. Next, the results of specific gravity, viscosity, flash points, and cloud point of obtained biodiesels were conformed to the ASTM D975 standard. Overall, the present study put forth the cost-effective approach for lignocellulosic biomass-based oleaginous lipid production toward the green synthesis of biodiesel.

Light Stress after Heterotrophic Cultivation Enhances Lutein and Biofuel Production from a Novel Algal Strain Scenedesmus obliquus ABC-009.

Scenedesmus obliquus ABC-009 is a microalgal strain that accumulates large amounts of lutein, particularly when subjected to growth-limiting conditions. Here, the performance of this strain was evaluated for the simultaneous production of lutein and biofuels under three different modes of cultivation - photoautotrophic mode using BG-11 medium with air or 2% CO2 and heterotrophic mode using YM medium. While it was found that the highest fatty acid methyl ester (FAME) level and lutein content per biomass (%) were achieved in BG-11 medium with CO2 and air, respectively, heterotrophic cultivation resulted in much higher biomass productivity. While the cell concentrations of the cultures grown under BG-11 and CO2 were largely similar to those grown in YM medium, the disparity in the biomass yield was largely attributed to the larger cell volume in heterotrophically cultivated cells. Post-cultivation light treatment was found to further enhance the biomass productivity in all three cases and lutein content in heterotrophic conditions. Consequently, the maximum biomass (757.14 ± 20.20 mg/l/d), FAME (92.78 ± 0.08 mg/l/d), and lutein (1.006 ± 0.23 mg/l/d) productivities were obtained under heterotrophic cultivation. Next, large-scale lutein production using microalgae was demonstrated using a 1-ton open raceway pond cultivation system and a low-cost fertilizer (Eco-Sol). The overall biomass yields were similar in both media, while slightly higher lutein content was obtained using the fertilizer owing to the higher nitrogen content.

Biodiesel (fatty acid methyl ester) from Chlorococcalean Chlorella vulgaris by single step in-situ transesterification

Objectives: To study the single step in-situ transesterification process for synthesis of fatty acid methyl ester (biodiesel) from microalgae biomass Chlorococcalean Chlorella vulgaris. Methods: The growth and lipid productivity of an isolated microalgae C. vulgaris were studied under Chu‘s 10 modified media under phototrophic cultivation conditions. In-situ transesterification of this dry biomass with methanol in presence of base catalyst at 60 º C was carried out to investigate the fatty acid methyl ester’s biochemical composition by FTIR & analysis performed using GCMS technique. The cetane number was also calculated. Findings: The biodiesel fraction from C. vulgaris biomass was found to be 85.58%. The 43.40% lipid fraction was obtained from the biomass of C. vulgaris. In the in-situ transesterification process, the optimal concentration of potassium hydroxide (KOH) and methanol yields an 85.58 percent biodiesel fraction. The presence of lipid compounds and the biochemical composition of fatty acid methyl ester were verified with the help of FTIR spectral analysis. The gas chromatography-mass spectrometry analysis explores the fatty acid methyl ester profile, which comprises 29.05% and 56.54 percent saturated and unsaturated FAMEs. Through GCMS, the fatty acid methyl ester composition of C. vulgaris microalgae species was revealed through six types of fatty acid methyl esters, of which 54.95%, 11-octadecenoic acid methyl ester, is the dominant one. The cetane number of C. vulgaris biodiesel was determined to be 67.726; this is comparable to diesel fuel according to ASTM-D613, and the presence of a higher fatty acid methyl ester composition indicates favourable biofuel qualities. Novelty: The calculation of cetane number by theoretical method and affirmation of ecofriendly single step in-situ transesterification method for biodiesel production. Keywords: Chlorococcalean Chlorella vulgaris; Biodiesel; GCMS; FTIR; Cetane Number

Fungal Fermented Palm Kernel Expeller as Feed for Black Soldier Fly Larvae in Producing Protein and Biodiesel.

Being the second-largest country in the production of palm oil, Malaysia has a massive amount of palm kernel expeller (PKE) leftover. For that purpose, black soldier fly larvae (BSFL) are thus employed in this study to valorize the PKE waste. More specifically, this work elucidated the effects of the pre-fermentation of PKE via different amounts of Rhizopus oligosporus to enhance PKE palatability for the feeding of BSFL. The results showed that fermentation successfully enriched the raw PKE and thus contributed to the better growth of BSFL. BSFL grew to be 34% heavier at the optimum inoculum volume of 0.5 mL/10 g dry weight of PKE as compared to the control. Meanwhile, excessive fungal inoculum induced competition between BSFL and R. oligosporus, resulting in a reduction in BSFL weight. Under optimum feeding conditions, BSFL also registered the highest lipid yield (24.7%) and protein yield (44.5%). The biodiesel derived from BSFL lipid had also shown good compliance with the European biodiesel standard EN 14214. The high saturated fatty acid methyl esters (FAMEs) content (C12:0, C14:0, C16:0) in derived biodiesel made it highly oxidatively stable. Lastly, the superior degradation rate of PKE executed by BSFL further underpinned the sustainable conversion process in attaining valuable larval bioproducts.

Multi-objective tailored optimization deciphering carbon partitioning and metabolomic tuning in response to elevated CO2 levels, organic carbon and sparging period.

Microalgae have garnered much contemplation as candidates to fix CO2 into valuable compounds. Although microalgae have been studied to produce various metabolites, they have not yet proved successful for commercialization. Since, handling such problems practically requires satisfying multiple parameters simultaneously, we put forth a multi-parameter optimization strategy to manipulate the carbon metabolism of Scenedesmus sp. to improve biomass production and enhance CO2 fixation to increase the production of fuel-related metabolites. The Box-Behnken design method was applied with CO2 concentration, CO2 sparging time and glucose concentration as independent variables; biomass and total fatty acid methyl ester (total FAME) content were analyzed as response variables. The strain is supplemented with both CO2 and glucose with an aim to enhance carbon flux and rechannel it towards carbon fixation. As per the results obtained in this study, Scenedesmus sp. could effectively exploit high CO2 concentration (15%) for longer duration under high concentration of glucose supplementation (9g/L) producing a biomass of 635.24±39.9μg/mL with a high total fatty acid methyl ester (FAME) content of 71.29±4.2μg/mg, significant acetyl-CoA carboxylase enzyme activity and a favorable fatty acid profile: 35.8% palmitic acid, 10.5% linoleic acid and 30.6% linolenic acid. The carbohydrate content was maximum at 10% CO2 sparged for the longest duration of 90min under glucose concentration of 9g/L. This study puts forth an optimal design that can provide evidence on comprehending the carbon assimilation mechanism to enhance production of biomass and biofuels and provide conditions to microalgal species to tolerate CO2 rich flue gas.

Biodiesel Generation from Palm Kernel Biomass via an In-situ Transesterification Approach

This study investigated an in-situ transesterification of palm kernel biomass at variable reaction times (4 h, 5 h and 6 h) and catalyst loading (2 wt%, 3 wt.% and 5 wt.%). The biodiesel yields were observed to vary with these parameters. GC-MS analysis showed high fatty acid methyl esters (FAMEs) contents for all the prepared biodiesel samples (C-18:1, C-14:0, C-16:0, and C-18:0). 2 wt.% catalyst loading and 4 h reaction time were observed to be the best reaction conditions from the experimented parameters that gave the best biodiesel yield at 300 rpm mixing intensity. The in-situ method recorded a higher degree of oil extraction and efficient conversion of oil to biodiesel (93.93%) compared to the conventional transesterification method which gave 89.45%. The kinematic viscosity, acid value and iodine value of 3.96 mm2/s, 0.56 mg KOH g–1 and 120 g 100 g–1 were found to be within the limits of ASTM D6751-09 and EN14214 standards. These results confirm that efficient production of biodiesel from palm kernel biomass could be possible through an in-situ acidic transesterification process.
 Keywords: Biodiesel, fatty acid methyl ester, palm kernel biomass, transesterification

Comparative study of different catalysts mediated FAME conversion from macroalga Padina tetrastromatica biomass and hydrothermal liquefaction facilitated bio-oil production

Marine macroalgae offer an endurable source of renewable biomass, which do not require cultivable area, fertilizers for cultivation for bioproducts production. In this study, marine brown macroalga Padina tetrastromatica as an alternate sustainable feedstock for the production of liquid fuels. Padina tetrastromatica biomass was collected from Mandapam; the coastal region of Rameswaram, Tamil Nadu, India. and the algal oil was extracted using sequential extractions using various solvents. Petroleum ether (PE) and dichloromethane (DCM) solvent fractions were found to have high lipids and further utilized for biodiesel production, wherein four different heterogeneous nanocatalysts (TiO2, Bio-Fe, GO, and MgO) and commercial homogeneous catalysts (HCl and NaOH) were employed for the transesterification. High fatty acid methyl ester (FAME) recovery (92.3%) was achieved from TiO2 mediated transesterification than the other conventional catalysts. Further, the conversion of algal biomass into bio-oil and by-products was carried out using hydrothermal liquefaction (HTL). Subsequently, the compounds were characterized by FT-IR and GC-MS analysis. The quality parameters of liquid biofuels were examined and they are in accordance with the international fuel standards. Thus, brown macroalga Padina tetrastromatica may be considered as an alternate feedstock for biofuel and other bioproducts production and TiO2 would be a suitable catalyst for the conversion of FAME.

Dual nutrient heterogeneity modes in a continuous flow photobioreactor for optimum nitrogen assimilation to produce microalgal biodiesel

The impact of different nitrogen sources on the microalga, Chlorella vulgaris, was studied in a newly developed microalgal-bacterial photobioreactor via a dual nutrient heterogeneity mode. The mechanisms of nitrogen transformation and valorisation were unveiled, and subsequently, optimized via dual nutrient heterogeneity feeding modes comprising of various NH4+-N and NO3−-N concentrations. The nitrogen-assimilation mechanism from the microalgal-bacterial consortium was found to reduce microalgal growth inhibition, stemming at high NH4+-N concentrations. Accordingly, the total nitrogen removal efficiency was enhanced from 40.91% to 96.38% accompanied with maximum microalgal biomass production of up to 792 mg/L at a balanced or higher NH4+-N loading from mixed nitrogen environment. The harvested microalgal biomass contained high lipid accumulation of approximately 30% when fed with optimum NH4+-N and NO3−-N loadings at 60 and 58 mg/d, respectively. At this mixed nitrogen species loadings, high unsaturated fatty acid methyl esters (FAME) were attained. Indeed, the major FAME species (97%–100%) fell within the C16-18 range, signifying biodiesel characteristics conformity to the requirements for quality biodiesel application. Therefore, the dual heterogeneity modes of balanced NH4+-N and NO3−-N loadings into photobioreactor could offer effective microalgal nitrogen assimilation for sustainable wastewater treatment and microalgae-based biodiesel production simultaneously.