Generation Biodiesel Research Articles

Valorization of durian peel as a carbon feedstock for a sustainable production of heterogeneous base catalyst, single cell oil and yeast-based biodiesel

The present study reports a successful attempt to produce single cell oil (SCO), heterogeneous base catalyst and yeast-based biodiesel from durian peel as a promising carbon feedstock by means of the waste-to-energy concept. For this purpose, first, durian peel (DP) was hydrolyzed by dilute sulfuric acid to obtain xylose-rich DP hydrolysate (XDPH) and post-hydrolysis DP solid residue (DPS). Candida viswanathii PSY8, a newly isolated oleaginous yeast, showed high SCO accumulation (5.1 ± 0.1 g/L) and SCO content (35.3 ± 0.13 %) on undetoxified XDPH medium. A novel heterogeneous base catalyst (DPS-K) prepared from DPS by wet impregnation technique with KOH, exhibited considerable catalytic activity to convert SCO-rich wet yeast of C. viswanathii PSY8 into yeast-based biodiesel (FAME) via direct transesterification with a maximum FAME yield of 94.3 % under optimal conditions (6 wt% catalyst, 10:1 methanol to wet yeast ratio, 75 °C, and 2 h). Moreover, most of the yeast-based biodiesel properties obtained from the FAME profiles were correlated well with the biodiesel standards limit of Thai, ASTMD6751 and EN 14214. Additionally, the energy output of FAME produced about 37.5 MJ/kg was estimated. Thus, this present finding demonstrated the favorable strategy for sustainable and eco-friendly production of new generation biodiesel.

Metal–organic framework‐supported hydroxyapatite (UiO‐66@HAp): an efficient catalyst for the microwave‐assisted transesterification of palm oil

AbstractBiodiesel has recently emerged as a renewable and environmentally benign fuel substitute for fossil‐derived energy sources. The use of heterogeneous solid catalysts for the generation of biodiesel from biomass‐derived fats and oils is sustainable. Among various reported catalyst supports, metal–organic frameworks (MOFs) have been popular choices for enhancing catalytic activity for biodiesel synthesis because of several outstanding features including porosity, high surface area, adjustable structures, and uniform pore sizes. In this research, the authors synthesized a novel nanocomposite of MOF‐supported hydroxyapatite (UiO‐66@HAp) using a facile impregnation technique and the characterization of the as‐synthesized catalyst was performed by different spectroscopic methods including powder X‐ray diffraction (PXRD), Fourier transform infrared (FTIR), X‐ray photoelectron spectroscopy (XPS), field emission gun‐scanning electron microscope (FEG‐SEM), energy dispersive X‐ray spectroscopy (EDS), high resolution transmission electron microscopy (HR‐TEM), thermogravimetric analysis (TGA), and N2 adsorption–desorption techniques. After successful synthesis, the catalytic property of the prepared material was evaluated in the palm oil transesterification into biodiesel. Product formation was confirmed by the 1H nuclear magnetic resonance (NMR) spectroscopy, 13C NMR, FTIR, and gas chromatography–mass spectrometry (GC–MS) of the biodiesel. The influence of different reaction variables such as catalyst dosage, methanol/oil molar ratio, temperature of the reaction, and reaction time was also studied. The outcomes revealed that the maximum biodiesel yield (∼97%) was obtained when 6 wt% catalyst was used with a 6:1 ratio of methanol/oil at 70 °C for 1 h. It was also observed that, even after 5 cycles of reuse, the catalyst was capable of producing significant amounts of biodiesel (over 90%). The results suggest that the synthesized novel catalyst holds a promising future in the sustainable production of biodiesel.

Sustainable biodiesel production from waste olive oil: Utilizing olive pulp-derived catalysts for environmental and economic benefits

This paper introduces an environmentally and economically advantageous biodiesel production method using waste olive oil and pulp-derived catalysts. It tackles the critical issue of olive waste management by reusing discarded materials, reducing pollution, and minimizing landfill use. This sustainable approach preserves natural resources and reduces the carbon footprint associated with waste disposal. Olive pulp-derived catalysts offer a cost-effective and eco-friendly alternative to traditional catalysts, enhancing the economic viability of biodiesel production. Despite its low oil content, the waste olive pulp (WOP) is efficiently utilized for biodiesel production. The patent explores Sulfonated Carbon (SC) derived from dried olive pulp, serving as a robust acidic catalyst for transesterification. Characterization techniques comprising XRD, FTIR, and FESEM analyze SC properties. Biodiesel development optimization from waste olive oil (WOO) employs Response Surface Methodology (RSM), resulting in optimal conditions: a methanol-to-oil molar ratio of 15:1, a 60 °C reaction temperature, a 5-h transesterification time, and a 4% catalyst dose, yielding an impressive 94% biodiesel yield. The biodiesel's chemical structure is confirmed through analytical tools such as FT-IR, 1HNMR, and 13CNMR.In summary, this study highlights the potential of sulfonated carbon as a catalyst for sustainable biodiesel generation from waste olive oil. It offers a safe, efficient, and environmentally friendly alternative to traditional catalysts, delivering both environmental and economic benefits.

The potential of Yarrowia lipolytica in converting bioenergy resources: a preliminary review

Yarrowia lipolytica, a yeast species capable of producing oil or oily fatty acids, has the ability to utilize multiple carbon sources, including glycerol, acetic acid, and glucose, allows for the use of inexpensive carbon sources. Waste cooking oil can be utilized as an alternative carbon source while also there is potential in increasing the oil yield due to the presence of glycerol compounds. The study aims to explore the potential of Yarrowia lipolytica in producing lipid based bioenergy from by-product such waste cooking oils. One of the greatest challenges that will affect life is our continued reliance on fossil fuels, which are still derived from petroleum and fossils. Fuel is not only the primary source of energy that has a significant impact on every aspect, but its sustainability remains the primary concern as we search for alternative solutions that can circumvent these issues. Using yeast lipids, specifically Yarrowia lipolytica, has not been investigated, in addition to producie biodiesel, this yeast can use waste cooking oil as a growth medium and produce lipids. The third generation of biodiesel uses microorganism-produced lipids, which is new and worthy of further research to solve the problem of unsustainable and environmentally unfriendly diesel fuel. Yarrowia lipolytica's ability to accumulate lipids, produce wax esters synthase enzymes, and FAEE/FAME still have great potential.

On the effect of injection pressure on spray combustion and soot formation processes of gasoline/second generation biodiesel blend

70GB, which comprises 70% gasoline and 30% biodiesel, shows excellent potential for application in gasoline compression ignition due to its superior lubrication capability, renewability, environmental friendliness, high ignitability contributed by biodiesel namely as Hydrogenated catalytic biodiesel (HCB), and high volatility conferred by gasoline. However, the spray combustion and emission characteristics of 70GB fuel have not yet been quantitatively evaluated. In this work, we performed a comprehensive simulation focusing on the ignition delay, heat release rate, flame lift-off length, flame structure, and soot formation of 70GB in a constant volume chamber under various fuel injection pressure. Numerical results showed that, different injection pressure strongly impact the HRR without affecting the maximum temperature. Increasing the injection pressure from 80 to 120 Mpa, increased the heat release rates by 23. %. The ignition delay was marginally affected by increasing injection pressure, while a 5.7 mm increase in flame lift-off length observed with higher injection pressure. Additionally, 65% lower soot formation was typically predicted for higher injection pressure 120MPa. In particular, the soot mass is primarily controlled by enhancing the atomization and evaporation processes, as well as improving fuel-air mixing rate, which was achieved by increasing the injection pressure. Furthermore, the role of soot oxidation was insignificant in reducing soot with increasing injection pressure, while the soot initiation step and soot surface growth step play an important role in soot suppression with increasing injection pressure for 70G fuel.

Examining the robustness of selected microalgae to grow in landfill leachate

Microalgae is widely recognized as a leading candidate for future bio-oil production, serving dual purposes: biodiesel generation and bioremediation. Identifying a sustainable cultivation medium is essential, aiming to minimize production costs. Landfill leachate emerges as a prospective growth medium for microalgae. However, due to the diverse substances within landfill leachate that may impede microalgal growth, careful selection of robust species becomes crucial. This study examined the growth of four microalgae species—Chlamydomonas reindhartii, Chlorella vulgaris, Chlorella ovalis, and Nannochloropsis oculata—in landfill leachate. Prior to utilization, the landfill leachate underwent treatment to remove the total ammonium nitrogen (TAN). Cultivation spanned 30 days, during which various parameters, including ammonium removal, growth rate, and oil content, were monitored. Initially, all microalgae exhibited a decline in numbers, succeeded by a subsequent increase in concentration after several days. Results revealed Nannochloropsis oculata to have the highest growth rate, while Chlamydomonas reindhartii displayed the lowest. Generally, the oil content of all species at the end of cultivation was lower than that of their respective inocula. Chlorella vulgaris exhibited the highest oil content, followed by Chlamydomonas reindhartii, Chlorella ovalis, and Nannochloropsis oculata.

Ultrasound irradiation-assisted biodiesel synthesis from waste oils employing a retrievable and strong CoFe2O4/GO/SrO nanocatalyst

A novel heterogeneous CoFe2O4/GO/SrO nanocatalyst was synthesized using ultrasonic irradiation, and employed for synthesizing biodiesel from waste edible oil (WEO). To this end, a 2-step esterification-transesterification reaction utilizing ultrasound was applied. The surface attributes of CoFe2O4/GO/SrO was specified by XRD, FTIR, FESEM, EDX/Map, BET, DLS, CO2-TPD, and VSM analyses. CO2-TPD analysis indicated that the CoFe2O4/GO/SrO nanocatalyst has favorable catalytic activity for transesterification. CCD-based RSM approach was employed to examine the influence of parameters and ascertain optimal conditions under ultrasonic irradiation (24 KHz, 200 W, 70 % duty cycles and 60 % amplitude). Also, the utmost biodiesel yield (98.63 %) was achieved using CoFe2O4/GO/SrO under optimum conditions (i.e., time = 53.76 min, temperature = about 69 °C, CH3OH/oil proportion = 16.3:1, and nanocatalyst dosage = 5 wt%), which is the highest biodiesel performance ever attained using WEO. However, the highest biodiesel yield under optimal conditions by magnetic-stirrer at 600 rpm was 72.9 %, which is much lower than utilizing ultrasonic irradiation. Further, the stability investigation indicated that the CoFe2O4/GO/SrO nanocatalyst has a yield of over 90 % after five reuse stages, which reveals its remarkable stability. Besides, the kinetics of biodiesel production displayed that the reaction between methanol and WEO utilizing CoFe2O4/GO/SrO nanocatalyst is endothermic and the reaction rate enhances with temperature. On account of its high biodiesel yield, favorable catalytic activity, short reaction time, and remarkable stability, the CoFe2O4/GO/SrO nanocatalyst is strongly recommended for biodiesel generation from WEO in the presence of ultrasonic irradiation for industrial applications.

Bio-Nanoparticles Mediated Transesterification of Algal Biomass for Biodiesel Production

Immense use of fossil fuels leads to various environmental issues, including greenhouse gas emissions, reduced oil reserves, increased energy costs, global climate changes, etc. These challenges can be tackled by using alternative renewable fuels such as biodiesel. Many studies reported that biodiesel production from microalgae biomass is an environment-friendly and energy-efficient approach, with significantly improved fuel quality in terms of density, calorific value and viscosity. Biodiesel is produced using the transesterification process and the most sustainable method is utilizing enzymes for transesterification. Lipase is an enzyme with excellent catalytic activity, specificity, enantio-selectivity, compatibility and stability and hence it is applied in microalgae biodiesel production. But, difficulty in enzymatic recovery, high enzyme cost and minimal reaction rate are some of its drawbacks that have to be addressed. In this aspect, the nanotechnological approach of lipase immobilization in producing microalgae biodiesel is a promising way to increase production yield and it is due to the adsorption efficiency, economic benefit, recyclability, crystallinity, durability, stability, environmental friendliness and catalytic performance of the bio-nanoparticles used. Through increasing post-harvest biomass yield, absorption of CO2 and photosynthesis in the photobioreactor, the use of nanoparticle immobilized lipase during the generation of biodiesel from microalgae has the potential to also remove feedstock availability constraints. This review article discusses the production of microalgae biodiesel, and effect of nanoparticles and immobilized lipase nanoparticles on biodiesel production. The advantages of using lipase nanoparticles and the challenges in introducing the immobilized lipase on nanoparticles in large-scale microalgae biodiesel production are also discussed. Reducing the water and land use, energy and nutrient footprints of integrated algae-based operations must be the main goal of larger-scale experiments as well as ongoing research and development in order to expedite the adoption of microalgae-based biodiesel production. Also, the cost-effectiveness and large-scale availability of nanoparticles and the impact of lipase nanoparticles on engine performance should be analyzed for commercialization of microalgae biodiesel.

Novel Co3O4 decorated with rGO nanocatalyst to boost microwave-assisted biodiesel production and as nano-additive to enhance the performance-emission characteristics of diesel engine

In this study, a novel Co3O4 decorated with rGO nanocatalyst was utilized in synergy with microwave heating as a novel approach for the generation of biodiesel. In this process, 98.04 % biodiesel yield was achieved by adopting response surface methodology algorithm under MEOH/oil molar ratio of 12.75:1, Co3O4@rGO loading of 1.53 wt%, microwave time of 7.17 min, and stirring speed of 512 rpm. The catalyst can be reused for seven times with biodiesel yields beyond 85 %. Co3O4@rGO was used as a nano-additive in the diesel engine to investigate the emission and performance of biodiesel blended with diesel. The Co3O4@rGO nanoparticles were dispersed into the B20 fuel with concentrations of 50 and 100 ppm. The outcomes discovered that the brake thermal efficiency of B20Co3O4@rGO50 is 1.22 % greater than B20, and the brake specific fuel consumption is declined by 5.05 %. The emissions from the diesel engine i.e. CO (29.88 %) and UHC (16.38 %) were significantly lowered compared to B20. The emission of NOx for B20Co3O4@rGO100 is 7.4 % lower than B20 and greater than conventional petrodiesel. Owing to its remarkable stability, excellent biodiesel yield, effective utilization in diesel engine, and high catalytic activity, the Co3O4@rGO is strongly proposed for industrial biodiesel generation utilizing microwave radiation.

Chromatographic assessment of biodiesel production from Peganum harmala seed oil using environmentally benign nano-catalysts.

This work gives a comprehensive chromatographic assessment of biodiesel generation from plant seed oil using ecologically friendly nano-catalysts. Researchers all over the world are actively looking for new ways to satisfy the urgent need for clean and renewable energy sources. The resultant biodiesel was fully characterized utilizing modern techniques like scanning electron microscopy, energy diffraction X-ray and X-ray diffraction. The biodiesel gas chromatography/mass spectrometry analysis revealed four significant peaks of fatty acid methyl esters, indicating high-quality biodiesel production. Furthermore, the biodiesel fuel qualities were discovered to be comparable with international standards such as ASTM D-6571 and EN-14214. This indicates that the iron-modified clay nano-catalyst can be used as a catalyst for large-scale biodiesel production. This work is important because it could lead to the large-scale production of a novel, non-food feedstock. We may lessen our reliance on fossil fuels and contribute to a more sustainable and ecologically friendly energy future by leveraging the usage of biodiesel produced in this way. The chromatographic assessment of biodiesel production from non-edible seed oil using environmentally benign nano-catalysts holds significant promise in advancing sustainable and eco-friendly biodiesel production methods, contributing to a cleaner and more environmentally responsible energy sector.

Magnetic carbon nanotubes doped cadmium oxide as heterogeneous catalyst for biodiesel from waste cooking oil

The exploration for innovative heterogeneous catalyst materials bearing unique chemical and physical properties has become a focal point in the field of biodiesel synthesis. In this study, a novel heterogeneous nanocatalyst composed of carbon nanotubes (CNT) coated with magnetic iron oxide and doped with cadmium oxide (CdO) nanoparticles denoted as MCNT@CdO was synthesized. This nanocatalyst was used in the production of biodiesel derived from Waste Cooking Oil (WCO). Several analytical techniques such as field-emission scanning electron microscopy (FESEM) for morphological assessment, Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) for structural determination, Energy Dispersive X-ray Spectrometer (EDX) for chemical composition analysis, and vibrating sample magnetometer (VSM) for the evaluation of magnetic properties, were tested. Also, the effects of various parameters such as molar ratios of methanol to oil (1:1, 5:1, 10:1, 20:1, and 30:1), catalyst dosages ranging from 0.01 to 0.2 g, reaction times from 60 to 240 min, and reaction temperatures between 25 °C and 120 °C were studied. Based on the findings, the optimal reaction conditions were at the magnetic Carbon Nanotube (MCNT) to Cadmium Oxide Nanoparticles (CdO NPs) ratio of 1:0.5, a molar ratio of WCO to Methanol of 1:10, a reaction duration of 180 min, and a reaction temperature of 120 °C. Moreover, under the most favorable reaction conditions, the catalyst demonstrated satisfactory catalytic efficiency (> 92%) in transforming the triglycerides of WCO into fatty acid methyl esters (FAMEs) for biodiesel production. Therefore, these innovative heterogeneous composites are proposed as alternative catalysts for future biodiesel generation methodologies.

Upgrading MnO2@CuO with GO as a superior heterogeneous nanocatalyst for transesterification of dairy waste oils to biodiesel through electrolysis procedure

In this research, the electrolysis procedure was employed to synthesize biodiesel from dairy waste oil (DWO) utilizing MnO2@CuO and MnO2@CuO@GO as novel heterogeneous nanocatalysts. The structural attributes of MnO2@CuO and MnO2@CuO@GO nanocatalysts were scrutinized utilizing Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron Microscopy (FESEM), Mapping, Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), Temperature-Programmed Desorption (CO2/TPD), Raman, X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) analyses. Further, Proton Nuclear Magnetic Resonance (H NMR), Gas Chromatography–Mass Spectrometry (GC-MS), and FTIR spectra were utilized to characterize the chemical structure of biodiesel and DWO. According to the Box-Behnken Design statistical method, the highest biodiesel yield utilizing MnO2@CuO and MnO2@CuO@GO nanocatalysts was 94.15 and 98.07 %, respectively, which were obtained after 52.64 and 49.3 min, respectively. According to the results, MnO2@CuO@GO has a higher ability to generate biodiesel compared to MnO2@CuO. After 7 consecutive reuse cycles, the yield of biodiesel using MnO2@CuO and MnO2@CuO@GO nanocatalysts was 80.14 and 90.77 %, respectively, demonstrating that MnO2@CuO@GO is much more stable than MnO2@CuO. The kinetics of biodiesel generation showed that the reaction between DWO and methanol in the presence of MnO2@CuO@rGO is non-spontaneous and endothermic (ΔHo = 47.54 kJ/mol). In general, MnO2@CuO@GO, because of its easy synthesis, high biodiesel efficiency, and remarkable stability, is considered as a promising catalyst for industrial applications.

Boosting Biodiesel Production from Dairy-Washed Scum Oil Using Beetle Antennae Search Algorithm and Fuzzy Modelling

The major goal of this study was to develop a robust fuzzy model to mimic the generation of biodiesel from the transesterification of dairy-washed milk scum (DWMS) oil. Four process parameters were considered: the molar ratio of methanol to oil, the concentration of KOH, the reaction temperature, and the reaction time. The proposed technique was divided into two steps: fuzzy modelling and optimum parameter identification. The capability of fuzzy tools to capture and make use of linguistic variables and fuzzy sets is one of their main benefits. This means that fuzzy logic allows for the representation and manipulation of values that fall across a continuum rather than merely relying on crisp values or binary categories. When dealing with non-linear relationships, this is especially helpful since it gives a more accurate and nuanced depiction of the underlying data. As a result, an accurate fuzzy model was initially built based on collected data to simulate the biodiesel production in terms of the molar ratio of methanol to oil, the concentration of KOH, the temperature of the reaction, and the reaction duration. In the second phase, the beetle antennae search (BAS) algorithm was applied to identify the optimal values of the process parameters to boost the production of biodiesel. The BAS algorithm draws inspiration from beetle behavior, particularly how they navigate using their antennae. It employs a swarm-intelligence method by deploying virtual beetles that swarm over the problem area in search of the best solution. One of its main features is the BAS algorithm’s capacity to balance exploration and exploitation. This is accomplished through the algorithm’s adaptable step-size mechanism during the search phase. As a result, the algorithm can first investigate a large portion of the problem space before gradually moving closer to the ideal answer. Compared with ANOVA, and thanks to fuzzy, the RMSE decreased from 7 using ANOVA to 0.73 using fuzzy (a decrease of 89%). The predicted R2 increased from 0.8934 using ANOVA to 0.9614 using fuzzy (an increase of 7.6). Also, the optimisation results confirmed the superiority of the BAS algorithm. Biodiesel production increased from 92% to 98.16%.

TRIBOLOGICAL ANALYSIS OF BIODIESEL DERIVED WASTE PALM COOKING OIL (WPCO)

The demand for sustainable and renewable energy sources is rising globally, which has increased interest in biodiesel manufacturing. The generation of biodiesel derived waste palm cooking oil (WPCO) is the main topic of this study. A versatile and easily accessible feedstock for the synthesis of biodiesel is palm frying oil, which is frequently used in culinary applications. WPCO is transformed into biodiesel using a process called transesterification, in which the oil's triglycerides combine with an alcohol, usually methanol, in the presence of a catalyst.
 The oils were analyzed for their chemical and physical properties such as viscosity and density. The frictional test was carried out using Pin-on-Disc Tribometer for different loads and speeds. The findings show that lubricants based on WPCO and WPME have remarkable anti-wear properties and have promise for usage in industrial and automotive applications. WPCO is found to have better performance to be used as an engine lubricant while WPME has the lowest potential to be a lubricant because of its low viscosity and high coefficient of friction. It can be found that WPCO which has higher viscosity presents a wear scar diameter of 1.888 mm and a total average CoF of 0.4296. As for WPME, the wear scar diameter is 2.062 mm with a CoF of 0.5483. The surface area of WPCO values was found to be about 9.2% less than WPME. The higher the CoF, the larger the wear scar diameter. The lubricant film of WPME is too thin to provide total surface separation. Contact between the surface asperities occurs.

Biodiesel Production Optimization from Waste Cooking Oil Using Animal Bone Catalyst

The goal of the current study is to use a heterogeneous catalyst made from biological-waste (animal bone) to optimize the process parameters needed to transform used cooking oil (WCO) into methyl- esters. The methyl esters and synthetic calcium oxide (CaO) from animal dumps were both analyzed. At temperatures between 900 and 950oC, calcined catalyst was obtained. Utilizing central composite architecture, reaction effects from temperature (40–80oC), time for the reaction (30–180min), as well as CL (1–0.15×102 w/w%) were examined in a 3-level, 3-factor array. To identify the most important parameter, ANOVA testing as well as R.S.M optimization are utilized for the studies. The linear terms of CL (p-value of 0.0146), reaction time (p-value 0.0339), as well as temperature of the reaction combination (p-value of 0.0344) had greatest impact on the biodiesel yield. The quadratic terms of CL (p-value = 0.0271) and temperature of the combining reaction (p-value = 0.0508) had the greatest impact on the oil yield. Therefore, it is practical to apply C.C.D design, R.S.M, as well as ANOVA to optimize the generation of biodiesel from used cooking oil.

Performance evaluation of ANFIS and RSM in modeling biodiesel synthesis from soybean oil

The parameters of biodiesel generation from Soybean oil having the molar ratio, reaction duration, and catalyst concentration for constant temperature, were modelled Using response surface methodology. a molar ratio of 6–12, NaOH of 1–2% w/w, time of 30–60 min, and temperature of 35–55 °C. an adaptive neuro-fuzzy inference system (ANFIS) and the response surface methodology-based Box–Behnken experimental design. a significant regression model with an R2 value of 0.9411 was obtained. The ANFIS model was used to link each of the four input factors with the outcome variable (biodiesel yield). In the training, an R2 value of 0.9918 was attained. The findings showed that the constructed models accurately depicted the processes they described.

Life cycle engineering (LCE) study for Synechococcus HS-9 biomass production as potential raw material for a third generation biodiesel production

The LCE study aims to reduce the environmental impact of the biomass production of Synechococcus HS-9. It is the main feedstock in producing biodiesel as a potential alternative fuel from using Indonesia’s natural resources. The LCE study shows that the use of electricity and compressors contributed the highest to the environmental impact. Synechococcus HS-9 dry biomass production process affects the environment of 8.38x10-9Pt. The five significant impacts include Marine Aquatic Ecotoxicity Pot. (MAETP), Human Toxicity Potential (HTP inf.), Freshwater Aquatic Ecotoxicity Pot. (FAETP), Abiotic Depletion (ADP elements) and Global Warming Potential (GWP). The LCE design solution significantly reduces environmental impact by scenario changing electrical energy from State Electricity Company (PLN) using coal to electricity from renewable energy sources. On the other design solution, the best generation compressor scenario (new technology) can reduce the environmental impact by an average of 20% compared to the average generation compressor (current technology). The average GWP value is generated successively from the use of renewable energy, namely municipal waste energy at 7%, hydropower energy at 10%, onshore wind power at 7.05%, geothermal energy at 12.08%, PV at 13.84%, and natural gas at 50% of GWP value generated by the PLN electricity source using coal.

Using ZnAl–LDH@SiO2 as a catalyst for the electrocatalytic conversion of waste frying oil into biodiesel

In this study, a novel electrocatalytic conversion system via simultaneous esterification and transesterification, based on a ZnAl–layered double hydroxide (LDH)@SiO2, was investigated for fatty acid methyl ester (FAME) production from waste frying oil (WFO). A mechanism is proposed for the (trans)esterification process to generate CH3O− and OH− on the ZnAl–LDH@SiO2 as the semiconductor heterogeneous catalyst. The inclusion of SiO2 enhanced the catalyst's basicity and caused a better exposure of atoms of oxygen atoms on the catalyst's surface which contributed to the formation of methoxides as a nucleophilic attack on the triglyceride's carbonyl. Also, ZnAl–LDH@SiO2 as an electrocatalyst reduces the beginning potential rate and increases the charge carriers transport. The results showed that 98.4% FAME yield was obtained at higher water content from WFO after 90 min of reaction at 25 °C using 2 wt% of the ZnAl–LDH@SiO2 catalyst, and a methanol to WFO (M:WFO) molar ratio of 6:1. ZnAl–LDH@SiO2 was also effective for WFO containing 3.3 wt% of free fatty acid (FFA), and indicated high stability for WFO (trans)esterification after 5 runs. The electrocatalytic conversion system has the potential to advance a new process development for the conversion of feedstock containing high FFA and water to produce the second generation of biodiesel.

Fish Waste: A Potential Source of Biodiesel

The continuously increasing energy requirement on one hand and the incessant depletion of non-renewable fossil fuels on the other urge us to focus on alternative renewable energy sources such as biofuels. Biofuels including biodiesel, bioethanol, biobutanol, biohydrogen, etc., are generated from different biological sources, and their waste which stands as the best alternative in the present scenario. Specifically, the utilization of biological wastes as raw materials for the production of biofuels is considered as best waste management practice. To date, most of the biodiesel production research has been carried out with plant, algal, and microbial samples, or their waste. It is a well-known fact that diesel can also be produced from specific oily fish and their waste using different methods. In addition, fish waste constitutes a major quantity compared to other food waste which is a serious concern. Furthermore, the disposal of fish waste shows an impact on both the environment and the economy. Hence, the development of protocols for the efficient production of biodiesel from fish waste is the ultimate goal. However, insufficient knowledge and less effort in the conversion of fish waste to biodiesel impede the achievement of this goal. Therefore, this review intends to summarize the mechanism of biodiesel production from fish waste. Also, various physico-chemical factors involved in biodiesel production from fish waste were discussed. In addition, research on biodiesel generation from various fish wastes or waste fish oil was also emphasized in detail, which will be helpful for commercial practice. Overall, this information will be useful for improvement in biodiesel production from fish waste.

13C-metabolic flux analysis of lipid accumulation in the green microalgae Tetradesmus obliquus under nitrogen deficiency stress

Metabolic fluxes (MF) serve as the functional phenotypes of biochemical processes and are crucial to describe the distribution of precursors within metabolic networks. There is a lack of experimental observations for carbon flux towards lipids, which is important for biodiesel generation. Here, the accumulation of lipid, and MF in Tetradesmus obliquus under nitrogen deficiency stress (NF) using a 13C isotope tracer at different time intervals was investigated. The 13C based MF showed enhanced de novo synthesis of G3P and PEP, indicating increased carbon flux from CO2 into lipid synthesis. An increase in palmitic acid (3500 μmol/mg), linoleic acid (2100 μmol/mg), and oleic acid (2000 μmol/mg) was observed. The accumulation of C16:0 under NF was mainly related to de novo synthesis while C18:3 was accumulated through a non de novo pathway. Under NF stress, T. obliquus had higher flux in PPP and glycolysis pathway, together, it might provide more NADPH and substrate acetyl-CoA for fatty acid synthesis.