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Biodiesel is an alternative to fossil-derived diesel with similar properties and several environmental benefits. Biodiesel production using conventional catalysts such as homogeneous, heterogeneous, or enzymatic catalysts faces a problem regarding catalysts deactivation after repeated reaction cycles. Heterogeneous nanocatalysts and nanobiocatalysts (enzymes) have shown better advantages due to higher activity, recyclability, larger surface area, and improved active sites. Despite a large number of studies on this subject, there are still challenges regarding its stability, recyclability, and scale-up processes for biodiesel production. Therefore, the purpose of this study is to review current modifications and role of nanocatalysts and nanobiocatalysts and also to observe effect of various parameters on biodiesel production. Nanocatalysts and nanobiocatalysts demonstrate long-term stability due to strong Brønsted-Lewis acidity, larger active spots and better accessibility leading to enhancethe biodiesel production. Incorporation of metal supporting positively contributes to shorten the reaction time and enhance the longer reusability. Furthermore, proper operating parameters play a vital role to optimize the biodiesel productivity in the commercial scale process due to higher conversion, yield and selectivity with the lower process cost. This article also analyses the relationship between different types of feedstocks towards the quality and quantity of biodiesel production. Crude palm oil is convinced as the most prospective and promising feedstock due to massive production, low cost, and easily available. It also evaluates key factors and technologies for biodiesel production in Indonesia, Malaysia, Brazil, and the USA as the biggest biodiesel production supply., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This work reports the use of an acid-activated Brazilian smectite natural clay-based catalyst in the esterification of fatty acids at atmospheric pressure and without a co-solvent. Conversion levels of 99%, 98%, 93% and 80% were reached for caprylic, lauric, stearic and oleic methyl esters, respectively, using 1:3 fatty acid/methanol molar ratio, heating bath at 100 °C after 4 h. A conversion level of 89% was achieved for methyl esters from a fatty acid residue of the palm oil refining industry in the same reaction condition. The acid-activated clay provided better performance than the commercial catalyst K-10 . The effects of catalyst amount, temperature, fatty acid/alcohol molar ratio and time were investigated. The heating activation of the catalyst immediately before the catalytic test increased the conversion from 94% to 99% using 1:1.5 stearic acid/methanol molar ratio, heating bath at 100 °C after 4 h. The catalyst was reused five times. The conversion decreases less than 5% in the first three reuses. The smectite natural clay and the catalyst were characterized by X-ray fluorescence, X-ray diffraction, n -butylamine thermodesorption, nitrogen adsorption analysis, thermogravimetric analysis and differential thermal analysis. [ABSTRACT FROM AUTHOR]

Passion fruit is one popular fruits in Brazil, and its annual production represents 70 % of the world production. About 60 % of fruit is mesocarp and epicarp (peel) and contains high levels of pectin that can be extracted using heating or alternative technologies. The purpose of the present work was to investigate the potential of high pressure to extract the pectin from passion fruit peel. The results showed that the extraction yield almost doubled (from 7.4 to 14.34 %) when high pressure was used as a pretreatment. The esterification degree and galacturonic acid of the pectin extracted were higher by 50 and 65 %, respectively. High pressure as a pretreatment was found to be an effective, time-saving, and eco-friendly method for the extraction of pectin from passion fruit peel. [ABSTRACT FROM AUTHOR]

Brazilian biodiesel production has experienced a very fast growing. After the first plant in 2005, more than 60 plants are running and producing about 2 million tons/year in less than 4 years of the national biodiesel programm. In addition to regular transesterification plants, there is a commercial esterification plant running with heterogeneous catalysis producing biodiesel from palm fatty acids. A new process denominated hydroesterification is becoming more important since it is able to use any acid fatty material integrating hydrolysis and esterification reactions. In addition to an european standard biodiesel, hydroesterification produces a very pure glycerol during hydrolysis step. Pure glycerol is a multiple application molecule including hydrogen production to be applied with fatty acid reactions producing high valued bioprodcts [ABSTRACT FROM AUTHOR]

During the poultry industrialization process the so-called sludge oil, a residual chicken fat, is recovered in the wastewater treatment plant and its use presents potential as raw material for biodiesel production. Thus, the aim of the study was to prepare blends of sludge oil with soybean oil to obtain fatty acid methyl esters (FAME) through the homogeneous alkaline transesterification reaction. To perform this study, a simple pre-treatment process - heating and subsequent filtration - was used, allowing sludge oil to be mixed with soybean oil to compose blends, without the need to use more sophisticated pre-treatment processes. After this step, blends ranging from 5% to 90% (m/m) of sludge oil mixed with soybean oil were prepared. The results showed that the molar ratio (1:6 oil blend:methanol), catalyst concentration 0.5% NaOH (m cat /m oil ), at 65 °C for 60 min yielded FAME above 99.0 and 90.0% (m/m) for blends with up to 5 and 15% sludge oil, respectively. By increasing the temperature to 70 °C, under the same selected parameters, the blend with 10% sludge oil provided yield above 99.0% (m/m), presenting appropriate physicochemical properties, within the parameters required by National Agency of Petroleum, Natural Gas and Biofuels (ANP). These findings show the great potential sludge oil provides to reduce Brazil's dependency on soybean oil for biodiesel production. Highlights Sludge oil, a waste raw material for biodiesel production, is not yet explored in Brazil.A procedure for biodiesel production using soybean oil and sludge oil blends was proposed.The best reaction condition was 1:6 oil blend:MeOH molar ratio; 0.5% NaOH (m cat /m oil ), at 70 °C for 60 min.Biodiesel yield was higher than 99% (m/m) under optimal reaction conditions.Sludge oil represents a promising waste raw material for biodiesel production.

One of the ways to produce biodiesel is through fatty acid esterification via heterogeneous catalysis. The water treatment plants in Manaus - Amazonas/Brazil produce about 20 tons of sludge per day. In order to establish an application to this abundant waste as a new heterogeneous catalyst, acid and heat treatments were performed and characterized by X-ray diffraction, X-ray fluorescence, infrared spectroscopy, thermogravimetric analysis, surface area, and scanning electron microscopy. The sludge is mainly composed of Si, Al, and Fe. Only the sludge without heat treatment showed S levels after acid treatment, proving the sulfation in these materials. The obtained materials were applied as catalysts, where the activity was evaluated by fatty acid esterification with methanol. The process was optimized using the best catalyst (WTS3M) and oleic acid, where under the following reaction conditions: 15:1 methanol:acid molar ratio, 5 wt% of catalyst, 100 °C and 3 h of reaction, resulted in conversions higher than 97%. The application of water treatment sludge as a catalyst with high catalytic activity for methyl oleate synthesis and the possibility of regeneration were demonstrated. This study will thus aid in the cost-effective reduction of water treatment sludge and increase the potential for additional biofuel production. Image 1 • A new catalyst was developed from the sludge produced at the water treatment plant. • The best catalyst (WTS3M) was the H 2 SO 4 3M-treated sludge. • WTS3M reached 97% of acid-biodiesel conversion at mild conditions. • WTS3M showed high catalytic activity in the esterification of different fatty acids. • A low-cost and eco-friendly catalyst for biodiesel synthesis was developed. [ABSTRACT FROM AUTHOR]

• Synthesis and evaluation of new potential biolubricants from castor oil fatty acids. • The less polar samples (BIOBUT) showed better pour point (−48 °C). • BIOWAT samples showed a higher viscosity values (>470 mm2/s at 40 °C). • Thermogravimetric analyses indicated that BIOWAT shows better thermal stability. • Synthesized samples have interesting properties for application as biolubricants. Plants oils have been increasingly gaining acceptance in world markets, due to their great potential as raw material to replace conventional mineral oils for formulation of lubricants. In this study, samples of new potential bio-based lubricant molecules were synthesized from castor oil fatty acids. The synthesis occurred in three steps: esterification with 2-ethyl-1-hexanol, epoxidation and opening of oxirane rings with different nucleophilic agents: 1-butanol (BIOBUT) and water (BIOWAT). The main objective was to study the influence of hydroxyl groups and branching level on physicochemical properties and thermal degradation of samples. The products obtained in each step were characterized by 1H NMR and their physicochemical properties. The results indicated that the less polar samples (BIOBUT) exhibited a better low-temperature performance (PP −48 °C). Furthermore, BIOBUT has superior oxidation stability (IP 4.22 h) compared to BIOWAT (IP 3.27 h). However, the BIOWAT showed a higher viscosity values (> 470 mm2/s at 40 °C). Thermogravimetric analyses have indicated that BIOWAT shows better thermal stability. Finally, the activation energy determined for the first thermal event for BIOWAT (151 kJ.mol−1) was higher than BIOBUT. [ABSTRACT FROM AUTHOR]

Residues of açaí seeds (Euterpe oleracea Mart.) were a novel source for the synthesis of the acid heterogeneous catalyst applied in the conversion of low free fatty acid waste cooking oil (WCO) to biodiesel. Yield of activated carbon (AC) and catalyst (CAT), as well as density of SO 3 H groups and total acidity, was analyzed in an entirely random designed experiment using multiple linear regression, one-way ANOVA, and Tukey's post hoc test. Time, temperature, dosage of KOH, and ratio of H 2 SO 4 /AC were the predictor variables with 3 levels each, at a significance level of α = .05. A significant yield variation portion of AC was explained by the experimental factors (R 2  = .891, F (3, 23) = 62.9, p < .0001), as did the yield of CAT (R 2  = .960, F (3, 23) = 185.7, p < .0001), density of SO 3 H (R 2  = .969, F (3, 23) = 242.2, p < .0001), and total acidity (R 2  = .973, F (3, 23) = 280.6, p < .0001). Levels of time (p = .001) and KOH dosage (p = .006) were significant to the yield of AC, and temperature levels were not influent on density of SO 3 H (p = .731) or total acidity (p = .762). CAT showed a S BET of 249 m 2  g -1 , V pore of 0.104 cm 3  g -1 , low crystallinity, high thermal stability, and a mesoporous amorphous structure. Optimized catalytic tests resulted in 89% conversion of WCO and 11 cycles of reuse, better than pure H 2 SO 4 or pure KOH (p < .0001) and also better than many biomass-derived catalysts reported in the literature.

As a consequence of intense industrialization in the last few decades, the amount of agro-industrial wastes has increasing, where new forms of valorization are crucial. In this work, five residual biomasses from Maranhão (Brazil) were investigated as supports for immobilization of lipase from Thermomyces lanuginosus (TLL). The new biocatalysts BM-TLL (babaçu mesocarp) and RH-TLL (rice husk) showed immobilization efficiencies >98% and hydrolytic activities of 5.331 U g -1 and 4.608 U g -1 , respectively, against 142 U g -1 by Lipozyme ® TL IM. High esterification activities were also found, with 141.4 U g -1 and 396.4 U g -1 from BM-TLL and RH-TLL, respectively, against 113.5 U g -1 by TL IM. Results of porosimetry, SEM, and BET demonstrated BM and RH supports are mesoporous materials with large hydrophobic area, allowing a mixture of hydrophobic adsorption and confinement, resulting in hyperactivation of TLL. These biocatalysts were applied in the production of hexyl laurate, where RH-TLL was able to generate 94% conversion in 4 h. Desorption with Triton X-100 and NaCl confirmed that new biocatalysts were more efficient with 5 times less protein than commercial TL IM. All results demonstrated that residual biomass was able to produce robust and stable biocatalysts containing immobilized TLL with better results than commercial preparations.

The present work evaluated the use of ultrasound to extract sequentially phenolics and pectin from mango peel. Initially, the influence of ethanol and ultrasound on the phenolics extraction was investigated. The results showed that the ultrasound did not affect the extraction yield of these compounds. The best total phenolics yield (67%) was obtained with an extraction solution consisting of 50% of ethanol in water (v/v) and without ultrasound application, according to the experimental design. As an innovative extraction methodology, the residue of this extraction was then used to extract pectin assisted by ultrasound. The use of ultrasound increased over than 50% of the pectin extraction yield and did not affect its quality, measured by the galacturonic acid content and the degree of esterification. The sequential extraction of phenolics and pectin shows to be an alternative to use the whole residue from mango peel., (Copyright © 2018 Elsevier Ltd. All rights reserved.)