Esterification using a liquid lipase to remove residual free fatty acids in biodiesel

Kinetic and thermodynamic study of enzymatic hydroesterification mechanism to fatty acid methyl esters synthesis

Eversa® Transform 2.0 lipase used as biocatalyst to biodiesel (fatty acid methyl esters - FAME) synthesis has been the target of interesting studies due to its thermostability and cost-effectiveness. In these researches, data about reaction conditions that result in satisfactory yields were investigated. Nevertheless, kinetic and thermodynamic parameters considering this enzyme are scarce. This paper presents an estimation of kinetic and thermodynamic parameters for the Eversa® Transform 2.0-mediated hydroesterification to FAME synthesis. Kinetic studies were performed for different methanol, water and lipase loads in distinct temperatures. Parameters adjusted by the thermodynamic model indicate that the hydrolysis is decisive in the overall hydroesterification reaction rate and the esterification reaction is endothermic (ΔH_e = 38.98 kJ/mol). Formation of enzymatic complexes is favored by increasing the temperature, especially the enzyme-methanol inhibition complex. Statistical analysis showed that the model was not overparameterized, and the small confidence interval indicated good reliability of the estimated parameters.

Preparation of polyethersulfone/magnesium silicate membranes via casting and electrospinning and their application in the removal of free fatty acids from biodiesel

Due to the reversible nature of reactions in biodiesel production, a purification process is necessary for the biodiesel to meet international standards. As an effective method, dry washing has been applied in biodiesel purification for years, but it still faces limitations and challenges. In this work, a magnesium silicate (MS) was synthesized using the hydrothermal method. Two types of composite membranes were prepared by doping the prepared magnesium silicate into polyethersulfone (PES) via casting and electrospinning, respectively. Structural and physical properties of the composite membranes were characterized. The composite membranes were applied as adsorbents to remove free fatty acids (FFAs) from crude biodiesel. Adsorption isotherm and kinetic studies were performed at different temperatures (20, 40 and 60 °C). For both membranes, the obtained adsorption capacity was higher at low temperature (20 °C). Maximum adsorption capacity was found with the electrospun membrane to be 852 mg g⁻¹, calculated from the Langmuir model. Adsorption kinetics for both membranes can be well described using the pseudo-second-order model. In addition, the internal diffusion was not negligible during the adsorption process based on the intraparticle diffusion analysis. As revealed by thermodynamic study, the adsorption processes were all exothermic with a spontaneous nature. Reusability of the membrane adsorbents was evaluated, in which the electrospun membrane showed a promising performance with 94% adsorption capacity remaining over 8 cycles of adsorption and desorption.

The casted and electrospun PES composite membranes showed ideal removal performance of free fatty acids. The electrospun membrane exhibited not only high adsorption capacity but also excellent reusability over 8 times of recycling.

Integrated Cleaner Biocatalytic Process for Biodiesel Production from Crude Palm Oil Comparing to Refined Palm Oil

An integrated cleaner biocatalyst process was performed for biodiesel production from crude palm oil (CPO) and refined palm oil (RPO). It was evaluated on process efficiency in terms of high purity of biodiesel as well as by-products without purification, less wastewater, less time consuming, and a simple downstream process. A first saponification step was carried out in both f CPO and RPO, a high purity of glycerol (86.25% and 87.5%) was achieved, respectively, while free fatty acids (FFASs) in soap were obtained after hexane extraction. High yields of FFASs were obtained from both CPO and RPO (98.83% and 90.94%). Subsequently, the FFAs were esterified to biodiesel by a biocatalyst of immobilized lipase. The highest biodiesel yields achieved were of 92.14% and 92.58% (CPO and RPO). Remarkably, biodiesel yields obtained from CPO and RPO achieved satisfactory values and the biocatalyst used could be reused for more than 16–17 cycles.

Combining technology with liquid-formulated lipases for in-spec biodiesel production

Enzymatic biodiesel production has been at the forefront of biofuels research in recent decades because of the significant environmental advantages it offers, while having the potential to be as effective as conventional chemically catalyzed biodiesel production. However, the higher capital cost, longer reaction time, and sensitivity of enzyme processes have restricted their widespread industrial adoption so far. It is also posited that the lack of research to bring the biodiesel product into final specification has scuppered industrial confidence in the viability of the enzymatic process. Furthermore, the vast majority of literature has focused on the development of immobilized enzyme processes, which seem too costly (and risky) to be used industrially. There has been little focus on liquid lipase formulations such as the Eversa Transform 2.0, which is in fact already used commercially for triglyceride transesterification. It is the objective of this review to highlight new research that focuses on bringing enzymatically produced biodiesel into specification via a liquid lipase polishing process, and the process considerations that come with it.