Solvent-free methanolysis of canola oil in a packed-bed reactor with use of Novozym 435 plus loofa

Statistical Optimization of Biodiesel Production from Salmon Oil via Enzymatic Transesterification: Investigation of the Effects of Various Operational Parameters

The enzymatic transesterification of Atlantic salmon (Salmo salar) oil was carried out using Novozym 435 (immobilized lipase from Candida antartica) to produce biodiesel. A response surface modelling design was performed to investigate the relationship between biodiesel yield and several critical factors, including enzyme concentration (5, 10, or 15%), temperature (40, 45, or 50 °C), oil/alcohol molar ratio (1:3, 1:4, or 1:5) and time (8, 16, or 24 h). The results indicated that the effects of all the factors were statistically significant at p-values of 0.000 for biodiesel production. The optimum parameters for biodiesel production were determined as 10% enzyme concentration, 45 °C, 16 h, and 1:4 oil/alcohol molar ratio, leading to a biodiesel yield of 87.23%. The step-wise addition of methanol during the enzymatic transesterification further increased the biodiesel yield to 94.5%. This is the first study that focused on Atlantic salmon oil-derived biodiesel production, which creates a paradigm for valorization of Atlantic salmon by-products that would also reduce the consumption and demand of plant oils derived from crops and vegetables.

Synthesis and characterization of fatty acid oat β-glucan ester and its structure-curcumin loading capacity relationship

An amphiphilic fatty acid oat β-glucan ester (FAOGE) was first synthesized, and its structure-curcumin loading capacity (CLC) relationship was investigated. The DS of product increased with the addition of acyl imidazole, decreased with Mw of β-glucan, and did not relate to the acyl chain length. Characterizations by FT-IR and (1)H NMR evidenced the presence of ester groups in FAOGE and confirmed its successful synthesis. The aqueous self-aggregation behavior of FAOGE was revealed by transmission electron microcopy and dynamic light scattering. With the aid of response surface methodology, a quadratic polynomial equation was obtained to quantitatively describe the structure-CLC relationship of FAOGE by using Mw of β-glucan, acyl chain length, and DS as variables. The CLC increased with Mw of β-glucan and acyl chain length but maximized at a medium DS. The maximum CLC value was obtained as 4.05 μg/mg. Hence, FAOGE is a potential candidate in solubilizing and delivering hydrophobic food ingredients.

Effects of methanol on lipases: molecular, kinetic and process issues in the production of biodiesel

The biotechnological production of biodiesel is based on transesterification/esterification reactions between a source of fatty acids and a short-chain alcohol, usually methanol, catalysed by enzymes belonging to the class known as lipases. Several lipases used in industrial processes, although stable in the presence of other organic solvents, are inactivated by methanol at or below the concentration optimal for biodiesel production, making it necessary to use stepwise methanol feeding or pre-treatment of the enzyme. In this review article we focus on what is currently know about methanol inactivation of lipases, a phenomenon which is not common to all lipase enzymes, with the goal of improving the biocatalytic process. We suggest that different mechanisms can lead to inactivation of different lipases, in particular substrate inhibition and protein unfolding. Attempts to improve the performances of methanol sensitive lipases by mutagenesis as well as process engineering approaches are also summarized.

Three-factor response surface optimization of nano-emulsion formation using a microfluidizer

Emulsification of sunflower oil in water by microfluidization was studied. Response surface methodology (RSM) and the central composite design (CCD) were applied to determine the effects of certain process parameters on performance of the apparatus for optimization of nano-emulsion fabrication. Influence of pressure, oil content and number of passes on the disruption of emulsions was studied. Quadratic multiple regression models were chosen for two available responses, namely Sauter mean diameter (SMD) and Polydispersity index (PdI). Analysis of variance (ANOVA) showed a high coefficient of determination (R(2)) value for both responses, confirming adjustment of the models with experimental data. The SMD and the PdI decreased as the pressure of emulsification increased from 408 to 762.3 bar for the oil content of 5 vol% and from 408 to 854.4 bar for the oil content of 13 vol%, and thereafter, increasing the pressure up to 952 bar led to increasing the both responses. The results implied that laminar elongational flow is the alternative disruption mechanism in addition to inertia in turbulence flow, especially at low treatment pressures. Both of responses improved with increase in number of passes from 2 to 4 cycles. The oil content depicted low effect on responses; however, interaction of this parameter with other regressors pointed remarkable impact. Also, the effect of pressure on Kolmogorov micro-scale was studied. The results implied that Kolmogorov equation did not take into account the over-processing and was applicable only for disruption of droplets in the inertial turbulent flow.

Development of a novel integrated continuous reactor system for biocatalytic production of biodiesel

A novel integrated immobilized enzyme-reactor system involving a continuous stirred tank reactor with two packed bed reactors in series was developed for the continuous production of biodiesel. The problem of methanol solubility into oil was solved by introducing a stirred tank reactor to dissolve methanol into partially converted oil. This step made the process perfectly continuous without requiring any organic solvent and intermittent methanol addition in the process. The substrate feeding rate of 0.74 mL/min and enzyme loading of 0.75 g per reactor were determined to be optimum for maximum biodiesel yield. The integrated continuous process was stable up to 45 cycles with biodiesel productivity of 137.2 g/L/h, which was approximately 5 times higher than solvent free batch process. In comparison with the processes reported in literature using expensive Novozyme 435 and hazardous organic solvent, the present process is completely green and perfectly continuous with economic and environmental advantages.

Aerobic pretreatment of olive oil mill wastewater using Ralstonia eutropha

Olive oil mill wastewater (OMW) has a high polluting power, with total phenolics (TP) around 2.5 g l(-1) and chemical oxygen demand (COD) 85 g l(-1). Biological systems offer advantages in treating this type of agro-industrial wastewater. The performance of phenol-adapted Ralstonia eutropha for aerobic biotreatment of OMW has been studied, and a TP concentration of 250 mg l(-1) found to be fully degraded within 24 h. This simple procedure may be adopted as a pretreatment prior to the normal aerobic or anaerobic techniques used for treating OMW. The biodegradative capability of this non-pathogenic gram-negative bacterium towards the TP and COD content of OMW has been evaluated. The adapted free cells were found able to decrease TP and COD in the undiluted OMW by 56% and 42%, respectively. The Monod equation was found suitable to describe the capacity of the cells for growing on undiluted OMW, giving micromax 0.083 per day and Ks = 1846 mg l(-1). Using a packed-bed reactor the performance of loofa-immobilized R. eutropha was assessed and the reduction in TP and COD shown to be 73% and 64%, respectively.