Lipase-Catalyzed Transesterification of Rapeseed Oil for Biodiesel Production with tert-Butanol

Cold flow properties of biodiesel from waste cooking oil and a new improvement method

Biodiesel despite its positive advantages when using it as a fuel in replacement of diesel, suffers a major drawback in the cold flow properties (CFP). During winters, plugging of the filters as well as crystallization of the fatty acid are two of the leading problems that makes the fuel to not reach injectors and the combustion chamber and therefore the engine does not start. Cold flow properties of waste cooking oil biodiesel (WCOB) through the reduction of cloud point (CP), pour point (PP) and the cold filter plugging point (CFPP) where investigated in this work. The effectiveness of an approaches using the combination of two techniques, controlled winterization and addition of fatty acids 2-ethylhexyl esters (FAEhE) to reduce CP, PP and CFPP was studied. The change in CP, PP and CFPP corresponded to a decrease in the saturated ethyl esters content. A reduction of the palmitic and stearic acid ethyl esters content of 20,63 % and 8.64 % respectively was found. There was not significant effect on the fuel properties due to changes in the chemical composition of liquid fractions. However, using a Factorial Design and Response Surface Methodology optimization, the lowest CP, PP and CFPP for WCOB biodiesel could be obtained working with a winterization temperature of -5 °C, adding a 10 % of FAEhE and cooling during 30 min.

ANCUT1, a novel thermoalkaline cutinase from Aspergillus nidulans and its application on hydroxycinnamic acids lipophilization

One of the four cutinases encoded in the Aspergillus nidulans genome, ANCUT1, is described here. Culture conditions were evaluated, and it was found that this enzyme is produced only when cutin is present in the culture medium, unlike the previously described ANCUT2, with which it shares 62% amino acid identity. The differences between them include the fact that ANCUT1 is a smaller enzyme, with experimental molecular weight and pI values of 22 kDa and 6, respectively. It shows maximum activity at pH 9 and 60 °C under assayed conditions and retains more than 60% of activity after incubation for 1 h at 60 °C in a wide range of pH values (6-10) after incubations of 1 or 3 h. It has a higher activity towards medium-chain esters and can modify long-chain length hydroxylated fatty acids constituting cutin. Its substrate specificity properties allow the lipophilization of alkyl coumarates, valuable antioxidants and its thermoalkaline behavior, which competes favorably with other fungal cutinases, suggests it may be useful in many more applications.

An Effective Strategy for the Production of Lauric Acid-Enriched Monoacylglycerol via Enzymatic Glycerolysis from Black Soldier Fly (Hermetia illucens) Larvae (BSFL) Oil

Here, we developed an efficient strategy for the production of lauric acid-enriched monoacylglycerol (MAG) via enzymatic glycerolysis using black soldier fly (Hermetia illucens) larvae (BSFL) oil. The effects of the substrate molar ratio, reaction temperature, type of immobilized lipase, and organic solvent on the MAG content and conversion degree of BSFL oil were optimized. The maximum substrate conversion rate (97.88%) and MAG content (70.84%) were obtained in a tert-butanol system at 50 °C with a glycerol/BSFL oil molar ratio of 4:1 by using immobilized MAS1 lipase as a catalyst. The MAG content in the purified product reached 97.7%, with lauric acid accounting for 50.2%. Improved oxidation stability was observed after glycerolysis. Overall, this study provides a new strategy for the preparation of lauric acid-enriched MAG from BSFL oil.

A systematic review of the genera Geobacillus and Parageobacillus: their evolution, current taxonomic status and major applications

The genus Geobacillus, belonging to the phylum Firmicutes, is one of the most important genera and comprises thermophilic bacteria. The genus Geobacillus was erected with the taxonomic reclassification of various Bacillus species. Taxonomic studies of Geobacillus remain in progress. However, there is no comprehensive review of the characteristic features, taxonomic status and study of various applications of this interesting genus. The main aim of this review is to give a comprehensive account of the genus Geobacillus. At present the genus acomprises 25 taxa, 14 validly published (with correct name), nine validly published (with synonyms) and two not validly published species. We describe only validly published species of the genera Geobacillus and Parageobacillus. Vegetative cells of Geobacillus species are Gram-strain-positive or -variable, rod-shaped, motile, endospore-forming, aerobic or facultatively anaerobic, obligately thermophilic and chemo-organotrophic. Growth occurs in the pH range 6.08.5 and a temperature of 37-75 °C. The major cellular fatty acids are iso-C15:o, iso-C16:0 and iso-C17:o. The main menaquinone type is MK-7. The G-+C content of the DNA ranges between 48.2 and 58 mol%. The genus Geobacillus is widely distributed in nature, being mostly found in many extreme locations such as hot springs, hydrothermal vents, marine trenches, hay composts, etc. Geobacillus species have been widely exploited in various industrial and biotechnological applications, and thus are promising candidates for further studies in the future.

Enzymatic Synthesis of Biodiesel by Direct Transesterification of Rapeseed Cake

Increase in energy demand and limited sources of fossil fuels force the world’s population to seek new energy sources Biodiesel obtained by transesterification of oils with an alcohol in the presence of catalysts is an example of renewable fuel. The aim of the study was to assess the best conditions for enzymatic biodiesel synthesis by direct transesterification of rapeseed cake using Taguchi method. The influence of alcohol (methanol, ethanol, propanol, and butanol), temperature (30–60 °C), C. antarctica lipase B concentration (0.5–2 %), time (6–48 h) and rapeseed cake to alcohol ratio (1:2–1:5) was examined in the synthesis of fatty acid alkyl esters. Optimum conditions for direct enzymatic transesterification of rapeseed cake are: 30 °C, 12 h, 0.5 % of lipase and ethanol in 4:1 ratio to rapeseed cake.

Response surface methodology assisted biodiesel production from waste cooking oil using encapsulated mixed enzyme

In the recent scenario, consumption of petroleum fuels has increased to greater height which has led to deforestation and decline in fossil fuels. In order to tackle the perilous situation, alternative fuel has to be generated. Biofuels play a vital role in substituting the diesel fuels as they are renewable and ecofriendly. Biodiesel, often referred to as green fuel, could be a potential replacement as it could be synthesized from varied substrates, advantageous being the microalgae in several ways. The present investigation was dealt with the interesterification of waste cooking oil using immobilised lipase from mixed cultures for biodiesel production. In order to standardize the production for a scale up process, the parameters necessary for interesterification had been optimized using the statistical tool, Central Composite Design - Response Surface Methodology. The optimal conditions required to generate biodiesel were 2 g enzyme load, 1:12 oil to methyl acetate ratio, 60 h reaction time and 35 °C temperature, yielding a maximum of 93.61% biodiesel. The immobilised lipase beads remain stable without any changes in their function and structure even after 20 cycles which made this study, less cost intensive. In conclusion, the study revealed that the cooking oil, a residue of many dining centers, left as waste product, can be used as a potential raw material for the production of ecofriendly and cost effective biofuel, the biodiesel.

An alternative method for production of microalgal biodiesel using novel Bacillus lipase

In this study, enzymatic interesterification is carried out using encapsulated lipase as biocatalyst with methyl acetate as acyl acceptor in a solvent-free system. Lipase, isolated from a marine bacterial isolate, Bacillus sp.S23 (KF220659.1) was immobilized in sodium alginate beads. This investigation elaborated on the effects of various parameters, namely enzyme loading, temperature, water, molar ratio, reaction time and agitation for interesterification. The study resulted in the following optimal conditions: 1.5 g immobilized lipase, 1:12 molar ratio of oil to methyl acetate, 35 °C, 8 % water, 60 h reaction time, 250 rpm of agitation. With the standardized condition, the maximum conversion efficiency was 95.68 %. The immobilized beads, even after ten cycles of repeated usage showed high stability in the presence of methyl acetate and no loss of lipase activity. The microalgal biodiesel composition was analyzed using gas chromatography. The current study was efficient in using immobilized lipase for the interesterification process, since the method was cost-effective and eco-friendly, no solvent was involved and the enzyme was encapsulated in a natural polymer.

Est10: A Novel Alkaline Esterase Isolated from Bovine Rumen Belonging to the New Family XV of Lipolytic Enzymes

A metagenomic fosmid library from bovine rumen was used to identify clones with lipolytic activity. One positive clone was isolated. The gene responsible for the observed phenotype was identified by in vitro transposon mutagenesis and sequencing and was named est10. The 367 amino acids sequence harbors a signal peptide, the conserved secondary structure arrangement of alpha/beta hydrolases, and a GHSQG pentapeptide which is characteristic of esterases and lipases. Homology based 3D-modelling confirmed the conserved spatial orientation of the serine in a nucleophilic elbow. By sequence comparison, Est10 is related to hydrolases that are grouped into the non-specific Pfam family DUF3089 and to other characterized esterases that were recently classified into the new family XV of lipolytic enzymes. Est10 was heterologously expressed in Escherichia coli as a His-tagged fusion protein, purified and biochemically characterized. Est10 showed maximum activity towards C4 aliphatic chains and undetectable activity towards C10 and longer chains which prompted its classification as an esterase. However, it was able to efficiently catalyze the hydrolysis of aryl esters such as methyl phenylacetate and phenyl acetate. The optimum pH of this enzyme is 9.0, which is uncommon for esterases, and it exhibits an optimal temperature at 40°C. The activity of Est10 was inhibited by metal ions, detergents, chelating agents and additives. We have characterized an alkaline esterase produced by a still unidentified bacterium belonging to a recently proposed new family of esterases.

Production of sugars and levulinic acid from marine biomass Gelidium amansii

This study focused on optimization of reaction conditions for formation of sugars and levulinic acid from marine algal biomass Gelidium amansii using acid catalyst and by using statistical approach. By this approach, optimal conditions for production of sugars and levulinic acid were found as follows: glucose (reaction temperature of 139.4 degrees C, reaction time of 15.0 min, and catalyst concentration of 3.0%), galactose (108.2 degrees C, 45.0 min, and 3.0%), and levulinic acid (160.0 degrees C, 43.1 min, and 3.0%). While trying to optimize the conditions for the production of glucose and galactose, levulinic acid production was found to be minimum. Similarly, the production of glucose and galactose were found to be minimum while optimizing the conditions for the production of levulinic acid. In addition, optimized production of glucose required a higher reaction temperature and shorter reaction time than that of galactose. Levulinic acid was formed at a high reaction temperature, long reaction time, and high catalyst concentration. The combined results of this study may provide useful information to develop more economical and efficient systems for production of sugars and chemicals from marine biomass.