Lipase Activity of Tropical Oilseed Plants for Ethyl Biodiesel Synthesis and Their Typo- and Regioselectivity

Enzymatic Preparation, In-Depth Molecular Analysis, and In Vitro Digestion Simulation of Palmitoleic Acid (ω-7)-Enriched Fish Oil Triacylglycerols

In this study, an enzymatic reaction was developed for synthesizing pure triacylglycerols (TAG) with a high content of palmitoleic acid (POA) using fish byproduct oil. The characteristics of synthesized structural TAGs rich in POA (POA-TAG) were analyzed in detail through ultrahigh-performance liquid chromatography Q Exactive orbitrap mass spectrometry. Optimal conditions were thoroughly investigated and determined for reaction systems, including the use of Lipozyme TL IM and Novozym 435, 15 wt % lipase loading, substrate mass ratio of 1:3, and water content of 2.5 and 0.5 wt %, respectively, resulting in yields of 67.50 and 67.45% for POA-TAG, respectively. Multivariate statistical analysis revealed that TAG 16:1/16:1/20:4, TAG 16:1/16:1/16:1, TAG 16:1/16:1/18:1, and TAG 16:0/16:1/18:1 were the main variables in Lipozyme TL IM and Novozym 435 enzyme-catalyzed products under different water content conditions. Finally, the fate of POA-TAG across the gastrointestinal tract was simulated using an in vitro digestion model. The results showed that the maximum release of free fatty acids and apparent rate constants were 71.44% and 0.0347 s-1, respectively, for POA-TAG lipids, and the physical and structural characteristics during digestion depended on their microenvironments. These findings provide a theoretical basis for studying the rational design of POA-structural lipids and exploring the nutritional and functional benefits of POA products.

Lipase and Its Unique Selectivity: A Mini-Review

Contrary to other solid catalysts, enzymes facilitate more sophisticated chemical reactions because most enzymes specifically interact with substrates and release selective products. Lipases (triacylglycerol hydrolase, EC 3.1.1.3), which can catalyze the cleavage and formation of various acyl compounds, are one of the best examples of enzymes with a unique substrate selectivity. There are already several commercialized lipases that have become important tools for various lipid-related studies, although there is still a need to discover novel lipases with unique substrate selectivity to facilitate more innovative reactions in human applications such as household care, cosmetics, foods, and pharmaceuticals. In this mini-review, we focus on concisely demonstrating not only the general information of lipases but also their substate selectivities: typoselectivity, regioselectivity, and stereoselectivity. We highlight the essential studies on selective lipases in terms of enzymology. Furthermore, we introduce several examples of analysis methodology and experimental requirements to determine each selectivity of lipases. This work would stress the importance of integrating our understanding of lipase chemistry to make further advances in the relevant fields.

Revisiting Jatropha curcas Monomeric Esterase: A Dienelactone Hydrolase Compatible with the Electrostatic Catapult Model

Jatropha curcas contains seeds with a high oil content, suitable for biodiesel production. After oil extraction, the remaining mass can be a rich source of enzymes. However, data from the literature describing physicochemical characteristics for a monomeric esterase from the J. curcas seed did not fit the electrostatic catapult model for esterases/lipases. We decided to reevaluate this J. curcas esterase and extend its characterization to check this apparent discrepancy and gain insights into the enzyme's potential as a biocatalyst. After anion exchange chromatography and two-dimensional gel electrophoresis, we identified the enzyme as belonging to the dienelactone hydrolase family, characterized by a cysteine as the nucleophile in the catalytic triad. The enzyme displayed a basic optimum hydrolysis pH of 9.0 and an acidic pI range, in contrast to literature data, making it well in line with the electrostatic catapult model. Furthermore, the enzyme showed low hydrolysis activity in an organic solvent-containing medium (isopropanol, acetonitrile, and ethanol), which reverted when recovering in an aqueous reaction mixture. This enzyme can be a valuable tool for hydrolysis reactions of short-chain esters, useful for pharmaceutical intermediates synthesis, due to both its high hydrolytic rate in basic pH and its stability in an organic solvent.

An alternative solution for α-linolenic acid supplements: in vitro digestive properties of silkworm pupae oil in a pH-stat system

α-Linolenic acid (ALA) is recognised to have a regulatory effect on cardiovascular diseases. Due to the low bioavailability of linseed oil (LINO), which is the most common ALA supplement, it is necessary to find a replacement for ALA supplements that is more easily accepted by the human body. The content of ALA in silkworm pupae oil (SPO) is 32.60 ± 0.67%, and SPO can be substituted as a dietary lipid to meet the demand of the human body. In the present study, a pH-stat system was used to investigate the release degree of free fatty acids (FFAs) from SPO and construct a first-order kinetic model. Digestion experiments in vitro with different lipids showed that the maximum release FFA levels were SPO > SO (soybean oil) > LO (lard oil) > MSO (mulberry seed oil) > LINO, and the first-order kinetic apparent rate constants were LINO > SPO > LO > SO > MSO. Triacylglycerol (TAG) and fatty acid composition are the decisive factors in determining the level of lipid digestion. Therefore, the maximum level of FFAs released from SPO (84.34 ± 1.37%) was much higher than that of LINO (49.78 ± 0.52%) when the hydrolysis rates were 0.2114 s^-1 and 0.2249 s^-1, respectively. In addition, the smaller emulsion droplet size (609.24 ± 43.46 nm) and weaker surface charge (-17.93 ± 0.42 mV) also resulted in higher levels of SPO under in vitro digestion conditions. Meanwhile, due to low melting and crystallisation temperature, SPO is quickly absorbed by the human body. Overall, SPO can be used as a new alternative for ALA supplements based on its superior digestive properties.

Optimization of novel halophilic lipase production by Fusarium solani strain NFCCL 4084 using palm oil mill effluent

Among different sources of lipases, fungal lipases have continued to attract a wide range of applications. Further, halophilic lipases are highly desirable for biodiesel production due to the need to mitigate environmental pollution caused as result of extensive use of fossil fuels. However, currently, the high production cost limits the industrial application of lipases. In order to address this issue, we have attempted to optimize lipase production by Fusarium solani NFCCL 4084 and using palm oil mill effluent (POME) based medium. The production was optimized using a combinatory approach of Plackett-Burman (PB) design, one factor at a time (OFAT) design and face centred central composite design (FCCCD). The variables (malt extract, (NH4)2SO4, CaCl2, MgSO4, olive oil, peptone, K2HPO4, NaNO3, Tween-80, POME and pH) were analyzed using PB design and the variables with positive contrast coefficient were found to be K2HPO4, NaNO3, Tween-80, POME and pH. The significant variables selected were further analyzed for possible optimum range by using OFAT approach and the findings revealed that K2HPO4, NaNO3, and Tween-80 as the most significant medium components, and thus were further optimized by using FCCCD. The optimum medium yielded a lipase with an activity of 7.8 U/ml, a significant 3.2-fold increase compared to un-optimized medium. The present findings revealed that POME is an alternative and suitable substrate for halophilic lipase production at low cost. Also, it is clearly evident that the combinatory approach employed here proved to be very effective in producing high activity halophilic lipases, in general.

Lipases obtained from orange wastes: Commercialization potential and biochemical properties of different varieties and fractions

Brazil is the world's leading orange supplier for juice production purposes. However, the production process generates high amount of wastes, which leads to disposal problems. Orange wastes can be used for lipases production, incorporating the biorefinery concept into juice industries. Thus, the aim of the present study was to investigate the wastes of orange production chain as source of lipases based on different varieties (Pera, Hamlin, Valencia, and Natal), as well as on different fractions of wastes. The mass balance of the juice/wastes (2007-2016 crops) was evaluated, and lipases from different varieties and fraction were biochemically characterized. Overall, the wastes corresponded to approximately 43% of the fruit mass. All the fractions of all varieties showed lipase activity in emulsified olive oil and in p-nitrophenyl substrates. The highest lipase activities were obtained by Natal pulp in emulsified olive oil, Natal frit, and Hamlin peel in p-NPB and Hamlin frit in p-NPL and p-NPP. The bagasse, peel, and frit lipases from the different orange varieties showed optimum pH from 6.0 to 8.0 and optimal temperature from 30 °C to 60 °C. Thus, it is possible concluding that the orange processing for juice production purposes generates a large amount of wastes, which can be destined to profitable purposes as lipases production. Lipases produced by different fractions and varieties are biochemically diverse, enabling the application a wide range of processes. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2734, 2019.

Solvent-Free Biodiesel Production Catalyzed by Crude Lipase Powder from Seeds: Effects of Alcohol Polarity, Glycerol, and Thermodynamic Water Activity

The aim of this work was to evaluate the potential of crude lipase powders made from Adansonia grandidieri and Jatropha mahafalensis seeds for the synthesis of fatty acid alkyl esters in a solvent-free system. The influence of the nature of the alcohol, the amount of glycerol, and hydration of the powder was investigated. Results showed that the activity of these crude lipase powders was inversely proportional to the alcohol polarity and the amount of the glycerol in the reaction medium. To ensure optimum activity, A. grandidieri and J. mahafalensis powders must be conditioned to a water activity of 0.33 and 0.66. To obtain a fatty acid ethyl ester yield greater than 95% with A. grandidieri, ethanol should be introduced at an amount corresponding to a triacylglycerol to ethanol molar ratio of 2:1 every 15 h for 96 h and use 25% of preconditioned crude lipase powders (2 additions of 12.5%).