Effect of Treatment with Compressed Propane on Lipases Hydrolytic Activity

Activity and stability of lipase from Candida Antarctica after treatment in pressurized fluids

Lipase B from Candida antarctica (CalB) is one of the biocatalysts most used in organic synthesis due to its ability to act in several medium, wide substrate specificity and enantioselectivity, tolerance to non-aqueous environment, and resistance to thermal deactivation. Thus, the objective of this work was to treat CalB in supercritical carbon dioxide (SC-CO₂) and liquefied petroleum gas (LPG), and measure its activity before and after high-pressure treatment. Residual specific hydrolytic activities of 132% and 142% were observed when CalB was exposed to SC-CO₂ at 35 ℃, 75 bar and 1 h and to LPG at 65 ℃, 30 bar and 1 h, respectively. Residual activity of the enzyme treated at high pressure was still above 100% until the 20th day of storage at low temperatures. There was no difference on the residual activity loss of CalB treated with LPG and stored at different temperatures over time. Greater difference was observed between CalB treated with CO₂ and flash-frozen in liquid nitrogen (- 196 ℃) followed by storage in freezer (- 10 ℃) and CalB stored in freezer at - 10 ℃. Such findings encourage deeper studies on CalB as well as other enzymes behavior under different types of pressurized fluids aiming at industrial application.

Supplementation of Bile Acids and Lipase in Broiler Diets for Better Nutrient Utilization and Performance: Potential Effects and Future Implications – A Review

Bile acids are used for better emulsification, digestion and absorption of dietary fat in chicken, especially in early life. Similarly, exogenous lipases have also been used for the improvement of physiological limitation of the chicken digestive system. Owing to potential of both bile acids and lipases, their use has been increased in recent years, for better emulsification of dietary fat and improvement of growth performance in broilers. In the past, pancreatic lipases were used for supplementation, but recently, microbial lipase is getting attention in poultry industry as a hydrolysis catalyst. Bile acids strengthen the defence mechanism of body against bacterial endotoxins and also play a key role in lipid regulation and sugar metabolism as signaling molecules. It has been demonstrated that bile acids and lipases may improve feed efficiency by enhancing digestive enzyme activity and ultimately leading to better fat digestion and absorption. Wide supplemental range of bile acids (0.004% to 0.25%) and lipases (0.01% to 0.1%) has been used in broiler diets for improvement of fat digestibility and their performance. Combinations of different bile acids have shown more potential to improve feed efficiency (by 7.14%) even at low (0.008%) levels as compared to any individual bile acid. Lipases at a lower level of 0.03% have exhibited more promising potential to improve fat digestibility and feed efficiency. However, contradicting results have been published in literature, which needs further investigations to elucidate various nutritional aspects of bile acids and lipase supplementation in broiler diet. This review focuses on providing insight on the mechanism of action and potential application of bile acids and lipases in broiler diets. Moreover, future implications of these additives in poultry nutrition for enhancing nutrient utilization and absorption are also discussed.

Investigating the effect of starch/Fe3O4 nanoparticles on biodesulfurization using molecular dynamic simulation

The application of dibenzothiophene (DBT) as a source of energy leads to air pollution. The key solution to overcome this drawback is desulfurization. Magnetic nanoparticles have shown an excellent performance in the desulfurization of dibenzothiophene. In this study, molecular dynamic (MD) simulation was considered for the first time to gain insight about the molecule interactions in the biodesulfurization (BDS) process of DBT using Rhodococcus erythropolis IGTS8, in the presence and absence of starch/magnetic nanoparticles. According to the MD simulation results, the density of the system in the presence of starch/Fe₃O₄ was ascending while in the absence of these nanoparticles, the density was descending. Starch/magnetic nanoparticles caused more rapid equilibrium state in the biodesulfurization process. The energy diagram showed that magnetic nanoparticles decrease the energy fluctuation and increase the difference of non-bounding energy and potential energy (8 times) compared to (BDS) without nanoparticle, which reflects higher bounded energy in the system using starch/magnetic nanoparticles. The height of RDF peak in the presence of starch/Fe₃O₄ was 4 times more than the RDF peak in the absence of nanoparticle. In addition, the nanoparticles decreased the fluctuations around optimal temperature in BDS up to 5% compared to other state.

Effect of starch/CNT on biodesulfurization using molecular dynamic simulation

Nowadays, fossil fuel is the most important source of energy. However, the sulfur oxide release through oxidation of the available sulfur and the resultant air pollution has turned into an issue. In biodesulfurization (BDS) process, the sulfur from the recalcitrant organic compounds dissolved in crude oil fractions will be removed biologically. Carbon nanotubes (CNTs) exhibit good catalytic performance in dibenzothiophene (DBT) oxidation. Molecular dynamic simulation is the best and the only way to reach this end. Through this study, molecular dynamic simulations are applied to compute the effects of starch/CNTs on BDS process of DBT during 5 ns. The changes of cell length, energy, dynamic temperature, relative concentration of DBT, and radial distribution function (RDF) in the absence and presence of starch/CNTs were investigated. Regarding to the energy diagram, the fluctuation because of temperature fluctuations reaches the stable state. The high level of the first peak in RDF diagram showed the high and long desulfurization by microorganism. All the results showed stable and reasonable equilibrium state of the system. According to the graphs, the simultaneous in the presence of starch/CNT and Rhodococcus erythropolis increase the removal efficiency of nitrate reached 85% and in the absence of nanoparticle was 35.44%.

X-Ray Crystallography as a Tool to Determine Three-Dimensional Structures of Commercial Enzymes Subjected to Treatment in Pressurized Fluids

The study of enzyme function often involves a multi-disciplinary approach. Several techniques are documented in the literature towards determining secondary and tertiary structures of enzymes, and X-ray crystallography is the most explored technique for obtaining three-dimensional structures of proteins. Knowledge of three-dimensional structures is essential to understand reaction mechanisms at the atomic level. Additionally, structures can be used to modulate or improve functional activity of enzymes by the production of small molecules that act as substrates/cofactors or by engineering selected mutants with enhanced biological activity. This paper presentes a short overview on how to streamline sample preparation for crystallographic studies of treated enzymes. We additionally revise recent developments on the effects of pressurized fluid treatment on activity and stability of commercial enzymes. Future directions and perspectives on the the role of crystallography as a tool to access the molecular mechanisms underlying enzymatic activity modulation upon treatment in pressurized fluids are also addressed.

Expression and characterization of a lipase-related protein in the malpighian tubules of the Chinese oak silkworm, Antheraea pernyi

Lipases are ubiquitous enzymes in nature, which play a crucial role in fat metabolism by catalyzing the hydrolysis of triacylglycerol to free fatty acids and glycerol. However, reports concerning insect lipase are rare. In this study, we studied the expression and activity of a lipase-related protein from Antheraea pernyi (ApLRP). Recombinant ApLRP was expressed in Escherichia coli cells and used to raise rabbit anti-ApLRP polyclonal antibodies. ApLRP mRNA and protein expression were abundant in the midgut and malpighian tubules, respectively. After challenge with four different microorganisms (E. coli, Beauveria bassiana, Micrococcus luteus and nuclear polyhedrosis virus), the expression levels of ApLRP mRNA in midgut were inducted significantly compared with the control. The different pathogens induced different ApLRP gene expression patterns. The optimum temperature and pH for the enzyme's activity were 35°C and 7.0, respectively. ApLRP activity was stimulated in the presence of Mg2+, Na+, Ca2+ and b-mercaptoethanol; while Zn2+, Cu2+ and Fe3+ inhibited its activity. Detergents such as SDS, glycerol and Tween-20 increased the lipase activity by 20-30%. Our results indicated that ApLRP might play an important role in the innate immunity of insects.

Analysis of Comparative Sequence and Genomic Data to Verify Phylogenetic Relationship and Explore a New Subfamily of Bacterial Lipases

Thermostable and organic solvent-tolerant enzymes have significant potential in a wide range of synthetic reactions in industry due to their inherent stability at high temperatures and their ability to endure harsh organic solvents. In this study, a novel gene encoding a true lipase was isolated by construction of a genomic DNA library of thermophilic Aneurinibacillus thermoaerophilus strain HZ into Escherichia coli plasmid vector. Sequence analysis revealed that HZ lipase had 62% identity to putative lipase from Bacillus pseudomycoides. The closely characterized lipases to the HZ lipase gene are from thermostable Bacillus and Geobacillus lipases belonging to the subfamily I.5 with ≤ 57% identity. The amino acid sequence analysis of HZ lipase determined a conserved pentapeptide containing the active serine, GHSMG and a Ca²⁺-binding motif, GCYGSD in the enzyme. Protein structure modeling showed that HZ lipase consisted of an α/β hydrolase fold and a lid domain. Protein sequence alignment, conserved regions analysis, clustal distance matrix and amino acid composition illustrated differences between HZ lipase and other thermostable lipases. Phylogenetic analysis revealed that this lipase represented a new subfamily of family I of bacterial true lipases, classified as family I.9. The HZ lipase was expressed under promoter P_lac using IPTG and was characterized. The recombinant enzyme showed optimal activity at 65°C and retained ≥ 97% activity after incubation at 50°C for 1h. The HZ lipase was stable in various polar and non-polar organic solvents.

Synthesis of fructooligosaccharides from Aspergillus niger commercial inulinase immobilized in montmorillonite pretreated in pressurized propane and LPG

Commercial inulinase from Aspergillus niger was immobilized in montmorillonite and then treated in pressurized propane and liquefied petroleum gas (LPG). Firstly, the effects of system pressure, exposure time, and depressurization rate, using propane and LPG, on enzymatic activity were evaluated through central composite design 2³. Residual activities of 145.1 and 148.5% were observed for LPG (30 bar, 6 h, and depressurization rate of 20 bar min⁻¹) and propane (270 bar, 1 h, and depressurization rate of 100 bar min⁻¹), respectively. The catalysts treated at these conditions in both fluids were then used for the production of fructooligosaccharides (FOS) using sucrose and inulin as substrates in aqueous and organic systems. The main objective of this step was to evaluate the yield and productivity in FOS, using alternatives for enhancing enzyme activity by means of pressurized fluids and also using low-cost supports for enzyme immobilization, aiming at obtaining a stable biocatalyst to be used for synthesis reactions. Yields of 18% were achieved using sucrose as substrate in aqueous medium, showing the potential of this procedure, hence suggesting a further optimization step to increase the process yield.

Deciphering the metabolic capabilities of a lipase producing Pseudomonas aeruginosa SL-72 strain

Pseudomonads have been reported for their metabolic, nutritional and ecological versatility, which motivated us to prospect the metabolic profile of a lipolytic strain Pseudomonas aeruginosa SL-72. The strain SL-72 was found to produce high levels of lipase and pectinase (1,555.62 IU/mL and 1,490.33 IU/mL, respectively), esterase and amylase, besides low levels of xylanase, proteinase and cellulase. The strain also tested positive for different plant growth-promoting traits-production of ammonia, hydrogen cyanide, siderophores, phosphate solubilization, nitrate reduction and antifungal activity. The high levels of activity of aryl sulphatase, alkaline phosphatase and fluorescein diacetate hydrolase makes it a useful strain for enhanced nutrient cycling in soil. The strain SL-72 produced rhamnolipids, a biosurfactant and its production was enhanced when starch was used as carbon source (0.256 g/L) and utilized polycyclic hydrocarbon compounds viz. anthracene, phenanthrene, pyrene, fluorene and its mixture. The multifaceted nature of the culture illustrates its promise in bioremediation, industry, besides its use as an inoculant.

Overview of fungal lipase: a review

Lipases (triacylglycerolacyl hydrolases, EC3.1.1.3) are class of enzymes which catalyze the hydrolysis of long-chain triglycerides. In this review paper, an overview regarding the fungal lipase production, purification, and application is discussed. The review describes various industrial applications of lipase in pulp and paper, food, detergent, and textile industries. Some important lipase-producing fungal genera include Aspergillus, Penicillium, Rhizopus, Candida, etc. Current fermentation process techniques such as batch, fed-batch, and continuous mode of lipase production in submerged and solid-state fermentations are discussed in details. The purification of lipase by hydrophobic interaction chromatography is also discussed. The development of mathematical models applied to lipase production is discussed with special emphasis on lipase engineering.