Cloning, expression and characterisation of phospholipase B from Saccharomyces cerevisiae and its application in the synthesis of l-alpha-glycerylphosphorylcholine and peanut oil degumming

A novel thermo-responsive phospholipase A1 with high selectivity and efficiency in enzymatic oil degumming

The limited availability of phospholipase A1 (PLA1) has posed significant challenges in enzymatic degumming. In this study, a novel PLA1 (UM2) was introduced to address this limitation, which had a unique thermo-responsive ability to switch phospholipase and lipase activities in response to temperature variations. Remarkably, UM2 displayed an unprecedented selectivity under optimized conditions, preferentially hydrolyzing phospholipids over triacylglycerols-a specificity superior to that of commercial PLA1. Moreover, UM2 demonstrated high efficiency in hydrolyzing phospholipids with a predilection for phosphatidylcholine (PC) and phosphatidylethanolamine (PE). A practical application of UM2 on crude flaxseed oil led to a dramatic reduction in phosphorus content, plummeting from an initial 384.06 mg/kg to 4.38 mg/kg. Broadening its industrial applicability, UM2 effectively performed enzymatic degumming for other distinct crude vegetable oils with a unique phospholipid composition. Collectively, these results highlighted the promising application of UM2 in the field of oil degumming.

Monoacylglycerol lipase from marine Geobacillus sp. showing lysophospholipase activity and its application in efficient soybean oil degumming

Enzymatic degumming is an essential refining process to improve oil quality. In this study, a monoacylglycerol lipase GMGL was derived from marine Geobacillus sp., and was found that not only took monoacylglycerol (MAG) as substrate, but also had activity toward lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE) and glycerolphosphatidylcholine (GPC). Binding free energy showed LPC and LPE could bind with enzyme stably as MAG. It presented great potential in the field of enzymatic degumming. The phosphorus content in crude soybean oil decreased from 680.50 to 2.01 mg/kg and the yield of oil reached to 98.80 % after treating with phospholipase A1 (Lecitase Ultra) combined with lipase GMGL. An ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed to identify 21 differential phospholipids between crude soybean oil and enzymatic treatment. This work might shed some light on understanding the catalytic mechanism of monoacylglycerol lipase and provide an effective strategy for enzymatic degumming.

Enhancing Soluble Expression of Phospholipase B for Efficient Catalytic Synthesis of L-Alpha-Glycerylphosphorylcholine

Phospholipase B (PLB) harbors three distinct activities with broad substrate specificities and application fields. Its hydrolyzing of sn-1 and sn-2 acyl ester bonds enables it to catalyze the production of L-alpha-glycerylphosphorylcholine (L-α-GPC) from phosphatidylcholine (PC) without speed-limiting acyl migration. This work was intended to obtain high-level active PLB and apply it to establish an efficient system for L-α-GPC synthesis. PLB from Pseudomonas fluorescens was co-expressed with five different molecular chaperones, including trigger factor (Tf), GroEL-GroES (GroELS), DnaK-DnaJ-GrpE (DnaKJE), GroELS and DnaKJE, or GroELS and Tf or fused with maltose binding protein (MBP) in Escherichia coli BL21(DE3) to improve PLB expression. PLB with DnaKJE-assisted expression exhibited the highest catalytic activity. Further optimization of the expression conditions identified an optimal induction OD600 of 0.8, IPTG concentration of 0.3 mmol/L, induction time of 9 h, and temperature of 25 °C. The PLB activity reached a maximum of 524.64 ± 3.28 U/mg under optimal conditions. Subsequently, to establish an efficient PLB-catalyzed system for L-α-GPC synthesis, a series of organic-aqueous mixed systems and surfactant-supplemented aqueous systems were designed and constructed. Furthermore, the factors of temperature, reaction pH, metal ions, and substrate concentration were further systematically identified. Finally, a high yield of 90.50 ± 2.21% was obtained in a Span 60-supplemented aqueous system at 40 °C and pH 6.0 with 0.1 mmol/L of Mg2+. The proposed cost-effective PLB production and an environmentally friendly PLB-catalyzed system offer a candidate strategy for the industrial production of L-α-GPC.

Bright Side of Fusarium oxysporum: Secondary Metabolites Bioactivities and Industrial Relevance in Biotechnology and Nanotechnology

Fungi have been assured to be one of the wealthiest pools of bio-metabolites with remarkable potential for discovering new drugs. The pathogenic fungi, Fusarium oxysporum affects many valuable trees and crops all over the world, producing wilt. This fungus is a source of different enzymes that have variable industrial and biotechnological applications. Additionally, it is widely employed for the synthesis of different types of metal nanoparticles with various biotechnological, pharmaceutical, industrial, and medicinal applications. Moreover, it possesses a mysterious capacity to produce a wide array of metabolites with a broad spectrum of bioactivities such as alkaloids, jasmonates, anthranilates, cyclic peptides, cyclic depsipeptides, xanthones, quinones, and terpenoids. Therefore, this review will cover the previously reported data on F. oxysporum, especially its metabolites and their bioactivities, as well as industrial relevance in biotechnology and nanotechnology in the period from 1967 to 2021. In this work, 180 metabolites have been listed and 203 references have been cited.

Efficient production of a novel alkaline cold-active phospholipase C from Aspergillus oryzae by molecular chaperon co-expression for crude oil degumming

A novel alkaline cold-active phospholipase C (PLC) gene (AoPC) from Aspergillus oryzae was cloned. AoPC exhibited the highest sequence similarity of 32.5% with that of a PLC from Arabidopsis thaliana. The gene was co-expressed in Pichia pastoris with molecular chaperone PDI (protein disulfide isomerases), and the highest PLC activity of 82, 782 U mL^-1 was achieved in a 5-L fermentor. The recombinant enzyme (AoPC) was most active at pH 8.0 and 25 °C, respectively, and it was stable over a broad pH range of 4.5-9.0 and up to 40 °C. It is the first fungal alkaline PLC. The application of AoPC (with 25% citric acid, w/w) in oil degumming process significantly reduced the phosphorus of crude soybean oil by 93.3% to a commercially acceptable level (<10 mg kg^-1). Therefore, the relatively high yield and excellent properties of AoPC may possess it great potential in crude oil refining industry.

Enhancing the thermostability of phospholipase D from Streptomyces halstedii by directed evolution and elucidating the mechanism of a key amino acid residue using molecular dynamics simulation

To enhance the thermostability of phospholipase D (PLD), error-prone polymerase chain reaction method was used to create mutants of PLD (PLD_sh) from Streptomyces halstedii. One desirable mutant (S163F) with Ser to Phe substitution at position 163 was screened with high-throughput assay. S163F exhibited a 10 °C higher optimum temperature than wild-type (WT). Although WT exhibited almost no activity after incubating at 50 °C for 40 min, S163F still displayed 27% of its highest activity after incubating at 50 °C for 60 min. Furthermore, the half-life of S163F at 50 °C was 3.04-fold higher than that of WT. The analysis of molecular dynamics simulation suggested that the Ser163Phe mutation led to the formation of salt bridge between Lys300 and Glu314 and a stronger hydrophobic interaction of Phe163 with Pro341, Leu342, and Trp460, resulting in an increased structural rigidity and overall enhanced stability at high temperature. This study provides novel insights on PLD tolerance to high temperature by investigating the structure-activity relationship. In addition, it provides strong theoretical foundation and preliminary information on the engineering of PLD with improved characteristics to meet industrial demand.

A Thermolabile Phospholipase B from Talaromyces marneffei GD-0079: Biochemical Characterization and Structure Dynamics Study

Phospholipase B (EC 3.1.1.5) are a distinctive group of enzymes that catalyzes the hydrolysis of fatty acids esterified at the sn-1 and sn-2 positions forming free fatty acids and lysophospholipids. The structural information and catalytic mechanism of phospholipase B are still not clear. Herein, we reported a putative phospholipase B (TmPLB1) from Talaromyces marneffei GD-0079 synthesized by genome mining library. The gene (TmPlb1) was expressed and the TmPLB1 was purified using E. coli shuffle T7 expression system. The putative TmPLB1 was purified by affinity chromatography with a yield of 13.5%. The TmPLB1 showed optimum activity at 35 °C and pH 7.0. The TmPLB1 showed enzymatic activity using Lecithin (soybean > 98% pure), and the hydrolysis of TmPLB1 by ³¹P NMR showed phosphatidylcholine (PC) as a major phospholipid along with lyso-phospholipids (1-LPC and 2-LPC) and some minor phospholipids. The molecular modeling studies indicate that its active site pocket contains Ser125, Asp183 and His215 as the catalytic triad. The structure dynamics and simulations results explained the conformational changes associated with different environmental conditions. This is the first report on biochemical characterization and structure dynamics of TmPLB1 enzyme. The present study could be helpful to utilize TmPLB1 in food industry for the determination of food components containing phosphorus. Additionally, such enzyme could also be useful in Industry for the modifications of phospholipids.