Thermophilic lipase from Thermomyces lanuginosus: Gene cloning, expression and characterization

Improved deinking and biobleaching efficiency of enzyme consortium from Thermomyces lanuginosus VAPS25 using genetic Algorithm-Artificial neural network based tools

The present study reports the combined enzymatic production efficiency of thermophilic fungus Thermomyces lanuginosus VAPS25 using a combinatory artificial intelligence-based tool, resulting in 2.7 IU/ml, 5.2 IU/ml, and 18.85 U/ml activity of endoglucanase, amylase, and lipase, respectively with good thermostability at 90 °C (pH 8-10). Interestingly, the metal ions viz. Cu²⁺ and Mg²⁺ increased the endoglucanase activity to 5 folds, i.e.,5.6 IU/ml compared to control. Further, the amylase and lipase activity was also enhanced by Fe²⁺ and Co²⁺ to 5.4 IU/ml and 19.57 U/ml, respectively. Additionally, the deinking efficiency was improved by 68.9%, 42.7%, and 52.8% by endoglucanase, amylase, and lipase, respectively, while the consortium increased the deinking efficiency to 72.7%. The bio-bleached paper strength parameters such as burst index, breaking length, tear index, and tensile index of sheets were significantly improved by 1.38%, 13.54%, 7.54%, and 20.88%, respectively. These enzymes at an industrial scale would help develop an economical paper recycling process.

Application of surfactants in papermaking industry and future development trend of green surfactants

In this work, the application of chemical surfactants, including cooking aids, detergents, surface sizing agents, and deinking agents as core components, is introduced in the wet end of pulping and papermaking. This method for the combined application of enzymes and surfactants has expanded, promoting technological updates and improving the effect of surfactants in practical applications. Finally, the potential substitution of green surfactants for chemical surfactants is discussed. The source, classification, and natural functions of green surfactants are introduced, including plant extracts, biobased surfactants, fermentation products, and woody biomass. These green surfactants have advantages over their chemically synthesized counterparts, such as their low toxicity and biodegradability. This article reviews the latest developments in the application of surfactants in different paper industry processes and extends the methods of use. Additionally, the application potential of green surfactants in the field of papermaking is discussed. KEY POINTS: • Surfactants as important chemical additives in papermaking process are reviewed. • Deinking technologies by combined of surfactants and enzymes are reviewed. • Applications of green surfactant in papermaking industry are prospected.

Characterization of a novel sn1,3 lipase from Ricinus communis L. suitable for production of oleic acid-palmitic acid-glycerol oleate

The hydrolysis properties of lipase in castor was evaluated using two different substrate forms (tripalmitic glycerides and trioleic glycerides) to catalyze the reaction under different operational conditions. RcLipase was obtained from castor seeds and results show that RcLipase is a conservative serine lipase with a conserved catalytic center (SDH) and a conserved pentapeptide (GXSXG). This enzyme exhibited the greatest activity and tolerance to chloroform and toluene when it was expressed in Pichia pastoris GS115 at 40 ℃ and pH 8.0. Zn and Cu ions exerted obvious inhibitory effects on the enzyme, and displayed good hydrolytic activity for long-chain natural and synthetic lipids. HPLC analysis showed that this enzyme has 1,3 regioselectivity when glycerol tripalmitate and oleic acid are used as substrates. The fatty acid composition in the reaction product was 21.3% oleic acid and 79.1% sn-2 palmitic acid.

Cell Surface Display of Thermomyces lanuginosus Lipase in Pichia pastoris

A cell surface displayed system in Pichia pastoris GS115 was developed by using GCW61, a glycosylphosphatidylinositol-modified cell wall protein from P. pastoris, as the anchor protein. Thermomyces lanuginosus lipase (TLL) was successfully displayed on the P. pastoris cell wall by fusing GCW61 gene with TLL2 gene (NCBI Accession: O59952) that was optimized with codon bias and synthesized. Cell surface displayed TLL2 was confirmed by the immunofluorescence microscopy. Flask fermentation was performed for 144 h with lipase activity up to 1964.76 U/g. Enzymatic properties of cell surface displayed TLL2 were also investigated. Displayed TLL2 occurred the maximum activity at pH 9 and 55°C and demonstrated characteristics of wide thermal adaptability and alkaline pH resistance. The optimum substrate was p-nitrophenyl hexanoate. Bivalent metal ions Ca²⁺, Mn²⁺, and Zn²⁺ had the activation effect on displayed TLL2, while Cu²⁺, Fe²⁺, Fe³⁺, K⁺, Li⁺, Na⁺, and Co²⁺ ions had the inhibitory effect on it. Since cell surface displayed TLL2 required less purification steps compared with free enzyme and showed high enzyme activities, it would be able to be further applied in various potential applications.

Kinetic Parameter Estimation and Mathematical Modelling of Lipase Catalysed Biodiesel Synthesis in a Microreactor

Development of green, clean, and sustainable processes presents new challenges in today’s science. Production of fuel is no exception. Considering the utilisation of various renewable sources, the synthesis of biodiesel, characterised as more environmentally-friendly then fossil fuel, has drawn significant attention. Even though the process based on chemical transesterification in a batch reactor still presents the most used method for its production, enzyme catalysed synthesis of biodiesel in a microreactor could be a new approach for going green. In this research, edible sunflower oil and methanol were used as substrates and lipase from Thermomyces lanuginosus (Lipolase L100) was used as catalyst for biodiesel synthesis. Experiments were performed in a polytetrafluoroethylene (PTFE) microreactor with three inlets and in glass microreactors with two and three inlets. For a residence time of 32 min, the fatty acids methyl esters (FAME) yield was 30% higher than the yield obtained for the glass microreactor with three inlets. In comparison, when the reaction was performed in a batch reactor (V = 500 mL), the same FAME yield was achieved after 1.5 h. In order to enhance the productivity of the process, we used proposed reaction kinetics, estimated kinetic parameters, and a mathematical model we developed. After validation using independent experimental data, a proposed model was used for process optimization in order to obtain the highest FAME yield for the shortest residence time.

Production optimization, characterization, and covalent immobilization of a thermophilic Serratia rubidaea lipase isolated from an Algerian oil waste

A new thermophilic non-induced lipase producer named Serratia rubidaea strain Nehal-mou was isolated from oil waste in Tissemsilat, Algeria. The most influential lipase production parameters were screened by the Plackett-Burman design for enhancing enzyme yield. An optimum condition of a 1.5% of glucose, a 0.01% of potassium, and a 0.025% of manganese contents resulted in a 41.13 U/mL. This yield was 6.29 times higher than the one achieved before the application of the Box-Behnken Design. Lipase activity showed a high organic solvent tolerance following its exposure to hexane, ethanol, methanol, and acetone. Lipase was also perfectly stable in the presence of 10 mM Fe²⁺, K⁺, and Na⁺ ions with more than 75% of the retaining activity. The enzyme half-life times were 22 h, 90 min, and 25 min at 50, 60, and 70 °C respectively. Polyvinyl alcohol (PVA)/boric acid/Starch/CaCO₃ were utilized as a carrier for lipase covalent immobilization in order to be used efficiently. The Scanning Electron Microscopy (SEM) Technique and the Fourier Transform Infrared Spectroscopy (FTIR) Method confirmed the covalent bonding success and the excellent carrier characteristics. Thus, the immobilization yield reached 73.5% and the optimum temperature was shifted from 40 to 65 °C. The immobilized lipase kept 80% of its total activity after 10 cycles and had 3 and 3.2-fold half-lives at 70, and 80 °C respectively compared to the free enzyme.

Integrated Functional-Omics Analysis of Thermomyces lanuginosus Reveals its Potential for Simultaneous Production of Xylanase and Substituted Xylooligosaccharides

Thermophiles have several beneficial properties for the conversion of biomass at high temperatures. Thermomyces lanuginosus is a thermophilic filamentous fungus that was shown to secrete 40 glycoside hydrolases and 25 proteases when grown on different carbon sources. Among the 13 identified glycoside hydrolases with high expression levels, 9 were reduced sugar glycosidases (RSGs) belonging to seven GH families, and 7 of the 10 identified proteases were exopeptidases belonging to six different protease families. High expression of RSGs and exopeptidases may allow the fungus to efficiently degrade oligosaccharides and oligopeptides in saprophytic habitats. There were no xylan side chain-degrading enzymes predicted in the genome of T. lanuginosus, and only one thermophilic GH11 xylanase (g4601.t1) and one GH43 xylosidase (g3706.t1) were detected by liquid chromatography-mass spectrometry/mass spectrometry when T. lanuginosus grown on xylan, which led to the accumulation of substituted xylooligosaccharides (SXOS) during corncob xylan degradation where SXOS output made up more than 8% of the total xylan. The SXOS are beneficial prebiotics and important inducers for enzymes secretion of microorganisms. Thus, T. lanuginosus exhibits distinct advantages in utilizing cheap raw materials producing one thermostable xylanase and the high value-added SXOS as well as microbial inoculants to compost by batch fermentation.

How the Triton X-100 modulates the activity/stability of the Thermomyces lanuginose lipase: Insights from experimental and molecular docking approaches

The lipase and Triton X-100 mixture is common for stabilization, immobilization and application processes of these kinds of enzymes. The objective of this article was to study the structural behavior and catalytic performance of Thermomyces lanuginose lipase in the presence of Triton X-100 at 25 °C and different pHs. The structural changes were followed by circular dichroism, correlating them with the catalytic performance, which is reported as the initial lipase activity in the hydrolysis of p‑nitro phenyl butyrate at zero time and residual activity after 48 h of incubation in the absence or presence of surfactant, at the selected pHs. Computational simulations allowed to explain the correlations between the physicochemical changes and the formation of surfactant protein complex, leading to the elucidation of the main interactions that drive activity and stability of this lipase in presence of the Triton X-100 surfactant. Main results showed the Triton X-100-enzyme complex modulates the site active geometry, favoring a better substrate-enzyme adjustment, which influences the activity and stability at evaluated pHs. This study contributes to understand the effect of some additives commonly used to improve the biocatalytic performance on several applications for different industrial fields.

Expression and characterization of thermotolerant lipase with broad pH profiles isolated from an Antarctic Pseudomonas sp strain AMS3

A gene encoding a thermotolerant lipase with broad pH was isolated from an Antarctic Pseudomonas strain AMS3. The recombinant lipase AMS3 was purified by single-step purification using affinity chromatography, yielding a purification fold of approximately 1.52 and a recovery of 50%. The molecular weight was approximately ∼60 kDa including the strep and affinity tags. Interestingly, the purified Antarctic AMS3 lipase exhibited broad temperature profile from 10-70 °C and stable over a broad pH range from 5.0 to pH 10.0. Various mono and divalent metal ions increased the activity of the AMS3 lipase, but Ni2+ decreased its activity. The purified lipase exhibited the highest activity in the presence of sunflower oil. In addition, the enzyme activity in 25% v/v solvents at 50 °C particularly to n-hexane, DMSO and methanol could be useful for catalysis reaction in organic solvent and at broad temperature.

Efficient heterologous expression of Fusarium solani lipase, FSL2, in Pichia pastoris, functional characterization of the recombinant enzyme and molecular modeling

The gene coding for a lipase of Fusarium solani, designated as FSL2, shows an open reading frame of 906bp encoding a 301-amino acid polypeptide with a molecular mass of 30kDa. Based on sequence similarity with other fungal lipases, FSL2 contains a catalytic triad, consisting of Ser144, Asp198, and His256. FSL2 cDNA was subcloned into the pGAPZαA vector containing the Saccharomyces cerevisiae α-factor signal sequence and this construct was used to transform Pichia pastoris and achieve a high-level extracellular production of a FSL2 lipase. Maximum lipase activity was observed after 48h. The optimum activity of the purified recombinant enzyme was measured at pH 8.0-9.0 and 37°C. FSL2 is remarkably stable at alkaline pH values up to 12 and at temperatures below 40°C. It has high catalytic efficiency towards triglycerides with short to long chain fatty acids but with a marked preference for medium and long chain fatty acids. FSL2 activity is decreased at sodium taurodeoxycholate concentrations above the Critical Micelle Concentration (CMC) of this anionic detergent. However, lipase activity is enhanced by Ca²⁺ and inhibited by EDTA or Cu²⁺ and partially by Mg²⁺ or K⁺. In silico docking of medium chain triglycerides, monogalctolipids (MGDG), digalactolipids (DGDG) and long chain phospholipids in the active site of FSL2 reveals structural solutions.

Enhanced production of Thermomyces lanuginosus lipase in Pichia pastoris via genetic and fermentation strategies

This study attempted to enhance the expression level of Thermomyces lanuginosus lipase (TLL) in Pichia pastoris using a series of strategies. The tll gene was first inserted into the expression vector pPIC9 K and transformed into P. pastoris strain GS115. The maximum hydrolytic activity of TLL reached 4,350 U/mL under the optimal culture conditions of a 500 mL shaking flask containing 20 mL culture medium with the addition of 1.2 % (w/v) methanol, cultivation for 144 h at pH 7.0 and 27 °C. To further increase the TLL expression and copy number, strains containing two plasmids were obtained by sequential electroporation into GS115/9k-TLL #3 with a second vector, either pGAPZαA-TLL, pFZα-TLL, or pPICZαA-TLL. The maximum activity of the resultant strains GS115/9KTLL-ZαATLL #40, GS115/9KTLL-FZαATLL #46 and GS115/9KTLL-GAPTLL #45 was 6,600 U/mL, 6,000 U/mL and 4,800 U/mL, respectively. The tll copy number in these strains, as assessed by real-time quantitative PCR, was demonstrated to be seven, five, and three, respectively, versus two copies in GS115/9k-TLL #3. When a co-feeding strategy of sorbitol/methanol was adopted in a 3-L fermenter, the maximum TLL activity of GS115/9k-TLL #3 increased to 27,000 U/mL after 130 h of fed-batch fermentation, whereas, the maximum TLL activity was 19,500 U/mL after 145 h incubation when methanol was used as the sole carbon source.

Efficient production of biodiesel from waste grease: one-pot esterification and transesterification with tandem lipases

A novel concept and efficient method for producing biodiesel (FAME) from grease (15-40wt% free fatty acid, FFA) were developed by using tandem lipases for one-pot esterification of FFA and transesterification of triglyceride with methanol in a solvent-free system. Combining immobilized Candida antarctica lipase B (CALB) (Novozyme 435) favoring the esterification and immobilized Thermomyces lanuginosus lipase (TLL) (Lipozyme TLIM) preferring the transesterification at 2:8 (wt/wt) gave FAME in 80% yield, being better than that with Novozyme 435 or Lipozyme TLIM. Recombinant Escherichia coli (Calb/Tll) co-expressing CALB and TLL was engineered as a more efficient tandem-lipases system. Using wet or dry cells (4wt%) gave FAME in 87% or 95% yield, which is much better than that with E. coli cells expressing either CALB or TLL alone. Cells of E. coli (Calb/Tll) were recycled for five times and retained 75% productivity, thus being practical for producing biodiesel from grease.

Thermorecovery of cyanobacterial fatty acids at elevated temperatures

We have developed a genetic system we call "thermorecovery" that allows us to lyse cyanobacterial cultures and hydrolyze membrane lipids to release free fatty acids (FFAs), a biofuel precursor. The system uses thermostable lipases encoded by genes from thermophilic organisms that have been transferred into the cyanobacterial genome and can be synthesized by turning off CO(2) availability and subsequently activated by increasing the concentrated culture temperature. When synthesized in FFA-producing strains, the lipase Fnl from Fervidobacterium nodosum Rt17-B1 released the most FFA. Of the seven candidate lipases investigated, Fnl-synthesizing strains yielded 42.7±1.5 mg/l FFA at 47°C. We also determined that the optimal production conditions for SD338, the Synechocystis strain synthesizing Fnl, was to keep the cell concentrates at 46°C for two days after a one-day CO(2) limitation pretreatment of the culture. A 4-l continuous semi-batch production experiment with SD338 showed that daily harvested cultures (1l) released an average of 43.9±6.6 mg fatty acid and this productivity lasted for at least 20 days without significant decline. This improved thermorecovery process can be used in conjunction with other means to genetically engineer cyanobacteria to produce biofuels or biofuel precursors as the final step in recovery of membrane lipids.