In Silico and Experimental Characterization of Chimeric Bacillus thermocatenulatus Lipase with the Complete Conserved Pentapeptide of Candida rugosa Lipase

In Silico and Experimental Studies on the Effect of α3 and α5 Deletion on the Biochemical Properties of Bacillus thermocatenulatus Lipase

To investigate the effect of α3 and α5 helices on the biochemical characterization of Bacillus thermocatenulatus lipase (BTL2), both helices were deleted from native BTL2 lipase. After structural modeling and characterization, the truncated btl2 gene (Δbtl2) was cloned into E. coli BL21 under the control of the T7 promoter. After cultivation and induction of the recombinant bacteria, the Δα3α5 lipase was purified by Ni-NTA column chromatography. Next, the biochemical properties of the Δα3α5 lipase were compared with the previously expressed and purified native lipase. In the presence of the substrate tributyrin (C4), the maximum activity of native and Δα3α5 lipase was 9360 and 5000 U/mg, respectively. The deletion changed the substrate specificity from tributyrin (C4) to tricaprylin (C8) substrate. Native and Δα3α5 lipase showed similar activity patterns at all temperatures and pH values, with the activity of Δα3α5 lipase being approximately 20% lower than native lipase. Triton X100 increased the activity of native and Δα3α5 lipases by 2.1- and 2.5-fold, respectively.

Structural features, temperature adaptation and industrial applications of microbial lipases from psychrophilic, mesophilic and thermophilic origins

Microbial lipases are very prominent biocatalysts because of their ability to catalyze a wide variety of reactions in aqueous and non-aqueous media. Here microbial lipases from different origins (psychrophiles, mesophiles, and thermophiles) have been reviewed. This review emphasizes an update of structural diversity in temperature adaptation and industrial applications, of psychrophilic, mesophilic, and thermophilic lipases. The microbial origins of lipases are logically dynamic, proficient, and also have an extensive range of industrial uses with the manufacturing of altered molecules. It is therefore of interest to understand the molecular mechanisms of adaptation to temperature in occurring lipases. However, lipases from extremophiles (psychrophiles, and thermophiles) are widely used to design biotransformation reactions with higher yields, fewer byproducts, or useful side products and have been predicted to catalyze those reactions also, which otherwise are not possible with the mesophilic lipases. Lipases as a multipurpose biological catalyst have given a favorable vision in meeting the needs of several industries such as biodiesel, foods, and drinks, leather, textile, detergents, pharmaceuticals, and medicals.

Identification of a Novel Lipase with AHSMG Pentapeptide in Hypocreales and Glomerellales Filamentous Fungi

Lipases are enzymes that hydrolyze triglycerides to fatty acids and glycerol. A typical element in lipases is a conserved motif of five amino acids (the pentapeptide), most commonly G-X-S-X-G. Lipases with the pentapeptide A-X-S-X-G are present in species of Bacillus, Paucimonas lemoignei, and the yeast Trichosporon asahii; they are usually thermotolerant and solvent resistant. Recently, while searching for true lipases in the Trichoderma harzianum genome, one lipase containing the pentapeptide AHSMG was identified. In this study, we cloned from T. harzianum strain B13-1 the lipase ID135964, renamed here as ThaL, which is 97.65% identical with the reference. We found that ThaL is a lid-containing true lipase of cluster III that belongs to a large family comprising highly conserved proteins in filamentous fungi in the orders Hypocreales and Glomerellales, in which predominantly pathogenic fungi are found. ThaL was expressed in conidia, as well as in T. harzianum mycelium, where it was cultured in liquid minimal medium. These results—together with the amino acid composition, absence of a signal peptide, mitochondrial sorting prediction, disordered regions in the protein, and lineage-specific phylogenetic distribution of its homologs—suggest that ThaL is a non-canonical effector. In summary, AHSMG-lipase is a novel lipase family in filamentous fungi, and is probably involved in pathogenicity.

Improving the thermostability of Serratia marcescens B4A chitinase via G191V site-directed mutagenesis

Chitinases with high thermostability are important for many industrial and biotechnological applications. This study was conducted to enhance the stability of Serratia marcescens B4A chitinase by site directed mutagenesis of G191 V. Further characterization showed that the thermal stability of the mutant showed marked increase of about 5 and 15 fold at 50 and 60 °C respectively, while the optimum temperature and pH was retained. Kinetic analysis showed decreased K_m and V_max of the mutant in comparison with the wild type chitinase of about 1.3 and 3 fold, respectively. Based on structural prediction, it was speculated that this replacement shortened an important loop concomitant with the extension of adjacent β sheets. Accordingly, a higher thermostability of G191 V up to 90 °C supporting the decreased flexibility of unfolded state was also indicated. Finally, a practical proof of kinetic and thermal stabilization of chitinase was provided through decreased flexibility and entropic stabilization of its surface loops.

Study the effect of F17S mutation on the chimeric Bacillus thermocatenulatus lipase

Lipases (triacylglycerol acylhydrolase, EC 3.1.1.3) are one of the highest value commercial enzymes as they have potential applications in biotechnology for detergents, food, pharmaceuticals, leather, textiles, cosmetics, and paper industries; and are currently receiving considerable attention because of their potential applications in biotechnology. Bacillus thermocatenulatus Lipase 2 (BTL2) is one of the most important research targets, because of its potential industrial applications. In this study, the effect of substitution Phe17 with Ser in mutated BTL2 lipase, which conserved pentapeptide (112Ala-His-Ser-Gln-Gly116) was replaced with similar sequences (207Gly-Glu-Ser-Ala-Gly211) of Candida rugosa lipase (CLR) at the nucleophilic elbow region. Docking results confirmed the mutated lipase to be better than the chimeric lipase. So, cloning was conducted, and the mutated and chimeric btl2 genes were expressed in Escherichia coli, and then the enzymes were purified by anion exchange chromatography. The mutation increased lipase lipolytic activity against most of the applied substrates, with the exception of tributyrin when compared with chimeric lipase. Further, the mutated lipase exhibited higher activity than the chimeric lipase at all temperatures. Optimum pH of the mutated lipase was obtained at pH 9.5, which was more than the chimeric one. Enzyme activity of the mutated lipase in the presence of organic solvents, detergents, and metal ions was also improved than the chimeric lipase.

Optimized production of biodiesel from waste cooking oil by lipase immobilized on magnetic nanoparticles

Biodiesel, a non-toxic and biodegradable fuel, has recently become a major source of renewable alternative fuels. Utilization of lipase as a biocatalyst to produce biodiesel has advantages over common alkaline catalysts such as mild reaction conditions, easy product separation, and use of waste cooking oil as raw material. In this study, Pseudomonas cepacia lipase immobilized onto magnetic nanoparticles (MNP) was used for biodiesel production from waste cooking oil. The optimal dosage of lipase-bound MNP was 40% (w/w of oil) and there was little difference between stepwise addition of methanol at 12 h- and 24 h-intervals. Reaction temperature, substrate molar ratio (methanol/oil), and water content (w/w of oil) were optimized using response surface methodology (RSM). The optimal reaction conditions were 44.2 °C, substrate molar ratio of 5.2, and water content of 12.5%. The predicted and experimental molar conversions of fatty acid methyl esters (FAME) were 80% and 79%, respectively.