Showing papers on "Lipase published in 1995"

Lipases with improved surfactant resistance

Abstract: The present invention provides mutant lipases which retain lipase activity, but have improved surfactant resistance and are thus highly advantageous for use in detergent compositions. Preferred lipases of this type include modified functional forms of a lipase of Pseudomonas alcaligenes having one or more amino acid substituents at or near the surface which effect interaction of the hydrophobic portions of surfactant molecules with initiation sites on the enzyme for surfactant denaturation.

Lipase, microorganism producing same, method for preparing said lipase and uses thereof

Abstract: A lipase from a Pseudomonas strain is disclosed. The lipase is active in a broad alkaline pH range. Novel microorganism strains producing the lipase, and methods for preparing said lipase, are also disclosed. In addition, the uses of the lipase and compositions containing same are disclosed.

Modified pseudomonas lipases and their use

Abstract: Lipase variants of a parent Pseudomonas lipase are provided, wherein the amino acid sequence has been modified in such way that the hydrophobicity at the surface of the enzyme has been increased. In particular, variants of lipase from Pseudomonas glumae and Pseudomonas alcaligenes are provided.

Analogs of reaction intermediates identify a unique substrate binding site in Candida rugosa lipase.

Abstract: The structures of Candida rugosa lipase-inhibitor complexes demonstrate that the scissile fatty acyl chain is bound in a narrow, hydrophobic tunnel which is unique among lipases studied to date. Modeling of triglyceride binding suggests that the bound lipid must adopt a "tuning fork" conformation. The complexes, analogs of tetrahedral intermediates of the acylation and deacylation steps of the reaction pathway, localize the components of the oxyanion hole and define the stereochemistry of ester hydrolysis. Comparison with other lipases suggests that the positioning of the scissile fatty acyl chain and ester bond and the stereochemistry of hydrolysis are the same in all lipases which share the alpha/beta-hydrolase fold.

Enzymatic ring-opening polymerization of lactones to polyesters by lipase catalyst : unusually high reactivity of macrolides

Abstract: Enzymatic ring-opening polymerization of macrolides was carried out by using various lipases as catalysts. The monomers used in this study were 11-undecanolide (12-membered, UDL) and 15-pentadecanolide (16-membered, PDL). Among the enzymes examined, lipases derived from Pseudomonas fluorescens (lipase P) and from Candida cylindracea (lipase B) gave polyUDL with high molecular weight in a high yield. From 1H and 13C NMR analysis, the polymer was found to possess the terminal structure of a carboxylic acid group at one end and a hydroxyl group at the other. The rate of the UDL polymerization using lipase P was larger than that using lipase B, whereas the polymerization of UDL using lipase B produced the polymer of higher molecular weight in comparison with that obtained by using lipase P. Lipases from Pseudomonas sp. and porcine pancreas showed a catalytic activity for the polymerization of UDL. PDL was also polymerized by lipase catalyst to give the corresponding polyester. The enzymatic polymerizations of...

Chemo-enzymatic epoxidation of unsaturated carboxylic acids

Abstract: Unsaturated carboxylic acids are converted to percarboxylic acids catalyzed by an immobilized lipase from Candida antarctica (Novozym 435 R ). These unsaturated percarboxylic acids are only intermediates and epoxidize themselves in good yields and almost without consecutive reactions. The mechanism of the oxygen-transfer is found to be predominantly intermolecular and the formation of the percarboxylic acids proceeds via two different catalytic reactions. The lipase is surprisingly stable under the reaction conditions; it is recovered and reused fifteen times to produce epoxy-stearic acid on a multi-gram scale.

Lipase-Catalyzed Ring-Opening Polymerization of 12-Dodecanolide

Abstract: Enzymatic ring-opening polymerization of a 13-membered lactone, 12-dodecanolide (DDL), was performed in bulk by using various lipases of different origin as catalyst. The polymerization using lipases derived from the Pseudomonas family proceeded faster than that using other lipases, producing the corresponding polymer in high yields. High polymerization temperature (75 °C) resulted in the formation of the polymer with molecular weight more than 1 x 10 4 . Among the enzymes examined, an immobilized Pseudomonas sp. lipase on the Celite showed the highest activities toward the polymerization. Lipase from Candida cylindracea also afforded poly(DDL) with high molecular weight. The polymerization behavior of DDL through enzyme catalysis has been compared with that of e-caprolactone (e-CL). The polymerization of DDL proceeded much faster than that of e-CL, the behavior of which may be due to the difference of the specificity in the enzymatic catalysis.

Substrate specificities of bacterial polyhydroxyalkanoate depolymerases and lipases: bacterial lipases hydrolyze poly(omega-hydroxyalkanoates)

Abstract: The substrate specificities of extracellular lipases purified from Bacillus subtilis, Pseudomonas aeruginosa, Pseudomonas alcaligenes, Pseudomonas fluorescens, and Burkholderia cepacia (former Pseudomonas cepacia) and of extracellular polyhydroxyalkanoate (PHA) depolymerases purified from Comamonas sp., Pseudomonas lemoignei, and P. fluorescens GK13, as well as that of an esterase purified from P. fluorescens GK 13, to various polyesters and to lipase substrates were analyzed. All lipases and the esterase of P. fluorescens GK13 but none of the PHA depolymerases tested hydrolyzed triolein, thereby confirming a functional difference between lipases and PHA depolymerases. However, most lipases were able to hydrolyze polyesters consisting of an omega-hydroxyalkanoic acid such as poly(6-hydroxyhedxanoate) or poly(4-hydroxybutyrate). The dimeric ester of hydroxyhexanoate was the main product of enzymatic hydrolysis of polycaprolactone by P. aeruginosa lipase. Polyesters containing side chains in the polymer backbone such as poly (3-hydroxybutyrate) and other poly(3-hydroxyalkanoates) were not or were only slightly hydrolyzed by the lipases tested.

Enzymatic preparation of biosurfactants from sugars or sugar alcohols and fatty acids in organic media under reduced pressure

Abstract: Biosurfactants were prepared by enzymatic esterification of sugars and sugar alcohols in nonaqueous media. Sorbitol monooleate was produced in pure molten substrates, with reduced pressure to remove water. The results were compared to synthesis in organic solvent, with and without water removal. Synthesis in organic solvent with water removal, obtained by refluxing through a desiccant under reduced pressure, proved to be the most efficient method in terms of total yield and side-products formation. This process was applied to the production of different surfactants, by changing the nature of the hydrophilic and hydrophobic moieties. Yields above 90% of monoesters were obtained after 24 h when the reaction was carried out in 2-methyl-2-butanol with Novozym 435 (Type B lipase from Candida antarctica) with an excess of hydroxyl donor.

Ontogenetic development of digestive enzyme activities in larval walleye pollock, Theragra chalcogramma

Abstract: Activities of digestive enzymes trypsin, amylase and lipase in laboratory-reared walleye pollock, Theragra chalcogramma, were measured from hatching to Day 39 (just before notochord flexion) in 1993. All measurements were conducted individually or semi-individually (groups of two larvae of the same standard length). Close relationships between digestive enzyme activities and morphological development of digestive organs were observed. Activities of trypsin and lipase were low during the transition period from endogenous to exogenous energy. Amylase activity was constant with large variance during the same period. Specific enzyme activities of trypsin and amylase indicated high values with large variance during the early period. All three enzyme activities increased with age afterthe transition period, and the specific enzyme activities became constant. The existence of two types of lipase was suggested. One lipase showed a peak of specific activity at Day 4 and might be related to yolk-sac absorption. The activity of the other lipase increased with age after Day 14 and might be related to digestion of prey lipid. Our results suggest that digestive enzymes included in food organisms supplement larval pollock digestive enzymes.

Enzymatic transesterification of palm olein with nonspecific and 1,3-specific lipases.

Abstract: The enzymatic transesterification of palm olein was conducted in a low-moisture medium with nonspecific and 1,3-specific lipases from microbial sources. The enzymes were first immobilized on Celite, lyophilized for 4 h and then added to a reaction medium that consisted of 10% (wt/vol) palm olein in water-saturated hexane. The catalytic performance of the enzymes was evaluated by determining the changes in triglyceride (TG) composition and concentrations by reverse-phase high-performance liquid chromatography (HPLC) and the formation of free fatty acids by titration. Studies with lipase fromCandida rugosa showed that the degree of hydrolysis was reduced by drying the immobilized preparation and that the best drying time was 4 h. In all cases, the transesterification process resulted in the formation of PPP, a TG initially undetected in the oil, and increases in the concentrations of OOO (1.3–2.1-fold), OOL (1.7–4.5-fold), and OLL (1.7–4.3-fold), where P, O, and L are palmitic, oleic, and linoleic acids, respectively. SOS (where S is stearic acid), another TG not detected in the oil, was synthesized byRhizomucor miehei andPseudomonas lipases, with the latter producing more of this TG. There was a corresponding decrease in the concentrations of POP, PLP, POO, and POL. PPP concentration ranged from 1.9% (w/w) forMucor javanicus lipase to 6.2% (w/w) forPseudomonas lipase after 24 h. The greatest degree and fastest rate of change were caused byPseudomonas lipase, followed by the enzymes fromR. miehei andAspergillus niger. The effects of transesterification and hydrolysis of palm olein by the various lipases resulted in changes in the overall degree of saturation of the triglyceride components. There seems to be no clear correlation between the enzyme positional specificity and the products formed. Possible mechanisms for the formation of PPP, OOL, OLL, OOO, and SOS are discussed.

Do organic solvents affect the catalytic properties of lipase? Intrinsic kinetic parameters of lipases in ester hydrolysis and formation in various organic solvents

Abstract: When it is assumed that organic solvents do not interfere with the binding process nor with the catalytic mechanism, the contribution of substrate-solvent interactions to enzyme kinetics can be accounted for by just replacing substrate concentrations in the equations by thermodynamic activities. It appears from the transformation that only the affinity parameters (K(m), K(sp)) are affected by this. Thus, in theory, the values of these corrected, intrinsic parameters (K(m) (int), k(sp) (int)) and the maximal rate (V(1)) should be equal for all media. This was tested for hydrolysis, transesterification, and esterification reactions catalyzed by pig pancreas lipase and Pseudomonas cepacia lipase in various organic solvents. Correction was carried out via experimentally determined activity coefficients for the substrates in these solvents or, if not feasible, from values in data bases. However, although the kinetic performances of each enzyme in the solvents became much more similar after correction, differences still remained. Analysis of the enzyme suspensions revealed massive particles, which explains the low activity of enzymes in organic solvents. However, no correlation was found between estimates of the amount of catalytically available enzyme (present at the surface of suspended particles or immobilized on beads) and the maximal rates observed. Moreover, the solvents had similar effects on the intrinsic parameters of suspended and immobilized enzyme. The possible causes for the effects of the solvents on the catalytic performance of the enzymes, remaining after correction for solvent-substrate interactions and the amount of participating enzyme, are discussed with respect to the premises on which the correction method is based. (c) 1995 John Wiley & Sons, Inc.

The three genes lipB, lipC, and lipD involved in the extracellular secretion of the Serratia marcescens lipase which lacks an N-terminal signal peptide.

Abstract: The extracellular lipase of Serratia marcescens Sr41, lacking a typical N-terminal signal sequence, is secreted via a signal peptide-independent pathway. The 20-kb SacI DNA fragment which allowed the extracellular lipase secretion was cloned from S. marcescens by selection of a phenotype conferring the extracellular lipase activity on the Escherichia coli cells. The subcloned 6.5-kb EcoRV fragment was revealed to contain three open reading frames which are composed of 588, 443, and 437 amino acid residues constituting an operon (lipBCD). Comparisons of the deduced amino acid sequences of the lipB, lipC, and lipD genes with those of the Erwinia chrysanthemi prtDEC, prtEEC, and prtFEC genes encoding the secretion apparatus of the E. chrysanthemi protease showed 55, 46, and 42% identity, respectively. The products of the lipB and lipC genes were 54 and 45% identical to the S. marcescens hasD and hasE gene products, respectively, which were secretory components for the S. marcescens heme-binding protein and metalloprotease. In the E. coli DH5 cells, all three lipBCD genes were essential for the extracellular secretion of both S. marcescens lipase and metalloprotease proteins, both of which lack an N-terminal signal sequence and are secreted via a signal-independent pathway. Although the function of the lipD gene seemed to be analogous to those of the prtFEC and tolC genes encoding third secretory components of ABC transporters, the E. coli TolC protein, which was functional for the S. marcescens Has system, could not replace LipD in the LipB-LipC-LipD transporter reconstituted in E. coli. These results indicated that these three proteins are components of the device which allows extracellular secretion of the extracellular proteins of S. marcescens and that their style is similar to that of the PrtDEF(EC) system.

A Lipid-Coated Lipase as an Enantioselective Ester Synthesis Catalyst in Homogeneous Organic Solvents

Abstract: The authors studied the enantioselective preparation of esters using lipase as catalyst. The surface of the lipase was coated with lipids to assist in directing the formation of the ester by solubilizing the hydrophobic incipient tail of the ester.

Cutinase from Fusarium solani pisi hydrolyzing triglyceride analogues. Effect of acyl chain length and position in the substrate molecule on activity and enantioselectivity.

Abstract: Triglyceride analogues were synthesized in which one of the primary acyl ester functions has been replaced by an alkyl group and the secondary acyl ester bond has been replaced by an acyl amino bond. The chain length at either position was varied, and both (R)- and (S)-enantiomers of each compound were synthesized. These pseudo triglycerides contain only one hydrolyzable ester bond, and they are ideally suited to studying the influence of the chain length at the 1-, 2-, and 3-position on lipase activity and on stereopreference. These substrates were used to characterize cutinase from Fusarium solani pisi. Our results show that the activity of cutinase is very sensitive to the length and distribution of the acyl chains and that the highest activities are found when the chains at positions 1 and 3 contain three or four carbon atoms. The enzyme preferentially hydrolyzes the (R)-enantiomers, but this preference is strongly dependent on the acyl chain length distribution, with (R) over (S) activity ratios varying from about 30 to 1. This enantioselectivity was found in three different assay systems: a mixed micellar, a reverse micellar, and a monolayer study. Our data suggest that at least two alkyl chains of the pseudo triglycerides must be fixed during hydrolysis. Therefore, these substrates were used to characterize mutants of cutinase with mutations in putative lipid binding domains. Two mutants (A85F and A85W) have increased activities. The results obtained with these mutants suggest an interaction of the acyl chain of the scissile ester bond with a surface loop, comprising residues 80-90, in the enzyme-substrate complex.

Working at controlled water activity in a continuous process: the gas/solid system as a solution.

Abstract: Fusarium solani cutinase and Candida cylindracea lipase were used to catalyze a transesterification reaction in a continuous gas/solid bioreactor. In this system, a solid phase composed of a packed enzymatic preparation was continuously percolated with carrier gas which fed substrate and removed reaction products simultaneously. Different conditions of immobilization were used and compared to the results obtained with a nonsupported enzyme. The enzymatic activity was found to be highly dependent of a key parameter: water activity (a(w)). Biocatalyst stability was greatly influenced by water activity and the choice of immobilization technique for the enzymatic material. For free and adsorbed enzymes, water requirements exhibited optima which corresponded to the complete hydration coverage of the protein. These optima presented a good correlation with the isotherm sorption curves obtained for the different preparations. In this work are reported the results concerning the possibility of using a continuous system able to operate at controlled water activity in a heterogeneous medium. Lipolytic enzyme in such a system appears to be a new process for the biotransformation of volatile esters.