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PubMed1987

Multiple effects of tumor necrosis factor on lipoprotein lipase in vivo.

A single dose of recombinant murine tumor necrosis factor (TNF) suppressed lipoprotein lipase activity in adipose tissue of fed rats, mice, and guinea pigs for 48 h, even though TNF itself is rapidly metabolized in vivo. Immunoprecipitation of [35S]lipoprotein lipase from fat pads pulse-labeled with [35S]methionine showed a decrease in relative synthesis of the enzyme, which correlated to the decrease in activity. There was no decrease in general protein synthesis and no change in distribution of the enzyme between adipocytes and extracellular locations in the tissue. This is in contrast to fasting in which case there is redistribution of the enzyme within the tissue, decrease in general protein synthesis, but no change in relative synthesis of lipoprotein lipase. TNF did not decrease lipoprotein lipase activity in any tissue other than the adipose but increased the activity in several cases, most markedly in the liver. No [35S]methionine was incorporated into lipoprotein lipase by liver slices from normal or TNF-treated animals. Thus, the increased activity can not be ascribed to enhanced hepatic synthesis of the enzyme. There was an increase in lipoprotein lipase activity in plasma, which correlated to the increase in liver. Thus, TNF suppresses lipoprotein lipase synthesis in adipocytes, but not in other tissues, and has some as yet undefined effect on lipoprotein lipase turnover in extrahepatic tissues, which results in increased transport of active lipase through plasma to the liver.

Adipose Tissue↗
PubMedDate not supplied

The effect of acute and chronic administration of nicotine on lipoprotein lipase activity.

Nicotine was injected intraperitoneally to rats and 2 h later lipoprotein lipase was determined in isolated perfused hearts. There was a significant increase in heparin releasable lipoprotein lipase activity which represents the functional pool without increase in total enzyme activity. When 1 microliter/h of a solution of nicotine (120 mg/ml) was delivered for 3 days from subcutaneously implanted miniosmotic pumps, total lipoprotein lipase activity in the heart increased 1.5-3.0 fold. Endogenous lipoprotein lipase activity in plasma doubled and there was a significant fall in plasma triglyceride levels. The effect of nicotine on heart lipoprotein lipase activity was evident also after 6 days of continuous delivery and was accompanied by a fall in adipose tissue lipoprotein lipase activity. No effect was seen when the dose of nicotine was halved. A positive correlation was seen between plasma nicotine levels and heart lipoprotein lipase activity, while adipose tissue lipoprotein lipase correlated negatively with plasma nicotine levels. Chronic administration of nicotine was accompanied by either weight loss or diminished weight gain. It is concluded that in the rat the acute effect of nicotine on the shift of lipoprotein lipase to the functional pool could be related to enhanced beta-adrenergic stimulation. The chronic effect of nicotine could have been mediated by the loss in body weight, due to reduced caloric intake.

Animals↗
PubMedDate not supplied

[Characteristics of lipases in the culture fluid of Penicillium roqueforti].

Lipases were isolated from the cultural broth of Penicillium roqueforti 141, purified and their properties were studied. The lipases differed in their amino acid composition and had a high content of polar amino acids , in particular aspartic and glutamic acids. The lipases contained also carbohydrates (1.4-3.3%): mannose, xylose and glucosamine. The lipases were stable to heating (up to 55 degrees C) and within a wide pH range. The optimal activity of lipases I and III was observed at 40 degrees C and pH 7.0, that of lipase II at 45 degrees C and pH 6.0. The effect of metal ions and various inhibitors on the activity of the lipases was studied. Ca2+, Mg2+ and Fe2+ ions did not activate the lipases. These were inhibited by a broad spectrum of reagents for sulfhydryl groups and by a phosphoorganic compound. This fact suggest that the lipases belong to "serine" enzymes containing sulfhydryl groups.

Amino Acids↗
PubMed1980

Boronic acid inhibitors of porcine pancreatic lipase.

Porcine pancreatic lipase was inhibited by alkane and arene boronic acids. The inhibition by octadecane boronic acid was competitive when measured against the hydrolysis of dissolved tripropionin in the presence of siliconized glass beads. The value of Ki in this system was 1.34 x 10(3) molecules micron-2. The ratio of substrate to inhibitor concentrations giving 50% inhibition was in the range of 700 to 2200, indicating that lipase has a greater affinity for boronic acids than for tripropionin. Boronic acids did not interfere with the interaction of lipase with the siliconized glass/water interface, demonstrating that the binding of lipase to substrate interfaces, the first step in lipase action, was not the step at which inhibition occurred. The boronic acid binding site on lipase is at or near the active center serine since modification of this residue by diethyl p-nitrophenyl phosphate was prevented by boronic acids. Modification of the active center serine residue by diethyl p-nitrophenyl phosphate also prevented boronic acid binding. Binding of a chromophoric boronic acid, 7-nitrobenzo-2-oxa-1,3-diazolyl m-aminobenzene boronic acid, to lipase was demonstrated by equilibrium gel filtration on polyacrylamide beads (Bio-Gel P-60) in the presence of 4 mM sodium taurodeoxycholate. The complex contained 1 molecule of boronic acid per molecule of lipase and had a dissociation constant Kd of 5 x 10(-6) M. The boronic acid was not bound in the absence of taurodeoxycholate. Boronic acids are believed to be analogs of the tetrahedral intermediate in the action of lipase.

Animals↗
PubMed1993

Infusion of atherogenic lipoprotein particles increases hepatic lipase activity in the rabbit.

Hepatic lipase plays a key role in the turnover of potentially atherogenic lipoprotein remnants and in determining the relative distribution of high density lipoprotein (HDL) particle size subclasses. Rabbits fed a cholesterol-enriched diet have been found to accumulate potentially atherogenic chylomicron remnants and beta-very low density lipoprotein (beta-VLDL) and show a rapid increase in liver and postheparin plasma hepatic lipase activity. To determine whether the particles that accumulate during cholesterol feeding are a stimulus for this increase in hepatic lipase activity, we infused normal chow-fed rabbits with a chylomicron remnant plus beta-VLDL-enriched plasma fraction isolated from rabbits fed 0.5% cholesterol-supplemented chow. The infusion of this plasma fraction for 4 h increased hepatic lipase activity up to 2.9-fold over control rabbits and resulted in a loss of larger sized HDL particles consistent with the action of hepatic lipase. The increase in activity was significantly correlated with the concentration of infusate phospholipid, unesterified cholesterol, and esterified cholesterol, but not with the infusate triglyceride concentration. The change in the plasma cholesterol concentration of recipient rabbits, which reflects the degree of lipoprotein accumulation in these rabbits, was also significantly correlated with the change in hepatic lipase activity. However, a chylomicron remnant and beta-VLDL-depleted fraction of plasma from cholesterol-fed rabbits did not increase hepatic lipase activity. Furthermore, triglyceride presented as an artificial lipid emulsion (Intralipid) was not able to stimulate hepatic lipase activity, although triglyceride is a substrate for hepatic lipase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Serum amylase and lipase in the evaluation of acute abdominal pain.

The purpose of this study was to determine 1) the incidence and magnitude of elevation in admission serum amylase and lipase levels in extrapancreatic etiologies of acute abdominal pain, and 2) the test most closely associated with the diagnosis of acute pancreatitis. Serum amylase and lipase levels were obtained in 306 patients admitted for evaluation of acute abdominal pain. Patients were categorized by anatomic location of identified pathology. Logistic regression analysis was used to compare the enzyme levels between patient groups and to determine the correlation between elevation in serum amylase and lipase. Twenty-seven (13%) of 208 patients with an extrapancreatic etiology of acute abdominal pain demonstrated an elevated admission serum amylase level with a maximum value of 385 units (U)/L (normal range 30-110 U/L). Twenty-six (12.5%) of these 208 patients had an elevated admission serum lipase value with a maximum of 3685 U/L (normal range 5-208 U/L). Of 48 patients with abdominal pain resulting from acute pancreatitis, admission serum amylase ranged from 30 to 7680 U/L and lipase ranged from 5 to 90,654 U/L. Both serum amylase and lipase elevations were positively associated with a correct diagnosis of acute pancreatitis (P < 0.001) with diagnostic efficiencies of 91 and 94 per cent, respectively. A close correlation between elevation of admission serum amylase and lipase was observed (r = 0.87) in both extrapancreatic and pancreatic disease processes. Serum amylase and lipase levels may be elevated in nonpancreatic disease processes of the abdomen. Significant elevations (greater than three times upper limit of normal) in either enzyme are uncommon in these disorders. The strong correlation between elevations in the two serum enzymes in both pancreatic and extrapancreatic etiologies of abdominal pain makes them redundant measures. Serum lipase is a better test than serum amylase either to exclude or to support a diagnosis of acute pancreatitis.

Abdominal Pain↗
PubMed1997

Influence of haemodialysis on lipase activity.

Our aim was to determine whether the increase in serum pancreatic lipase values, reported in patients with chronic renal failure maintained on haemodialysis, is the result of haemoconcentration by fluid removal during dialysis, or whether it is due to lipase stimulation by endothelial lipoprotein lipase, induced by the heparin used as an anticoagulant. We therefore compared the increases in serum lipase, when heparin was used, with those observed when this was replaced by the antithrombotic agent, defibrotide, which has no effect on lipoprotein lipase. In addition, in order to determine the effects of haemoconcentration, variations in total protein concentration and haematocrit values were determined on the same samples, both before and after dialysis. The results showed a statistically significant post-dialysis increase in lipase only when heparin was used (p < 0.03). There was also a mean percentage post-dialysis increase of 16.2% in total protein (p < 0.0001) and 15.5% in haematocrit (p < 0.0001), due to fluid removal. No significant correlation in percentage increases was found between lipase vs total protein or haematocrit values. These findings suggest that heparin-induced lipoprotein lipase stimulation is the principal cause of the post-dialysis increase in pancreatic lipase, and that fluid removal during dialysis makes only a minor contribution to this increase.

Adult↗
PubMed1997

The acid lipase gene family: three enzymes, one highly conserved gene structure.

Human gastric lipase (HGL; triacylglycerol lipase; EC 3.1.1.3) plays an important role in the digestion of dietary triglycerides in the gastrointestinal tract, especially in patients suffering from pancreatic lipase deficiencies. The enzyme is secreted by the fundic mucosa of the stomach and hydrolyzes the ester bonds of triglycerides under acidic pH conditions, while cholesteryl esters are not attacked. The 379-amino acid protein is highly homologous to two other acidic lipases, rat lingual lipase (RLL; triacylglycerol lipase; EC 3.1.1.3) and human lysosomal acid lipase (HLAL; cholesteryl esterase; EC 3.1.1.13). To determine whether this remarkable similarity is also present at the genomic level, we have elucidated the respective gene structures by screening three bacteriophage lambda libraries and by polymerase chain reaction-based intron amplification. The genes encoding HGL, RLL, and HLAL are composed of 10 exons interrupted by nine introns and span about 14 kb, 18.7 kb, and 38.8 kb of genomic DNA, respectively. The HGL and RLL gene organizations are identical, suggesting that RLL is the rat gastric lipase expressed in the serous von Ebner glands of the tongue. The positions of the HLAL intervening sequences are also absolutely conserved, except for the location of intron 1. Our results support the concept that HLAL and HGL/RLL are members of a gene family of lipases that most likely have evolved by duplication of an ancestral gene and subsequently assumed distinct roles in neutral lipid metabolism due to sequence divergence and different expression patterns.

Animals↗
PubMed1998

A single step purification, immobilization, and hyperactivation of lipases via interfacial adsorption on strongly hydrophobic supports

A number of bacterial lipases can be immobilized in a rapid and strong fashion on octyl-agarose gels (e.g., lipases from Candida antarctica, Pseudomonas fluorescens, Rhizomucor miehei, Humicola lanuginosa, Mucor javanicus, and Rhizopus niveus). Adsorption rates in absence of ammonium sulfate are higher than in its presence, opposite to the observation for typical hydrophobic adsorption of proteins. At 10 mM phosphate, adsorption of lipases is fairly selective allowing enzyme purification associated with their reversible immobilization. Interestingly, these immobilized lipase molecules show a dramatic hyperactivation. For example, lipases from R. niveus, M. miehei, and H. lanuginosa were 6-, 7-, and 20-fold more active than the corresponding soluble enzymes when catalyzing the hydrolysis of a fully soluble substrate (0.4 mM p-nitrophenyl propionate). Even higher hyperactivations and interesting changes in stereospecificity were also observed for the hydrolysis of larger soluble chiral esters (e.g. (R,S)-2-hydroxy-4-phenylbutanoic ethyl ester). These results suggest that lipases recognize these "well-defined" hydrophobic supports as solid interfaces and they become adsorbed through the external areas of the large hydrophobic active centers of their "open and hyperactivated structure". This selective interfacial adsorption of lipases becomes a very promising immobilization method with general application for most lipases. Through this method, we are able to combine, via a single and easily performed adsorption step, the purification, the strong immobilization, and a dramatic hyperactivation of lipases acting in the absence of additional interfaces, (e.g., in aqueous medium with soluble substrate). Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗
PubMed2005

High-level heterologous expression and properties of a novel lipase from Ralstonia sp. M1.

The mature lipase LipA and its 56aa-truncated chaperone DeltaLipBhis (with 6xhis-tag) from Ralstonia sp. M1 were over-expressed in Escherichia coli BL21 under the control of T7 promoter with a high level of 70 and 12mg protein per gram of wet cells, respectively. The simply purified lipase LipA was effectively refolded by Ni-NTA purified chaperone DeltaLipBhis in molar ratio 1:1 at 4 degrees C for 24 hours in H2O. The in vitro refolded lipase LipA had an optimal activity in the temperature range of 50-55 degrees C and was stable up to 45 degrees C with more than 84% activity retention. The maximal activity was observed at pH 10.75 for hydrolysis of olive oil and found to be stable over alkaline pH range 8.0-10.5 with more than 52% activity retention. The enzyme was found to be highly resistant to many organic solvents especially induced by ethanolamine (remaining activity 137-334%), but inhibited by 1-butanol and acetonitrile (40-86%). Metal ions Cu2+, Sn2+, Mn2+, Mg2+, and Ca2+ stimulated the lipase slightly with increase in activity by up to 22%, whereas Zn2+ significantly inhibited the enzyme with the residual activity of 30-65% and Fe3+ to a lesser degree (activity retention of 77-86%). Tween 80, Tween 60, and Tween 40 induced the activation of the lipase LipA (222-330%) and 0.2-1% (w/v) of Triton X-100, X-45, and SDS increased the lipase activity by up to 52%. However, 5% (w/v) of Triton X-100, X-45, and SDS inhibited strongly the activity by 31-89%. The inhibitors including DEPC, EDTA, PMSF, and 2-mercaptoethanol (0.1-10mM) inhibited moderately the lipase with remaining activity of 57-105%. The lipase LipA hydrolyzed a wide range of triglycerides, but preferentially short length acyl chains (C4 and C6). In contrast to the triglycerides, medium length acyl chains (C8 and C14) of p-nitrophenyl (p-NP) esters were preferential substrates of this lipase. The enzyme preferentially catalyzed the hydrolysis of cottonseed oil (317%), cornoil (227%), palm oil (222%), and wheatgerm oil (210%) in comparison to olive oil (100%).

Bacterial Proteins↗
PubMed2000

Production, properties and application to nonaqueous enzymatic catalysis of lipase from a newly isolated Pseudomonas strain.

A potent bacterium for lipase production was isolated from soil and identified as Pseudomonas species. It produced lipase constitutively. A mutant of this strain with a lipase productivity 3.25-fold higher was obtained by treatment with ultraviolet (UV) and nitrosoguanidine (NTG). Its fermentation condition was optimized to a lipase yield of 87.5 U/ml. The lipase had maximum activity at pH 9.0 and 45 degrees C. It was stable at pHs from 7.0 to 11.0 and below 60 degrees C. The effects of metal ions, surfactants and bile salts were also studied. The lipase was 1,3-specific. In organic solvents, the thermal stability of the lipase was significantly enhanced. Its optimum temperature was also slightly increased. The optimum water activity was found between 0.5 and 0.6. The lipase was successfully applied in organic phase to catalyze the glycerolysis of palm oil for monoglyceride (MG) production, and the enantioselective esterification of (R,S)-2-octanol. The enantioselectivity of the lipase could be enhanced substantially by treatment with an amphipathic.

Journal Article↗
PubMed2000

Lipase-mediated hydrolysis of blackcurrant oil.

Four commercially available lipases, both free and immobilized, were tested for their ability to catalyze hydrolysis of blackcurrant (Ribes nigrum) oil using two different approaches. The lipase from Mucor miehei was studied free and immobilized in two different ways. The former series of enzymic reactions were performed in tap water at 40 degrees C, but the latter series of enzymic processes were carried out in mixtures of isooctane and phosphate buffer (in a typical 2/1 ratio of the components) at 30 degrees C. These conditions were optimized to increase and/or to maximize the yields of the products, which were priority targets in this study. A rate of hydrolysis and a selective preference of the hydrolytic enzymes towards fatty acids, with a special focus on enrichment of alpha-linolenic acid and/or gamma-linolenic acid, were studied. Higher rates of hydrolysis of the blackcurrant oil in the former series of reactions were observed with the immobilized lipase from Pseudomonas cepacia used as biocatalyst. In the latter approach, the most favorable results of the rate of hydrolysis of the target blackcurrant oil were achieved with the immobilized lipase from Mucor miehei employed as biocatalyst. Only three lipases, selected from a series of lipases tested during this investigation, displayed specificity towards alpha-linolenic acid and gamma-linolenic acid, i.e. the immobilized lipase from P. cepacia, lipase from M. miehei and lipase from P. fluorescens.

Journal Article↗
PubMed1999

Modulator-mediated synthesis of active lipase of Pseudomonas sp. 109 by Escherichia coli cell-free coupled transcription/translation system.

Catalytically active lipase was synthesized using Escherichia coli S30 extract from the signal-deleted lipL gene (lipL) in the presence of its N-terminal hydrophobic fragment-truncated modulator (rLimL) that was purified from the overexpressing E. coli cells. The specific activity of the lipase thus synthesized was 125 times higher than that of the purified one from Pseudomonas sp. 109. No lipase activity was detected in the absence of rLimL, even though the lipase protein itself was synthesized. Active lipase was also produced in vitro by coexpression of rlipL and the modulator gene (rlimL), although a much smaller amount of the lipase was formed. In the absence of rLimL, aggregates of the lipase were formed during its folding process. The addition of rLimL proportionally raised both lipase solubility and enzyme activity. An unstable but high activity peak of the lipase was found during its folding process.

Journal Article↗
PubMed1995

Lipid structural reorganization induced by the pancreatic lipase cofactor, procolipase.

Pancreatic colipase and its precursor, procolipase, facilitate interfacial lipid hydrolysis catalyzed by pancreatic lipase. To better understand how procolipase functions, its interactions with mixed-lipid monolayers at the argon-buffer interface have been characterized. The lipid mixtures consisted of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine and either 1,3-dioleoylglycerol, a model lipase substrate, or 13,16-cis,cis-docosadienoic acid, a model lipase product. Analysis of the lipid composition dependence of procolipase-induced surface pressure increases shows thermodynamically that procolipase interacts strongly and preferentially with the lipase substrate or product. This finding was confirmed by fluorescence measurements of procolipase interaction with pyrene lipid analogs. Analysis of the quantity of procolipase adsorbed to the lipid monolayers shows that interfacial packing obeys a simple, geometric model. The partial molecular areas obtained for procolipase (708 A2) and the phosphatidylcholine (70 A2) agree with their known cross-sectional areas. However, the areas for the fatty acid (14 A2) and diacylglycerol (18 A2) are less than half the expected values, indicating the formation of substrate multilayers. Overall, the results indicate a previously unrecognized role for procolipase, recruiting substrate laterally to its vicinity and, hence, to pancreatic lipase with which procolipase forms a 1:1 interfacial complex. Accompanying this preferential interaction of procolipase with lipase substrates is their rearrangement normal to the interface. These previously unrecognized properties of this lipase cofactor should have relevance for the regulation of other lipases, like lipoprotein lipase, which are regulated by cofactor proteins.

Adsorption↗
PubMed2002

Novel zinc-binding center and a temperature switch in the Bacillus stearothermophilus L1 lipase.

The bacterial thermoalkalophilic lipases optimally hydrolyze saturated fatty acids at elevated temperatures. They also have significant sequence homology with staphylococcal lipases, and both the thermoalkalophilic and staphylococcal lipases are grouped as the lipase family I.5. We report here the first crystal structure of the lipase family I.5, the structure of a thermoalkalophilic lipase from Bacillus stearothermophilus L1 (L1 lipase) determined at 2.0-A resolution. The structure is in a closed conformation, and the active site is buried under a long lid helix. Unexpectedly, the structure exhibits a zinc-binding site in an extra domain that accounts for the larger molecular size of the family I.5 enzymes in comparison to other microbial lipases. The zinc-coordinated extra domain makes tight interactions with the loop extended from the C terminus of the lid helix, suggesting that the activation of the family I.5 lipases may be regulated by the strength of the interactions. The unusually long lid helix makes strong hydrophobic interactions with its neighbors. The structural information together with previous biochemical observations indicate that the temperature-mediated lid opening is triggered by the thermal dissociation of the hydrophobic interactions.

Amino Acid Sequence↗
PubMed1987

The regulatory and basal phosphorylation sites of hormone-sensitive lipase are dephosphorylated by protein phosphatase-1, 2A and 2C but not by protein phosphatase-2B.

The activity of hormone-sensitive lipase, the rate-limiting enzyme in adipose tissue lipolysis, is controlled by cAMP-mediated phosphorylation at a specific regulatory phosphorylation site. The lipase is also phosphorylated at a site, termed basal, without any effects on its activity [Strålfors et al. (1984) Proc. Natl Acad. Sci. USA 81, 3317-3321]. The capacity of protein phosphatase-1, 2A, 2B and 2C to dephosphorylate the lipase, selectively phosphorylated by glycogen synthase kinase-4 and cAMP-dependent protein kinase at the basal and regulatory phosphorylation sites, was compared with that towards glycogen phosphorylase and phosphorylase kinase (alpha subunit). Protein phosphatase-1, 2A and 2C were found to dephosphorylate both phosphorylation sites of hormone-sensitive lipase, while protein phosphatase-2B had no measureable activity towards any of the sites. When the activities of protein phosphatase-1, 2A and 2C were normalized with respect to the reference substrates, they were found to dephosphorylate the lipase regulatory site in the approximate relations of 1:4:3 and the basal site in the approximate relations of 1:6:4. Protein phosphatase-1 showed 20% higher and protein phosphatase-2A and 2C 80% higher activity towards the basal site compared to the regulatory site. The two phosphorylation sites of the lipase were comparable to good substrates for protein phosphatase-2A and 2C, but relatively poor substrates for protein phosphatase-1. Protein phosphatase-2C activity towards the lipase was completely dependent on Mg2+ with a half-maximal effect at 3 mM. Protamine increased the lipase dephosphorylation by protein phosphatase-1 3-5-fold with half-maximal effect at 0.6 microgram/ml, and by protein phosphatase-2A about 2-fold with half-maximal effect at 3-5 micrograms/ml, thus illustrating the potential for control of these lipase phosphatase activities.

Adipose Tissue↗
PubMed1991

Modulation of lingual lipase development by glucocorticoid in the rat.

Lingual lipase in the rat is present in the neonatal period and undergoes developmental increase during postnatal life. To evaluate the role of glucocorticoid in the control of lingual lipase during development, suckling rats were adrenalectomized at d 10 and various hormone replacements were performed. Adrenalectomy abolished the developmental increase of lingual lipase. Low doses of dexamethasone (0.2 and 0.5 microgram/100 g body wt) restored the lingual lipase to near normal level in adrenalectomized animals. High doses of dexamethasone (20 micrograms/100 g body wt), when given to similarly adrenalectomized animals, however, led to a reduction of lingual lipase levels. Inhibition by dexamethasone is through the action of the hormone inasmuch as the coadministration of RU38486, a glucocorticoid type II receptor antagonist, completely abolished the inhibitory action. Inhibition is also steroid specific, with dexamethasone and triamcinolone acetonide being more effective. The results suggest a unique bimodal regulation of lingual lipase by dexamethasone in the rat serous glands. Because of the possible importance of lingual lipase as an alternative enzyme for fat digestion in neonates, the inhibitory action of high doses of glucocorticoid on lingual lipase development may have important implications. The use of steroidal compounds in the hastening of lung maturation and treatment of inflammatory disease might conceivably compromise their lingual lipase development, hence their capacities of fat digestion and malabsorption in the same period.

Adrenal Glands↗
PubMed2001

Lipase production in two-step fed-batch culture of organic solvent-tolerant Pseudomonas aeruginosa LST-03.

Efficient lipase production by two-step fed-batch culture of an organic solvent-tolerant bacterium, Pseudomonas aeruginosa LST-03, was investigated. When FB synthetic medium was used in flask culture, no lipase activity was detected, whereas lipase was produced at 2.3 I.U./ml in C2 complex medium. However, lipase production was induced in FB medium when a fatty acid was added to the culture broth in the stationary phase. Among fatty acids tested, long chain saturated fatty acids, such as C18 (stearic acid) and C20 (arachidic acid), were found to function as effective inducers for the production of lipase, giving an activity level almost the same as that obtained in C2 medium in flask culture. Two-step lipase production, comprised of a growth phase in fed-batch mode and a production phase in which lipase was induced by the addition of 5% (v/v) stearic acid, was carried out in a jar-fermentor. In the growth phase, the maximum cell concentration at 16 h was only 20 in terms of the optical density at 660 nm (OD660), and a low level of lipase production (8 I.U./ml) was obtained after 167 h. This was considered to be due to the exhaustion of several medium components brought about by the use of an unsuitable medium or feeding solution. After analyzing the contents of the compounds in the culture broth by inductively coupled plasma spectrometry for metal ions and HPLC for anions, a modified FB medium was designed. When this modified FB medium was used in two-step fed-batch culture, the maximum cell concentration reached an OD660 of 55 (30.2 g-dry cells/l) at 16.5 h, and lipase was produced at 96 I.U./ml after 35 h, which is approximately 40 times higher than the production level obtained in flask culture using C2 medium.

Journal Article↗