Lipase fraction from the viscera of grey mullet (Mugil cephalus)

Do lipases and amylases of an endangered Indian carp Hypselobarbus pulchellus play a role in visceral fat dynamics; evidence of in vitro macromolecular interactions

Fat depots or triglycerides are hydrolysed by the action of lipases in fish to be used for energy and/or for growth and reproduction. In herbivores fishes, de novo synthesis of lipids from non- lipid substrates (glucose) leads to fat deposits and/or fatty infiltration in organs especially on ovaries limiting its normal functions. This study was aimed to understand lipases from the digestive tract (DT) of adult Hypselobarbus pulchellus of different sizes, their partial purification, characterisation and their isozymes. In-vitro hydrolysis study on interaction of carbohydrate with proteins was evaluated to establish specific protein selection that combat undue glucose release. Results of the study identified four lipase isoenzymes of ~ mol. wt 19.88, 24.29, 32.86, 54.56 kDa with optimal pH of 3.5 and 8, pH stability between pH 5.5-10; optimal temperature at 35 °C and heat stability between 35 and 45 °C. Characterisation studies indicated presence of thiol group in their active site and Ca, Na and Zn ions activated lipase activity. Rice bran as carbohydrate source when used along with azolla (plant protein) and fish meal (animal protein) may combat undue release of excess glucose that leads to visceral fat formation in H. pulchellus as assessed from in vitro studies.

Identification and characterization of two types of triacylglycerol lipase genes from Neocaridina denticulata sinensis

Triacylglycerol lipases (TGLs) can catalyze the hydrolysis reaction of triacylglycerol serving multiple functions in most organisms. Based on the genomic and transcriptomic databases of Neocaridina denticulata sinensis, two TGL genes from N. denticulata sinensis designated NdTGL1 and NdTGL2 were identified and characterized. NdTGL1 showed the highest expression in the stomach, followed by the testis and hepatopancreas, and NdTGL2 exhibited the maximum expression in the hepatopancreas, followed by the stomach and heart. Under the stimulation of copper ion, the expression of NdTGL1 peaked at 12 h and the expression of NdTGL2 elevated significantly at 24 h after stimulation (P < 0.05). It is speculated that NdTGLs may play an important role in the stress response of N. denticulata sinensis. Challenged with Vibrio parahaemolyticus, the expression profiles of NdTGL1 and NdTGL2 in the hepatopancreas was different, which indicates that the immune response of the V. parahaemolyticus challenge might lead to changes in triglyceride metabolism. The recombinant NdTGL (recNdTGL1 and recNdTGL2) were obtained and the enzymatic characterization of recNdTGL1 and recNdTGL2 were determined. The common maximum activity and stability of the recNdTGL1 and recNdTGL2 were observed at 45 °C and 10 °C, respectively. Both recNdTGL1 and recNdTGL2 exhibited the highest activity at pH 10.0. Furthermore, the recNdTGL1 and recNdTGL2 displayed the maximum stability at pH 5.0 and pH 8.0, respectively. In presence of different metal ions, the enzyme activity of recNdTGL1 and recNdTGL2 were inhibited by Cu²⁺ and Zn²⁺, and decreased by about 25%. Studies on the triacylglycerol lipases of N. denticulata sinensis provide theoretical support for studies related to fat metabolism in crustaceans and studies on response mechanism of digestive enzymes to microbial pathogens.

Effects of dietary xylooligosaccharide prebiotic supplementation on growth, antioxidant and intestinal immune-related genes expression in common carp Cyprinus carpio fed a high-fat diet

This study investigated the effects of xylooligosaccharide (XOS) supplementation on growth, intestinal enzyme, antioxidant and immune-related genes in common carp Cyprinus carpio fed a high-fat diet (HFD). One hundred and ninety two fish with an initial weight of 19.61 ± 0.96 g were allocated into 24 tanks (eight fish per tank in four replicate) and were fed the control diet, HFD, HFD with 0.5%, 1%, 2% and 3% XOS supplementation. From the result, fish offered HFD with 1% XOS supplementation significantly obtained a higher body mass index and feed efficiency ratio, whereas condition factor was higher in fish fed HFD supplemented with 2% XOS but no difference was attributed to other supplemented group compared to control group. Also, fish fed HFD supplemented with 1%-2% XOS significantly improved protease, lipase, creatine kinase and sodium/potassium ATPase activities compared to other groups. Fish offered HFD were significantly lower in superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), myeloperoxidase, acid phosphatase, lysozyme activities and immunoglobulin content, but the opposite result was found for aspartate transaminase, alanine transaminase activities, malondialdehyde, protein carbonyl and cortisol content as compared with the control. However, this effect was reversed with HFD supplemented with XOS. Also, interleukin 1β, interleukin 8, tumour necrosis factors, interferons, caspase-3 and caspase-9 in the intestine were all up-regulated in the HFD group, while the reverse pattern was found in SOD, GPX, lysozyme-C, complement 3 and mucin 5b (muc5b), than the control group. These effects were all enhanced by feeding the XOS diet, especially those fed 1%-3% supplementation. In conclusion, XOS inclusion can improve the growth, digestive enzymes, antioxidants and immune response of common carp fed HFD.

Natural Preservatives for Extending the Shelf-Life of Seafood: A Revisit

Consumer demand for minimally processed seafood that retains its sensory and nutritional properties after handling and storage is increasing. Nevertheless, quality loss in seafood occurs immediately after death, during processing and storage, and is associated with enzymatic, microbiological, and chemical reactions. To maintain the quality, several synthetic additives (preservatives) are promising for preventing the changes in texture and color, development of unpleasant flavor and rancid odor, and loss of nutrients of seafood during storage at low temperature. However, the use of these preservatives has been linked to potential health hazards. In this regard, natural preservatives with excellent antioxidant and antimicrobial properties have been extensively searched and implemented as safe alternatives in seafood processing, with the sole purpose of extending shelf-life. Natural preservatives commonly used include plants extracts, chitosan and chitooligosaccharide, bacteriocins, bioactive peptides, and essential oils, among others. This review provides updated information about the production, mode of action, applications, and limitations of these natural preservatives in seafood preservation.

Use of TPP and ATPS for partitioning and recovery of lipase from Pacific white shrimp (Litopenaeus vannamei) hepatopancreas

Lipase recovery from Pacific white shrimp hepatopancreas using a three-phase partitioning (TPP) system in combination with an aqueous two-phase system (ATPS) was studied. TPP system was formed with a simultaneous addition of salt directly to crude extract (CE) followed by an organic solvent addition. The various process parameters required for efficient purification of lipase were optimized. The best lipase yield (87.41%) and purification fold (PF) (3.49-fold) were obtained in the interphase of TPP system, which consisted of the CE to t-butanol ratio of 1:1 (v/v) in the presence of 50% (w/v) (NH4)2SO4. Subsequently, TPP fraction was subjected to ATPS. Effects of phase compositions including PEG molecular weight and concentration, types and concentration of salts, NaCl addition and system pH on lipase partitioning were investigated. With the application of 25% (w/w) PEG1000 and 15% (w/w) MgSO4, at pH 5.0 was found most appropriate since high lipase PF (5.19-fold) and yield (78.46%) in top phase were obtained. The partitioned enzyme exhibited optimal activity at pH 8.0 and 55 °C and was stable at a temperature range of 0-40 °C and a pH range of 7-10. The partitioned lipase showed high tolerance in the presence of ethanol and methanol. Hence, the combined partitioning systems, TPP-ATPS, were found to be an attractive technique for the recovery and partial purification of lipase from Pacific white shrimp hepatopancreas.

Lipase from liver of seabass (Lates calcarifer): Characteristics and the use for defatting of fish skin

Lipase from liver of seabass (Lates calcarifer), with a molecular weight of 60kDa, was purified to homogeneity using ammonium sulfate precipitation and a series of chromatographies, including diethylaminoethyl sepharose (DEAE) and Sephadex G-75 size exclusion columns. The optimal pH and temperature were 8.0 and 50°C, respectively. Purified lipase had Michaelis-Menten constant (K_m) and catalytic constant (k_cat) of 0.30mM and 2.16s^-1, respectively, when p-nitrophenyl palmitate (p-NPP) was used as the substrate. When seabass skin was treated with crude lipase from seabass liver at various levels (0.15 and 0.30units/g dry skin) for 1-3h at 30°C, the skin treated with lipase at 0.30 units/g dry skin for 3h had the highest lipid removal (84.57%) with lower lipid distribution in skin. Efficacy in defatting was higher than when isopropanol was used. Thus, lipase from liver of seabass could be used to remove fat in fish skin.

Influence of time, storage temperature and freeze/thaw cycles on the activity of digestive enzymes from gilthead sea bream (Sparus aurata)

In this study, we tested the effects of long-term storage (2 years) at -20 °C and short-term storage (several hours) in ice and freeze/thaw cycles on the activities of pancreatic, gastric and intestinal (brush border and cytosolic) digestive enzymes in a teleost fish species. The results revealed a significant lose in activity of pancreatic (trypsin, chymotrypsin, total alkaline proteases and α-amylase) and intestinal cytosolic (leucine-alanine peptidase) enzymes between 140 and 270 days of storage at -20 °C, whereas in contrast, the activity of all the assayed brush border enzymes remained constant during the first 2 years of storage at -20 °C. During short-term storage conditions, the most stable enzymes assayed were those of the enterocytes of the brush border, which did not show any change in activity after being held for 5 h in ice. Five freezing and thawing cycles did not affect the activity of the intestinal brush border enzymes and the cytosolic ones, whereas the activity of trypsin, α-amylase and bile-salt-activated lipase was significantly affected by the number of freezing and thawing cycles. No changes in pepsin activity were found in samples exposed to 1 and 2 freezing and thawing cycles.

Digestive enzyme activity in the intestine of Nile tilapia (Oreochromis niloticus L.) under pond and cage farming systems

The effect of different farming systems (cage, pond) upon digestive enzyme activities of Nile tilapia was evaluated. Juvenile Nile tilapia (87.61 ± 1.52 g) were simultaneously cultured in pond and cage systems during 90 days. Cages used nutritional biphasic plan (35 and 32 % crude protein-CP feeds) and ponds used nutritional triphasic plan (35, 32 and 28 % CP feeds). Biometric measurements were monthly performed for adjustments in feeding regimes and removal of intestine tissues to evaluate the performance of enzyme activities. Total proteolytic, amylase and lipase activities were not statistically different between the treatments throughout the periods analyzed (31, 63 and 94 days of culture). However, trypsin and chymotrypsin activities were higher with 31 and 63 days of culture in fish from pond system, suggesting that natural food may have influenced these activities. A positive correlation was observed between the recommended concentration of essential amino acids for Nile tilapia and specific aminopeptidases activity in fish cage system. Substrate-SDS-PAGE revealed 12 active proteolytic bands in both systems. However, integrated density (ID) values were higher in the bands of ponds. Specimens of either cage or pond exhibited five bands of amylolytic activity. Fish from cage and pond systems showed the highest values of ID within 31 days of cultivation. In this study, the complexity of digestive functions could be verified for animals maintained under commercial conditions. Some of the assessed enzymes may show adaptations of their activities and/or expression that allow the fish to achieve a more efficient nutrient assimilation.

Expression, purification and characterization of a functional, recombinant, cold-active lipase (LipA) from psychrotrophic Yersinia enterocolitica

A novel cold-active lipase gene encoding 294 amino acid residues was obtained from the Yersinia enterocolitica strain KM1. Sequence alignment and phylogenetic analysis revealed that this novel lipase is a new member of the bacterial lipase family I.1. The lipase shares the conserved GXSXG motif and catalytic triad Ser85-Asp239-His261. The recombinant protein LipA was solubly and heterogeneously expressed in Escherichia coli, purified by Ni-affinity chromatography, and then characterized. LipA was active over a broad range spanning 15-60°C with an optimum activity at 25°C and across a wide pH range from 5.0 to 11.0 with an optimum activity at pH 7.5. The molecular weight was estimated to be 34.2 KDa. The lipase could be activated by Mg(2+) and a low concentration (10%) of ethanol, dimethyl sulfoxide, methanol and acetonitrile, whereas it was strongly inhibited by Zn(2+), Cu(2+) and Mn(2+). This cold-active lipase may be a good candidate for detergents and biocatalysts at low temperature.

Characterization of digestive enzymes from de-oiled mackerel (Scomber japonicus) muscle obtained by supercritical carbon dioxide and n-hexane extraction as a comparative study

The oil in mackerel muscle was extracted using an environmental friendly solvent, supercritical carbon dioxide (SC-CO2) at a semi-batch flow extraction process and an n-hexane. The SC-CO2 was carried out at temperature 45 °C and pressures ranging from 15 to 25 MPa. The flow rate of CO2 (27 g/min) was constant at the entire extraction period of 2 h. The highest oil extracted residues after SC-CO2 extraction was used for activity measurement of digestive enzymes. Four digestive enzymes were found in water soluble extracts after n-hexane and SC-CO2 treated samples. Amylase, lipase and trypsin activities were higher in water soluble extracts after SC-CO2 treated samples except protease. Among the four digestive enzymes, the activity of amylase was highest and the value was 44.57 uM/min/mg of protein. The water soluble extracts of SC-CO2 and n-hexane treated mackerel samples showed same alkaline optimum pH and pH stability for each of the digestive enzymes. Optimum temperature of amylase, lipase, protease and trypsin was 40, 50, 60 and 30 °C, respectively of both extracts. More than 80 % temperature stability of amylase, lipase, protease and trypsin were retained at mentioned optimum temperature in water soluble extracts of both treated samples. Based on protein patterns, prominent protein band showed in water soluble extracts after SC-CO2 treated samples indicates no denaturation of protein than untreated and n-hexane.

Purification and characterization of an extracellular cold-adapted alkaline lipase produced by psychrotrophic bacterium Yersinia enterocolitica strain KM1

An extracellular cold-adapted alkaline lipase from the psychrotrophic Yersinia enterocolitica strain KM1 was purified 26-fold to homogeneity. The enzyme was active over a broad range spanning 0-60 °C with an optimum activity at 37 °C, and it was found to be alkaline-preferring with an optimum activity at pH 9.0. The molecular weight was estimated to be 34.3 KDa and monomeric. The lipase could be activated by Ca(2+) and low concentration (10%) of ethanol, dimethyl sulphoxide, methanol, and acetonitrile, whereas it was strongly inhibited by Zn(2+), Cu(2+), SDS, EDTA, and PMSF. Using p-nitrophenyl butyrate as a substrate at 37 °C, the Km and Vmax of the enzyme were found to be 16.58 mM and 5.24 × 10(5)  μM · min(-1), respectively. This extracellular cold-adapted alkaline lipase may be a good candidate for detergents and biocatalysts at low temperature.

Purification and properties of digestive lipases from Chinook salmon (Oncorhynchus tshawytscha) and New Zealand hoki (Macruronus novaezelandiae)

Lipases were purified from delipidated pyloric ceca powder of two New Zealand-sourced fish, Chinook salmon (Oncorhynchus tshawytscha) and hoki (Macruronus novaezelandiae), by fractional precipitation with polyethylene glycol 1000, followed by affinity chromatography using cholate-Affi-Gel 102, and gel filtration on Sephacryl S-300 HR. For the first time, in-polyacrylamide gel activity of purified fish lipases against 4-methylumbelliferyl butyrate has been demonstrated. Calcium ions and sodium cholate were absolutely necessary both for lipase stability in the gel and for optimum activity against caprate and palmitate esters of p-nitrophenol. A single protein band was present in native polyacrylamide gels for both salmon and hoki final enzyme preparations. Under denaturing conditions, electrophoretic analysis revealed two bands of 79.6 and 54.9 kDa for salmon lipase. It is proposed that these bands correspond to an uncleaved and a final form of the enzyme. One band of 44.6 kDa was seen for hoki lipase. pI values of 5.8±0.1 and 5.7±0.1 were obtained for the two salmon lipase forms. The hoki lipase had a pI of 5.8±0.1. Both lipases had the highest activity at 35°C, were thermally labile, had a pH optimum of 8-8.5, and were more acid stable compared to other fish lipases studied to date. Both enzymes were inhibited by the organophosphate paraoxon. Chinook salmon and hoki lipases showed good stability in several water-immiscible solvents. The enzymes had very similar amino acid composition to mammalian carboxyl ester lipases and one other fish digestive lipase. The salmon enzyme was an overall better catalyst based on its higher turnover number (3.7±0.3 vs. 0.71±0.05 s(-1) for the hoki enzyme) and lower activation energy (2.0±0.4 vs. 7.6±0.8 kcal/mol for the hoki enzyme) for the hydrolysis of p-nitrophenyl caprate. The salmon and hoki enzymes are homologous with mammalian carboxyl ester lipases.

A lipase with broad temperature range from an alkaliphilic gamma-proteobacterium isolated in Greenland

A gamma-proteobacterium related to the genera Alteromonadales and Pseudomonadales, isolated from a cold and alkaline environment in Greenland, has been shown to produce a lipase active between 5 degrees C and 80 degrees C, with optimal activity at 55 degrees C and pH 8. PCR-based screening of genomic DNA from the isolated bacterium, followed by genome walking, resulted in two complete open reading frames, which were predicted to encode a lipase and its helper protein, a lipase foldase. The amino acid sequence derived for the lipase showed resemblance to lipases from Pseudomonas, Rhodoferax, Aeromonas and Vibrio. The two genes were cloned into different expression systems in E. coli with or without a putative secretion sequence, but despite the fact that both recombinant lipase and lipase foldase were observed on SDS-PAGE, no recombinant lipase activity was detected. Attempts to refold the recombinant lipase in vitro using a purified lipase foldase remained unsuccessful.

Isolation of a lipase-secreting yeast for enzyme production in a pilot-plant scale batch fermentation

The production of lipase by twenty-nine yeasts isolated from the phylloplane of Hibiscus rosa-sinensis was evaluated. The highest lipase producers were Pseudozyma hubeiensis HB85A, Debaryomyces occidentalis-like HB83 and Cryptococcus sp. HB80. P. hubeiensis HB85A batch fermentations were carried out in a bioreactor and lipase production improved 3.2-fold as compared to flask submerged cultures. The production process was significantly reduced from 48 h (in flasks) to 18 h (in the bioreactor). The better hydrolytic activity was achieved with C16 p-nitrophenyl ester. Maximal activity was observed at pH 7.0, the optimum temperature was 50 degrees C at pH 7.0 and the enzyme was stable at 30 and 40 degrees C. The lipolytic activity was stimulated by Mg(2+), K(+) and Ba(2+) salts and EDTA and slightly inhibited by Ca(2+) salts. Non-ionic detergents such as Triton X-100, Tween 80 and Tween 20 strongly stimulated lipase activity, whereas SDS inhibited it. The lipase was stable in iso-octane and hexane at 80%.

Influence of cultivation conditions on the production of a thermostable extracellular lipase from Amycolatopsis mediterranei DSM 43304

Among several lipase-producing actinomycete strains screened, Amycolatopsis mediterranei DSM 43304 was found to produce a thermostable, extracellular lipase. Culture conditions and nutrient source modification studies involving carbon sources, nitrogen sources, incubation temperature and medium pH were carried out. Lipase activity of 1.37 +/- 0.103 IU/ml of culture medium was obtained in 96 h at 28 degrees C and pH 7.5 using linseed oil and fructose as carbon sources and a combination of phytone peptone and yeast extract (5:1) as nitrogen sources. Under optimal culture conditions, the lipase activity was enhanced 12-fold with a twofold increase in lipase specific activity. The lipase showed maximum activity at 60 degrees C and pH 8.0. The enzyme was stable between pH 5.0 and 9.0 and temperatures up to 60 degrees C. Lipase activity was significantly enhanced by Fe(3+) and strongly inhibited by Hg(2+). Li(+), Mg(2+) and PMSF significantly reduced lipase activity, whereas other metal ions and effectors had no significant effect at 0.01 M concentration. A. mediterranei DSM 43304 lipase exhibited remarkable stability in the presence of a wide range of organic solvents at 25% (v/v) concentration for 24 h. These features render this novel lipase attractive for potential biotechnological applications in organic synthesis reactions.

Membrane-bound 'synthetic lipase' specifically cultured under solid-state fermentation and submerged fermentation by Rhizopus chinensis: a comparative investigation

Rhizopus chinensis was able to produce synthetic lipases under both solid-state and submerged fermentations. These lipases were extracted from cell membrane using Triton X-100, and purified to homogeneity through ammonium sulfate precipitation, hydrophobic interaction chromatography and gel filtration chromatography. Judging from SDS-PAGE, the specific synthetic lipases associated with SSF (named as SSL) and SmF (named as SML) were different in the apparent molecular mass (62 and 40kDa). In term of hydrolytic activity, both enzymes exhibited maximum values at pH 8.0 and 40 degrees C; SSL appeared to be more pH tolerant and thermostable than SML. PMSF negligibly affected SSL but strongly reduced the activity of SML. Both enzymes showed clear preference for long-chained p-nitrophenyl esters, yielding maximum activity towards p-nitrophenyl palmitate (with SSL) and p-nitrophenyl laurate (with SML). In term of synthetic activity, lyophilized enzymes gave the highest values both at 30 degrees C, but at different pH memories (7.5 for SSL and 6.5 for SML). Most of ethyl esters synthesized by the two enzymes achieved good yields (>90%), and tetradecanoic acid and laurate acid separately served as the best acyl donors.