Highest Lipase Activity Research Articles

DETECTION OF SOME TYPES OF OILS THAT INDUCE LIPASE PRODUCTION IN SOME BACTERIAL ISOLATES

Bacterial lipases are a highly versatile class of hydrolytic enzymes which catalyze the hydrolysis of triglycerol to glycerol and fatty acids. They play an important role in biotechnological and industrial processes, including oleo chemical, food, pharmaceutical detergent formulation, cosmetic, leather, textile, and paper industries applications. Tremendous interest among scientists and industrialists has been arisen in the last decade in microbial lipases due to their versatility and ease of mass production.In the current work, natural oils such as Triglyceride, Tween 20, Tween 80, Olive oil, Sweet almond, Celery oil, Sesame, Rosemary oils were implemented to enhance lipase production by soil and pathogenic bacterial isolates. Results revealed that triglyceride and tween 80 had the best enhancing activity for lipase production in most isolates. It was also shown that Pseudomonas and Bacillus were the most potential lipase producing bacteria.A novel modified tributary agar was prepared by the addition of Sudan blue dye and used for the detection of lipase producers. It was shown to give a very clear zone even in the case of weak producing strains as compared to the original medium.Specific lipase activity had been determined Staphylococcus aureus (in the present research. The highest lipase activity was demonstrated by Pseudomonas (4.5u/ml), while Staphylococcus aureus did not show any lipase activity.

First report of six Sordariomycetes fungi isolated from plant litter in freshwater ecosystems of Korea

Freshwater ecosystems provide a complex environment for microorganisms. In this study, we isolated diverse fungal strains from plant litter in freshwaters. These strains were identified using molecular phylogenetic analyses of rDNA and/or other gene sequences (TUB, GAPDH, and EF1 ). In addition, we examined their morphological characteristics by microscopy and cultural characteristics on several media. We identified six previously unrecorded Sordariomycetes species in Korea, i.e., Colletotrichum godetiae, Discosia rubi, Robillarda sessilis , Monochaetia dimorphospora , Idriella lunata , and Phialemoniopsis endophytica . Of these, D. rubi and M. dimorphospora exhibited high extracellular amylase, lipase, and protease activities, suggesting that these fungal isolates might play an important role as decomposers in freshwater ecosystems. Plant litter could thus be a good source for isolating and investigating previously undocumented fungal species in freshwater environments.

Immobilized enzyme-driven value enhancement of lignocellulosic-based agricultural byproducts: Application in aroma synthesis

We have combined the advantages of immobilization and spouted bed drying to enhance lipase activity and stability for further use of this enzyme in esterification. Through covalent binding, Cercospora kikuchii lipase was immobilized onto agricultural byproducts activated with glutaraldehyde, sodium periodate, or epichlorohydrin. The immobilized derivatives showed high lipase activity retention (from 83.8 to 116.9%) and low residual moisture (average of 3.96%) and water activity (average of 0.19). The kinetic parameters KM and Vmax of the free lipase were 0.212 mM and 160.3 μmol/min/mg, respectively; lipase immobilized onto the support activated with 1.5% glutaraldehyde had lower KM (0.121 mM) and higher Vmax (275.4 μmol/min/mg). Lipase immobilized onto rice husk retained 60.3% of its initial enzyme activity after five reuse cycles, and its residual activity was high 88.7% after storage at 5 °C for six months. This immobilized derivative system was used to catalyze butyl butyrate synthesis. Under the best conditions for butyl butyrate production (temperature of 50 °C and enzyme concentration of 0.5 g), the esterification yields reached 95.0% and afforded a butyl butyrate concentration of 15.2 g/L. The enzyme stability, high activity retention after reuse cycles, and ability to catalyze butyl butyrate synthesis from butyric acid strongly indicate that the innovative one-step immobilization protocol reported herein is feasible for lipase immobilization onto the surface of eco-friendly supports.

Sustainable Lipase Production by Diutina rugosa NRRL Y-95 Through a Combined Use of Agro-Industrial Residues as Feedstock.

The potential use of alternative culture media towards the development of a sustainable bioprocess to produce lipases by Diutina rugosa is clearly demonstrated. First, a synthetic medium containing glucose, peptone, yeast extract, oleic acid, and ammonium sulfate was proposed, with lipase activity of 143U/L. Then, alternative culture media formulated with agro-industrial residues, such as molasses, corn steep liquor (CSL), and olive mill waste (OMW), were investigated. An experimental design was conducted, and only CSL concentration was found to have a positive effect in lipase production. The highest lipase activity (561U/L) was produced on a mixture of molasses (5g/L), CSL (6g/L), OMW (0.5% v/v), 0.5g/L of ammonium sulfate, and 3g/L of peptone at 24h of cultivation. Lipase production was also carried out in a 1-L bioreactor leading to a slightly higher lipase activity at 24h of cultivation. The semi-purified enzyme exhibits an optimum temperature and pH of 40°C and 7.0, respectively. Finally, the media cost per unit of lipase produced (UPC) was influenced by the medium components, specially by the inducer used. The lowest UPC was obtained when the agro-industrial residues were combined and used at the improved concentrations.

Extraction and Purification of Lipases Enzyme from Germinating Seeds of Four Crops

Lipase enzyme has attracted a lot of attention in recent years because of its diverse biotechnological applications. The present study was conducted to screen germinated seeds of four crops, namely sunflower (Helianthus annuus), flaxor linseed (Linum usitatissimum ), peanut (Arachis hypogaea ) and castor bean (Ricinus communis), for the activity of their lipases. to the study also included the extraction and purification of lipase from the seeds of the most promising crop using different solvents.
 The results indicated that the maximum enzymatic activity (0.669 U/ml) was obtained when 0.1 M Tris-HCl buffer extract was used after 3 days of seed germination of all the tested species, as compared to the other test solvents (acetone and water). Sunflower germinated seeds showed the highest lipase activity, which was higher by 159.67, 185.32, and 285.90 % over the activities of castor bean, flax, and peanut seeds, respectively. Among the used ranges of saturation of ammonium sulfate, the ratio of 70% was the best in precipitating the crude enzyme, showing a highest specific activity of 2.576 U/ mg protein.
 The first stage of gel filtration chromatography column by Sephadex G-200 indicated the presence of two non-identical peaks, one for protein and another for lipase activity, between the fractions of 18 to 23. The active fractions were pooled and loaded again in the Sephadex G-200 column and the eluted fractions showed two identical peaks, one for protein and another for lipase activity, between the fractions of 19 to 23. The final purification step by gel filtration showed a specific activity of 6.482 U/mg proteins with a yield of 38.75 % and 11.33 folds of time of purification. The study revealed that sunflower seeds are a better source of lipase as compared to the other used plant seeds, which can be used in different industries.

High-throughput sequencing-based characterization of the predominant microbial community associated with characteristic flavor formation in Jinhua Ham

Our purpose was to investigate the main bacterial microbiota and volatile profiles in the Chinese traditional dry-cured product—Jinhua ham during different processing stages and to analyze the role of the main microbiota in the formation of characteristic flavor. We determined the microbiota of Jinhua ham by using 16 S high throughput sequencing, and found that Staphylococcus constituted the predominant microbiota throughout the flavor formation process. Based on the volatile profiles of Jinhua dry-cured products from 11 different processing via SPME-GC-MS analysis, Aldehydes were the main groups of volatiles, with the most abundant ones being hexanal (13.89%) and nonanal (3.96%). To further investigate the relationship between predominant microbiota and the major volatile compounds in Jinhua ham, we screened and isolated genus Staphylococcus with high protease and lipase activities. The main Staphylococcus isolates, S. saprophyticus (53.4%) and S. equorum (31.0%) are related to the yields of aldehydes by producing hexanal, nonanal, benzaldehyde, and phenylacetaldehyde, indicating their contributions on the formation of characteristic flavor substances in Jinhua ham.

Effects of bio‐flocculated algae on the growth, digestive enzyme activity and microflora of freshwater fishCatla catla(Hamilton 1922)

In numerous ways, diets incorporating probiotics are beneficial to host animals. This study was conducted to evaluate the influence of bio-flocculated freshwater algae Chlorella vulgaris on the freshwater fish Catla catla. For the process of flocculating algae, probiotics Lactobacillus acidophilus (10307 MTCC) and Bacillus subtilis (MTCC 441) were used. The experimental fish were fed with Artemia franciscana enriched with flocculated algae for 60 days. A control group was fed with unenriched A. franciscana. After the experimental period, there was a significant decrease in anaerobic bacteria and a significant colonization of candidate probiotics in guts of fish fed with flocculated algae-enriched Artemia. This treatment group also had a better growth performance with a higher average body length and weight (8.7 ± 0.3 cm, 5.83 ± 0.9 g) and survival % (98 ± 1.02). High protease (7.8 µmg/protein−1) and lipase (2.56 µmg/protein−1) activity were also found in the enriched A. franciscana-fed fish group. Comparatively, higher protein, lipid and PUFA/HUFA contents were also reported in this treatment group. The study found that flocculated algae-enriched A. franciscana has a positive impact on gut microflora, growth parameters and survival as compared to the unenriched group, and hence, the flocculated algae serve a dual purpose in rearing of C. catla. This study supports the inference that a bio-flocculated algae-incorporated diet is a preferable method for larval rearing aquaculture.

Studies on the extremo-lipase produced by the halotolerant Oceanobacillus iheyensis strain QCS

In the current work, different studies were carried out on the lipase enzyme produced by the halotolerant Oceanobacillus iheyensis strain QCS, with an expectation to be an important candidate in the industrial applications. Lipase of strain QCS was halo-alkali-thermo-detergent-solvent stable. Maximum production of lipase was obtained after 72 h of incubation, at 40oC and pH 8 and 9 in a medium containing 25 % (w/v) NaCl and 1% (v/v) olive oil as a lipid substrate. This lipase was partially purified, highest lipase activity was obtained in 80% ammonium sulfate saturation, and in fraction eight of the Sephadex G-200 gel filtration chromatography. Lipase displayed wide spectrum of activity within a broad range of conditions including salinity, temperature and pH, it was optimally active at 25% (w/v) NaCl, 40°C and pH 8 and 9, respectively. The effect of many metal ions, detergents and organic solvents on the activity of lipase was evaluated. Interestingly, lipase was able to retain the majority of its activity in the presence of Ni2+, Mg2+, Oxi and Fairy detergents, ethyl acetate, dimethyl formamide and toluene, respectively. Overall, as the lipase from O. iheyensis strain QCS has a number of interesting properties especially its stability at extreme conditions; it could be used as a potential promising candidate for detergents industry, and as a biocatalyst in low water enzymatic processes.

Changes of protein oxidation, lipid oxidation and lipolysis in Chinese dry sausage with different sodium chloride curing salt content

The effect of sodium chloride (NaCl) curing salt content on protein oxidation, lipid oxidation and lipolysis of Chinese dry sausage was investigated. Two groups Chinese dry sausages with 2% and 4% (m/m) salt content were studied. The degree of protein oxidation increased during the processes in two groups sausages, while the content of phospholipids decreased, neutral lipids and free fatty acids increased. The degree of protein oxidation, lipid oxidation and lipolysis in 4% NaCl content group was higher than those in 2% NaCl content group, while 4% NaCl content group has higher lipase activity. In conclusion, 4% NaCl may facilitate the protein oxidation, lipid hydrolysis and oxidation in Chinese dry sausage, and the protein oxidation had strong correlation with lipid oxidation and lipolysis. The results could provide a basis for improving the technology of industrial production.

Ontogenetic changes in energetic reserves, digestive enzymes, amino acid and energy content of Lithodes santolla (Anomura: Lithodidae): Baseline for culture.

The southern king crab (SKC) Lithodes santolla is an important commercial species in southern South America. Fishing pressure has caused the deterioration of its stocks. Currently, culture techniques are being developed for producing SKC juveniles to enhance the natural population and to recover the fishing stock. Therefore, it is necessary to know about physiology, energetic and nutritional requirements for SKC maintenance in hatchery. Thus, this study aims to evaluate the biochemical and physiological changes in the midgut gland, muscle and hemolymph of juveniles, pre-adults and adults of wild SKC. The energetic reserves, digestive enzymes activity, amino acid profile and energy were quantified in twelve juveniles, ten pre-adult, and ten adult crabs. Juveniles showed high glycogen and low lipids in the midgut gland, and low proteins and low lactate in muscle. In the hemolymph, juveniles had high lipids. Pre-adults had high glycogen and lipids in the midgut gland, and both high protein and lactate in muscle. In the hemolymph, pre-adults had high lipids. Adults had low glycogen and high lipids in midgut gland, and both high proteins and high lactate in muscle. In hemolymph, adults had high glucose and lactate. Juveniles and pre-adults had high proteinase activity, whereas adults had high lipase activity. Major essential amino acids of SKC were arginine, methionine, and tryptophan, and the non-essential amino acids were glycine, aspartic acid and glutamic acid. On another hand, SKC had similar energy in the midgut gland and muscle, regardless of the ontogenetic stage. Moreover, we demonstrated that the biochemical energy calculation underestimates the actual measured values by a calorimeter. Thus, our results help to understand the physiological changes, energetic and nutritional requirements of L. santolla, and this study is a baseline for research on diet formulation for maintaining this species under culture conditions.

Effects of oral administration of acidifier and probiotic on growth performance, digestive enzymes activities and intestinal histomorphology in Salmo trutta caspius (Kessler, 1877)

This study was aimed to evaluate the single and combined effects of acidifier and probiotic on growth performance, digestive enzymes activities and intestinal histomorphology of Salmo trutta caspius. The juvenile fish with mean body weight 15±3 g were divided into 8 different treatments (in triplicates), including control, 5, 10 and 15 g sodium diformate kg-1 diet, respectively as T1, T2 and T3. Treatments namely T4, T5, T6 and T7 were received diets containing 0.2 g kg-1 commercial probiotic Bio-Aqua® in combination with 0, 5, 10 and 15 g sodium diformate kg-1 diet for 60 days, respectively. The results showed that T2 and T3 fish growth performance were improved significantly (p<0.05), following 30 days after administration, while T1 did not show the same pattern over the 60 days (p<0.05). The single probiotic treatment did not induce significant improvements in fish growth rate, digestive enzymes activities and intestinal morphometry though the combined treatments have been showed an intermediate level of improvement. The higher levels of chymotrypsin and trypsin have been observed at day 30 and the higher activities of lipase, protease and amylase could be seen at day 60 in the most acidifier treatments (p<0.05). The villi height and the thickness of epithelium have been reduced (p<0.05) because of single acidifier while the combined treatments led to either significant increase (p<0.05) or no change compared with corresponding single treatment. The addition of 1.0 g sodium diformate kg-1 diet can improve the fish growth rate in long-term by changing digestive enzymes activities, and combined treatments of probiotic and acidifier are mostly revealed antagonist effects.

The grease trap: uncovering the mechanism of the hydrophobic lid in Cutibacterium acnes lipase

Acne is one of the most common dermatological conditions, but the details of its pathology are unclear, and current management regimens often have adverse effects. Cutibacterium acnes is known as a major acne-associated bacterium that derives energy from lipase-mediated sebum lipid degradation. C. acnes is commensal, but lipase activity has been observed to differ among C. acnes types. For example, higher populations of the type IA strains are present in acne lesions with higher lipase activity. In the present study, we examined a conserved lipase in types IB and II that was truncated in type IA C. acnes strains. Closed, blocked, and open structures of C. acnes ATCC11828 lipases were elucidated by X-ray crystallography at 1.6-2.4 Å. The closed crystal structure, which is the most common form in aqueous solution, revealed that a hydrophobic lid domain shields the active site. By comparing closed, blocked, and open structures, we found that the lid domain-opening mechanisms of C. acnes lipases (CAlipases) involve the lid-opening residues, Phe-179 and Phe-211. To the best of our knowledge, this is the first structure-function study of CAlipases, which may help to shed light on the mechanisms involved in acne development and may aid in future drug design.

Waste frying oil hydrolysis and lipase production by cold-adapted Pseudomonas yamanorum LP2 under non-sterile culture conditions

ABSTRACT Non-sterile culture technique is currently used in some microbial processes. However, there is no study on the use of this technique in the production of microbial lipases and hydrolysis of waste frying oils. This study was conducted to hydrolyse waste frying oils and produce lipase under non-sterile culture conditions using locally isolated cold-adapted bacteria. Of 75 bacterial isolates, the psychrotolerant Pseudomonas yamanorum LP2 (Genbank number: KU711080) was determined to have the highest lipase activity. It was found that a combination of restricted nutrient availability, low temperature and high inoculum volume prevented microbial contaminants under non-sterile conditions. The most favourable parameters for lipase production under both sterile and non-sterile conditions were 15°C temperature, pH 8, 30 mL/L inoculum volume, 40 mL/L waste frying oil concentration, 10 mL/L Tween-80 and 72 h incubation time. The maximum lipase activities in sterile and non-sterile media were determined as 93.3 and 96.8 U/L, respectively. The present process designed for enzyme production and waste oil hydrolysis can reduce the cost of cultivation medium as well as energy consumption and workload. The potential of cold-adapted bacteria to produce lipase and hydrolyse waste oils under non-sterile culture conditions was first tested in the current study.

Appraisal of different levels of soybean meal in diets on growth, digestive enzyme activity, antioxidation, and gut histology of tilapia (Oreochromis niloticus).

This study was designed to determine the effect of fishmeal (FM) replacement with soybean meal (SBM) in the diet of tilapia (Oreochromis niloticus). Growth, digestive enzyme activity, antioxidation, and gut histomorphology were assessed in the fish fed with five different formulated diets that increasingly replaced FM. The SBM0 contained 100% FM, followed by 25% (SBM25), 50% (SBM50), 75% (SBM75), and 100% (SBM100). Juvenile tilapia having weight and length of 6.6 ± 0.1g and 5.4 ± 0.2cm, respectively, were randomly divided into five treatment groups. Each group had 40 individual fish and fed to visual satiation for 90days. Body weight gain and specific growth rate in fish fed with 25-75% SBM increased significantly (P< 0.01) compared with those in fish fed with SBM100. Fish having the same weight fed with diets SBM50, SBM75, and SBM100 showed a significantly (P< 0.01) longer intestine compared with those fed with SBM0 and SBM25. Villus height of the stomach and intestine was significantly (P< 0.01) greater in the fish fed with the diets SBM0, SBM25, and SBM50 compared with SBM75 and SBM100. Muscular thickness was inversely related with the increasing villus height. Protease activity increased significantly (P< 0.01) in the stomach, anterior intestine, and posterior intestine of fish fed with SBM0 compared with SBM100. In the stomach and anterior and posterior segments of the intestine, significantly (P< 0.01) higher lipase activity was observed in fish fed with the diets SBM0 and SBM25 compared with diet SBM100. In the stomach, anterior intestine, and posterior intestine, amylase activity was also significantly (P< 0.01) greater in SBM0 compared with SBM100. The antioxidant enzymes including superoxide dismutase and catalase of the liver were significantly (P< 0.01) higher in fish fed SBM100 compared with SBM0. These results suggest that the replacement of FM up to 75% with SBM could be possible considering the growth performances, gut health, and activities of digestive enzymes and antioxidant enzymes in O. niloticus.

Functional and safety assessment of Staphylococcus simulans PMRS35 with high lipase activity isolated from high salt-fermented fish (Budu) for starter development

The objective of this study was to examine the safety and functional properties of Staphylococcus simulans PMRS35 isolated from Budu. This strain possessed good lipase activity and moderate protease activity, tolerated 25% of salt, and did not exhibit decarboxylase activity. In addition, this strain displayed not only negative results towards pathogenic genes, hemolytic activity, and biofilm formation ability but also sensitivity to conventional antibiotics which included chloramphenicol, vancomycin, erythromycin, tetracycline, and gentamycin. Most importantly, the isolate maintained its viability towards simulated gastrointestinal tract conditions with survival rate of more than 80%. This strain showed pronounced values of auto-aggregation and cell surface hydrophobicity properties as 34.2 ± 1.4 and 39.14%, respectively. Additionally, the isolates showed strong antimicrobial activity against foodborne pathogens, particularly S. aureus. These results demonstrated that this species has potential for use as starter to improve the quality and the health functionality of fermented foods.

High bacterial colonization and lipase activity in microcomedones.

BackgroundAlthough acne vulgaris has a multifactorial aetiology, comedogenesis and bacteria colonization of the pilosebaceous unit are known to play a major role in the onset of inflammatory acne lesions. However, many aspects remain poorly understood such as where and when is the early stage of the Propionibacterium acnes colonization in follicular unit? Our research aimed at providing a precise analysis of microcomedone's structure to better understand the interplay between Propionibacterium acnes and follicular units, and therefore, the role of its interplay in the formation of acne lesions.MethodsMicrocomedones were sampled using cyanoacrylate skin surface stripping (CSSS). Their morphology was investigated with multiphoton imaging and their ultrastructure with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Bacterial lipase activity in the microcomedones was quantified using a dedicated enzymatic test as well as a Fourier Transform Infra‐Red (FTIR) analysis. The porphyrin produced by bacteria was analysed with HPTLC and fluorescence spectroscopy.ResultsThe imaging analysis showed that microcomedones' structure resembles a pouch, whose interior is mostly composed of lipids with clusters of bacteria and whose outer shell is made up of corneocyte layers. The extensive bacteria colonization is clearly visible using TEM. Even after sampling, clear lipase activity was still seen in the microcomedone. A high correlation, r = .85, was observed between porphyrin content measured with HPTLC and with fluorescence spectroscopy. These observations show that microcomedones, which are generally barely visible clinically, already contain a bacterial colonization.

ANNE SÜTÜNDE SABUNUMSU TAT: OLGU SUNUMU

<div><!--block-->It is known that refusing to breastfeed is a situation which can occur&nbsp; for many reasons. Some studies have reported that the soapy taste of frozen milk causes refusal to breastfeed in infants. Higher levels of lipase in breast milk can cause a soapy taste after having been stored. This study focuses on a 4 months old boy who refused breast milk for a week. He was born with his twin at 31 weeks and his birthweight was 2130 grams. The weight of the baby, who was only fed with breast milk, was 6200 grams. There were no pathological findings during the physical examination and no changes in the environment or the daily routine of his family. His mother was nursing his twin sibling in the NICU and our patient was fed frozen-thawed milk. The mother noticed that her frozen-thawed milk had a soapy taste. The lipase activity in frozen breast milk was found to be 2345 U/l. The mother was advised to mix freshly expressed breast milk with the stored milk. It was discovered that the baby did not reject the breast milk. The soapy taste in breast milk should be considered when babies are intolerant to the frozen milk of mothers. More research is needed to determine the etiology of the soapy taste in breast milk which is especially associated with higher lipase activity.&nbsp;</div>

Comparison of overfed Xupu and Landes geese in performance, fatty acid composition, enzymes and gene expression related to lipid metabolism.

ObjectiveThe aim of this study was to compare overfeeding performance, fatty acid composition, blood chemistry, enzymes and genes expression overfed Xupu and Landes geese.MethodsSixty male Xupu geese (80 d) and Landes geese (80 d) were selected. After a period of one-week of pre-overfeeding, Xupu and Landes geese were overfed three meals of 550 and 350 g/d, respectively, of a high-carbohydrate diet in the first week of the overfeeding period. The next week, geese were given four meals of 1,200 and 850 g/d, respectively, over 8 to 14 d. Finally, geese were given five meals of 1,600 and 1,350 g/d, respectively, for the last two weeks.ResultsAfter overfeeding for 28 d: Compared with Landes geese, Xupu geese liver weight and liver-to-body weight ratio decreased (p<0.05), while final weight, slaughter weight, total weight gain, abdominal fat weight, and feed-to-liver weight ratio increased (p<0.05). The levels of elaidic acid (C18:1t9), oleic acid (C18:1n-9), eicosenoic acid, and arachidonic acid in the liver of Xupu geese significantly increased (p<0.05), and the levels of myristic acid and stearic acid significantly decreased (p<0.05), while methyleicosanoate acid significantly increased (p<0.05). Xupu geese had higher plasma concentrations of triglyceride and very low density lipoprotein cholesterol (p<0.05), and decreased activities of alanine aminotransferase, aspartate aminotransferase, and lipase (LPS) (p<0.05). Landes geese had higher LPS activity (p<0.05), but lower cholinesterase activity (p<0.05) when compared with Xupu geese. The mRNA expression levels of fatty acid dehydrogenase (FADS) gene, elongase of long-chain fatty acid 1 (ELOVL1) gene, ELOVL5, and acyl-Co A: cholesterol acyltransferase 2 (ACAT2) gene were significantly upregulated (p<0.05) in Landes goose when compared with Xupu geese.ConclusionThis study demonstrates that the liver production performance of Landes geese was better than that of Xupu geese to some extent, which may be closely related to LPS activity, as well as the expression of FADS, ELOVL1, ELOVL5, and ACAT2.

Biochemical Characterization of Lipase Produced by &amp;lt;i&amp;gt;Bacillus&amp;lt;/i&amp;gt; spp. Isolated from Soil and Oil Effluent

The aim of the present work was to isolate Bacillus spp. With high lipase activity; to characterize the isolates using both biochemical and molecular methods; to produce lipase using Bacillus isolates and to study the biochemical and biophysical characteristics of the produced lipase. Sixty five Bacillus isolates were isolated from soil 20 isolates from guar field soil (G), 15 isolates from Abusabein field soil (B), 15 isolates from sun flower field soil (S) and 15 isolates from oil effluent (O). Lipase producing isolates were screened; a Chromogenic plate’s method was used. Enzyme activity was quantitatively assayed. Lipase production under submerged fermentation (SMF) conditions using a production medium that contained metal salts, Tween-20 and olive oil as substrate at different period 24, 48, 72 and 96 h, the optimum pH, temperature for lipase activity was determinated and kinetics as well. The isolates showed the highest lipase activity which was identified as Bacillus sp. The optimum pH, temperature, thermostability and kinetic of the produced enzymes were found in three isolates G14, O1 and B10 with the highest enzyme activity and best stability. The isolates G14, O1 and B10 revealed the highest lipase activity of 63.4, 41.2 and 28.3 U/ml, respectively. The results showed optimum pH of the lipase activity from isolates G14, O1 and B10 8.0, 6.0 and 6.0 and the optimum temperature 40, 60 and 75&#730C, respectively. Lipase enzymes from isolates O1 and B10 were found to be more thermostable after incubation time for 120 min at 90&#730C. The Vmax and Km values of lipase for isolates G14, OI and B10 were 17.6, 135 and 24.4 μmole&#8729min&#87221 and 1.3, 1.6 and 0.681 mM, respectively. According to these results Bacillus spp. with high lipase activity and thermostability can be used to promote food, pharmaceuticals, paper, detergents agrochemicals industries and pollution control in Sudan.

Potential of faba bean lipase and lipoxygenase to promote formation of volatile lipid oxidation products in food models

Faba bean can respond to the need for plant-based proteins for human consumption. The aim of this work was to study the role of lipid-modifying enzymes in faba bean in causing off-flavour compounds during processing. The faba bean exhibited high lipase and lipoxygenase (LOX) activities, with pH optima being 8.0 and 6.0, respectively. Faba bean LOX preferred free fatty acids (FFAs) over triacylglycerols as substrates, and together with other LOX pathway enzymes, it formed specific volatile products, as measured using headspace solid-phase microextraction–gas chromatography. During the preparation of the food models (i.e. the extracts and emulsions), enzymatic lipid oxidation occurred. The inclusion in the emulsions of rapeseed oil, especially of rapeseed oil FFAs, remarkably increased the amounts of volatile products. The largest quantities of products were formed in food models at pH 6.4, which is close to the pH optimum of LOX. Further studies on lipase in food models are needed.