In situ bioconversion of coconut oil via coconut solid state fermentation by Geotrichum candidum ATCC 34614

Coconut base solid state fermentation was carried out by Geotrichum candidum ATCC 34614 for in situ coconut oil bioconversion. Coconut oil, which contains highly saturated medium chain triglycerides, was partially bioconverted into a combination of medium chain diglycerides, medium chain monoglycerides and medium chain fatty acids by this fungus lipolytic activity. The product demonstrated improved aroma, flavor, thermal behavior and antibacterial activity. Maximum triglycerides conversion (76.5 %) occurred at 40 % moisture content and 50 % oil content after 25 days of incubation. Bioconverted coconut oil revealed as much as 95 % antibacterial activity as well as altered thermal characteristic towards lower melting and higher crystallization points. The fermented culture also revealed highly fruity and flora notes which contained five main short- and medium-chain esters known as aromatic compounds. The present study established the possibility of using G. candidum ATCC 34614 in coconut solid culture for bioconversion of coconut oil, which improves the fermented product characteristics

Production of a Solvent, Detergent, and Thermotolerant Lipase by a Newly Isolated Acinetobacter sp. in Submerged and Solid-State Fermentations

The lipase production ability of a newly isolated Acinetobacter sp. in submerged (SmF) and solid-state (SSF) fermentations was evaluated. The results demonstrated this strain as one of the rare bacterium, which is able to grow and produce lipase in SSF even more than SmF. Coconut oil cake as a cheap agroindustrial residue was employed as the solid substrate. The lipase production was optimized in both media using artificial neural network. Multilayer normal and full feed forward backpropagation networks were selected to build predictive models to optimize the culture parameters for lipase production in SmF and SSF systems, respectively. The produced models for both systems showed high predictive accuracy where the obtained conditions were close together. The produced enzyme was characterized as a thermotolerant lipase, although the organism was mesophile. The optimum temperature for the enzyme activity was 45°C where 63% of its activity remained at 70°C after 2 h. This lipase remained active after 24 h in a broad range of pH (6–11). The lipase demonstrated strong solvent and detergent tolerance potentials. Therefore, this inexpensive lipase production for such a potent and industrially valuable lipase is promising and of considerable commercial interest for biotechnological applications

Purification and characterization of nitric oxide inhibitory peptides from Actinopyga lecanora through enzymatic hydrolysis

Actinopyga lecanora, commonly known as sea cucumber, is a rich protein source. This marine protein source was hydrolyzed using six proteases to generate anti-inflammatory hydrolysates and bioactive peptides. Bromelain hydrolysates after 1 h hydrolysis exhibited the highest nitric oxide (NO) inhibitory activity reflecting anti-inflammatory activity. A sequence of two fractionation methods was employed to fractionate the peptides based on their hydrophobicity using a semi-preparative RP-HPLC and isoelectric points using isoelectric focusing technique. Based on these fractionation methods, basic peptides with relatively higher hydrophobicity provided higher NO-inhibitory activity than did acidic peptides. Furthermore, using Q-TOF mass spectrometry; 12 peptide sequences were successfully identified. The inhibitory effect of the purified peptides from A. lecanora on NO production by lipopolysaccharide (LPS)-stimulated RAW 264.7 cells was investigated. The three identified bioactive peptides, namely LREMLSTMCTARGA, AVGPAGPRG and VAPAWGPWPKG, exhibited the highest NO-inhibitory activity with values of 76.3, 66.6 and 69.9%, respectively. These results revealed that A. lecanora could be used as an economical protein source for the production of high-value bioactive peptides with potent anti-inflammatory activity using RAW 264.7 cell lines as model. These peptides may be useful ingredients in food and pharmaceutical applications

High level expression and characterization of a novel thermostable, organic solvent tolerant, 1,3-regioselective lipase from Geobacillus sp. strain ARM

The mature ARM lipase gene was cloned into the pTrcHis expression vector and over-expressed in Escherichia coli TOP10 host. The optimum lipase expression was obtained after 18h post induction incubation with 1.0mM IPTG, where the lipase activity was approximately 1623-fold higher than wild type. A rapid, high efficient, one-step purification of the His-tagged recombinant lipase was achieved using immobilized metal affinity chromatography with 63.2% recovery and purification factor of 14.6. The purified lipase was characterized as a high active (7092Umg -1), serine-hydrolase, thermostable, organic solvent tolerant, 1,3-specific lipase with a molecular weight of about 44kDa. The enzyme was a monomer with disulfide bond(s) in its structure, but was not a metalloenzyme. ARM lipase was active in a broad range of temperature and pH with optimum lipolytic activity at pH 8.0 and 65°C. The enzyme retained 50% residual activity at pH 6.0-7.0, 50°C for more than 150min

Modeling of glutamic acid production by Lactobacillus plantarum MNZ

Background: L-glutamic acid, the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism acts as a precursor of \u3b3-amino butyric acid (GABA). In the present study, culture condition for enhanced glutamic acid production by Lactobacillus plantarum MNZ was optimized and the influence of such conditions on GABA production was evaluated. Results: Results indicated that glutamic acid increased up to 3-fold (3.35) under the following condition: pH 4.5, temperature 37\ub0C, 12% (w/v) glucose and 0.7% (w/v) ammonium nitrate; whilst GABA production was enhanced up to 10-fold under the following condition: pH 4.5, temperature 37oC, 6% (w/v) glucose and 0.7% (w/v) ammonium nitrate. Conclusions: This is the first report for dual biosynthesizing activities of a lactic acid bacterium for the production of glutamic acid and GABA. The results of this study can be further used for developing functional foods rich inglutamic acid and subsequently GABA as a bioactive compound

A modeling study by response surface methodology and artificial neural network on culture parameters optimization for thermostable lipase production from a newly isolated thermophilic Geobacillus sp. strain ARM

Background: Thermostable bacterial lipases occupy a place of prominence among biocatalysts owing to their novel, multifold applications and resistance to high temperature and other operational conditions. The capability of lipases to catalyze a variety of novel reactions in both aqueous and nonaqueous media presents a fascinating field for research, creating interest to isolate novel lipase producers and optimize lipase production. The most important stages in a biological process are modeling and optimization to improve a system and increase the efficiency of the process without increasing the cost. Results: Different production media were tested for lipase production by a newly isolated thermophilic Geobacillus sp. strain ARM (DSM 21496 = NCIMB 41583). The maximum production was obtained in the presence of peptone and yeast extract as organic nitrogen sources, olive oil as carbon source and lipase production inducer, sodium and calcium as metal ions, and gum arabic as emulsifier and lipase production inducer. The best models for optimization of culture parameters were achieved by multilayer full feedforward incremental back propagation network and modified response surface model using backward elimination, where the optimum condition was: growth temperature (52.3°C), medium volume (50 ml), inoculum size (1%), agitation rate (static condition), incubation period (24 h) and initial pH (5.8). The experimental lipase activity was 0.47 Uml-1 at optimum condition (4.7-fold increase), which compared well to the maximum predicted values by ANN (0.47 Uml-1) and RSM (0.476 Uml-1), whereas R2 and AAD were determined as 0.989 and 0.059% for ANN, and 0.95 and 0.078% for RSM respectively. Conclusion: Lipase production is the result of a synergistic combination of effective parameters interactions. These parameters are in equilibrium and the change of one parameter can be compensated by changes of other parameters to give the same results. Though both RSM and ANN models provided good quality predictions in this study, yet the ANN showed a clear superiority over RSM for both data fitting and estimation capabilities. On the other hand, ANN has the disadvantage of requiring large amounts of training data in comparison with RSM. This problem was solved by using statistical experimental design, to reduce the number of experiments

Comparison of estimation capabilities of response surface methodology (RSM) with artificial neural network (ANN) in lipase-catalyzed synthesis of palm-based wax ester

<p>Abstract</p> <p>Background</p> <p>Wax esters are important ingredients in cosmetics, pharmaceuticals, lubricants and other chemical industries due to their excellent wetting property. Since the naturally occurring wax esters are expensive and scarce, these esters can be produced by enzymatic alcoholysis of vegetable oils. In an enzymatic reaction, study on modeling and optimization of the reaction system to increase the efficiency of the process is very important. The classical method of optimization involves varying one parameter at a time that ignores the combined interactions between physicochemical parameters. RSM is one of the most popular techniques used for optimization of chemical and biochemical processes and ANNs are powerful and flexible tools that are well suited to modeling biochemical processes.</p> <p>Results</p> <p>The coefficient of determination (R²) and absolute average deviation (AAD) values between the actual and estimated responses were determined as 1 and 0.002844 for ANN training set, 0.994122 and 1.289405 for ANN test set, and 0.999619 and 0.0256 for RSM training set respectively. The predicted optimum condition was: reaction time 7.38 h, temperature 53.9°C, amount of enzyme 0.149 g, and substrate molar ratio 1:3.41. The actual experimental percentage yield was 84.6% at optimum condition, which compared well to the maximum predicted value by ANN (83.9%) and RSM (85.4%). The order of effective parameters on wax ester percentage yield were; respectively, time with 33.69%, temperature with 30.68%, amount of enzyme with 18.78% and substrate molar ratio with 16.85%, whereas R²and AAD were determined as 0.99998696 and 1.377 for ANN, and 0.99991515 and 3.131 for RSM respectively.</p> <p>Conclusion</p> <p>Though both models provided good quality predictions in this study, yet the ANN showed a clear superiority over RSM for both data fitting and estimation capabilities.</p

Purification and characterization of membrane-bound polyphenoloxidase (mPPO) from Snake fruit [Salacca zalacca (Gaertn.) Voss].

Membrane-bound polyphenoloxidase (mPPO) an oxidative enzyme which is responsible for the undesirable browning reaction in Snake fruit (Salacca zalacca (Gaertn.) Voss) was investigated. The enzyme was extracted using a non-ionic detergent (Triton X-114), followed by temperature-induced phase partitioning technique which resulted in two separate layers (detergent-poor phase at the upper layer and detergent-rich phase at the lower layer). The upper detergent-poor phase extract was subsequently fractionated by 40–80% ammonium sulfate and chromatographed on HiTrap Phenyl Sepharose and Superdex 200 HR 10/30. The mPPO was purified to 14.1 folds with a recovery of 12.35%. A single prominent protein band appeared on native-PAGE and SDS–PAGE implying that the mPPO is a monomeric protein with estimated molecular weight of 38 kDa. Characterization study showed that mPPO from Snake fruit was optimally active at pH 6.5, temperature 30 °C and active towards diphenols as substrates. The Km and Vmax values were calculated to be 5.46 mM and 0.98 U/ml/min, respectively, when catechol was used as substrate. Among the chemical inhibitors tested, l-cysteine showed the best inhibitory effect, with an IC50 of 1.3 ± 0.002 mM followed by ascorbic acid (1.5 ± 0.06 mM), glutathione (1.5 ± 0.07 mM), EDTA (100 ± 0.02 mM) and citric acid (186 ± 0.16 mM)

Thermostable lipase from a newly isolated Staphylococcus xylosus strain; process optimization and characterization using RSM and ANN

Normal feed forward back-propagation artificial neural network (ANN) and cubic backward elimination response surface methodology (RSM) were used to build a predictive model of the combined effects and optimization of culture parameters for the lipase production of a newly isolated Staphylococcus xylosus . The results demonstrated a high predictive accuracy of artificial neural network compared to response surface methodology. The optimum operating condition obtained from the ANN model was found to be at 30\ub0C incubation temperature, pH 7.5, 60 hrs incubation period, 1.8% inoculum size and 60 rpm agitation. The lipase production increased 3.5 fold for optimal medium. The produced enzyme was characterized biochemically and this is the first report about a mesophilic staphylococci bacterium with a high thermostable lipase which is able to retain 50% of its activity at 70\ub0C after 90 min and at 60\ub0C after 120 min. This lipase is also acidic and alkaline resistant which remains active after 24 hrs in a broad range of pH (4-11)

Purification and characterization of angiotensin converting enzyme-inhibitory peptides derived from Stichopus horrens: stability study against the ACE and inhibition kinetics

Stichopus horrens is the most popular species of sea cucumber due to strong beliefs of its numerous medicinal properties. In this study, ACE-inhibitory peptides of S. horrens generated through enzymatic hydrolysis using Alcalase were isolated. Three peptides EVSQGRP, CRQNTLGHNTQTSIAQ and VSRHFASYAN were found to exhibit high inhibition potency with IC50 values of 0.05, 0.08 and 0.21 mM, respectively. It was found that the EVSQGRP, VSRHFASYAN and SAAVGSP exhibiting mixed inhibition patterns were susceptible to degradation by ACE as well, suggesting that the mixed-mode inhibition could be a result of new generated peptide fragments while CRQNTLGHNTQTSIAQ inhibited ACE in a non-competitive manner. In-vivo ACE inhibition studies showed that 400 mg/kg of Alcalase-generated proteolysate stabilized the blood pressure in normotensive rats. These results suggest that the hydrolysed protein components of S. horrens possess bioactive peptides that can be exploited as functional food ingredients against hypertension