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Infection and Drug Resistance 2022Long-term chemotherapy and immunosuppressants in acute myeloid leukaemia (AML) patients can result in a high risk of opportunistic infections. is an opportunistic...
Long-term chemotherapy and immunosuppressants in acute myeloid leukaemia (AML) patients can result in a high risk of opportunistic infections. is an opportunistic pathogen that exists in nature, but infection caused by is rare in the clinic. Notably, the sensitivity and detection time of conventional diagnostic tools for this fungus usually falls short of the needs of clinical diagnosis, resulting in treatment failure. Currently, metagenomics next-generation sequencing (mNGS) has played an important role in the detection of pathogens. Here, we report a case of pneumonia in a haematopoietic stem cell transplantation (HSCT) patient, detected by the mNGS method.
PubMed: 35965849
DOI: 10.2147/IDR.S376045 -
EFSA Journal. European Food Safety... Aug 2022The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164. The enzyme is chemically...
The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164. The enzyme is chemically modified by DuPont Nutrition Biosciences (now IFF) to produce a thermolabile form. The food enzyme is free from viable cells of the production organism. It is intended to be used in milk processing for cheese production. The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.98 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,320 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 1,300. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched and five matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but is considered low except for individuals sensitised to mustard proteins, but this risk will not exceed that of mustard consumption. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
PubMed: 35949932
DOI: 10.2903/j.efsa.2022.7460 -
EFSA Journal. European Food Safety... Aug 2022The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164 by Takabio. The enzyme is...
The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164 by Takabio. The enzyme is chemically modified to produce a thermolabile form. The food enzyme is free from viable cells of the production organism. It is intended to be used in milk processing for cheese production. The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.98 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,320 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 1,300. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched and five matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but is considered low except for individuals sensitised to mustard proteins, but this risk will not exceed that of mustard consumption. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
PubMed: 35936946
DOI: 10.2903/j.efsa.2022.7459 -
Molecules (Basel, Switzerland) Jul 2022Four commercial immobilized lipases biocatalysts have been submitted to modifications with different metal (zinc, cobalt or copper) phosphates to check the effects of...
Four commercial immobilized lipases biocatalysts have been submitted to modifications with different metal (zinc, cobalt or copper) phosphates to check the effects of this modification on enzyme features. The lipase preparations were LipozymeTL (TLL-IM) (lipase from ), Lipozyme435 (L435) (lipase B from ), LipozymeRM (RML-IM), and LipuraSelect (LS-IM) (both from lipase from ). The modifications greatly altered enzyme specificity, increasing the activity versus some substrates (e.g., TLL-IM modified with zinc phosphate in hydrolysis of triacetin) while decreasing the activity versus other substrates (the same preparation in activity versus - or - methyl mandelate). Enantiospecificity was also drastically altered after these modifications, e.g., LS-IM increased the activity versus the isomer while decreasing the activity versus the isomer when treated with copper phosphate. Regarding the enzyme stability, it was significantly improved using octyl-agarose-lipases. Using all these commercial biocatalysts, no significant positive effects were found; in fact, a decrease in enzyme stability was usually detected. The results point towards the possibility of a battery of biocatalysts, including many different metal phosphates and immobilization protocols, being a good opportunity to tune enzyme features, increasing the possibilities of having biocatalysts that may be suitable for a specific process.
Topics: Copper; Enzymes, Immobilized; Fungal Proteins; Lipase; Phosphates; Salts
PubMed: 35889359
DOI: 10.3390/molecules27144486 -
Frontiers in Chemistry 2022Violacein (Viol) is a bacterial purple water-insoluble pigment synthesized by and other microorganisms that display many beneficial therapeutic properties including...
Enzymatic Active Release of Violacein Present in Nanostructured Lipid Carrier by Lipase Encapsulated in 3D-Bioprinted Chitosan-Hydroxypropyl Methylcellulose Matrix With Anticancer Activity.
Violacein (Viol) is a bacterial purple water-insoluble pigment synthesized by and other microorganisms that display many beneficial therapeutic properties including anticancer activity. Viol was produced, purified in our laboratory, and encapsulated in a nanostructured lipid carrier (NLC). The NLC is composed of the solid lipid myristyl myristate, an oily lipid mixture composed of capric and caprylic acids, and the surfactant poloxamer P188. Dormant lipase from was incorporated into the NLC-Viol to develop an active release system. The NLC particle size determined by dynamic light scattering brings around 150 nm particle size and ≈ -9.0 mV with or without lipase, but the incorporation of lipase increase the PdI from 0.241 to 0.319 (≈32%). For scaffold development, a 2.5 hydroxypropyl methylcellulose/chitosan ratio was obtained after optimization of a composite for extrusion in a 3D-bioprinter developed and constructed in our laboratory. Final Viol encapsulation efficiency in the printings was over 90%. Kinetic release of the biodye at pH = 7.4 from the mesh containing NLC-lipase showed roughly 20% Viol fast release than without the enzyme. However, both Viol kinetic releases displayed similar profiles at pH = 5.0, where the lipase is inactive. The kinetic release of Viol from the NLC-matrices was modeled and the best correlation was found with the Korsmeyer-Peppas model (R = 0.95) with < 0.5 suggesting a Fickian release of Viol from the matrices. Scanning Electron Microscope (SEM) images of the NLC-meshes showed significant differences before and after Viol's release. Also, the presence of lipase dramatically increased the gaps in the interchain mesh. XRD and Fourier Transform Infrared (FTIR) analyses of the NLC-meshes showed a decrease in the crystalline structure of the composites with the incorporation of the NLC, and the decrease of myristyl myristate in the mesh can be attributed to the lipase activity. TGA profiles of the NLC-meshes showed high thermal stability than the individual components. Cytotoxic studies in A549 and HCT-116 cancer cell lines revealed high anticancer activity of the matrix mediated by mucoadhesive chitosan, plus the biological synergistic activities of violacein and lipase.
PubMed: 35873038
DOI: 10.3389/fchem.2022.914126 -
International Journal of Molecular... Jun 2022One of the indispensable applications of lipases in modification of oils and fats is the possibility to tailor the fatty acid content of triacylglycerols (TAGs), to meet...
One of the indispensable applications of lipases in modification of oils and fats is the possibility to tailor the fatty acid content of triacylglycerols (TAGs), to meet specific requirements from various applications in food, nutrition, and cosmetic industries. Oleic acid (C18:1) and stearic acid (C18:0) are two common long fatty acids in the side chain of triglycerides in plant fats and oils that have similar chemical composition and structures, except for an unsaturated bond between C9 and C10 in oleic acid. Two lipases from (RML) and (ROL) show activity in reactions involving oleate and stearate, and share high sequence and structural identity. In this research, the preference for one of these two similar fatty acid side chains was investigated for the two lipases and was related to the respective enzyme structure. From transesterification reactions with 1:1 (molar ratio) mixed ethyl stearate (ES) and ethyl oleate (EO), both RML and ROL showed a higher activity towards EO than ES, but RML showed around 10% higher preference for ES compared with ROL. In silico results showed that stearate has a less stable interaction with the substrate binding crevice in both RML and ROL and higher tendency to freely move out of the substrate binding region, compared with oleate whose structure is more rigid due to the existence of the double bond. However, Trp88 from RML which is an Ala at the identical position in ROL shows a significant stabilization effect in the substrate interaction in RML, especially with stearate as a ligand.
Topics: Fungal Proteins; Lipase; Molecular Docking Simulation; Oleic Acids; Rhizomucor; Rhizopus oryzae; Sequence Analysis, Protein; Stearates; Structure-Activity Relationship; Substrate Specificity
PubMed: 35806072
DOI: 10.3390/ijms23137072 -
Journal of Applied Microbiology Sep 2022To investigate the characteristics of two minority autochthonous LAB species, with particular regard to those properties that could be exploited in an improved cocoa...
AIMS
To investigate the characteristics of two minority autochthonous LAB species, with particular regard to those properties that could be exploited in an improved cocoa fermentation process from a quality and safety point of view.
METHODS AND RESULTS
Bacterial, yeast and mould strains characteristic of spontaneously fermented Dominican cocoa beans were isolated and identified by 16S or 26S rRNA gene sequencing. The potential of two autochthonous strains of LAB belonging to the species Lactiplantibacillus fabifermentans and Furfurilactibacillus rossiae were investigated. The two selected LAB strains were able to utilize glucose and fructose, produced mainly D-L lactic acid and had a good ability to resist to cocoa-related stress conditions such as low pH, high temperature and high osmotic pressure, as well as to grow in sterile cocoa pulp. The strains did not inhibit the growth of yeasts and acetic acid bacteria, that are essential to the cocoa fermentation process, and possessed a complex pool of peptidases especially active on hydrophobic amino acids. The strains also showed antifungal activity against mould species that can be found at the final stages of cocoa fermentation, as Aspergillus tamarii, A. nidulans, Lichtheimia ornata and Rhizomucor pusillus.
CONCLUSIONS
The tested strains are good candidates for the design of starter cultures for a controlled cocoa fermentation process.
SIGNIFICANCE AND IMPACT OF THE STUDY
This research showcases the potential of two alternative LAB species to the dominating Lactiplantibacillus plantarum and Limosilactibacillus fermentum as cocoa fermentation starters, with an interesting activity in improving the safety and quality of the process.
Topics: Bacteria; Cacao; Fermentation; Lactobacillus; Limosilactobacillus fermentum; Saccharomyces cerevisiae
PubMed: 35751485
DOI: 10.1111/jam.15687 -
International Journal of Molecular... Jun 2022The behavior against temperature and thermal stability of enzymes is a topic of importance for industrial biocatalysis. This study focuses on the kinetics and...
The behavior against temperature and thermal stability of enzymes is a topic of importance for industrial biocatalysis. This study focuses on the kinetics and thermodynamics of the thermal inactivation of Lipase PS from and Palatase from . Thermal inactivation was investigated using eight inactivation models at a temperature range of 40-70 °C. Kinetic modeling showed that the first-order model and Weibull distribution were the best equations to describe the residual activity of Lipase PS and Palatase, respectively. The results obtained from the kinetic parameters, decimal reduction time (D and t), and temperature required (z and z') indicated a higher thermal stability of Lipase PS compared to Palatase. The activation energy values (Ea) also indicated that higher energy was required to denature bacterial (34.8 kJ mol) than fungal (23.3 kJ mol) lipase. The thermodynamic inactivation parameters, Gibbs free energy (ΔG), entropy (ΔS), and enthalpy (ΔH) were also determined. The results showed a ΔG for Palatase (86.0-92.1 kJ mol) lower than for Lipase PS (98.6-104.9 kJ mol), and a negative entropic and positive enthalpic contribution for both lipases. A comparative molecular dynamics simulation and structural analysis at 40 °C and 70 °C were also performed.
Topics: Burkholderia cepacia; Enzyme Stability; Kinetics; Lipase; Molecular Dynamics Simulation; Rhizomucor; Temperature; Thermodynamics
PubMed: 35743268
DOI: 10.3390/ijms23126828 -
Foods (Basel, Switzerland) Jun 2022Hydrolysis of olive, rapeseed, linseed, almond, peanut, grape seed and menhaden oils was performed with commercial lipases of , , , and . In chromogenic plate tests,...
Hydrolysis of olive, rapeseed, linseed, almond, peanut, grape seed and menhaden oils was performed with commercial lipases of , , , and . In chromogenic plate tests, olive, rapeseed, peanut and linseed oils degraded well even after 2 h of incubation, and the , and lipases exhibited the highest overall action against the oils. Gas chromatography analysis of vegetable oils hydrolyzed by lipase revealed about 1.1 to 38.4-fold increases in the concentrations of palmitic, stearic, oleic, linoleic and α-linolenic acids after the treatment, depending on the fatty acids and the oil. The major polyunsaturated fatty acids produced by lipase treatment from menhaden oil were linoleic, α-linolenic, hexadecanedioic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acids, with yields from 12.02 to 52.85 µg/mL reaction mixture. Folin-Ciocalteu and ferric reducing power assays demonstrated improved antioxidant capacity for most tested oils after the lipase treatment in relation to the concentrations of some fatty acids. Some lipase-treated and untreated samples of oils, at 1.25 mg/mL lipid concentration, inhibited the growth of food-contaminating bacteria. The lipid mixtures obtained can be reliable sources of extractable fatty acids with health benefits.
PubMed: 35741908
DOI: 10.3390/foods11121711 -
Journal, Genetic Engineering &... May 2022Protease is one of the most important industrial enzymes. The importance of protease bioproduction comes from meeting the increasing demand for this enzyme especially in...
BACKGROUND
Protease is one of the most important industrial enzymes. The importance of protease bioproduction comes from meeting the increasing demand for this enzyme especially in the cheese industry. Rhizomucor miehei protease is the preferred substitute for the traditional rennet. Solid-state fermentation (SSF) shows promising results in enzyme production. An optimization strategy was applied to optimize the production of Rhizomucor miehei protease in a solid medium. The components of the fermentation medium were screened by using the one-factor-at-a-time (OFAT) approach. The optimization process then was performed by using the response surface methodology (RSM) approach based on five factors (fermentation time, temperature, pH, moisture content, nitrogen concentration) at five levels. Specific milk clotting activity and milk clotting activity/proteolytic activity ratio were considered as response variables in the optimization process.
RESULTS
Among several combinations, wheat bran was selected as the best substrate. Casein was selected based on preliminary screening of nitrogen sources. The optimal conditions identified by RSM analysis were found to be 81.21 h, 41.11°C, 6.31, 80%, and 1.33% for fermentation time, temperature, pH, moisture content, and casein concentration, respectively. The performed fermentation process under the optimized conditions gave an enzymatic extract with the values of 5.11 mg/mL, 2258.13 Soxhlet unit/mL, 441.90 Soxhlet unit/mg, 1.14 protease unit/mg, and 388.66 for protein content, milk clotting activity, specific clotting activity, specific proteolytic activity, and milk clotting activity/proteolytic activity ratio, respectively. The aforementioned values were close to the predicted values.
CONCLUSION
The high milk clotting activity and the relatively low proteolytic activity signify higher specificity of the produced enzyme, which is favorable in cheese making. The observed results reveal the efficiency of the applied statistical approaches in obtaining desired values of response variables and minimizing experimental runs, as well as achieving good predictions for response variables.
PubMed: 35635657
DOI: 10.1186/s43141-022-00358-9