52 research outputs found
Eco-friendly mangrove-derived nanocomposite coating for sustainable biofouling and corrosion protection in Persian Gulf field trials
No full text: Marine biofouling and corrosion impose major environmental and operational costs on maritime industries. This study aims to develop an eco-friendly, mangrove-derived nanocomposite coating that sustainably mitigates both challenges. Aluminum oxide and titanium dioxide nanoparticles were green-synthesized using Avicennia marina leaf extract and integrated with multi-walled carbon nanotubes (MWCNTs) into a polydimethylsiloxane (PDMS) matrix. Structural characterization (XRD, FTIR, FESEM-EDS, UV-Vis) confirmed uniform nanoparticle dispersion and hybrid formation with enhanced photocatalytic efficiency. The optimized 0.5 wt% Al2O3-TiO2@MWCNT/PDMS coating exhibited superior antibacterial performance, achieving 96.5 % inhibition against S. aureus, 97.2 % against E. coli, and 95.8 % against P. aeruginosa, alongside 98.7 % anti-algal suppression of Nannochloropsis oculata. Corrosion current density reached as low as 0.008 μA/cm2, while polarization resistance increased to 4750 kΩ·cm2. Four-month field trials in the Persian Gulf demonstrated a 68 % reduction in fouling coverage relative to control PDMS panels. Through green synthesis and the exclusion of toxic biocides, this coating minimizes ecological risk and supports UN Sustainable Development Goals 9 and 14 by providing a scalable, durable, low-impact solution for marine infrastructure protection
Identification of a novel tailor-made chitinase from white shrimp Fenneropenaeus merguiensis
No full textFenneropenaeus merguiensis (commonly named banana shrimp) is one of the most important farmed crustacean worldwide species for the fisheries and aquaculture industry. Besides its nutritional value, it is a good source of chitinase, an enzyme with excellent biological and catalytic properties for many industrial applications. In the present study, a putative chitinase-encoding cDNA was synthesized from mRNA from F. merguiensis hepatopancreas tissue. Subsequently, the corresponding cDNA was cloned, sequenced and functionally expressed in Escherichia coli, and the recombinant F. merguiensis chitinase (rFmCHI) was purified by His-tag affinity chromatography. The bioinformatics analysis of aminoacid sequence of rFmCHI displayed a cannonical multidomain architecture in chitinases which belongs to glycoside hydrolase family 18 (GH18 chitinase). Biochemical characterization revealed rFmCHI as a monomeric enzyme of molecular weight 52 kDa with maximum activity at 40 °C and pH 6.0 Moreover, the recombinant enzyme is also stable up to 60 °C, and in the pH range 5.0-8.0. Steady-state kinetic studies for colloidal chitin revealed KM, Vmax and kcat values of 78.18 μM, 0.07261 μM. min−1 and 43.37 s−1, respectively. Overall, our results aim to demonstrate the potential of rFmCHI as suitable catalyst for bioconversion of chitin waste.Sin financiación5.999 Q1 JCR 20210.882 Q1 SJR 2021No data IDR 2021UE
Nano-organic supports for enzyme immobilization: Scopes and perspectives
No full textA variety of organic nanomaterials and organic polymers are used for enzyme immobilization to increase enzymes stability and reusability. In this study, the effects of the immobilization of enzymes on organic and organic-inorganic hybrid nano-supports are compared. Immobilization of enzymes on organic support nanomaterials was reported to significantly improve thermal, pH and storage stability, acting also as a protection against metal ions inhibitory effects. In particular, the effects of enzyme immobilization on reusability, physical, kinetic and thermodynamic parameters were considered. Due to their biocompatibility with low health risks, organic support nanomaterials represent a good choice for the immobilization of enzymes. Organic nanomaterials, and especially organic-inorganic hybrids, can significantly improve the kinetic and thermodynamic parameters of immobilized enzymes compared to macroscopic supports. Moreover, organic nanomaterials are more environment friendly for medical applications, such as prodrug carriers and biosensors. Overall, organic hybrid nanomaterials are receiving increasing attention as novel nano-supports for enzyme immobilization and will be used extensively
Novel cold-adapted lipase from Psychrobacter sp. C18 immobilized on reduced graphene oxide-cellulose nanomatrix with high activity and stability
No full textHere, biocompatible hybrid graphene oxide-cellulose nanocrystals (rGO-CNC) were synthesized and used as nanomatrix to immobilize a novel recombinant cold-adopted lipase from Psychrobacter sp. C18. Different steps of the nanomatrix synthesis and the lipase immobilization were verified by FT-IR, DLS, SEM, circular dichroism, spectrofluorimetry, and spectrophotometer-based kinetic and thermodynamic studies. According to our results, the values of kcat for physically and covalently immobilized lipase were 1.06 and 2.47 times higher than that of the soluble lipase, respectively. Moreover, the remaining activity of lipases during storage stability at 4 °C for 30 days were estimated to be 2.47 and 1.25 more than that of the soluble lipase, respectively. In addition, covalently immobilized lipases were reused after 5 successive cycles while retained about 60 % of its initial activity. Although the physical adsorption strategy increased the catalytic efficiency by 2.45 times, compared with soluble lipase, the thermal stability of covalently immobilized lipase was 5.2 times higher than that of the soluble enzyme. Additionally, covalently immobilized lipase showed remarkable resistance against extreme changes in environmental conditions such as metal ions, organic solvents, and pH changes. Altogether, based on our results, the covalently immobilized novel cold-adopted lipase is a suitable candidate for biotechnological and industrial applications
Investigation of activity and stability of papain by adsorption on multi-wall carbon nanotubes
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Isolation and Molecular Identification of Xylanase-Producing Bacteria from Ulva flexuosa of the Persian Gulf
No full textThe marine ecosystem is one of the richest sources of biologically active compounds, such as enzymes, among which seaweed is one of the most diverse marine species and has a rich diversity of bacteria that produce different enzymes. Among these, the bacteria-derived xylanase enzyme has many applications in the fruit juice, paper, and baking industries; so, to consider the economic value of the xylanase enzyme and the isolation and identification of xylanase-producing bacteria is of particular importance. In this study, specimens of the alga Ulva flexuosa species were collected from the coasts of Bandar Abbas and Qeshm Island. The bacteria coexisting with the algae were isolated using a nutrient agar medium. The bacteria producing the xylanase enzyme were then screened by a specific solid culture medium containing xylan, and the activity of the xylanase enzyme isolated from the bacteria was measured using a xylan substrate. The bacteria with the highest enzymatic activity were selected and identified by 16S rRNA gene sequence analysis, and the culture medium conditions for the enzyme production by the selected bacterial strains were optimized. Among the bacterial community, two strains with the highest xylanase activity, which belonged to the genera Bacillus and Shewanella, were identified as Bacillus subtilis strain HR05 and Shewanella algae strain HR06, respectively. The two selected bacteria were registered in the NCBI gene database. The results demonstrated that the two selected strains had different optimal growing conditions in terms of pH and temperature, as well as the sources of carbon and nitrogen for enzyme production. It seems that the xylanase enzyme isolated from the bacterial strains HR05 and HR06, which coexist with alga Ulva flexousa, could be potential candidates for biotechnology and various industries, such as pulp production, paper, and food manufacture, due to their high activity and optimal alkaline pH
Novel additive for sperm cryopreservation media: Holotheria parva coelomic cavity extract protects human spermatozoa against oxidative stress—A pilot study
No full textCryopreservation is the most effective method for preserving semen for a long period of time. However, during the freeze–thaw process, production of reactive oxygen species (ROS) leads to a steep reduction in sperm fertility indices. In this study, we tested the effects of the extract of the coelomic cavity of five Holotheria parva, a marine organism rich in antioxidants, for its ROS-scavenging activity and cryoprotective effects on oxidative stress. Using a total of 50 semen samples, our results demonstrated that doses of 250 and 500 μg/ml of H. parva coelomic cavity extract significantly increased sperm vitality as compared to the control (p <.05). The addition of 250 μg/ml of the extract exerted a significant positive effect on sperm motility. Moreover, sperm DNA damage and ROS production were significantly reduced at extract concentrations of 250 and 500 μg/ml (p <.05). To the best of our knowledge, the results of this study represent the first demonstration of the possibility of improving sperm parameters and reducing ROS production and DNA damage by supplementing sperm freezing media with H. parva coelomic extract. Our results suggested that H. parva coelomic extract could be useful for improving the fertilising ability of frozen-thawed human semen
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