Suchergebnisse

The present study aims to improve the hydrophobicity and durability of bacterial cellulose (BC) nonwoven by functionalization with poly(fluorophenol). To this end, laccase was first entrapped onto BC and then used to polymerize the fluorophenol {4-[4-(trifluoromethyl) phenoxy] phenol} in-situ. The polymerization of fluorophenol by laccase was confirmed through 1H NMR and MALDI-TOF analyses. The effect of poly(fluorophenol) on BC nonwoven was determined by evaluation of the surface hydrophobicity and olephobicity properties such as water contact angle (WCA), oil contact angle (OCA), surface energy and water/oil absorption time. After BC functionalization with poly(fluorophenol) (20 mM), the WCA increased from 54.5 ± 1.2° to 120 ± 1.5° while the surface energy decreased (11.58 ± 1.4 mN/m). The OCA was also increased from 46.5 ± 2.5° to 87 ± 2° along to the decrease of surface energy (8.7 ± 1.5°). X-ray photoelectron spectroscopy (XPS) analysis confirmed an increase in the fluorine content in BC from 5.27 to 17.57%. The findings confirmed the polymerization of fluorophenol by laccase and its entrapment onto a BC nanofiber structure. The durability of the functionalization with poly(fluorophenol) was confirmed by evaluating the washing fastness, tensile strength after washing and dimensional stability. The results indicate that the functionalized BC nonwoven had higher tensile strength (×10 times) and better dimensional stability (30%) than the non-functionalized BC nonwoven material. ; This work was supported by the Portuguese Foundationfor Science and Technology (FCT) under the scope of thestrategic funding of UID/BIO/04469/2019 unit and Bio-TecNorteoperation (NORTE-01-0145-FEDER-000004). This work wasalso supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government (MSIT) (No. NRF-2019R1A2C1009217). ...

Bacterial cellulose (BC) was obtained by static cultivation using commercial BC gel from scoby. BC membranes (oven dried and freeze-dried) were swelled with 8% NaOH, in absence and in presence of ultrasound (US), for 30, 60 and 90 min. The influence of swelling conditions on both physico-chemical properties and molecules entrapment was evaluated. Considering the highest levels of entrapment, an optimum swelling procedure was established: 8% NaOH for 30 min. at room temperature in the presence of US. Native and PEGylated laccase from Myceliophthora Thermophila was immobilized on BC membranes and a different catalytic behaviour was observed after immobilization. Native laccase presented activity values similar to published reports (5-7 U/gBC) after immobilization whereas PEGylated enzymes showed much lower activity (1-2 U/gBC). BC swelled membranes are presented herein as a potential support for the preparation of immobilized enzymes for industrial applications, like phenolics polymerization. ; The authors would like to acknowledge Portuguese Foundation for Science and Technology (FCT)under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI01-0145-FEDER-006684) and BioTecNorte operation (NORTE01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors would like also to acknowledge the Basic Science Research Program through the National Research Foundation of Korea (NRF), which was funded by the Ministry of Education (2015R1D1A1A01060747). This work also received funding from the European Union Horizon 2020 research and innovation programme under grant agreement NMP-06-2015-683356 FOLSMART. ...

Improper domestic food handling in rural areas of China is an important public health issue leading to foodborne illness. However, the underlying factors responsible for poor domestic food hygiene practices have not been comprehensively studied. Here, a cross-sectional study was conducted in Anhui Province, China between 2015 - 2016, using a questionnaire to collect data from 819 respondents, selected using multistage cluster random sampling techniques. Multivariate logistic regression analysis was then used to assess the demographic factors associated with improper food handling. Results showed that 525 (64.1%) of respondents used improper food handling techniques. The factors associated with improper food handling included gender, age, education, income, and occupation. Males (vs. females), adults aged ≥ 50 years (vs. those aged 18 - 30 years), individuals with primary school education or lower (vs. individuals with a bachelor's degree or higher), individuals with annual incomes of < 4,387 USD (vs. income ≥ 13,161 USD), and workers (vs. other occupation groups) were more likely to report inappropriate food handling practices in rural areas. The results obtained from the present work may provide the basis for training in domestic food safety hygiene/handling practices in rural areas of China in order to reduce the incidence of foodborne illnesses.