Depending on different applications or materials that integrate with the substrate as well as the transduction method used in the biosensors, different materials of the substrate are considered. This research focuses on selecting the appropriate substrate in designing biosensors, detecting microorganisms in the environment. In this study, the glass slide (glass), Polyethylen plastic (PE plastic), and the cellulose paper (cellulose acetate (CA) & cellulose nitrate (CN)) are investigated substrates for coating AgNPs/ZIF-8 – material used as an optical signal amplification in further steps, using structural analysis techniques – Scanning Electron Microscopy (SEM) for morphology characterization and the Energy Dispersive Spectrometer (EDS) for optical characterization. A morphology characterization with SEM showed that cellulose paper is a better substrate in comparing with the other substrates (glass, PE), because the sensity of distribution on CN was the highest (85-90%) when it coated with AgNPs/ZIF-8. According to EDS analysis, the ratios of Ag in mixture on CN substrate (15.38±0.39% mass) is slightly higher than CA substrate (13.58±0.39% mass); and about 53 times higher than glass substrate (0.37±0.13% mass) and PE plastic substrate (0.29±0.08%). Therefore, cellulose paper (CA) will be suggested to select for further research as a new material with cost (inexpensive) and effectiveness in coating AgNPs/ZIF-8.

This paper presents the possibillity of using native microoganisms from the brewery’s post-treatment sludge in order to create fertilizers by the windrow composting. The result showed that there are 3 representive useful microoganisms in the following: C1, C4 and C6. At the same time, the change in the composition of supplementary fiber into 4 treatment has resulted in the following : the everage C/N ratio of treatment are from 20 to 29, the average pH of the ratios is 7,82; total nitrogen fixation average is 2108; the highest is 5108; the smallest is 8107, microoganisms which are capable of decomposing cellulose average is 7 x 106; the highest is 9106, the lowest is 5106. Total Salmonella and E. coli are 0; the after-testing products meet the standard in the Viet Nam Bank for Agriculture and Rural Development.