Добірка наукової літератури з теми "Dibromonitrilopropionamide (DBNPA)"

Abstract Microorganism growth in industrial systems is controlled through the use of biocides and biodispersants. There is, however, no simple means of determining the efficacy of these control mechanisms, but it is currently tested using complex bacterial culturing techniques. Biolog Ecoplates® have been used to detect bacterial population changes in various communities. These microtitre plates comprise 31 different carbon substrates (in triplicate) with wells. When a sample is added to the wells, bacteria capable of metabolising the relevant carbon sources respire the substrates, causing the tetrazolium dye in the well to turn purple, indicating a positive result. Hypothetically, the higher the microbial diversity, the more substrates will be utilised and vice versa. The objective of this study was to test this hypothesis, using Biolog Ecoplates® as a potential simple indicator to determine the efficiency of a biocide to control microbial growth in cooling water systems by monitoring the changes in the microbial metabolic pattern. This study proved the hypothesis using Biolog Ecoplates®, indicating that the addition of biocides at various concentrations resulted in fewer substrates being utilised, indicative of a decrease in microbial species diversity.

Conventional methods for water disinfection, especially chlorination, have a lot of disadvantages and should be perfected or substituted with safer and more efficient methods. One of the possible solutions to this problem is the application of sorbents with high disinfection efficacy. In this study, the opportunity of producing sorbents with biocidal properties based on non-oxidizing biocides and anion exchange resins (AERs) was investigated. A wide range of different type of AERs were tested for the ability to sorb biocides (dibromonitrilopropionamide (DBNPA) and polyhexamethyleneguanidine (PHMG)) and to exert disinfection activity. Most suitable AERs for production of biocidal sorbents were outlined.

Biocides are widely used in water treatment for microbiological control. The rise of antimicrobial resistance and the need to assure properly managed water systems require a better understanding of the mechanisms of action of biocides and of their impact on cell’s viability as a function of dosage concentrations. The present work addresses these two aspects regarding the biocides benzalkonium chloride (BAC) and dibromonitrilopropionamide (DBNPA)—two biocides commonly found in the water treatment industry. For that, the following parameters were studied: culturability, membrane integrity, metabolic activity, cellular energy, and the structure and morphology of cells. Also, to assess cell’s death, a reliable positive control, consisting of cells killed by autoclave (dead cells), was introduced. The results confirmed that BAC is a lytic biocide and DBNPA a moderate electrophilic one. Furthermore, the comparison between cells exposed to the biocides’ minimum bactericidal concentrations (MBCs) and autoclaved cells revealed that other viability parameters should be taken into consideration as “death indicators.” The present work also shows that only for the concentrations above the MBC the viability indicators reached values statistically similar to the ones observed for the autoclaved cells (considered to be definitively dead). Finally, the importance of considering the biocide mechanism of action in the definition of the viability parameter to use in the viable but non-culturable (VBNC) determination is discussed.