Enzyme Immobilization on Nanomaterials for Biosensor and Biocatalyst in Food and Biomedical Industry.

Enzymes exhibit a great catalytic activity for several physiological processes. Utilization of immobilized enzymes has a great potential in several food industries due to their excellent functional properties, simple processing and cost effectiveness during the past decades. Though they have several applications, they still exhibit some challenges. To overcome the challenges, nanoparticles with their unique physicochemical properties act as very attractive carriers for enzyme immobilization. The enzyme immobilization method is not only widely used in the food industry but is also a component methodology in the pharmaceutical industry. Compared to the free enzymes, immobilized forms are more robust and resistant to environmental changes. In this method, the mobility of enzymes is artificially restricted to changing their structure and properties. Due to their sensitive nature, the classical immobilization methods are still limited as a result of the reduction of enzyme activity. In order to improve the enzyme activity and their properties, nanomaterials are used as a carrier for enzyme immobilization. Recently, much attention has been directed towards the research on the potentiality of the immobilized enzymes in the food industry. Hence, the present review emphasizes the different types of immobilization methods that is presently used in the food industry and other applications. Various types of nanomaterials such as nanofibers, nanoflowers and magnetic nanoparticles are significantly used as a support material in the immobilization methods. However, several numbers of immobilized enzymes are used in the food industries to improve the processing methods which not only reduce the production cost but also the effluents from the industry.

Distribution of biocide resistant genes and biocides susceptibility in multidrug-resistant Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii - A first report from the Kingdom of Saudi Arabia.

PURPOSES: The aim of this study was to determine the frequency of biocide resistant genes, qacA, qacE and cepA in multidrug resistant (MDR) bacteria: Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii and to correlate the presence or absence of resistant genes with biocides susceptibility. MATERIALS AND METHODS: The study included 44 MDR K. pneumoniae, P. aeruginosa and A. baumannii microorganisms. The bacteria were screened for the presence of biocide resistant genes by the polymerase chain reaction (PCR) method. The test organisms were isolated from various clinical specimens in the Qassim region, Saudi Arabia. The in vitro susceptibility tests of the three biocides (benzalkonium chloride, cetrimide and chlorhexidine gluconate) were studied against the test isolates by broth microdilution method following Clinical and Laboratory Standards Institute guidelines. RESULTS: With the distribution of biocide resistant genes in K. pneumoniae, all 9 isolates (100%) possessed cepA; 4 (44.4%) and 1 (11.1%) isolate contained qacA and qacE genes respectively. Among 24 isolates of A. baumannii tested, cepA, qacA and qacE genes were found in 54.2%, 16.7% and 33.3% of isolates respectively. Among 11 P. aeruginosa isolates, 63.6% contained cepA gene, 18.2% contained qacE genes, and none of the isolates harboured qacA gene. There was no significant correlation between presence or absence of biocide resistant genes and high MIC values of the test isolates (p≥0.2). CONCLUSION: Our observations imply that there was no significant correlation between presence or absence of biocide resistant genes and MICs observed in MDR K. pneumoniae, P. aeruginosa and A. baumannii. Further studies are required to find to confirm the trend of reduced susceptibility to biocides of problematic nosocomial pathogens.