Bacterial laccases: some recent advances and applications

Laccases belong to the large family of multi-copper oxidases (MCOs) that couple the one-electron oxidation of substrates with the four-electron reduction of molecular oxygen to water. Because of their high relative non-specific oxidation capacity particularly on phenols and aromatic amines as well as the lack of requirement for expensive organic cofactors, they have found application in a large number of biotechnological fields. The vast majority of studies and applications were performed using fungal laccases, but bacterial laccases show interesting properties such as optimal temperature above 50 °C, optimal pH at the neutral to alkaline range, thermal and chemical stability and increased salt tolerance. Additionally, bacterial systems benefit from a wide range of molecular biology tools that facilitates their engineering and achievement of high yields of protein production and set-up of cost-effective bioprocesses. In this review we will provide up-to-date information on the distribution and putative physiological role of bacterial laccases and highlight their distinctive structural and biochemical properties, discuss the key role of copper in the biochemical properties, discuss thermostability determinants and, finally, review biotechnological applications with a focus on catalytic mechanisms on phenolics and aromatic amines.info:eu-repo/semantics/publishedVersio

Studying implementation beyond deficit analysis: The top-down view reconsidered

__Abstract__ Contemporary researchers of policy implementation make a plea for explaining variation in policy outputs. At the same time still much implementation research, dispersed across the social sciences, entails studies of single cases in which a perceived gap between the intentions and the results of a public policy is analyzed. In this article a case is made for the lasting relevance of studying single policy processes, seen ‘from the top’, provided that the multi-dimensional character of these processes is taken into account. Empirical material from a study of educational inclusion policy in the United Kingdom shows how public policies may refer to different values (normative dimension), imply ongoing policy formation between a variety of actors, each with particular stakes (political dimension), while policy goals seldom speak for themselves (practical dimension). By consequence, in implementation research the issues of, respectively, what needs explanation (the explanandum), locus specification, and the appropriate unit of observation and analysis need attention