Lichens as agents of biodeterioration

noOne of the major roles lichens play in shaping the natural world, both physically and biologically, is as agents in soil development: formerly considered only in a geological context, recent research has shown that they are capable of biodeteriorating stone substrata within a relatively short timescale. Chemical alteration of the substratum is achieved by the disruptive action of many species, particularly those capable of producing an oxalate at the thallus–substratum interface . The oxalate contributes significantly to the bulk and composition of the thallus itself and persists as an obvious encrustation after the lichen’s death. In the past, these disfiguring oxalate residues on ancient monuments have been variously interpreted as resulting from former mechanical/chemical renovation treatments, atmospheric pollution , and climatic weathering. The origin and nature of oxalate accretions, the factors involved in pedogenesis , and the development of lichen mosaics are reviewed. Aesthetic disfigurement versus physical damage to stonework is considered, and various aspects of stonework conservation are discussed

Microalgal Biomass of Industrial Interest: Methods of Characterization

International audienceMicroalgae represent a new source of biomass for many applications. The advantage of microalgae over higher plants is their high productivities. The photoautotrophic microalgae include all photosynthetic microorganisms, i.e. Cyanobacteria (prokaryotes) or microalgae (eukaryotes). These microorganisms are characterized by a large biodiversity and chimiodiversity. Then, the analysis of microalgal and cyanobacterial biomass often needs specific adaptations of the classical protocols for extraction as well as for quantification of their contents. This chapter reviewed the main analytical methods used for the analysis of microalgae biomass and its main vaporizable compounds: proteins, polysaccharides, lipids, pigments and secondary metabolites